EP4669511A2 - Systèmes et procédés d'impression tridimensionnelle par stéréolithographie - Google Patents

Systèmes et procédés d'impression tridimensionnelle par stéréolithographie

Info

Publication number
EP4669511A2
EP4669511A2 EP24761105.6A EP24761105A EP4669511A2 EP 4669511 A2 EP4669511 A2 EP 4669511A2 EP 24761105 A EP24761105 A EP 24761105A EP 4669511 A2 EP4669511 A2 EP 4669511A2
Authority
EP
European Patent Office
Prior art keywords
pixel
pixels
voxel
additional
voxels
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24761105.6A
Other languages
German (de)
English (en)
Inventor
David Bryan LAVO
Hany Basam Eitouni
Pierre Pascal Anatole LIN
Patrick HENDRY
Scott Allen MULLIN
Mikel RUIZ MARTINEZ
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Southwest Greene International Inc
Original Assignee
Southwest Greene International Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Southwest Greene International Inc filed Critical Southwest Greene International Inc
Publication of EP4669511A2 publication Critical patent/EP4669511A2/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
    • B29C64/30—Auxiliary operations or equipment
    • B29C64/386—Data acquisition or data processing for additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor

Definitions

  • additive manufacturing techniques such as three-dimensional (3D) printing
  • 3D printing are rapidly being adopted as useful techniques for a number of different applications, including rapid prototyping and fabrication of specialty components.
  • 3D printing include powderbased printing, fused deposition modeling (FDM), and stereolithography (SLA).
  • Photopolymer-based 3D printing technology may produce a 3D structure in a layer-by-layer fashion by using light to selectively cure polymeric precursors into a polymeric material within a photoactive resin.
  • Photopolymer-based 3D printers that use bottom up illumination may project light upwards through an optically transparent window of a vat containing photoactive resin to cure at least a portion of the resin.
  • Such printers may build a 3D structure by forming one layer at a time, where a subsequent layer adheres to the previous layer.
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) mapping, by the computer processor, the digital model on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; (c) mapping, by the computer processor, the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of sub-pixels or sub-voxels, to generate an additional image containing a set of sub-pixels or sub-voxels of the additional grid that overlap with at least a portion of the digital model; (d) generating a difference image, the difference image corresponds to a difference
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; map the digital model on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; map the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of sub-pixels or sub-voxels, to generate an additional image containing a set of sub-pixels or sub-voxels of the additional grid that overlap with at least a portion of the digital model; generate a difference image by subtracting the image from the additional image; and modify a light intensity of the set of pixels or voxels based on
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) providing, by a computer processor, a plurality of grids of pixels or voxels corresponding to a plurality of slices of a digital model of the 3D object, the plurality of grids comprising: a grid comprising a set of pixels or voxels that correspond to a slice of the plurality of slices, wherein a pixel or voxel of the set is assigned with a light intensity value based on an overlap between the set and the slice; and an additional grid comprising an additional set of pixels or voxels that correspond to an additional slice of the plurality of slices, wherein the additional slice is adjacent to the slice in the digital model; (b) identifying, by the computer processor, (i) a first pixel or voxel of the set that does not overlap with the additional set and (ii) a second pixel or voxel of the set
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: provide a plurality of grids of pixels or voxels corresponding to a plurality of slices of a digital model of the 3D object, the plurality of grids comprising: a grid comprising a set of pixels or voxels that correspond to a slice of the plurality of slices, wherein a pixel or voxel of the set is assigned with a light intensity value based on an overlap between the set and the slice, and an additional grid comprising an additional set of pixels or voxels that correspond to an additional slice of the plurality of slices, wherein the additional slice is adjacent to the slice in the digital model; identify, by the computer processor, (i) a first pixel or voxel of the set that does not overlap with the additional set and (ii) a second pixel or voxel of the set
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity, and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; (b) determining, by the computer processor, a distance between the first pixel or voxel and the second pixel or voxel; (c) subsequent to (b), (i) if the distance is above a distance threshold, reducing the second light intensity of the second pixel or voxel, or (ii) if the distance is less than or equal to the distance threshold,
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity, and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; determine a distance between the first pixel or voxel and the second pixel or voxel; reduce the second light intensity of the second pixel or voxel if the distance is above a distance threshold, or maintain or increase the second light intensity of the second pixel or voxel if the distance is less than or equal to the distance threshold.
  • a computer processor in digital communication with computer memory,
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity, and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; (b) comparing the second light intensity to a threshold intensity level; and (c) subsequent to (b), (i) if the second light intensity is less than the threshold intensity level, reducing the second light intensity of the second pixel or voxel, or (ii) if the second light intensity is greater than or equal to the threshold intensity level, maintaining or increasing the second light intensity of the second pixel or
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity, and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; compare the second light intensity to a threshold intensity level; and reduce the second light intensity of the second pixel or voxel if the second light intensity is less than the threshold intensity level, or maintain or increase the second light intensity of the second pixel or voxel if the second light intensity is greater than or equal to the threshold intensity level.
  • a computer processor in digital communication with computer memory, configured
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a plurality of slices of a digital model corresponding to at least a portion of the 3D object; (b) mapping, by the computer processor, a slice of the plurality of slices on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels; (c) generating, by the computer processor, an alignment score between the slice and the grid of pixels or voxels at the relative alignment position; determining an alignment of the slice with the grid of pixels or voxels; (d) determining, by the computer processor, if the alignment score meets a quality threshold; and (e) subsequent to (d), (1) if the alignment score meets the quality threshold, mapping an additional slice of the plurality of slices onto an additional grid of pixels or voxels at the relative alignment position, or (2) if the alignment score does not
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a plurality of slices of a digital model corresponding to at least a portion of the 3D object; map a slice of the plurality of slices on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels; generate an alignment score between the slice and the grid of pixels or voxels at the relative alignment position; determining an alignment of the slice with the grid of pixels or voxels; determine if the alignment score meets a quality threshold; and map an additional slice of the plurality of slices onto an additional grid of pixels or voxels at the relative alignment position if the alignment score meets the quality threshold, or re-mapping the slice on the grid of pixels or voxels at a different relative alignment position if the alignment score does not meet the quality threshold.
  • a computer processor in digital communication with computer memory, configured
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) mapping, by the computer processor, the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; (c) identifying, by the computer processor, an exterior pixel or voxel, wherein the exterior pixel or voxel partially overlaps with the digital image; (d) adjusting, by the computer processor, a position of the exterior pixel or voxel; (e) modifying, by the computer processor, a light intensity of the exterior pixel or voxel such that the light intensity is lower than a light intensity of an interior pixel or voxel; and (f
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; map the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; identify an exterior pixel or voxel, the exterior pixel or voxel partially overlaps with the digital image; adjust a position of the exterior pixel or voxel; modify a light intensity of the exterior pixel or voxel such that the light intensity is lower than a light intensity of an interior pixel or voxel; and generate a modified pattern of the digital image, wherein the modified pattern is usable by the 3D printer to print the at least the portion of the 3D object.
  • a computer processor in digital communication with computer
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) identifying, by the computer processor, (i) at least one interior pixel or voxel of the digital image and (ii) at least one exterior pixel or voxel of the digital image; (c) assigning, by the computer processor, (i) a light intensity of the at least one interior pixel or voxel and (ii) an additional light intensity of the at least one exterior pixel or voxel, to generate a light intensity profile of the digital image, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object, wherein the light intensity is higher than the additional light intensity; and (d) assigning a duration of exposure for printing, wherein the duration of exposure is sufficient to cause the exterior
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; identify (i) at least one interior pixel or voxel of the digital image and (ii) at least one exterior pixel or voxel of the digital image; assign (i) a light intensity of the at least one interior pixel or voxel and (ii) an additional light intensity of the at least one exterior pixel or voxel, to generate a light intensity profile of the digital image, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object, wherein the light intensity is higher than the additional light intensity; and assign a duration of exposure for printing, wherein the duration of exposure is sufficient to cause the exterior pixel or voxel to cure.
  • a computer processor in digital communication with computer memory, configured to: obtain
  • the present disclosure provides a method for printing a three- dimensional (3D) object by a 3D printer with a plurality of lights, comprising: (a) directing the plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, wherein the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern; (b) modifying a light intensity profile of an overlapped region of the pattern with the additional light; and (c) generating a modified pattern for the printing.
  • the present disclosure provides a system for printing a three- dimensional (3D) object by a 3D printer, comprising: a plurality of optical sources configured to provide a plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern; a computer processor in digital communication with computer memory, configured to modify a light intensity profile of an overlapped region of the pattern with the additional light and generate a modified pattern for the printing.
  • a plurality of optical sources configured to provide a plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, the
  • the present disclosure provides a method for printing at least one three-dimensional (3D) object, comprising: (a) directing a light to a resin disposed adjacent to a surface, wherein the light (i) comprises a pattern corresponding to a cross-section of the at least one 3D object and (ii) is sufficient to cause a domain of the resin to solidify based on the pattern; (b) removing at least a portion of the solidified domain from the surface; (c) subsequent to (b), detecting (i) a remaining portion of the solidified domain on the surface, (ii) the at least the portion of the solidified domain that is removed from the surface, or (iii) an excess of the resin remaining on the surface; and (d) based on the detecting in (c), modifying an additional pattern of an additional light, wherein the additional light is usable to print an additional cross- section of the at least one 3D object.
  • the present disclosure provides a system for printing at least one three-dimensional (3D) object, comprising: an optical source configured to provide a light to a resin disposed adjacent to a surface, wherein the light (i) comprises a pattern corresponding to a cross-section of the at least one 3D object and (ii) is sufficient to cause a domain of the resin to solidify based on the pattern; a sensor configured to detect, subsequent to removal of at least a portion of a solidified domain from the surface, (i) a remaining portion of the solidified domain on the surface, (ii) the at least the portion of the solidified domain that is removed from the surface, or (iii) an excess of the resin remaining on the surface; and a computer processor in digital communication with computer memory and configured to modify an additional pattern of an additional light from the optical source, wherein the additional light is usable to print an additional cross-section of the at least one 3D object.
  • an optical source configured to provide a light to a resin disposed adjacent to a surface, wherein the light (i
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion; and (b) rescaling, by the computer processor, the portion along at least two directions and the additional portion along the at least two directions, such that: (i) the portion and the additional portion are rescaled along a first direction of the at least two directions in accordance with a first set of different scaling factors; and (ii) the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising at least three portions; and (b) rescaling, by the computer processor, the at least three portions along a direction in accordance with at least three different scaling factors comprising a first scaling factor, a second scaling factor, and a third scaling factor, such that: (i) a first portion of the at least three portions is rescaled along the direction in accordance with the first scaling factor; (ii) a second portion of the at least three portions is rescaled along the direction in accordance with the second scaling factor that is different from the first scaling factor; and (iii) a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling factor
  • the present disclosure provides a method for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured to be printed by the 3D printer using a same source of resin; (b) rescaling, by the computer processor, the portion along a direction in accordance with a first scaling factor; and (c) rescaling, by the computer processor, the additional portion along the direction in accordance with a second scaling factor that is different from the first scaling factor, wherein, subsequent to the rescaling in (b) and (c), the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion; and (b) rescale the portion along at least two directions and the additional portion along the at least two directions, such that: (i) the portion and the additional portion are rescaled along a first direction of the at least two directions in accordance with a first set of different scaling factors; and (ii) the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising at least three portions; and (b) rescale the at least three portions along a direction in accordance with at least three different scaling factors comprising a first scaling factor, a second scaling factor, and a third scaling factor, such that: (i) a first portion of the at least three portions is rescaled along the direction in accordance with the first scaling factor; (ii) a second portion of the at least three portions is rescaled along the direction in accordance with the second scaling factor that is different from the first scaling factor; and (iii) a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling factor, where
  • the present disclosure provides a system for processing a three- dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured to be printed by the 3D printer using a same source of resin; (b) rescale the portion along a direction in accordance with a first scaling factor; and (c) rescale the additional portion along the direction in accordance with a second scaling factor that is different from the first scaling factor, wherein, subsequent to the rescaling in (b) and (c), the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured
  • the present disclosure provides a method for processing a 3D object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) determining, by the computer processor and based on the digital image, an exterior intensity level and an exterior exposure time of a light for at least one exterior unit of the digital image; (c) modifying, by the computer processor, the exterior intensity level to generate a modified exterior intensity level of the light for the at least one exterior unit; and (d) modifying, by the computer processor, the exterior exposure time to generate a modified exterior exposure time of the light for the at least one exterior unit, wherein the light at the modified exterior intensity level over the exterior exposure time is usable to print the at least the portion of the 3D object.
  • the present disclosure provides a system for processing a 3D object for printing by a 3D printer, comprising a computer processor in digital communication with computer memory, wherein the computer processor is configured to: (a) obtain a digital image corresponding to at least a portion of the 3D object; (b) determine, based on the digital image, an exterior intensity level and an exterior exposure time of a light for at least one exterior unit of the digital image; (c) modify the exterior intensity level to generate a modified exterior intensity level of the light for the at least one exterior unit; and (d) modify the exterior exposure time to generate a modified exterior exposure time of the light for the at least one exterior unit, wherein the light at the modified exterior intensity level over the exterior exposure time is usable to print the at least the portion of the 3D object.
  • FIGS. 1A and IB illustrate an exemplary downscaling of a 10 x 10 pixel image, according to some embodiments
  • FIGS. 1C and ID illustrate an exemplary downscaling of a 9.67 x 10 pixel image, according to some embodiments
  • FIGS. IE and IF show an exemplary 3D printing with grayscaling, according to some embodiments.
  • FIG. 2A illustrates an example of a sampling to determine a plurality of pixels that overlap with a digital model, according to some embodiments
  • FIG. 2B illustrates an example of a sampling to determine a plurality of sub-pixels that overlap with a digital model, according to some embodiments
  • FIG. 2C shows an image of a slice that is aligned with a grid of pixels, according to some embodiments
  • FIG. 2D shows an image of a slice that is misaligned with a grid of pixels, according to some embodiments
  • FIG. 2E shows an image of another slice that is misaligned with a grid of pixels, according to some embodiments
  • FIG. 3A illustrates an image of a digital slice with whole native pixels, according to some embodiments
  • FIG. 3B illustrates an image of the digital slice at a 4x super-scaled resolution, according to some embodiments;
  • FIG. 3C illustrates a difference image of FIG. 3A and FIG. 3B, according to some embodiments
  • FIG. 3D illustrates an overlay ed images of FIG. 3A (white pixels) and FIG. 3C (gray sub-pixels), according to some embodiments;
  • FIGS. 3E-3G illustrate exemplary difference rate, according to some embodiments.
  • FIG. 3H shows an exemplary method of calculating difference rate for different regions, according to some embodiments.
  • FIG. 4A illustrates an exemplary portion of a 3D object, according to some embodiments.
  • FIG. 4B shows an exemplary light intensity profile for pixels at downskin surface, according to some embodiments.
  • FIGS. 4C-4H illustrates printing with different downscaling and grayscaling algorithm and parameters, according to some embodiments
  • FIGS. 5A-5D show a printing process for consecutive slices 73-76, according to some embodiments.
  • FIGS. 5E-5H show a printing process for consecutive slices 73-76, according to some embodiments.
  • FIG. 51 shows another example of applying boundary limited smoothing in printing consecutive slices 143-151, according to some embodiments.
  • FIG. 5J shows the comparison of reducing light intensity and increasing light intensity of such gray pixels or voxels, according to some embodiments
  • FIG. 6 shows an example of a 3D printing system, according to some embodiments.
  • FIGS. 7 and 8 show additional examples of a 3D printing system, according to some embodiments.
  • FIG. 9A illustrates an exemplary projected light with a pixel shifter, according to some embodiments.
  • FIG. 9B shows a pixel shifting process, according to some embodiments.
  • FIGS. 9C-9F show exemplary images by pixel shifting and grayscaling, according to some embodiments.
  • FIG. 10A shows an exemplary image with no attenuation at the boundaries, according to some embodiments.
  • FIG. 10B shows an exemplary image with 15% attenuation, according to some embodiments
  • FIG. 10C shows an exemplary image with 25% attenuation, according to some embodiments
  • FIG. 10D shows an exemplary blooming control at different attenuation, according to some embodiments.
  • FIG. 10E shows two exemplary blooming controls at different attenuation, according to some embodiments.
  • FIG. 10F shows exemplary blooming controls at different attenuation level and depth, according to some embodiments.
  • FIG. 10G shows an exemplary image with 50% attenuation at a depth of 6 pixels, according to some embodiments.
  • FIG. 10H shows an exemplary image with 70% attenuation at a depth of 6 pixels, according to some embodiments
  • FIG. 101 shows an exemplary image with no limit applied in global erosion, according to some embodiments.
  • FIG. 10J shows an exemplary image with thin areas protected from global erosion, according to some embodiments.
  • FIG. 10K shows an exemplary image with thin areas protected from erosion, according to some embodiments.
  • FIG. 10L shows an exemplary light intensity profile for a 3D object, according to some embodiments.
  • FIG. 11A shows a digital model comprising two areas, according to some embodiments.
  • FIG. 11B shows image distortion, according to some embodiments.
  • FIG. 12A illustrates a failure of a portion of the printed slice, according to some embodiments.
  • FIG. 12B shows the failed object 1203, according to some embodiments.
  • FIG. 12C shows a heat map of the object 1203, according to some embodiments.
  • FIG. 12D shows a modified pattern for the subsequent slice or layer with the object 1203 completely blacked out, according to some embodiments
  • FIG. 13 shows a computer system that is programmed or otherwise configured to implement methods provided herein, according to some embodiments
  • FIG. 14A shows an exemplary 3D object 1400 for printing, according to some embodiments
  • FIG. 14B shows the perimeter of the 3D object 1400 in the x-y plane, according to some embodiments;
  • FIG. 15A shows the comparison of the start OD and end OD by printing with constant scaling factors or constant scale factors, according to some embodiments;
  • FIG. 15B shows the difference between the start OD and end OD for the printed 3D objects, according to some embodiments.
  • FIG. 16A shows the comparison of the start OD and end OD by printing with dynamic scaling factors or dynamic scale factors, according to some embodiments
  • FIG. 16B shows the Z position error (desired position - actual position), according to some embodiments.
  • FIG. 17A shows the Z position error by printing with the constant scale factors, according to some embodiments.
  • FIG. 17B shows the Z position error by printing with the dynamic scale factors, according to some embodiments.
  • FIG. 18A shows a side view of an exemplary 3D object 1800, according to some embodiments.
  • FIG. 18B shows a perspective view of the exemplary 3D object 1800, according to some embodiments.
  • FIG. 18C shows the dimensions of an exemplary 3D object, according to some embodiments.
  • three-dimensional object generally refers to an object or a part that is printed by three-dimensional (“3D”) printing.
  • the 3D object may be at least a portion of a larger 3D object or an entirety of the 3D object.
  • the 3D object may be fabricated (e.g., printed) in accordance with a computer model of the 3D object.
  • pixel generally refers to the smallest addressable element in an image display (e.g., an optical source) that can be electrically stimulated to irradiate light.
  • the optical source can comprise a grid or array of pixels, and the grid of pixels can be stimulated with a pattern of intensities within each pixel (e.g., based on a digital model of a 3D object that is mapped onto the grid of pixels), to project a patterned light towards a mixture as disclosed herein.
  • voxel as used herein, generally refers to a three-dimensional unit element representing a volumetric pixel.
  • the optical source can comprise a grid or array of voxels, and the grid of voxels can be stimulated with a pattern of intensities within each voxel (e.g., based on a digital model of a 3D object that is mapped onto the grid of voxels), to project a patterned light towards a mixture as disclosed herein.
  • a voxel data may be organized into a voxelized bitmap pattern that includes an intensity value for each voxel and/or an exposure time.
  • the voxelized bitmap may be considered an organized collection of individual voxels, each voxel having its own depth that is independent of the other voxels.
  • each voxel is generally treated individually and has its own curing depth (which can be determined by the exposure time and/or intensity value assigned to each voxel) to determine each voxel’s geometry independent of any other voxel data.
  • sub-pixel generally refers to a sub-region of the pixel. While an optical source may not be capable of selectively irradiating light at a sub-pixel resolution, a digital model can be analyzed and modified by a computer processor at a sub-pixel level.
  • a pixel can comprise at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 11, at least about 12, at least about 13, at least about 14, at least about 15, at least about 16, at least about 25, at least about 36, at least about 49, at least about 64, at least about 81, at least about 100, or more sub-pixels.
  • a grid of sub-pixels within a pixel can be symmetrical, e.g. m x m sub-pixels, wherein the integer m is an integer greater than or equal to 2 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more).
  • the grid of sub-pixels can be a 2x2 grid of sub-pixels, a 3x3 grid of sub-pixels, a 4x4 grid of sub-pixels, a 5x5 grid of sub-pixels, a 6x6 grid of sub-pixels, a 7x7 grid of sub-pixels, a 8x8 grid of sub-pixels, a 9x9 grid of sub-pixels, a 10x10 grid of subpixels, etc.
  • a grid of sub-pixels within a pixel may not be symmetrical.
  • sub-voxel generally refers to a sub-region of the voxel.
  • a voxel can comprise at least about 2, at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 11, at least about 12, at least about 13, at least about 14, at least about 15, at least about 16, at least about 25, at least about 36, at least about 49, at least about 64, at least about 81, at least about 100, or more sub-voxels.
  • a grid of sub-voxels within a voxel can be symmetrical, e.g.
  • m x m x m sub-voxels in all of the x-y plane, x-z plane, and y-z plane wherein the integer m is an integer greater than or equal to 2 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more).
  • the grid of sub-voxels can be a 2x2x2 grid of sub-voxels, a 3x3x3 grid of sub-voxels, a 4x4x4 grid of sub-voxels, a 5x5x5 grid of sub-voxels, a 6x6x6 grid of sub-voxels, a 7x7x7 grid of sub-voxels, a 8x8x8 grid of sub-voxels, a 9x9x9 grid of sub-voxels, a 10x10x10 grid of sub-voxels, etc.
  • a grid of sub-voxels within a voxel may not be symmetrical in at least one of the planes, at least two of the planes, or all of the planes (x-y plane, x-z plane, and y-z plane).
  • the term “mixture” or “viscous liquid,” as interchangeably used herein, generally refers to a material that is usable to print a 3D object.
  • the mixture may be referred to as a resin.
  • the mixture may be dispensed from a nozzle and over an area.
  • Such area can be an area of a platform (e.g., a print window) or a film (e.g., an opaque, transparent, and/or a semi-transparent film).
  • the mixture may be a liquid, semi-liquid, or solid.
  • the mixture may have a viscosity sufficient to be self-supporting on the print window without flowing or sufficient flowing.
  • the viscosity of the mixture may range, for example, from about 4,000 centipoise (cP) to about 2,000,000 cP.
  • the mixture may be pressed (e.g., by a wiper or a build head) into a film of the mixture on or over such area (e.g., the print window, the film, etc.).
  • a thickness of the film of the mixture may be adjustable.
  • the mixture may include a photoactive resin.
  • the photoactive resin may include a polymerizable and/or cross-linkable component (e.g., a precursor) and a photoinitiator that activates curing of the polymerizable and/or cross-linkable component, to thereby subject the polymerizable and/or cross-linkable component to polymerization and/or cross-linking.
  • the photoactive resin may include a photoinhibitor that inhibits curing of the polymerizable and/or cross-linkable component.
  • the mixture may include a plurality of particles (e.g., polymer particles, metal particles, ceramic particles, combinations thereof, etc.). In such a case, the mixture may be a slurry or a photopolymer slurry.
  • the mixture may be a paste.
  • the plurality of particles may be added to the mixture.
  • the plurality of particles may be solids or semi-solids (e.g., gels).
  • Examples of non-metal material include metallic, intermetallic, ceramic, polymeric, or composite materials.
  • the plurality of particles may be suspended throughout the mixture.
  • the plurality of particles in the mixture may have a distribution that is monodisperse or polydisperse.
  • the mixture may contain additional optical absorbers and/or non-photoreactive components (e.g., fillers, binders, plasticizers, stabilizers such as radical inhibitors, etc.).
  • the 3D printing may be performed with at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more mixtures.
  • a plurality of mixtures comprising different materials e.g., different photoactive resin and/or different plurality of particles
  • grayscale generally refers to a light intensity level that is more than 0% but less than 100%, for example, 5%, 10%, 20%, or 50% of the maximum light intensity that a proj ector can emit.
  • grayscaling generally refers to the process of assigning or applying a grayscale light intensity.
  • the term “particles,” as used herein, generally refers to any particulate material that may be incorporated into the mixture.
  • the particles may be incorporated to alter (e.g., increase, decrease, stabilize, etc.) a material property (e.g., viscosity) of the mixture.
  • the particles may be configured to be melted or sintered (e.g., not completely melted).
  • the particulate material may be in powder form.
  • the particles may be inorganic materials.
  • the inorganic materials may be metallic (e.g., aluminum or titanium), intermetallic (e.g., steel alloys), ceramic (e.g., metal oxides) materials, or any combination thereof.
  • the powders may be coated by one or more polymers.
  • the term “metal” or “metallic” generally refers to both metallic and intermetallic materials.
  • the metallic materials may include ferromagnetic metals (e.g., iron and/or nickel).
  • the particles may have various shapes and sizes.
  • a particle may be in the shape of a sphere, cuboid, or disc, or any partial shape or combination of shapes thereof.
  • the particle may have a cross-section that is circular, triangular, square, rectangular, pentagonal, hexagonal, or any partial shape or combination of shapes thereof.
  • the particles may sinter (or coalesce) into a solid or porous object that may be at least a portion of a larger 3D object or an entirety of the 3D object.
  • the 3D printing may be performed with at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more types of particles.
  • a film of a mixture or “a layer of mixture,” as used interchangeably herein, generally refers to a layer of the mixture that is usable to print a 3D object.
  • the film of the mixture may have a uniform or non-uniform thickness across the film of the mixture.
  • the film of the mixture may have an average thickness or a variation of the thickness that is below, within, or above a defined threshold (e.g., a value or a range).
  • the average thickness or the variation of the thickness of the film of the mixture may be detectable and/or adjustable during the 3D printing.
  • An average (mean) thickness of the film of the mixture may be an average of thicknesses from at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 100, 200, 300, 400, 500, 1000, 2000, 3000, 4000, 5000, or more positions within the film of the mixture.
  • An average (mean) thickness of the film of the mixture may be an average of thicknesses from at most about 5000, 4000, 3000, 2000, 1000, 500, 400, 300, 200, 100, 50, 40, 30, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, or 2 positions within the film of the mixture.
  • a variation of the thickness of the film of the mixture may be a variance (i.e., sigma squared or “o 2 ”) or standard deviation (i.e., sigma or “o”) within a set of thicknesses from the at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 100, 200, 300, 400, 500, 1000, 2000, 3000, 4000, 5000, or more positions within the film of the mixture.
  • a variation of the thickness of the film of the mixture may be a variance or standard deviation within a set of thicknesses from the at most about 5000, 4000, 3000, 2000, 1000, 500, 400, 300, 200, 100, 50, 40, 30, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, or 2 positions within the film of the mixture.
  • the term “platform,” as used herein, generally refers to a structure that supports a mixture (e.g., a liquid) or a film of the mixture during 3D printing.
  • the mixture may have a viscosity that is sufficient to permit the mixture to remain on or adjacent to the platform during 3D printing.
  • the platform may be flat.
  • the platform may include an optically transparent or semi-transparent print window or exposure window (e.g., glass or a polymer) to direct light (e.g., one or more lights) through the window and to the mixture or the film of the mixture. Alternatively or in addition to, the light may be directed from above and/or one or more sides of the platform.
  • the platform may have various shapes.
  • the platform may be a rectangle or a ring, for example.
  • the platform may comprise one or more walls adjacent to the platform, such as at least 1, 2, 3, or 4 walls.
  • the walls may enclose the platform.
  • a property e.g., viscosity
  • the walls prevent flow of the mixture out of the open platform.
  • the platform may be part (e.g., a bottom portion) of a container or a vat.
  • the platform may be an “open platform” that is not bounded by any wall.
  • the open platform may not be vat or a container.
  • the open platform may not be part of a vat or a container.
  • the open platform may be a substrate or slab that does not have a depression (e.g., vat or container) for retaining a liquid. In such situations, the mixture may be sufficiently viscous such that the mixture remains on the open platform.
  • the open platform may include one or more sides that are not bounded.
  • the platform may comprise an area configured to hold the mixture.
  • the area may be at least a portion of the platform (e.g., at least a portion of a surface of the platform).
  • the area may be an additional object (e.g., a sheet, plaster, film, glass, window, etc.) disposed on or adjacent to the platform.
  • the area may be stationary relative to the platform. Alternatively or in addition to, the area may be movable relative to the platform.
  • At least a portion of the platform may be flexible. Alternatively or in addition to, at least a portion of the platform may be rigid. The platform may be movable between two or more locations. The platform may be positioned over or adjacent to a base. At least a portion of the base may be transparent or semi-transparent to direct light (e.g., sensor light or photoinitiation light) through the base and towards the platform.
  • the base may be flexible. Alternatively or in addition to, at least a portion of the base may be rigid.
  • Such base may be a slab, which slab may be transparent, semi-transparent, opaque, or not transparent.
  • print surface generally refers to at least a portion of the platform (e.g., a print area or print window or exposure window) or at least a portion of an object disposed on or adjacent to the platform (e.g., a film) that is configured to hold a film of the mixture or any excess thereof during the 3D printing.
  • the term “build head,” as used herein, generally refers to a structure that supports at least a portion of a printed 3D object (or another object onto which a 3D object may be printed). During the 3D printing, the build head or the at least the portion of the printed 3D object that is disposed on the build head may be in contact with a mixture (e.g., a film of a mixture), and at least a portion of the mixture may be formed into a new portion (e.g., layer) of the 3D object.
  • a mixture e.g., a film of a mixture
  • the term “sensor,” as used herein, generally refers to a device, system, or a subsystem that provides a feedback (e.g., electromagnetic radiation absorbance and/or reflectance, image, video, distance, pressure, force, electrical current, electrical potential, magnetic field, position, angle, displacement, distance, speed, acceleration, etc.).
  • a feedback e.g., electromagnetic radiation absorbance and/or reflectance, image, video, distance, pressure, force, electrical current, electrical potential, magnetic field, position, angle, displacement, distance, speed, acceleration, etc.
  • Such feedback may correspond to or be correlated with one or more components of the 3D printing system (e.g., a mixture of a film of a mixture, the build head, the platform, etc.) or the 3D printing process (e.g., deposition of a film of a mixture over an area of the platform, etc.).
  • Examples of the sensor can include, but are not limited to, light sensor, speed sensor, pressure sensor, tactile sensor, chemical sensor, current sensor, electroscope, galvanometer, hall effect sensor, hall probe, magnetic anomaly detector, magnetometer, magnetoresistance, magnetic field sensor (e.g., microelectromechanical systems (MEMS) magnetic field sensor), metal detector, planar hall sensor, voltage detector, etc.
  • MEMS microelectromechanical systems
  • the senor can include, but are not limited to, capacitive displacement sensor, flex sensor, free fall sensor, gyroscopic sensor, impact sensor, inclinometer, piezoelectric sensor, linear encoder, liquid capacitive inclinometers, odometer, photoelectric sensor, piezoelectric sensor, position sensor, angular rate sensor, rotary encoder, shock detector (i.e., impact monitor), tilt sensor, ultrasonic thickness gauge, variable reluctance sensor, velocity receiver, a colorimeter, infrared sensor, photodetector, phototransistor, force sensor, tactile sensor, strain gauge, temperature sensor, Doppler radar, motion detector, proximity sensor, speed sensor, etc.
  • the sensor may be a switch, comprising, for example, a contact switch (e.g., a high precision contact switch), a limit switch, a reed switch.
  • the sensor may be a level.
  • one or more parameters may be maintained or adjusted to maintain or improve print quality (e.g., a quality of the film of the mixture prior to printing at least a portion of the 3D object, or the printed portion of the 3D object, etc.).
  • the film of the mixture that is usable to print the 3D object may or may not be redeposited (e.g., adjacent to the area of the platform) prior to printing at least a portion of the 3D object.
  • the film of the mixture that is usable to print the 3D object may be removed and a new film of the mixture may be re-deposited prior to printing at least a portion of the 3D object. Access mixture from the removed film may or may not be recycled to deposit the new film of the mixture.
  • the film of the mixture may be re-deposited until a desired (e.g., pre-determined) thickness, average thickness, a variation of the thickness, area, average area, and/or a variation of the area is obtained.
  • One or more lights may be used to initiate (activate) curing of a portion of the mixture, thereby to print at least a portion of the 3D object.
  • the one or more lights e.g., from one or more optical sources
  • the one or more lights may be used to inhibit (prevent) curing of a portion of the mixture adjacent to an area of the platform (e.g., a print window, a film on or adjacent to the platform, etc.).
  • the one or more lights may be used by one or more sensors to determine a profile and/or quality of the mixture (e.g., the film of the mixture) prior to, during, and subsequent to printing the at least the portion of the 3D object.
  • the 3D printing may be performed with one wavelength.
  • the 3D printing may be performed with at least about 2, 3, 4, 5, 6, 7, 8, 9, 10 or more wavelengths that are different.
  • the 3D printing may be performed with at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more lights.
  • the 3D printing may be performed with at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more optical sources, and it may be desirable to prevent curing of a portion of the mixture (e.g., a film of the mixture) adjacent to the area of the platform (e.g., a print window, a film on or adjacent to the platform, etc.).
  • the one or more lights may comprise electromagnetic radiation.
  • electromagnetic radiation generally refers to one or more wavelengths from the electromagnetic spectrum including, but not limited to x-rays (about 0.1 nanometers (nm) to about 10.0 nm; or about 10 18 Hertz (Hz) to about 10 16 Hz), ultraviolet (UV) rays (about 10.0 nm to about 380 nm; or about 8* 10 16 Hz to about 915 Hz), visible light (about 380 nm to about 750 nm; or about 8* 10 14 Hz to about 4* 10 14 Hz), infrared (IR) light (about 750 nm to about 0.1 centimeters (cm); or about 4* 10 14 Hz to about 5* 10 11 Hz), and microwaves (about 0.1 cm to about 100 cm; or about 10 8 Hz to about 5x l0 n Hz).
  • x-rays about 0.1 nanometers (nm) to about 10.0 nm; or about 10 18 Hertz (Hz) to
  • the one or more optical sources may comprise an electromagnetic radiation source.
  • electromagnetic radiation source generally refers to a source that emits electromagnetic radiation.
  • the electromagnetic radiation source may emit one or more wavelengths from the electromagnetic spectrum.
  • the term “profile,” as used herein, generally refers to a view (e.g., image or video) and/or electromagnetic spectrum with respect to such components.
  • the view may be a side view, bottom-up view, or top-down view.
  • the view may comprise an outline, silhouette, contour, shape, form, figure, structure of the components.
  • the electromagnetic spectrum may be absorption, emission, and/or fluorescence spectrum of at least a portion of the electromagnetic radiation (e.g., IR radiation).
  • the profiles may be indicative of one or more features of the components.
  • the senor may be capable of sensing or detecting and/or analyzing zero-dimensional (e.g., a single point), one-dimensional (ID), two- dimensional (2D), and/or 3D profiles (e.g., features) of the components.
  • zero-dimensional e.g., a single point
  • ID one-dimensional
  • 2D two- dimensional
  • 3D profiles e.g., features
  • the 3D printing system may be surrounded by an enclosure (e.g., a case or fabric).
  • the enclosure may prevent external energy (e.g., ambient light) from interfering with one or more lights used during the 3D printing.
  • the term “green body,” as used herein, generally refers to a 3D object that has a polymeric material and a plurality of particles (e.g., metal, ceramic, or both) that are encapsulated by the polymeric material.
  • the plurality of particles may be in a polymer (or polymeric) matrix.
  • the plurality of particles may be capable of sintering or melting.
  • the green body may be self-supporting.
  • the green body may be heated in a heater (e.g., in a furnace) to bum off at least a portion of the polymeric material and coalesce the plurality of particles into at least a portion of a larger 3D object or an entirety of the 3D object.
  • brown body generally refers to a green body that has been treated (e.g., solvent treatment, heat treatment, pressure treatment, etc.) to remove at least a portion (e.g., at least 20 percent (%), 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or more; at most 100%, 95%, 90%, 80%, 70%, 60%, 50%, 4%, 30%, 20%, or less) of the polymeric material within the green body.
  • the brown body may comprise the plurality of particles of the green body.
  • the plurality of particles may be capable of sintering or melting.
  • the brown body may be self-supporting.
  • the brown body may be heated in a heater (e.g., in a furnace) to burn off at least a portion of any remaining polymeric material and coalesce the plurality of particles into at least a portion of a larger 3D object or an entirety of the 3D object.
  • a heater e.g., in a furnace
  • Photopolymer-based 3D printing technology can produce a 3D structure in a layer-by-layer fashion, wherein a layer of a mixture (e.g., a photoactive resin) is exposed to a stimulus (e.g., light) to selectively cure polymeric precursors into a polymeric material within the layer of mixture to create a layer of the 3D structure.
  • a layer of a mixture e.g., a photoactive resin
  • a stimulus e.g., light
  • photopolymer-based 3D printers that use bottom up illumination may project light upwards through a transparent or semi-transparent window (e.g., a window of an open platform or a vat) to cure at least a portion of the mixture disposed adjacent to the window.
  • a transparent or semi-transparent window e.g., a window of an open platform or a vat
  • a digital model such as a computer-aided design (CAD) stored in a non-transitory computer storage medium (e.g., medium)
  • CAD computer-aided design
  • a non-transitory computer storage medium e.g., medium
  • Each digital layer or slice of the plurality of digital layers or slices can be used by the 3D printing system to generate a light pattern based on a grid of pixels or voxels for selectively curing at least a portion of the mixture, thereby producing a 3D structure in the layer-by-layer fashion.
  • printed 3D structure may have defects or inaccuracies that are smaller than the width of a pixel, e.g., due to a staircase effect (e.g., aliasing).
  • printed 3D structure may have defects or inaccuracies that are larger than the width of a pixel, e.g., due to light scattering off of metal particles within the mixture, projected light overspray, light scattering in boundary material, overcuring of polymeric monomers, etc.
  • the curing reaction can self-catalyze and over-cure in regions of the resin that are not directly exposed to the curing light (or photoinitiation light), but adjacent to (e.g., directly adjacent to) a border region of the curing light.
  • the resin adjacent to the exposed edge of the slice of the 3D structure can be at least partially cured.
  • inaccuracies in 3D printing due to the aforementioned overcuring of monomers and/or light scattering by particles can be referred to as blooming.
  • diagonal, or curved features (e.g., lines, borders, etc.) of the digital model of the 3D printing structure is printed as group of straight lines and steps (e.g., corresponding to the resolution of the grid of pixels), thus resulting in edge-like artifacts in the printed 3D structure.
  • slicing a 3D object into 2 dimensional (2D) slices can be a form of downscaling, which may lead to a loss of information or detail.
  • the 3D object can be sliced at a super-scaled resolution, for example, a 3x super-scaled resolution.
  • gray scaling or pixel shifting can achieve subpixel resolution to minimize the loss of information or detail.
  • FIGS. 1A and IB illustrate an exemplary downscaling of a 10 x 10 pixel image.
  • the 10 x 10 pixel image is super-scaled to 30 x 30 subpixel image.
  • the dimension of the image in FIG. 1A is an integer multiple of the pixel, when it is downscaled to the 10 x 10 pixel image (FIG. IB), no grayscaling is necessary.
  • gray scaling can be applied to the portion of the image that are partially contained in the pixel (e.g., a light intensity of less than 100% of the maximum intensity can be assigned to and applied to the boundary pixel).
  • pixels 111 can be assigned partial intensity value (gray value), for example 67% intensity corresponding to the containment level.
  • FIGS. IE and IF show an exemplary 3D printing with grayscaling.
  • 112 are voxels with full containment level and 100% intensity (white voxels) and voxel 113 is a gray voxel (with less than 100% intensity).
  • the voxel 113 will have only partial curing, thus generating a part 123 that is smaller than a full voxel 122.
  • a method for processing a 3D object for printing by a 3D printer at sub-pixel precision can comprise obtaining (e.g., by a computer processor) a digital model corresponding to at least a portion of the 3D object.
  • the method can further comprise mapping (e.g., by the computer processor) the digital model on a grid of pixels or voxels, wherein an individual pixel or voxel (e.g., each pixel or voxel) of the grid of pixels or voxels can comprise a plurality of sub-pixels or sub-voxels.
  • a sub-pixel or sub-voxel can be fully contained within the digital model, partially contained within the digital model, or outside of the digital model.
  • the mapping can be for determining a set of sub-pixels or sub-voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model.
  • the mapping can be for assigning a containment level to a sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels based on the overlap.
  • the method can further comprise modifying (e.g., by the computer processor) the containment level of at least one sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels, to generate a containment level profile of the digital model corresponding to the grid of pixels or voxels.
  • the containment level profile can be usable by the 3D printer to print the at least the portion of the 3D object.
  • FIG. 2A illustrates an example of a sampling to determine a plurality of pixels that overlap with a digital model.
  • An outer boundary 100 of a digital model of a 3D object e.g., a digital 2D model of 3D object
  • a grid of pixels comprising pixels 110A, HOB, 110C, and HOD.
  • 110A is fully contained in the digital model.
  • 110B, 110C, and 110D are partially contained in the digital model. Without sub -pixel ati on as disclosed herein, pixels 110B, 110C, and 110D as a whole can be identified to overlap with boundary 100 and may be assigned a 100% light intensity value for the optical source.
  • FIG. 2B illustrates an example of a sampling to determine a plurality of sub-pixels that overlap with a digital model.
  • the same digital model of the 3D object as shown in FIG. 2A can be mapped onto the same grid of pixels, except that, in FIG. 2B, each pixel is divided (e.g., by the computer processor), into a plurality of sub-pixels (e.g., 3x3 sub-pixels).
  • sub -pixel ati on only a portion of each of the pixels HOB, 110C, and 100D can be identified to overlap with the boundary 100, and the identified subset of sub-pixels can be further processed (e.g., to further modify the containment level of one or more sub-pixels of the subset of subpixels) in accordance with the methods disclosed herein.
  • the individual pixel can comprise m x n sub-pixels, wherein m and n can be independently, an integer greater than or equal to 2, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. In some embodiments, m and n can be different. In some embodiments, m and n can be the same. In some embodiments, the individual pixel can comprise m x m subpixels, wherein m is an integer greater than or equal to 2, for example, m can be 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. In some embodiments, the individual pixel can comprise m x m sub-pixels, wherein m is an integer greater than or equal to 3, for example, m can be 3, 4, 5, 6, 7, 8, 9, 10, or more.
  • the individual voxel can comprise j x £ x / sub-voxels, wherein j, k, and I can be independently, an integer greater than or equal to 2, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. In some embodiments, j, k. and I can be different. In some embodiments, j, k, and I can be the same. In some embodiments, the individual voxel can comprise j j x j sub-voxels, wherein j is an integer greater than or equal to 2, for example, j can be 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. In some embodiments, the individual voxel can comprise j j x j sub-voxels, wherein j is an integer greater than or equal to 3, for example, m can be 3, 4, 5, 6, 7, 8, 9, 10, or more.
  • the mapping can comprise dividing each pixel or voxel into a plurality of smaller sub-pixels or sub-voxels while keeping the dimension of the pixel or voxel the same.
  • the mapping can comprise super-sampling.
  • Super-sampling can comprise scaling a digital model by a scaling factor or scale factor (K) in one or more of the X, Y, and Z dimensions, independently, increasing the number of data samples that are taken at or around each pixel location corresponding to a portion of a model design, and combining the resulting values of these multiple data sampled to obtain a final value for each pixel.
  • K scaling factor or scale factor
  • a sub-pixel or sub-voxel can be associated with a containment level.
  • a sub-pixel or sub-voxel that is fully contained within the digital model can have a containment level of 100%.
  • a sub-pixel or sub-voxel that is outside the digital model can have a containment level of 0%.
  • a sub-pixel or sub-voxel that is partially contained within the digital model can have a containment level based on how much of it is contained within the model.
  • the partial containment can be computed based on the geometry of the digital model and can be greater than 0% but less than 100%, for example, at least or at most about 0.1%, at least or at most about 0.5%, at least or at most about 1%, at least or at most about 2%, at least or at most about 3%, at least or at most about 4%, at least or at most about 5%, at least or at most about 6%, at least or at most about 7%, at least or at most about 8%, at least or at most about 9%, at least or at most about 10%, at least or at most about 15%, at least or at most about 20%, at least or at most about 25%, at least or at most about 30%, at least or at most about 40%, at least or at most about 50%, at least or at most about 60%, at least or at most about 70%, at least or at most about 80%, at least or at most about 90%, at least or at most about 95%, or at least or at most about 99%.
  • the containment level of the at least one sub-pixel or sub-voxel may be modified, while not reducing an overall containment level of a pixel or voxel comprising the at least one sub-pixel or sub-voxel to zero.
  • reduction of the overall containment level of the pixel or voxel can be a combinatorial effect of reducing containment level(s) of one or more sub-pixels or sub-voxel of the pixel or voxel.
  • reduction of the overall containment level of the pixel or voxel can be a combinatorial effect of (i) reducing containment level(s) of one or more first sub-pixels or sub-voxel of the pixel or voxel and (ii) increasing containment level(s) of one or more second sub-pixels or sub-voxel of the pixel or voxel.
  • reduction of the containment level(s) of the first sub-pixel(s) or subvoxels) may be greater than increased containment level(s) of the second sub-pixel(s) or subvoxels), such that in aggregate, the changes effect reduction in the overall containment level of the pixel or voxel as a whole.
  • reduction of the containment level of the at least one sub-pixel or sub-voxel may effect reduction of the containment level of the pixel or voxel as a whole to substantially zero.
  • the overall containment level of the pixel or voxel may be modified (e.g., reduced) by at least about 1%, at least about 2%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 99%, or about 100%.
  • the overall containment level of the pixel or voxel may be modified (e.g., reduced) by at most about 100%, at most about 99%, at most about 95%, at most about 90%, at most about 85%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 15%, at most about 10%, at most about 5%, at most about 2%, or at most about 1%.
  • Modification of the containment level of the at least one sub-pixel or sub-voxel can be the same regardless of the type or content(s) of the mixture.
  • the containment level of the at least one sub-pixel or sub-voxel can be different depending on the type or content(s) of the mixture.
  • the modification of the containment level of the at least one sub-pixel or sub-voxel can be different than that for a 3D object that is to be printed using a mixture that does not comprise the plurality of particles.
  • the modification of the containment level of the at least one sub-pixel or sub-voxel can be different than that for a 3D object that is to be printed using a mixture that comprises a plurality of ceramic particles.
  • light scattering by the metal particles and the ceramic particles can be different, and thus the modification of the containment level as disclosed herein may need to be different to compensate for the different optical properties between the metal particles and the ceramic particles.
  • the method can further comprise generating (e.g., by the computer processor) a representative containment level of the plurality of sub-pixels or sub-voxels of the individual pixel or voxel.
  • the representative containment level can be an average, a median, a mean, a mode, the largest value, the smallest value, a range (e.g., a difference between the largest value and the smallest value, etc.
  • the modifying of the containment level of the at least one sub-pixel or sub-voxel as disclosed herein can comprise adjusting a light intensity of a pixel or voxel comprising the at least one sub-pixel or sub-voxel.
  • a light intensity of a pixel or voxel comprising the at least one sub-pixel or sub-voxel having the modified containment level can be modified (e.g., as compared to the original intensity level of the pixel or voxel based on the digital model of the 3D object), e.g., to reflect modified containment level(s) of one or more sub-pixels or sub-voxels.
  • a light intensity can include a white level for 100% containment, a black level for 0% containment, and multiple grayscale levels between for partial containment within a digital model.
  • the grayscale levels can comprise about 1%, about 2%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.
  • the light intensity of pixel or voxel comprising the at least one sub-pixel or sub-voxel which has partial containment can be a binary profile, e.g., 0% or 100%.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels can be increased, e.g., increased by at least about 0.1%, at least about 0.5%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 99%, at least about 100%, at least about 150%, at least about 200%, at least about 300%, at least about 400%, at least about 500%, or more, as compared to the light intensity prior to the modification.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels can be decreased, e.g., decreased by at least about 0.1%, at least about 0.5%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 99%, or at substantially about 100%, as compared to the light intensity prior to the modification.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or subvoxel of the set of sub-pixels or sub-voxels can be increased to at least about 0.1%, at least about 0.5%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 99%, at least about 100% of a maximum light intensity (e.g., as determined by the parameters of the optical source).
  • a maximum light intensity e.g., as determined by the parameters of the optical source.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels can be increased to at most about 100%, at most about 99%, at most about 95%, at most about 80%, at most about 85%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 15%, at most about 10%, at most about 9%, at most about 8%, at most about 7%, at most about 6%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, at most about 1%, at most about 0.5%, at most about 0.1%, or less of a maximum light intensity.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or subvoxel of the set of sub-pixels or sub-voxels can be decreased to at least about 0.1%, at least about 0.5%, at least about 1%, at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 6%, at least about 7%, at least about 8%, at least about 9%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 99%, at least about 100% of a maximum light intensity.
  • the light intensity of the pixel or voxel comprising the at least one sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels can be decreased to at most about 100%, at most about 99%, at most about 95%, at most about 80%, at most about 85%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 15%, at most about 10%, at most about 9%, at most about 8%, at most about 7%, at most about 6%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, at most about 1%, at most about 0.5%, at most about 0.1%, or less of a maximum light intensity.
  • the highest light intensity i.e., 100% intensity
  • the lowest light intensity i.e., 0% intensity
  • any intermediate intensity level i.e., a gray scaled intensity, less than 100% but larger than 0%
  • the method can further comprise generating a representative light intensity of the plurality of sub-pixels or sub-voxels of the individual pixel or voxel.
  • the representative light intensity can be an average, a median, a mean, a mode, the largest value, the smallest value, a range (e.g., a difference between the largest value and the smallest value, etc.
  • a plurality of pixels or voxels can be assigned with the same type of representative light intensity.
  • a plurality of pixels or voxels can be assigned with different types of representative light intensity, e.g., depending on the shape of the digital model. For example, a first pixel or voxel corresponding to a first region of the digital model (e.g., a protruding edge of the digital model) can be assigned with an average light intensity of the plurality of sub-pixels or sub-voxels, while a second pixel or voxel corresponding to a second and different region of the digital model (e.g., a flat edge of the digital model) can be assigned with a median light intensity of the plurality of sub-pixels or sub -voxels.
  • a first region of the digital model e.g., a protruding edge of the digital model
  • a second pixel or voxel corresponding to a second and different region of the digital model e.g., a flat edge of the digital model
  • the containment level profile as disclosed herein can be indicative of a light intensity profile corresponding to the grid of pixels or voxels.
  • the light intensity profile can be usable by a light source operatively coupled to the 3D printer, as disclosed herein, to print the at least the portion of the 3D object from a mixture.
  • the method can further comprise generating an instruction for directing the light source to direct the light source to adjust a light based at least in part on the light intensity profile.
  • the method can further comprise using the instruction to direct the light source to direct the light comprising the light intensity profile to the mixture, to print the at least the portion of the 3D object from at least a portion of the mixture.
  • the downscaling and grayscaling can be performed, e.g., by a computer processor, with different algorithms.
  • the algorithm comprises applying a Gaussian filter.
  • a Gaussian filter is a mathematical convolution applied at a pixel or voxel of a 2D or 3D image that replaces an intensity value with a weighted average of the pixel or voxel and its neighboring pixels or voxels.
  • the weights are derived from a Gaussian distribution of a specified size and standard deviation.
  • Gaussian filter may result in a reduction of sharp transitions between intensity values and may blur edges of the 3D object.
  • the Gaussian filter can comprise a standard deviation parameter, wherein the amount of blurring or gray scaling increases with larger standard deviation.
  • the algorithm comprises a Downscale algorithm.
  • the Downscale algorithm is an algorithm from the open-source “scikit-learn” python library. It is a form of a mean (or averaging) filter that constructs native (whole) pixels from an equally-weighted average of neighboring subpixels, where the neighborhood is defined by native-pixel boundaries. The result is a downscaling where native-pixel values do not interact and so no blurring of edges occurs, but grayscaling is used to represent partial-pixel dimensions.
  • the algorithm comprises a Rescale algorithm.
  • the Rescale algorithm performs best-fit of native pixels with no grayscaling.
  • the Rescale algorithm is an algorithm from the open-source “scikit- learn” python library, and is a downscaling algorithm that performs a best fit of whole pixels to the arrangement of subpixels. The result is a lower-resolution but still mostly-accurate representation of the original pattern without any gray scaling.
  • the algorithm comprises a Decimation algorithm.
  • the Decimation algorithm is a simple process of selecting each Nth subpixel in a superscaled image, where N is the level of superscaling, and using its value for the corresponding whole pixel in the native-scale image.
  • the result is usually the least accurate and least blurred of the four algorithms, but is used when speed of operation is paramount or a rougher surface is actually desired.
  • the choice of algorithm depends on the desired trade-off of smoothness and sharpness.
  • one algorithm can be applied for a region of the slice of the 3D object, while another algorithm can be applied for a different region of the slice of the 3D object.
  • on algorithm can be applied to a subset of the slices while another algorithm can be applied for a different subset of the slices.
  • the digital model can be a digital slice of a plurality of digital slices corresponding to a 3D object.
  • modifying the containment level of at least one sub-pixel or sub-voxel performed to a digital slice of a plurality of digital slices can be different from that performed to another digital slice of a plurality of digital slices.
  • modifying the containment level of at least one sub-pixel or sub-voxel can be performed to a subset of digital slices of the plurality of digital slices.
  • modifying the containment level of at least one sub-pixel or sub-voxel can be performed to at least 2 subsets, at least 3 subsets, at least 4 subsets, at least 5 subsets, at least 6 subsets, at least 7 subsets, at least 8 subsets, at least 9 subsets, at least 10 subsets, at least 15 subsets, at least 20 subsets, at least 30 subsets, at least 40 subsets, at least 50 subsets, at least 60 subsets, at least 70 subsets, at least 80 subsets, at least 90 subsets, at least 100 subsets, at least 150 subsets, at least 200 subsets, at least 250 subsets, at least 300 subsets, or more of digital slices of the plurality of digital slices.
  • modifying the containment level of at least one sub-pixel or sub-voxel can comprise applying a pre-defined containment level filter to the sub-pixel or subvoxel and one or more neighboring sub-pixels or sub-voxels adjacent to the sub-pixel or subvoxel, wherein the pre-defined containment level filter defines containment levels for a plurality of sub-pixels or sub-voxels.
  • the smoothing can be performed at a region of a slice of a 3D object. In some embodiments, the smoothing can be performed for a slice or a subset of slices of the 3D object. In some embodiments, the selection can be based at least in part on a design feature of the portion of the 3D object. In some embodiments, the selection of a region or a slice for smoothing can be based at least on a complexity of the object. In some embodiments, for a region of a slice with a high complexity, a higher level of or more smoothing is needed in comparison to a region with a low complexity. In some embodiments, the selection can be manual. In some embodiments, the selection can be based on a preference or a request from an individual.
  • an adaptive smoothing method provided herein can comprise determining a complexity of a portion of a 3D object and based on the complexity, applying adaptive, e.g., different smoothing (e.g., different downscaling and gray scaling algorithm or parameters) to the 3D object.
  • the method can comprise mapping, by a computer processor, a digital image corresponding to at least a portion of the 3D object, on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model.
  • the method can further comprise mapping, by the computer processor, the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of subpixels or sub-voxels, to generate an additional image containing a set of sub-pixels or subvoxels of the additional grid that overlap with at least a portion of the digital model.
  • the method can further comprise generating a difference image, wherein the difference image corresponds to the difference between the image and the additional image.
  • the method can further comprise modifying a light intensity of the set of pixels or voxels based on the difference image.
  • each pixel or voxel of the set of pixels or voxels is fully contained in the at least a portion of the digital model. In some embodiments, each sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels is fully contained in the at least a portion of the digital model.
  • FIG. 3A illustrates an image of a digital slice with whole native pixels, i.e., each pixel is fully contained in the digital model.
  • FIG. 3B illustrates an image of the digital slice at a 4x super-scaled resolution.
  • FIG. 3C illustrates a difference image of FIG. 3A and FIG. 3B.
  • FIG. 3D illustrates an overlay ed images of FIG. 3A (white pixels) and FIG. 3C (gray subpixels).
  • the method can further comprise calculating a difference rate between the image and the additional image.
  • the difference rate can be calculated as the number, area, or volume of sub-pixels or sub-voxels of the difference image divided by the number, area, or volume of sub-pixels or sub-voxels of the additional image.
  • the difference rate can be calculated as the area or volume of sub-pixels or sub-voxels of the difference image divided by the area or volume of pixels or voxels of the additional image.
  • the difference rate can be calculated as the number, area, or volume of sub-pixels or sub-voxels of the difference image divided by number, area, or volume of sub-pixels or sub-voxels at the boundary area/region of the image or the additional image. In some embodiments, the calculation can be performed for the whole image or the additional image. In some embodiments, the calculation can be performed for a region or area of the image or the additional image. In some embodiments, the calculation can be performed for different regions or areas of the image.
  • the difference rate can comprise a total difference rate, a whole-pixel difference rate, and/or a boundary-pixel difference rate.
  • FIG. 3E illustrates an exemplary difference rate.
  • White regions, e.g., 301 and light gray regions, e.g., 302 together represent the region of the digital slice with the whole-white pixels.
  • Light gray regions e.g., 302 represent whole-white pixels that are contained in 4 subpixel boundary regions.
  • Darker gray regions e.g., 303 represent the difference between the super-scaled digital slice and digital slice with the whole white pixels at the boundary.
  • the total difference rate is 11.2%
  • the whole-pixel difference rate is 12.7%
  • the boundary-pixel difference rate is 54.8%.
  • FIG. 3F illustrates another exemplary difference rate.
  • White regions, e.g., 306 and 307 represents the region of the digital slice with the whole-white pixels.
  • Gray regions e.g., 305 represent the difference between the super-scaled digital slice and digital slice with the whole white pixels at the boundary.
  • the total difference rate is 16.8%
  • the whole-pixel difference rate is 20.2%
  • the boundary-pixel difference rate is 43.2%.
  • FIG. 3G illustrates another exemplary difference rate.
  • White regions e.g., 321 represent the region of the digital slice with the whole-white pixels.
  • Gray regions e.g., 322 represent the difference between the super-scaled digital slice and digital slice with the whole white pixels at the boundary.
  • the total difference rate is 27.2%
  • the whole-pixel difference rate is 37.3%
  • the boundary-pixel difference rate is 53.3%.
  • FIG. 3H shows an exemplary method of calculating difference rate for different regions.
  • the image is divided to a plurality of small regions, for example region 331 and 332.
  • the difference rate is calculated for each of the plurality of small regions.
  • a different standard deviation of Gaussian filter can be applied during smoothing for different regions. For example, region 332 has a higher difference rate than region 331, therefore a higher standard deviation can be applied to region 332 than that for region 331.
  • a smoothing can be performed for a region or area that has a difference rate that is higher than a threshold value.
  • different smoothing can be performed for different regions or areas that have different difference rates.
  • the method can further comprise applying a light intensity scaling factor to a subset of the set of pixels or voxels, and an additional light intensity scaling factor to an additional subset of the set of pixels or voxels, wherein the subset of the set of pixels or voxels has a different difference rate from the additional subset of the set of pixels or voxels.
  • higher scaling factor can be applied to area or region (e.g., a subset of the set of pixels or voxels) with higher difference rate.
  • the method can further comprise applying a Gaussian filter to a light corresponding to the sub-set of the set pixels and an additional Gaussian filter to a light corresponding to the additional subset of the set pixels, wherein a standard deviation of the Gaussian filter and a standard deviation of the additional Gaussian filter are different.
  • higher standard deviation of the Gaussian filter can be applied to area or region (e.g., a subset of the set of pixels or voxels) with higher difference rate.
  • the method can further comprise generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the method can further comprise generating printing instructions corresponding to a plurality of slices of the digital model.
  • the method can further comprise using the printing instructions to print the 3D object by the 3D printer.
  • a system for processing a 3D object with adaptive smoothing for printing by a 3D printer for comprising: a computer processor in digital communication with computer memory, configured to: map a digital model corresponding to at least a portion of the 3D object on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; map the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of sub-pixels or sub-voxels, to generate an additional image containing a set of sub-pixels or sub-voxels of the additional grid that overlap with at least a portion of the digital model; generate a difference image between the image and the additional image; and modify a light intensity of the set of pixels or voxels based on the difference image.
  • the computer processor can be further configured to calculate a difference rate between the image and the additional image.
  • the computer processor can be further configured to apply a light intensity scaling factor to a subset of the set of pixels or voxels, and an additional light intensity scaling factor to an additional subset of the set of pixels or voxels, where-in the subset of the set of pixels or voxels has a different difference rate from the additional subset of the set of pixels or voxels.
  • the computer processor can be further configured to apply a Gaussian filter to a light corresponding to the subset of the set pixels and an additional Gaussian filter to a light corresponding to the additional subset of the set pixels, wherein a standard deviation of the Gaussian filter and a standard deviation of the additional Gaussian filter are different.
  • the computer processor can be further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the computer processor can be further configured to generate printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the computer processor can be further configured to print the 3D object according to the printing instructions.
  • upward-facing surfaces which are the surfaces facing the light source
  • downward-facing surfaces which are surfaces not facing the light source. This is probably due to the difference in curing between the upskins and downskins.
  • An adaptive smoothing method provided herein can comprise determining a surface orientation (e.g., upskins or downskins) of a portion of a 3D object and based on the surface orientation, applying adaptive smoothing, e.g., different smoothing (e.g., different downscaling and gray scaling algorithm or parameters) to the 3D object.
  • adaptive smoothing e.g., different smoothing (e.g., different downscaling and gray scaling algorithm or parameters)
  • the method can comprise providing, by a computer processor, a plurality of grids of pixels or voxels corresponding to a plurality of slices of a digital model of the 3D object, wherein the plurality of grids comprising: (i) a grid comprising a set of pixels or voxels that correspond to a slice of the plurality of slices, wherein a pixel or voxel of the set is assigned with a light intensity value based on an overlap between the set and the slice; and (ii) an additional grid comprising an additional set of pixels or voxels that correspond to an additional slice of the plurality of slices, wherein the additional slice is adjacent to the slice in the digital model.
  • the method can further comprise identifying, by the computer processor, (i) a first pixel or voxel of the set that does not overlap with the additional set (e.g., pixels that are on upskins) and (ii) a second pixel or voxel of the set that overlaps with the additional set (e.g., pixels that are on downskins).
  • FIG. 4A illustrates an exemplary portion of a 3D object.
  • 401 shows the direction of the projected light.
  • 401 shows voxels on the upskins (up-ward facing surfaces).
  • 402 shows voxels on the downskins (down-ward facing surfaces).
  • the first pixel or voxel or the second pixel or voxel can correspond to at least a portion of a boundary region of the slice.
  • a boundary region as provided herein can be one or more regions of a slice of a plurality of slices of a digital model of a 3D object that borders a background of a digital space.
  • the background can comprise one or more pixels or voxels that would be assigned with substantially zero light intensity from a light source during 3D printing (e.g., during photocuring).
  • the boundary region can be an external boundary of the digital model.
  • the boundary region can be an internal boundary of the digital model.
  • the boundary region can be characterized by having a certain width along a direction away from the background and towards an inner portion (e.g., a center) of the slice of the digital model.
  • the width of the boundary region may be determined according to the size of the slice, the size of the digital model, or the desired printing resolution.
  • the width of the boundary region can be characterized by a number of pixels or voxels, e.g., at least or up to about 1 pixel (or voxel), at least or up to about 2 pixels (or voxels), at least or up to about 3 pixels (or voxels), at least or up to about 4 pixels (or voxels), at least or up to about 5 pixels (or voxels), at least or up to about 6 pixels (or voxels), at least or up to about 7 pixels (or voxels), at least or up to about 8 pixels (or voxels), at least or up to about 9 pixels (or voxels), or at least or up to about 10 pixels (or voxels).
  • a number of pixels or voxels e.g., at least or up to about 1 pixel (or voxel), at least or up to about 2 pixels (or voxels), at least or up to about 3 pixels (or voxels), at least or up to about 4 pixels
  • the boundary region can be characterized by having a pixel (or voxel) (i) that has a light intensity of greater than zero and (ii) that is away from a black pixel (or a black voxel) by at most about 1 pixel (or voxel), at most about 2 pixels (or voxels), at most about 3 pixels (or voxels), at most about 4 pixels (or voxels), at most about 5 pixels (or voxels), at most about 6 pixels (or voxels), at most about 7 pixels (or voxels), at most about 8 pixels (or voxels), at most about 9 pixels (or voxels), at most about 10 pixels (or voxels), at most about 15 pixels (or voxels), or at most about 20 pixels (or voxels).
  • each of the first pixel or voxel and the second pixel or voxel can correspond to at least a portion of a boundary region of the slice.
  • the additional slice can be directly adjacent to the slice in the digital model. In some embodiments, the additional slice can be a subsequently printed slice that is not directly adjacent to the slice in the digital model. In some embodiments, the additional slice can be within a certain distance away from the slice. In some embodiments, the additional slice can be 1 slice, 2 slices, 3 slices, 4 slices, 5 slices, 6 slices, 7 slices, 8 slices, 9 slices, 10 slices, or more, away from the slice.
  • the method can further comprise modifying, by the computer processor, (i) a first light intensity value that is assigned to the first pixel or voxel relative to (ii) a second light intensity value that is assigned to the second pixel or voxel, or vice versa.
  • the first light intensity value and the second light intensity value are assigned based on a degree of containment of the first pixel or voxel and the second pixel or voxel, respectively, by the slice.
  • the modifying can comprise adjusting (i) a first degree of containment of the first pixel or voxel relative to (ii) a second degree of containment of the second pixel or voxel, or vice versa. In some embodiments, the modifying can comprise modifying the first light intensity value but not the second light intensity value. [00176] In some embodiments, the modifying can comprise applying different degrees of a light intensity scaling factor to the first pixel or voxel and the second pixel or voxel.
  • the modifying can comprise applying different light intensity scaling factors to the first pixel or voxel and the second pixel or voxel.
  • the method can further comprise applying a Gaussian filter to a light source.
  • the method can further comprise applying a first standard deviation of the Gaussian filter for the first pixel or voxel and a second standard deviation of the Gaussian filter for the second pixel or voxel.
  • the first standard deviation can be larger than the second standard deviation.
  • the first standard deviation can be at least 1%, at least 2%, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200% larger than the second standard deviation.
  • the grid and the additional grid are usable by the 3D printer to print the slice and the additional slice, respectively, and wherein the slice is to be printed prior to the additional slice.
  • the method can further comprise generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the method can further comprise generating printing instructions corresponding to the slice.
  • the method can further comprise using the printing instructions to print the 3D object by the 3D printer.
  • a portion of the 3D object can be assigned with a light intensity profile while a different portion of the 3D object can be assigned with a different light intensity profile.
  • FIG. 4B shows an exemplary light intensity profile for pixels at a digital layer.
  • Pixel 411 is printed at intensity value of 205 wherein the adjacent pixel is printed at intensity value of 27.
  • Pixel 412 is printed at intensity value of 227 wherein the adjacent pixel is printed at intensity value of 27.
  • Pixel 413 is printed at intensity value of 48 wherein the two adjacent pixels are printed at intensity value of 24 and 227 respectively.
  • Pixel 414 is printed at intensity value of 205 wherein the two adjacent pixels are printed at intensity value of 27 and 230 respectively.
  • different regions of the 3D object can be assigned with different light intensity profile based on different smoothing algorithms.
  • the selection of the smoothing algorithms can be done by the user or operator or be automatically performed by the computer processor.
  • FIGS. 4C-4H illustrates printing with different downscaling and grayscaling algorithm and parameters.
  • FIG. 4C shows printing with Gaussian filter at a standard deviation of 0.5.
  • FIG. 4D shows printing with Gaussian filter at a standard deviation of 0.7.
  • FIG. 4E shows printing with Gaussian filter at a standard deviation of 0.9.
  • FIG. 4F shows printing with Rescale algorithm.
  • FIG. 4G shows printing with Anti-alias algorithm.
  • FIG. 4H shows printing with Downscale algorithm.
  • a system for processing a 3D object with surface orientation for printing by a 3D printer can comprise: a computer processor in digital communication with computer memory, configured to (i) provide a plurality of grids of pixels or voxels corresponding to a plurality of slices of a digital model of the 3D object, the plurality of grids comprising: a grid comprising a set of pixels or voxels that correspond to a slice of the plurality of slices, wherein a pixel or voxel of the set is assigned with a light intensity value based on an overlap between the set and the slice; and an additional grid comprising an additional set of pixels or voxels that correspond to an additional slice of the plurality of slices, wherein the additional slice is adjacent to the slice in the digital model; (ii) identify, by the computer processor, a first pixel or voxel of the set that does not overlap with the additional set and a second pixel or voxel of the set that overlaps with the additional set; and (iii
  • the computer processor can be further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the computer processor can be further configured to apply a Gaussian filter to a light source.
  • the computer processor can be configured to apply a first standard deviation of the Gaussian filter for the first pixel or voxel and a second standard deviation of the Gaussian filter for the second pixel or voxel. In some embodiments, the first standard deviation is larger than the second standard deviation.
  • a pixel or voxel of the plurality of grids is a pixel.
  • a pixel or voxel of the plurality of grids is a voxel.
  • the computer processor can be further configured to generate printing instructions corresponding to the slice.
  • the system can comprise a 3D printer configured to print the 3D object according to the printing instructions.
  • a 3D object may transitions between negative space and a large surface, e.g., a planar surface (a “ceiling” or “downskin”) or vice-versa (a “floor” or “upskin”), it may result in large regions of gray pixels.
  • the gray pixels may not cure well enough to be structurally viable, or may result in rough partially-formed surfaces. Methods and systems are needed to eliminate the smoothing artifacts while retaining the other benefits of grayscaling, such as increased resolution and surface smoothness.
  • the present disclosure provides methods and systems for boundary limited smoothing.
  • the method can comprise (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity (gray pixel or voxel); and (b) determining, by the computer processor, a distance between the first pixel or voxel and the second pixel or voxel.
  • the second light intensity can be lower than the first light intensity by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the second light intensity can be lower than the first light intensity by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, or less.
  • the method can further comprise subsequent to (b), (i) if the distance is above a distance threshold, reducing the second light intensity of the second pixel or voxel, or (ii) if the distance is less than or equal to the distance threshold, maintaining or increasing the second light intensity of the second pixel or voxel.
  • the second light intensity of the second pixel or voxel can be reduced by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the second light intensity of the second pixel or voxel can be reduced by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, or less.
  • the second light intensity of the second pixel or voxel can be increased by at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the second light intensity of the second pixel or voxel can be increased by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, or less.
  • the first light intensity is sufficient for curing of a resin during the printing.
  • the first pixel or voxel is at most 6 pixels, at most 5 pixels, at most 4 pixels, at most 3 pixels, at most 2 pixels, at most 1 pixel from the outermost boundary of the at least the portion of the digital model.
  • the first light intensity is substantially a maximum light intensity of a light directed from an optical source, e.g., a 100% intensity.
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity.
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model.
  • a grayscaling can be only performed to pixels that are within a distance threshold of the white pixels or voxels. For those pixels or voxels that are too far from the white pixels or voxels, no grayscaling will be performed, instead, the light intensity of the pixels or voxels can be reduced to 0 (black pixel or voxels), therefore those pixels or voxels are not printed in the present slice.
  • the distance threshold is less than or equal to about 15 pixels or voxels, less than or equal to about 14 pixels or voxels, less than or equal to about 13 pixels or voxels, less than or equal to about 12 pixels or voxels, less than or equal to about 11 pixels or voxels, less than or equal to about 10 pixels or voxels, less than or equal to about 9 pixels or voxels, less than or equal to about 8 pixels or voxels, less than or equal to about 7 pixels or voxels, less than or equal to about 6 pixels or voxels, less than or equal to about 5 pixels or voxels, less than or equal to about 4 pixels or voxels, or less.
  • the distance threshold is selected by a user of the 3D printer.
  • the distance threshold is automatically determined by the computer processor. In some embodiments, the distance threshold is determined based at least in part on a shape, a dimension, and/or a complexity of the at least the portion of the digital model.
  • the distance threshold value is determined by the material, based on an estimation/determination by the operator or user of the viability of partially cured voxels (or gray voxels) given the physical characteristics of that material. If the partially cured voxels (or gray voxels) have support from an adjacent voxel on the same layer or an adjacent layer, the distance threshold can be more than or equal to about 3 pixels or voxels, more than or equal to about 4 pixels or voxels, more than or equal to about 5 pixels or voxels, or more.
  • a lower distance threshold may be assigned, for examples, 1 pixel or voxel, or 2 pixels or voxels.
  • the distance between pixels or voxels can be measured in several ways, such as the Euclidean distance (straight-line) or Manhattan distance (sum of x and y differences), depending on the shape or complexity of the 3D object.
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model.
  • the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • FIGS. 5A-5D show a printing process for consecutive slices 73-76. From slice 73 (FIG. 5A) and 76 (FIG. 5D), there is a drastic change from a big hole to a small hole. Before applying boundary -limited smoothing, in slice 74 (FIG. 5B), there are about 5-6 pixels 501 that have about 25% intensity. Some of the pixels that are far from the white pixels may not have sufficient curing to adhere to an adjacent pixel. In slice 75 (FIG. 5C), there are about 5-6 pixels 502 that have about 75% intensity.
  • FIGS. 5E-5H show a printing process for consecutive slices 73-76.
  • boundary-limited smoothing only 2 pixels that are adjacent to the white pixels are assigned gray intensity value of 25% in slice 74 (FIG. 5F) and in printing slice 75 (FIG. 5G), only 2 additional pixels are assigned gray intensity value of 75%.
  • those gray pixels that are too far from the white pixel are assigned a 0 intensity.
  • the intensity of the second pixel or voxel can be maintained, allowing gray light intensity for the second pixel or voxel regardless of the distance between the second pixel or voxel and the first pixel or voxel.
  • the light intensity of a gray pixel or voxel which does not have support of a substantially full pixel from the same layer but has support of a substantially full pixel from the previous layer, can be increased.
  • FIG. 51 shows another example of applying boundary limited smoothing in printing consecutive slices 143-151, wherein fin-shaped supports gradually thin to meet part.
  • Gray pixels that are next to the white pixels are maintained the gray intensity value while gray pixels that are too far from the white pixels are modified to 0 pixels (black pixels). This may lead to vertical discontinuities (or the breaking of supports) and/or printing failures. If the gray pixels or voxels that do not have lateral support (on the same layer) but have vertical support from the previous layer are modified to full (white) intensity value, the vertical integrity of the printed part can be maintained.
  • FIG. 5J shows the comparison of reducing light intensity and increasing light intensity of such gray pixels or voxels.
  • the system for boundary limited smoothing can comprise a computer processor in digital communication with computer memory, configured to: (a) obtain a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; (b) determine a distance between the first pixel or voxel and the second pixel or voxel; (c) reduce the second light intensity of the second pixel or voxel if the distance is above a distance threshold, or maintain or increase the second light intensity of the second pixel or voxel if the distance is less than or equal to the distance threshold.
  • a pixel or voxel of the plurality of grids is a pixel.
  • a pixel or voxel of the plurality of grids is a voxel.
  • the computer processor can be further configured to generate printing instructions corresponding to the slice.
  • the system can comprise a 3D printer configured to print the 3D object according to the printing instructions.
  • a boundary-limited smoothing can be performed based on the light intensity of the gray pixels, instead of based on the distance of the gray pixel. If an intensity is too low, the gray pixel may not sufficiently cure to have a viable structure or adhesion to adjacent pixel in the same slice or a prior slice or a next slice. Therefore, methods and systems are needed to modify the light intensity profile to allow for viable printing.
  • the method can comprise (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity and
  • the first light intensity is sufficient for curing of a resin during the printing, and wherein the first pixel or voxel is near a boundary of the at least the portion of the digital model.
  • the first light intensity is substantially a maximum light intensity of a light directed from an optical source.
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity. In some embodiments, (c)(ii) comprises maintaining the second light intensity of the second pixel or voxel.
  • (c)(ii) comprises increasing the second light intensity of the second pixel or voxel.
  • the second light intensity of the second pixel or voxel can be increased by at least 1%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or more.
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model.
  • the threshold intensity level can be from 1% to 75% of the maximum light intensity of a light directed from an optical source. In some embodiments, the threshold intensity level is less than or equal to about 75%, the threshold intensity level is less than or equal to about 70%, the threshold intensity level is less than or equal to about 60%, the threshold intensity level is less than or equal to about 50%, less than or equal to about 40%, less than or equal to about 30%, less than or equal to about 20%, less than or equal to about 10%, the threshold intensity level is less than or equal to about 5%, or less. In some embodiments, the threshold intensity level can be about 75%, about 70%, about 60%, about 50%, about 40%, about 30%, about 20%, or about 10% of the maximum light intensity of a light directed from an optical source.
  • the threshold intensity level is selected by a user of the 3D printer. In some embodiments, the threshold intensity level is automatically determined by the computer processor. In some embodiments, the threshold intensity level is determined based at least in part on a shape, a dimension, or a complexity of the at least the portion of the digital model.
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • a system for boundary limited smoothing can comprise a computer processor in digital communication with computer memory, configured to: obtain, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises (i) a first pixel or voxel assigned with a first light intensity and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; compare the second light intensity to a threshold intensity level; and reduce the second light intensity of the second pixel or voxel if the second light intensity is less than the threshold intensity level, or maintain or increase the second light intensity of the second pixel or voxel if the second light intensity is greater than or equal to the threshold intensity level.
  • a pixel or voxel of the grid is a pixel. In some embodiments, a pixel or voxel of the grid is a voxel.
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the computer processor can be further configured to generate printing instructions corresponding to the slice.
  • the system can comprise a 3D printer configured to print the 3D object according to the printing instructions.
  • the boundary limited smoothing method can comprise (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to a slice of at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises: (i) a first pixel or voxel assigned with a first light intensity and (ii) a second pixel or voxel assigned with a second light intensity that is lower than the first light intensity, wherein the second light intensity is greater than zero intensity; (b) determining if the second pixel or voxel is supported by a pixel or voxel with a substantially maximum intensity at the same location on an adjacent slice; and (c) subsequent to (b), (i) if the second pixel or voxel is not supported by a pixel or voxel with a substantially maximum intensity at the same location on the adjacent slice, reducing the second light intensity of the second pixel or voxe
  • a digital model of a 3D object is sliced to a plurality of slices or layers of the 3D object and a slice is mapped to a grid of pixels or voxels to generate a pattern for printing.
  • a slice containing integer number of pixels or voxels can be fully contained in a grid of pixels or voxels with the boundary aligned with the boundary of the grid of pixels or voxels.
  • FIG. 2C shows an image of a slice that has 10x10 pixels which can be fully contained in the grid of pixels (with a boundary 221. In some cases, a slice containing non-integer number of pixels or voxels may not align with the boundary of the grid of pixels or voxels.
  • FIG. 2D shows an image of a slice that has 9x10 pixels which is misaligned with the boundary, e.g., 222, of the 10x10 grid of pixels by half pixel e.g., 223, horizontally.
  • FIG. 2E shows an image of a slice that has 9x9 pixels which is misaligned with the boundary, e.g., 231, of the 10x10 grid of pixels by half pixel, e.g., 232 horizontally and half pixel, e.g., 233 vertically.
  • the slices of the FIGS. 2C-2E may correspond to three slices of the plurality of slices. If the light source and grid of pixels are fixed (e.g., the boundary of the grid of pixels are fixed), the slice in FIG. 2C has an alignment with the grid while the slices in FIG. 2D and FIG. 2E are misaligned with the grid.
  • the present disclosure provides methods and systems that can perform pixel alignment to improve the printing accuracy and efficiency.
  • the critical slice can be a slice with the highest complexity. In some embodiments, the critical slice can be a slice with the largest size. In some embodiments. the critical slice can be selected manually by a user. In some embodiments, the critical slice can be selected by a computer processor.
  • a slice of the plurality of slices can be superscaled, downscaled, and grayscaled at each possible alignment of the pattern with the slice and the best alignment is determined.
  • a method for processing a 3D object for printing by a 3D printer can comprise (a) obtaining, by a computer processor, a plurality of slices of a digital model corresponding to at least a portion of the 3D object; (b) mapping, by the computer processor, a slice of the plurality of slices on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels; and (c) generating, by the computer processor, an alignment score between the slice and the grid of pixels or voxels at the relative alignment position.
  • step (b) can further comprise (i) determining a degree of containment of a pixel or voxel of the grid of pixels or voxels that overlaps with at least a portion of the slice, (ii) assigning a light intensity for the pixel or voxel, and (iii) generating a light intensity profile of the slice corresponding to the grid of pixels or voxels.
  • a pixel or voxel of the grid of pixels or voxels can comprise a plurality of sub-pixels or sub-voxels.
  • the light intensity for the pixel or voxel can be substantially 100% (white pixel) if the pixel is fully contained in the digital model.
  • the light intensity for the pixel or voxel can be less than 100% but higher than 0 intensity (gray pixel) if the pixel is partially contained in the digital model.
  • step (c) can comprise calculating an average pixel or voxel intensity.
  • the average pixel or voxel intensity can be calculated as the sum of all on-pixel light intensities divided by the number of on-pixels.
  • An on-pixel is a pixel that is not black or not at intensity 0.
  • a higher average pixel or voxel intensity relates to a better alignment.
  • the alignment score can comprise the average pixel or voxel intensity. In some embodiments, the alignment score can be from 0 to 1.
  • step (c) can comprise calculating a weighted pixel or voxel intensity. This method counts the number of pixels or voxels with 100%, 50% and 25% light intensities in the grayscaled patterns, and calculates a weighted sum with the most weight given to pixels or voxels with 100% light intensity and smaller weights given to pixels or voxels with 50% and 25%. All other light intensity values are given 0 weight. A higher weighted pixel or voxel intensity relates to a better alignment.
  • the alignment score can comprise the weighted pixel or voxel intensity. In some embodiments, the alignment score can be from 0 to 1.
  • step (c) can comprise calculating a pixel-value entropy.
  • This method calculates the entropy of pixel light intensities in each grayscaled pattern, and chooses the one with the lowest entropy as the best alignment.
  • the lowest entropy values will be produced by patterns with pixels or voxels with 100% and/or 0% intensities only and therefore no grayscaling is needed.
  • the pattern alignment with the lowest entropy has the fewest different gray intensity values and the lowest complexity.
  • the method can further comprise determining, by the computer processor, if the alignment score meets a quality threshold. In some embodiments, if the alignment score meets the quality threshold, the method can further comprise mapping an additional slice of the plurality of slices onto an additional grid of pixels or voxels at the relative alignment position. In some embodiments, if the alignment score does not meet the quality threshold, the method can further comprise re-mapping the slice on the grid of pixels or voxels at a different relative alignment position.
  • the quality threshold can be at least about 0.7, at least about 0.8, at least about 0.85, at least about 0.9, at least about 0.91, at least about 0.92, at least about 0.93, at least about 0.94, at least about 0.95, or more.
  • the quality threshold can be determined or assigned by a user or operator. In some embodiments, the quality threshold can be automatically determined or assigned by a computer processor.
  • the re-mapping can comprise moving the slice within the grid of pixels or voxels by a distance, wherein the distance is less than a dimension of a pixel or voxel of the grid of pixels or voxels.
  • the distance can be less than about 90%, less than about 80%, less than about 70%, less than about 60%, less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 10%, or less of a dimension of a pixel or voxel.
  • the distance can be larger than about 10%, larger than about 20%, larger than about 30%, larger than about 40%, larger than about 50%, larger than about 60%, larger than about 70%, larger than about 80%, larger than about 90%, or more of a dimension of a pixel or voxel.
  • the re-mapping can comprise rotating the slice within the grid of pixels or voxels by an angle of between 0 degree and 360 degrees.
  • the angle can be more than 1 degree, more than 5 degrees, more than 10 degrees, more than 20 degrees, more than 30 degrees, more than 50 degrees, more than 90 degrees, more than 100 degrees, more than 120 degrees, more than 150 degrees, more than 180 degrees, more than 200 degrees, more than 250 degrees, more than 270 degrees, more than 300 degrees, more than 330 degrees, more than 350 degrees, or more.
  • the angle can be less than 360 degrees, less than 350 degrees, less than 300 degrees, less than 270 degrees, less than 250 degrees, less than 200 degrees, less than 180 degrees, less than 150 degrees, less than 120 degrees, less than 100 degrees, less than 90 degrees, less than 60 degrees, less than 50 degrees, less than 30 degrees, less than 20 degrees, less than 10 degrees, less than 5 degrees, or less.
  • an alignment score is re-calculated for the slice. The re-mapping can be repeated until the alignment score meets a quality threshold.
  • the slice to be mapped (e.g., the critical slice) is selected by a user of the 3D printer. In some embodiments, the selecting of the critical slice from the plurality of slices can be performed automatically, by the computer processor.
  • the method can comprise performing at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, or more alignments, and selecting the alignment that has the highest alignment score.
  • the method can further comprise (i) determining a degree of containment of a pixel or voxel of the additional grid of pixels or voxels that overlap with at least a portion of the additional slice; (ii) assigning a light intensity for the pixel or voxel; and (iii) generating a light intensity profile of the additional slice corresponding to the additional grid of pixels or voxels, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object.
  • the method can further comprise generating printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the method can further comprise using the printing instructions to print the 3D object by the 3D printer.
  • a system for processing a 3D object with pixel alignment for printing by a 3D printer can comprise (i) a computer processor in digital communication with computer memory, configured to: map a slice of a plurality of slices of a digital model corresponding to at least a portion of the 3D object on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels; generate an alignment score between the slice and the grid of pixels or voxels at the relative alignment position; determine an alignment of the slice with the grid of pixels or voxels; determining if the alignment score meets a quality threshold; and map an additional slice of the plurality of slices onto an additional grid of pixels or voxels at the relative alignment position if the alignment score meets the quality threshold, or re-map the slice on the grid of pixels or voxels at a different relative alignment position if the alignment score does not meet the quality threshold.
  • the computer processor can be further configured to (i) determine a degree of containment of a pixel or voxel of the additional grid of pixels or voxels that overlap with at least a portion of the additional slice; (ii) assign a light intensity for the pixel or voxel; and (iii) generate a light intensity profile of the additional slice corresponding to the additional grid of pixels or voxels, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object.
  • the computer processor can be further configured to (i) determine a degree of containment of a pixel or voxel of the grid of pixels or voxels that overlaps with at least a portion of the slice, (ii) assign a light intensity for the pixel or voxel, and (iii) generate a light intensity profile of the slice corresponding to the grid of pixels or voxels.
  • a pixel or voxel of the grid is a pixel.
  • a pixel or voxel of the grid is a voxel.
  • the computer processor can be further configured to generate printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the computer processor can be further configured to print the 3D object according to the printing instructions.
  • a 3D printing system can comprise a pixel shifter.
  • a pixel shifter is an optomechanical device that uses the principal of refraction to laterally shift the projected image by tilting a small glass window between the digital micromirror device (DMD) and the projection optics.
  • DMD digital micromirror device
  • FIG. 9A illustrates an exemplary projected light with a pixel shifter.
  • a pixel With the pixel shifter, a pixel can be shifted diagonally, horizontally, or vertically by a distance from the original position of the pixel. Pixel shifting can help improve the resolution of 3D printed object.
  • the present disclosure provides methods and systems that combine pixel shifting and gray scaling for enhancing resolution of 3D object.
  • the method can comprise (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) mapping, by the computer processor, the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; (c) identifying, by the computer processor, an exterior pixel or voxel, wherein the exterior pixel or voxel partially overlaps with the digital image; (d) adjusting, by the computer processor, a position of the exterior pixel or voxel; (e) modifying, by the computer processor, a light intensity of the exterior pixel or voxel such that the light intensity is lower than a light intensity of an interior pixel or voxel; and (f) generating a modified pattern of the digital image, wherein the modified pattern is usable by the 3D printer to print the at least
  • (d) comprises moving the exterior pixel or voxel by a distance.
  • the distance is less than a dimension of a pixel or voxel.
  • the distance can be from about 5% to about 90% of a dimension of a pixel of voxel.
  • the distance is about l/6 th , about l/5 th , about l/4 th , about l/3 rd , about l/2 nd , about 2/3 rd , or about 3/4 th of the dimension of the pixel or voxel.
  • the distance is about 5%, about 10%, about 15%, about 17%, about 20%, about 25%, about 30%, about 33%, about 40%, about 45%, about 50%, about 60%, about 67%, about 70%, about 75%, about 80%, about 85%, or about 90% of the dimension of the pixel or voxel.
  • the moving can be horizontal, vertical, or diagonal.
  • the light intensity of the interior pixel or voxel is sufficient for curing of a resin during the printing.
  • the light intensity of the interior pixel or voxel can cure a resin to a pre-determined degree of curing during the printing.
  • the degree of curing can be at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more of full cure.
  • (e) further comprises (i) determining a degree of containment of the exterior pixel or voxel and (ii) assigning the light intensity for the exterior pixel or voxel.
  • the exterior pixel or voxel is assigned a gray intensity value, which is higher than 0% but lower than 100%.
  • the modifying comprises applying a light intensity scaling factor to the exterior pixel or voxel.
  • the scaling factor can be any value between 0 and 1.
  • the method can further comprise generating printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the method can further comprise using the printing instructions to print the 3D object by the 3D printer.
  • FIG. 9B shows a pixel shifting process.
  • Box 901 indicates a native pixel (unshifted pixel).
  • Box 902 indicates a shifted pixel that has been shifted by 1/3 pixel both horizontally and vertically.
  • Light gray regions e.g., 903, represent areas that are covered by the original unshifted pixels and the shifted pixels after the pixel-shifting.
  • Intermediate gray regions e.g., 904, represent areas that are covered by shifted pixels.
  • grayscaling can be applied for sub-pixels that are not covered by a full pixel after pixel-shifting (dark gray regions, e.g., 905).
  • FIGS. 9C-9F show exemplary images by pixel shifting and grayscaling.
  • FIG. 9C is the native image.
  • FIG. 9D is the image with grayscaling at perimeters (applying Gaussian filter with standard deviation of 0.95 and Kernel size of 3).
  • FIG. 9E is the image after applying pixel shifting.
  • FIG. 9F is the image with both pixel shifting and grayscaling.
  • FIGS. 9C-9F show that a combination of pixel shifting and gray scaling can improve the resolution of the images.
  • a system for processing a 3D object with pixel shifting and gray scaling for printing by a 3D printer can comprise a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; mapping the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; identify an exterior pixel or voxel, the exterior pixel or voxel partially overlaps with the digital image; adjust a position of the exterior pixel or voxel; modifying a light intensity of the exterior pixel or voxel such that the light intensity is lower than a light intensity of an interior pixel or voxel; and generate a modified pattern of the digital image, wherein the modified pattern is usable by the 3D printer to print the at least the portion of the 3D object.
  • the computer processor is further configured to (i) determine a degree of containment of the exterior pixel or voxel and (ii) assign the light intensity for the exterior pixel or voxel. In some embodiments, the computer processor is further configured to apply a light intensity scaling factor to the exterior pixel or voxel.
  • a pixel or voxel of the grid is a pixel.
  • a pixel or voxel of the grid is a voxel.
  • the computer processor can be further configured to generate printing instructions corresponding to a plurality of slices of the digital model. In some embodiments, the computer processor can be further configured to print the 3D object according to the printing instructions.
  • a region or area of a 3D object may need extra curing to increase the strength and the integrity of the 3D object.
  • a degree of curing can depend on the light intensity and exposure time. The extra curing can be achieved by increasing an exposure time of the resin or mixture from the light.
  • the method can comprise increasing an exposure time for an area while maintaining the exposure time for the other areas.
  • Another method to increase the curing of an area while maintaining the same exposure time for the whole slice can comprise applying a higher light intensity to the area than the other areas. Generally, the light intensity can not exceed the maximum intensity a projector can emit.
  • one method can be assigning a maximum (or substantially maximum) intensity to the area needing more curing and assigning a lower intensity to (e.g., attenuating) the area that does not need more curing. And by increasing the exposure time, the area with the lower intensity can achieve sufficient curing while the area with the higher intensity can have extra curing.
  • the present disclosure provides a method for processing a 3D object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) determining, by the computer processor and based on the digital image, an exterior intensity level and an exterior exposure time of a light for at least one exterior unit of the digital image; (c) modifying, by the computer processor, the exterior intensity level to generate a modified exterior intensity level of the light for the at least one exterior unit; and (d) modifying, by the computer processor, the exterior exposure time to generate a modified exterior exposure time of the light for the at least one exterior unit, wherein the light at the modified exterior intensity level over the exterior exposure time is usable to print the at least the portion of the 3D object.
  • the determining in the process (b) can be based on a geometry (e.g., a dimension or a shape), a containment level of the exterior unit in a grid of pixel or voxel, and/or a specification of the light (e.g., resolution, power output, etc.) of the 3D printing system.
  • a geometry e.g., a dimension or a shape
  • a containment level of the exterior unit in a grid of pixel or voxel e.g., resolution, power output, etc.
  • the process (c) can comprise decreasing the exterior intensity level to generate the modified exterior intensity level.
  • the modified exterior intensity level can be less than the exterior intensity level by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the modified exterior intensity level can be less than the exterior intensity level by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the process (d) can comprise increasing the exterior exposure time to generate the modified exterior exposure time.
  • the modified exterior exposure time can be greater than the exterior exposure time by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, at least about 150%, at least about 200%, at least about 250%, at least about 300%, at least about 350%, at least about 400%, at least about 450%, at least about 500%, or more.
  • the modified exterior exposure time can be greater than the exterior exposure time by at most about 500%, at most about 450%, at most about 400%, at most about 350%, at most about 300%, at most about 250%, at most about 200%, at most about 150%, at most about 100%, at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the modifying in (d) can be further based on the modified exterior intensity level. In some embodiments, the modifying in (d) can be further based on a pre-determined degree of curing for the exterior unit.
  • the pre-determined degree of curing can be substantially full curing (e.g., substantially no free monomer/polymer precursor remaining). In some embodiments, the pre-determined degree of curing can be at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more of the substantially full curing. In some embodiments, the pre-determined degree of curing can be at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, or less of the substantially full curing. In some embodiments, the modifying in (d) can be further based on a pre-determined physical property of the cured exterior unit, e.g., adhesion force, strength, etc.
  • a pre-determined physical property of the cured exterior unit e.g., adhesion force, strength, etc.
  • the method can further comprise: (i) determining, by the computer processor and based on the digital image, an interior intensity level and an interior exposure time of the light for at least one interior unit of the digital image; and (ii) modifying, by the computer processor and based on the modified exterior intensity level, the interior exposure time to generate a modified interior exposure time of the light for the at least one interior unit.
  • the interior unit can comprise a pixel or a voxel.
  • (ii) can comprise increasing the interior exposure time to generate the modified interior exposure time.
  • the modified interior exposure time can be longer than the interior exposure time by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the modified interior exposure time can be longer than the interior exposure time by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the interior exposure time and the exterior exposure time can be substantially the same. In some embodiments, the interior exposure time and the exterior exposure time can be different. In some embodiments, the interior exposure time can be longer than the exterior exposure time. In some embodiments, the interior exposure time can be longer than the exterior exposure time, by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the interior exposure time can be longer than the exterior exposure time, by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the modified interior exposure time and the modified exterior exposure time can be substantially the same. In some embodiments, the modified interior exposure time and the modified exterior exposure time can be different. In some embodiments, the modified interior exposure time can be longer than the modified exterior exposure time. In some embodiments, the modified interior exposure time can be longer than the modified exterior exposure time, by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more.
  • the modified interior exposure time can be longer than the modified exterior exposure time, by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the interior intensity level can remain substantially the same for the light for printing the at least the portion of the 3D object.
  • the interior intensity level can be substantially the maximum intensity a projector can emit.
  • the interior intensity level can be at least about 70%, at least about 80%, at least about 90%, at least about 95%, or more of the maximum intensity a projector can emit.
  • the interior intensity level can be modified.
  • the interior intensity level can be decreased by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, or more.
  • the interior intensity level can be decreased by at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less. In some embodiments, the interior intensity level can be modified to a lesser degree than the modification of the exterior intensity level. In some embodiments, the interior intensity level can be decreased less than the modification of the exterior intensity level by at least about 1%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, or more.
  • the exterior unit can comprise a plurality of pixels or voxels. In some embodiments, the exterior unit can comprise a plurality of pixels or voxels along the length of a diagonal dimension of the digital image. In some embodiments, the exterior unit can comprise at least 1, at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, or more pixels or voxels along the length of a diagonal dimension of the digital image. In some embodiments, the exterior unit can comprise at most 10, at most 9, at most 8, at most 7, at most 6, at most 5, at most 4, at most 3, at most 2, or less pixels or voxels along the length of a diagonal dimension of the digital image.
  • the exterior unit can comprise a pixel or voxel that overlaps partially but not completely with the digital image.
  • the exterior unit can comprise a pixel or voxel that overlaps at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more with the digital image.
  • the exterior unit can comprise a pixel or voxel that overlaps at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, or less with the digital image.
  • the exterior unit can further comprise an additional pixel or voxel, wherein the additional pixel or voxel overlaps substantially completely with the digital image.
  • the exterior unit can further comprise an additional pixel or voxel that is directly adjacent to the pixel or voxel, wherein the additional pixel or voxel overlaps substantially completely with the digital image.
  • the interior unit can comprise a plurality of pixels or voxels.
  • the modified light intensity profile can be generated for a slice of the 3D model based at least in part on the modified exterior intensity level.
  • the intensity level of one or more interior units may not and need not be modified as compared to that initially determined based on the digital image.
  • a patterned light comprising the modified light intensity profile can be projected to a resin (e.g., a film of resin) at the modified exterior exposure time, which modified exterior exposure time is greater than that initially determined based on the digital image.
  • a portion of the resin corresponding to the interior units e.g., pixels or voxels
  • FIG. 10L illustrates an exemplary light intensity profile for a 3D object.
  • 1021, 1022, 1023, and 1024 denote the boundaries of the 3D objects with a boundary width of 4 pixels.
  • the pixels in the boundaries are assigned a light intensity of 69% of the maximum intensity (attenuated by 31%).
  • 1011, 1012, 1013, and 1014 denote the interior pixels of the 3D object which are assigned a light intensity of 100% of the maximum intensity.
  • the 4 pixels at the boundary are printed with a 100% intensity, 4.5 s is needed for sufficient curing.
  • the exposure time can be increased to 6.5 s for sufficient curing of the boundary.
  • the pixels at 1011, 1012, 1013, and 1014 are also exposed for 6.5 s (4.5 s is needed for sufficient curing), the pixels (e.g., at 1011, 1012, 1013, and 1014) have extra curing.
  • the intensity level for the exterior unit can be less than the containment level of the at least one exterior unit. In some embodiments, the intensity level can be about 90%, about 80%, about 70%, about 60%, or about 50% of the containment level of the at least one exterior unit.
  • the method can further comprise generating a light intensity profile based on the modified intensity level (e.g., for exterior unit and/or interior unit) and exposure time (e.g., for exterior unit and/or interior unit), wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the modified intensity level e.g., for exterior unit and/or interior unit
  • exposure time e.g., for exterior unit and/or interior unit
  • a pixel or voxel of the exterior unit is a pixel. In some embodiments, a pixel or voxel of the exterior unit is a voxel. In some embodiments, a pixel or voxel of the interior unit is a pixel. In some embodiments, a pixel or voxel of the interior unit is a voxel.
  • the method can further comprise generating printing instructions corresponding to a plurality of slices of the digital model.
  • the method can further comprise using the printing instructions to print the 3D object by the 3D printer.
  • the present disclosure provides a method for processing a 3D object for printing by a 3D printer, comprising (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object; (b) identifying, by the computer processor, (i) at least one interior unit of the digital image and (ii) at least one exterior unit of the digital image; (c) assigning, by the computer processor, (i) a light intensity of the at least one interior unit and (ii) an additional light intensity of the at least one exterior unit, to generate a light intensity profile of the digital image, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object, wherein the light intensity is higher than the additional light intensity; and (d) assigning a duration of exposure for printing, wherein the duration of exposure is sufficient to cause the exterior unit to cure.
  • the present disclosure provides a system for processing a 3D object for printing by a 3D printer, comprising a computer processor in digital communication with computer memory, wherein the computer processor is configured to: (a) obtain a digital image corresponding to at least a portion of the 3D object; (b) determine, based on the digital image, an exterior intensity level and an exterior exposure time of a light for at least one exterior unit of the digital image; (c) modify the exterior intensity level to generate a modified exterior intensity level of the light for the at least one exterior unit; and (d) modify the exterior exposure time to generate a modified exterior exposure time of the light for the at least one exterior unit, wherein the light at the modified exterior intensity level over the exterior exposure time is usable to print the at least the portion of the 3D object.
  • the present disclosure provides a system for processing a 3D object for printing by a 3D printer can comprise a computer processor in digital communication with computer memory, configured to: (a) obtain a digital image corresponding to at least a portion of the 3D object; (b) identify (i) at least one interior unit of the digital image and (ii) at least one exterior unit of the digital image; (c) assign (i) a light intensity of the at least one interior unit and (ii) an additional light intensity of the at least one exterior unit, to generate a light intensity profile of the digital image, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object, wherein the light intensity is higher than the additional light intensity; and (d) assign a duration of exposure for printing, wherein the duration of exposure is sufficient to cause the exterior unit to cure.
  • the computer processor can be further configured to determine an exposure time needed to cure the at least one exterior unit at the light intensity to a degree of curing.
  • the computer processor can be further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object.
  • the computer processor can be further configured to generate printing instructions corresponding to a plurality of slices of the digital model.
  • the system can comprise the 3D printer configured to print the 3D object according to the printing instructions.
  • the computer processor can comprise an algorithm to (i) define a boundary of a specified width and (ii) attenuate an intensity level of pixels or voxels within the boundary.
  • the boundary can comprise at least one, at least 2, at least 3, at least 4, or more pixels or voxels.
  • the boundary can comprise at most 4, at most 3, at most 2, or less pixels or voxels.
  • attenuating the intensity level can comprise modifying the intensity level of the pixels or voxels within the boundary to less than the maximum intensity.
  • the intensity level of the pixels or voxels within the boundary can be reduced by at least 1%, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50% or more of the maximum intensity.
  • blooming can increase with dosage, e.g., intensity level and/or exposure time of a light. Blooming can occur at edges or boundaries of the 3D object. In some embodiments, blooming can occur at each printed layer. In some embodiments, reducing the intensity level of light for the pixels or voxels at the boundary can reduce the effect of blooming. In some embodiments, a method of reducing blooming can comprise (i) define a boundary of a specified width and (ii) attenuate (or reduce) an intensity level of pixels or voxels within the boundary.
  • the boundary of a layer can have a width in the direction orthogonal to the boundary that is at least one, at least 2, at least 3, at least 4, or more pixels or voxels. In some embodiments, the boundary of a layer can have a width in the direction orthogonal to the boundary that is at most 4, at most 3, at most 2, or less pixels or voxels. In some embodiments, attenuating the intensity level can comprise modifying the intensity level of the pixels or voxels within the boundary to less than the maximum intensity.
  • the intensity level of the pixels or voxels within the boundary can be reduced by at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more of the maximum intensity. In some embodiments, the intensity level of the pixels or voxels within the boundary can be reduced by at most about 90%, at most about 80%, at most about 70%, at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less of the maximum intensity.
  • Attenuation may not have the limitation of erosion by an increment of, for example, l/2 nd , l/3 rd , or l/4 th of a pixel.
  • attenuation can be applied for any levels.
  • attenuation can be applied from about 1% to about 99%.
  • attenuation can be applied at about 1% (e.g., 99% intensity for pixels within the boundary), at about 2%, at about 5%, at about 10%, at about 15%, at about 20%, at about 25%, at about 30%, at about 40%, at about 50%, at about 60%, at about 70%, at about 80%, or at about 90%.
  • FIG. 10A shows an exemplary image with no attenuation (e.g., 100% intensity for pixels within the boundary) at the boundaries.
  • FIG. 10B shows an exemplary image with 15% attenuation (e.g., 85% intensity for pixels within the boundary).
  • FIG. IOC shows an exemplary image with 25% attenuation (e.g., 75% intensity for pixels within the boundary).
  • Attenuation can achieve a linear reduction in blooming.
  • the reduction in blooming can be dependent on (i) level of attenuation (from 0% attenuation (full intensity) to 100% attenuation (complete erosion)) and/or (ii) the depth of attenuation (e.g., width of attenuated border or boundary).
  • FIG. 10D shows an exemplary blooming control at different attenuation.
  • the attenuation depth is 1 pixel.
  • the desired fin width is 0.45 nominal. Without attenuation, the printed fin has a width of about 0.62-0.67 nominal. Increasing the attenuation from 0% to 100% reduces the blooming, at a substantially linear reduction.
  • the dotted line shows the curve for fin width of 0.45 nominal.
  • the solid line is the trendline for the linear fitting of the data, with a R 2 value of 0.934.
  • FIG. 10E shows two exemplary blooming controls at different attenuation.
  • the data with symbols (x) show blooming control for attenuation depth of 1 pixel.
  • the dashed line is the trendline for the linear fitting of the data, with a R 2 value of 0.977.
  • the data with symbols (o) show blooming control for attenuation depth of 2 pixels.
  • the solid line is the trendline for the linear fitting of the data, with a R 2 value of 0.954.
  • the fin width is 6 pixels. The reduction in blooming is substantially linear as the attenuation increases.
  • FIG. 10F shows exemplary blooming controls at different attenuation level and depth (10-pixel, 8-pixel, 6-pixel, 4-pixel, and 2-pixel).
  • One pixel has a dimension of 35 pm. The nominal is 700 pm. Without blooming control, the baseline is 810 pm.
  • the attenuation depth increases from 2 pixels to 10 pixels, for the same attenuation level, the blooming is reduced.
  • the attenuation level increases from 0% to 80%, for the same attenuation depth, the blooming is reduced.
  • Attenuation can reduce blooming on thin geometries that may not withstand erosion. Attenuation can be applied to the 3D printing process with substantially uniformly thin geometries that may not withstand any erosion. Attenuation can also be applied to the 3D printing process with substantially uniformly thick geometries where attenuation can be combined with reduced erosion.
  • a 3D object can comprise mixed the geometries (e.g., thin geometry and thick geometry).
  • the printing may need adjustment to protect thin geometries from erosion and/or high levels of attenuation.
  • the printing method can define a minimum width limit beyond which erosion and attenuation are not allowed.
  • the printing method can identify thin features and exempt the thin features from erosion and/or attenuation (e.g., not subject the thin features to erosion and/or attenuation).
  • FIG. 10G shows an exemplary image with 50% attenuation at a depth of 6 pixels (e.g., the 6 pixels at the boundary are attenuated by 50%). The slice does not have thin features. Therefore, no attenuation limit is needed.
  • FIG. 10H shows an exemplary image with 70% attenuation at a depth of 6 pixels (e.g., the 6 pixels at the boundary are attenuated by 70%).
  • the attenuation may result in improper curing. Therefore, attenuation limit needs to be applied at the thin areas.
  • FIG. 101 shows an exemplary image with no limit applied in global erosion. Thin walls are eroded.
  • FIG. 10J shows an exemplary image with thin areas protected from global erosion. The thin areas are identified, and no erosion is applied to these areas.
  • FIG. 10K shows an exemplary image with thin areas protected from erosion. The thin areas are identified and a minimum width is defined during erosion.
  • a 3D printing method and system can comprise an array of light sources or projectors.
  • FIG. 11A shows a digital model comprising two areas. Area 1101 can be printed by light from one projector and area 1102 can be printed by light from another projector. The interface where area 1101 and area 1102 connect is called a seam. Maximum packing density of parts can be achieved if parts can be printed across the seam.
  • the projector or projection lens can have distortion (see FIG. 11B), wherein the projected light is distorted. The distortion is more severe at the edges or comers of the projected light. Referring to FIG.
  • the center of the seam 1113 can have a gap that can be a dimension of a few pixels, e.g., one pixel, two pixels, three pixels, or more.
  • Methods and systems are needed to correct the projected lights such that the gap at the seam is eliminated and the parts printed at the seam area do not lose resolution (e.g., maintaining the resolution at the seam area).
  • the method disclosed herein can comprise (a) directing a plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, wherein the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern; (b) modifying a light intensity profile of an overlapped region of the pattern with the additional light; and (c) generating a modified pattern for the printing.
  • the method can further comprise identifying a center of the overlapped region and an edge of the overlapped region.
  • the edge of the overlapped region can be a boundary of the overlapped region.
  • the center of the overlapped region can be an interior region.
  • the light can overlap with the additional light by at least 4 pixels, at least 5 pixels, at least 6 pixels, at least 7 pixels, at least 8 pixels, at least 9 pixels, at least 10 pixels or more. In some embodiments, wherein in (b), the light can overlap with the additional light by at most 10 pixels, at most 9 pixels, at most 8 pixels, at most 7 pixels, at most 6 pixels, at most 5 pixels, at most 4 pixels, or less. In some embodiments, the overlap can be a non-integer of pixels, e.g., 4.1 pixels. The required overlap can be determined by determining the extent of the distortion of the projector or projection lens.
  • the determination can comprise projecting the lights to a grid of pixels, aligning the corners of the projected lights, and determining the dimension of the gap at the seam.
  • the required overlap may generally be larger than the gap at the seam, e.g., by at least one pixel, at least two pixels, at least three pixels, at least four pixels, or more.
  • the modifying can comprise reducing the light intensity level for the overlapped region.
  • the light intensity level for the overlapped region can be reduced by at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, or more.
  • the light intensity level for the overlapped region can be reduced by at most about 60%, at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, or less.
  • the modifying can comprise applying a light intensity scaling factor at the overlapped region.
  • the modifying can comprise applying a lower light intensity scaling factor at the edge of the overlapped region than at the center of the overlapped region.
  • the scaling factor at the center can be substantially 1 or 100%.
  • the scaling factor at the edge can be from 0.1 to 0.99.
  • the scaling factor at the edge can be any number lower than 100%, for example, the scaling factor at the edge can be from 1% to 99%, from 1% to 90%, from 1% to 80%, from 1% to 70%, from 1% to 60%, from 1% to 50%, from 1% to 40%, or from 1% to 30%.
  • the light is directed through the surface and towards the resin.
  • the resin can be any suitable resin disclosed in the present disclosure.
  • the resin can comprise a plurality of particles.
  • the plurality of particles can comprise a plurality of metal particles or a plurality of ceramic particles.
  • the system disclosed herein can comprise a plurality of optical sources configured to provide a plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern; and a computer processor in digital communication with computer memory, configured to modify a light intensity profile of an overlapped region of the pattern with the additional light and generate a modified pattern for the printing.
  • the computer processor can be further configured to identifying a center of the overlapped region and an edge of the overlapped region.
  • a pixel or voxel of the grid is a pixel.
  • a pixel or voxel of the grid is a voxel.
  • the computer processor can be further configured to generate printing instructions corresponding to a plurality of slices of the digital model.
  • the system can comprise the 3D printer configured to print the 3D object according to the printing instructions.
  • a 3D printing method can comprise printing multiple objects at once. If there is a printing failure at one layer of an object or at one step of the printing, it may affect subsequent layers of the object.
  • the present disclosure provides methods and systems that can identify printing failure for at least one of the multiple objects during printing and black out (e.g., not to print) the at least one object in the subsequent layers such that failure propagation can be eliminated.
  • the present disclosure provides a method for printing a plurality of 3D objects, comprising: (a) directing a light to a resin disposed adjacent to a surface, wherein the light (i) comprises a pattern corresponding to a cross-section of the plurality of 3D objects and (ii) is sufficient to cause a domain of the resin to solidify based on the pattern; (b) removing at least a portion of the solidified domain from the surface; (c) subsequent to (b), detecting (i) a remaining portion of the solidified domain on the surface, (ii) at least the portion of the solidified domain that is removed from the surface, or (iii) an excess of the resin remaining on the surface; and (d) based on the detecting in (c), modifying an additional pattern of an additional light, wherein the additional light is usable to print an additional cross-section of the plurality of 3D objects.
  • (c) can comprise detecting (i) a remaining portion of the solidified domain on the surface. In some embodiments, (c) can comprise detecting (ii) the at least the portion of the solidified domain that is removed from the surface. In some embodiments, (c) can comprise detecting (iii) an excess of the resin remaining on the surface. In some embodiments, (c) can comprise detecting (i) a remaining portion of the solidified domain on the surface and (ii) at least the portion of the solidified domain that is removed from the surface. In some embodiments, (c) can comprise detecting (i) a remaining portion of the solidified domain on the surface and (iii) an excess of the resin remaining on the surface.
  • (c) can comprise detecting (ii) at least the portion of the solidified domain that is removed from the surface and (iii) an excess of the resin remaining on the surface. In some embodiments, (c) can comprise detecting (i) a remaining portion of the solidified domain on the surface, (ii) at least the portion of the solidified domain that is removed from the surface, and (iii) an excess of the resin remaining on the surface.
  • FIG. 12A illustrates a failure of a portion of a printed slice.
  • a digital image 1200 of a slice of a plurality of 3D objects comprises a 4 x 7 array of 3D objects to be printed.
  • a sub-object 1202 is detected to be remaining on the print surface 1201.
  • the sub-object 1202 corresponds to a part of the object 1203.
  • FIG. 12B shows that the object 1203 has two parts, i.e., part 1 and part 2.
  • the sub-object 1202 corresponds to part 1 of the object 1203.
  • the modifying can comprise removing at least a portion of the additional pattern of the additional light.
  • a portion of the additional pattern corresponding to an entire 3D object of the plurality of 3D objects can be removed.
  • a 3D object of the plurality of 3D objects can comprise a plurality of parts.
  • the failure can have occurred only at a part of the plurality of parts of the 3D objects.
  • the entire 3D object of the plurality of 3D objects that has failed in printing can be completely blacked-out in subsequent printing steps.
  • a heatmap can be used to define the dimension of the black out region.
  • a heatmap is generally generated by stacking all layers or slices of the digital model of the 3D object together, thereby enclosing all pixels from all layers or slices of the 3D object.
  • FIG. 12C shows an exemplary heatmap of a 3D object of the plurality of 3D objects that has failed in printing. By removing pixels corresponding to the heatmap in the modified pattern, the entire 3D object of the plurality of 3D objects that has failed in printing is completely blacked out.
  • FIG. 12D shows a modified patern for the subsequent slice or layer with the object 1203 completely blacked out.
  • the at least the portion of the additional pattern can comprise a substantially continuous boundary, i.e., is defined by a common boundary. In some embodiments, the at least the portion of the additional pattern can comprise a few parts or section that are not inter-connected.
  • the pattern of the light corresponds to a plurality of crosssections of the plurality of 3D objects from a common plane.
  • the additional pattern of the additional light corresponds to an additional plurality of cross-sections of the plurality of 3D objects from an additional common plane.
  • the modifying comprises removing at least a portion of the additional pattern that corresponds to a cross-section of the additional plurality of crosssections.
  • the method can further comprise identifying the cross-section of the additional plurality of cross-sections by analyzing the detected member in (c).
  • the identifying can be based on using a 2D projection of a 3D object of the plurality of 3D objects.
  • the 2D projection can comprise a substantially continuous boundary.
  • the 2D projection can comprise a plurality of parts that are not connected.
  • the common plane and the additional common plane can be substantially parallel to each other.
  • the method can further comprise, subsequent to (d), directing the additional light to an additional resin for printing the additional cross-sectional layer of the plurality of 3D object.
  • the removing can comprise directing a relative movement between (1) a build head configured to hold the at least the portion of the solidified domain and (2) the print surface.
  • the present disclosure provides a system for printing a plurality of 3D object, comprising: an optical source configured to provide a light to a resin disposed adjacent to a surface, wherein the light (i) comprises a pattern corresponding to a cross-section of the at least one 3D object and (ii) is sufficient to cause a domain of the resin to solidify based on the patern; a sensor configured to detect, subsequent to removal of at least a portion of a solidified domain from the surface, (i) a remaining portion of the solidified domain on the surface, (ii) the at least the portion of the solidified domain that is removed from the surface, or (iii) an excess of the resin remaining on the surface; and a computer processor in digital communication with computer memory and configured to modify an additional pattern of an additional light from the optical source, wherein the additional light is usable to print an additional cross-section of the at least one 3D object.
  • the optical source can be further configured to direct the additional light to an additional resin for printing the additional cross-sectional layer of the at least one 3D object.
  • the system can further comprise an actuator to direct a relative movement between (1) a build head configured to hold the at least the portion of the solidified domain and (2) the print surface for the removal of the at least a portion of a solidified domain from the print surface.
  • the light is directed through the surface and towards the resin.
  • the resin can be any suitable resin disclosed in the present disclosure.
  • the resin can comprise a plurality of particles.
  • the plurality of particles can comprise a plurality of metal particles or a plurality of ceramic particles.
  • Scaling Factor (or Scale Factor)
  • a green body of the printed 3D object can be subject to a treatment, e.g., debinding and/or sintering, to form a brown body.
  • the green body may shrink during the treatment.
  • the green body of the 3D object can be printed larger than the desired final dimensions.
  • a plurality of scaling factor (or scale factors, used interchangeably herein) can be applied when printing the green body.
  • a scale factor of the plurality of scale factors can be different from an additional scale factor of the plurality of scale factors.
  • the plurality of scale factors may depend on feedstock property (e.g., dispense quantity, thermal expansion coefficient, materials, polymer precursor loading, particle loading, etc.), systematic or repeatable variations in particle (e.g., metallic particle) loading, and layer thickness.
  • independent scale factor for X, Y, and Z axis dimensions can be used.
  • a scale factor can be used for X and Y dimensions and an additional scale factor can be used for Z dimension.
  • a scale factor can be from 1 to 2. In some embodiments, a scale factor can be from 0.6 to 1.
  • a scale factor for X axis can be from 1 to 2, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.
  • a scale factor for Y axis can be from 1 to 2, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.
  • a scale factor for Z axis can be from 1 to 2, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.
  • the X-scale factor and Y-scale factor can be 1.4.
  • the X-scale factor can be 1.56.
  • a portion of the digital model can refer to a section of the digital model obtained or identified prior to slicing the digital model into a plurality of digital slices usable for 3D printing. In some embodiments, a portion of the digital model can refer to at least a portion of a digital slice of a plurality of digital slices associated with (or derived from) the digital model.
  • a X-Y-Z axis system can be applied to the digital model.
  • a direction can refer to an X, a Y, or a Z axis.
  • a constant X-scale factor e.g., a scale factor or scaling factor in the X axis direction
  • Y-scale factor e.g., a scale factor or scaling factor in the X axis direction
  • Z-scale factor e.g., a constant X-scale factor (e.g., a scale factor or scaling factor in the X axis direction), Y-scale factor, and/or Z-scale factor can be used during the printing.
  • a variable (or dynamic) X-scale factor, Y-scale factor, and/or Z-scale factor can be used during the printing.
  • the scale factor can vary over the course of printing, e.g., due to systematic and repeatable variations in particle loading and layer thickness.
  • the variation can be more notable at the early stage of printing.
  • variation in particle loading can be stabilized over long printing, e.g., at a later stage of printing.
  • the present disclosure provides a method for processing a 3D object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion; and (b) rescaling, by the computer processor, the portion along at least two directions and the additional portion along the at least two directions, such that: (i) the portion and the additional portion are rescaled along a first direction of the at least two directions in accordance with a first set of different scaling factors; and (ii) the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • the portion is usable by the 3D printer to be printed prior to the additional portion.
  • the portion can be rescaled along the first direction via a scaling factor that is greater than that for rescaling the additional portion along the first direction.
  • the digital model can comprise a plurality of slices.
  • the digital model can comprise at least 10, at least 20, at least 30, at least 40, at least 50, at least 100, at least 200, at least 300, at least 400, at least 500, at least 600, at least 700, at least 800, at least 900, at least 1000, or more slices.
  • a layer/slice number n means the nth layer/slice.
  • Alice n means the n th slice to be printed.
  • a smaller layer number refers to a layer printed or to be printed earlier and a larger layer number refers to a layer printed or to be printed later.
  • layer 1 means the first layer to be printed
  • layer 2 means the second layer to be printed
  • layer 200 means the 200 th layer to be printed.
  • part orientation and support features can be determined and added to the 3D digital model.
  • the thickness of the slice can be determined based on the resolution of the printer and the desired thickness of the brown body of the printed 3D object.
  • the X-scale factor, Y-scale factor, and/or Z-scale factor can be larger at the early stage of printing than the late stage of printing. In some embodiments, the X-scale factor, Y-scale factor, and/or Z-scale factor can be determined by a scale factor curve as a function of layer number.
  • the scaling factor along the first direction and/or the second direction can be varied from the first slice to the last slice. In some embodiments, the scaling factor along the first direction can be varied following a scale factor curve from the first slice to the last slice. In some embodiments, the scale factor curve can be linear. In some embodiments, the scale factor curve can be nonlinear. In some embodiments, the scaling factor can be polynomial (e.g., 2 nd , 3 rd , 4 th , or 5 th order polynomial). In some embodiments, the scale factor curve can be higher order polynomial (e.g., 3 rd , 4 th , or 5 th order polynomial).
  • the scaling factor along the first direction can be varied following a scale factor curve from the first slice to m th slice wherein m is greater than 1 but less than n (the total number of slices) and following an additional scale factor curve from the m th slice to the n th slice.
  • the n slices can be divided to a plurality of group of slices wherein the plurality of group of slices can have a plurality of scale factors following a plurality of scale factor curves, wherein the plurality of scale factor curves can be different or same.
  • one scale factor curve of the plurality of scale factor curves can have a constant value.
  • the variation of the scaling factor along the first direction and/or the second direction can be at least about 0.01, at least about 0.05, at least about 0.1, at least about 0.2, at least about 0.3, at least about 0.4, at least about 0.5, or more. In some embodiments, the variation of the scaling factor along the first direction and/or the second direction can be at most about 0.5, at most about 0.4, at most about 0.3, at most about 0.2, at most about 0.1, or less.
  • a scaling factor for a slice in the first direction and a scaling factor for the slice in the second direction can be same. In some embodiments, a scaling factor for a slice in the first direction and a scaling factor for the slice in the second direction can be different.
  • the portion can be rescaled along the second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction.
  • the portion can be adjacent to the additional portion. In some embodiments, the portion may not be adjacent to the additional portion. In some embodiments, the portion is usable by the 3D printer to be printed subsequent to the additional portion.
  • one of the first direction and the second direction can be a printing direction of the 3D printer.
  • the first direction can be the printing direction of the 3D printer.
  • the second direction can be the printing direction of the 3D printer.
  • the first direction and the second direction can be substantially orthogonal to one another.
  • the rescaling can be performed on the digital model and the rescaled digital model can be subsequently sliced to a plurality of slices for printing. In some embodiments, the rescaling can be performed on the plurality of slices after the generation of the plurality of slices from the digital model.
  • the method can further comprise generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) is performed to the plurality of digital slices.
  • the method can further comprise generating, subsequent to (b) and by the computer processor, a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion.
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid of pixels.
  • the method can further comprise rescaling by the computer processor, the portion along a third direction and the additional portion along the third direction, such that: the portion and the additional portion are rescaled along the third direction in accordance with a third set of different scaling factors.
  • the third direction can be orthogonal to the first direction and/or the second direction.
  • the first, the second, and the third direction can be one of the X, Y, and Z axes.
  • the first set and the second set of different scaling factors can be determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • the third set of different scaling factors can be determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • the resin composition can vary during the printing. In some embodiments, the resin composition can be substantially constant during the printing. In some embodiments, a variation in the scaling factor for printing with a resin with a more uniform distribution of particles can be smaller than that for printing with a resin with a less uniform distribution of particles.
  • a variation in printing with a thicker film can be higher than in printing with a thinner film.
  • a printed green body can be subjected to sintering after printing.
  • a setter or a plate can be used to hold the green body at sintering.
  • the setter may have a drag force at the contact point with the green body.
  • the drag force may resist the movement (or shrinkage) of the side of the 3D object that is in contact with the setter.
  • the setter may not have symmetric drag force at different directions on the same plane.
  • the setter may have a higher drag force in a first direction than in a second direction, therefore a scaling factor in the first direction can be lower than in the second direction.
  • the method can further comprise generating a light intensity profile for a digital slice of the plurality of digital slice by any of the methods provided herein. In some embodiments, the method can further comprise modifying a light intensity level of a portion of the digital slice by any of the methods provided herein.
  • the present disclosure provides a method for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising at least three portions; and (b) rescaling, by the computer processor, the at least three portions along a direction in accordance with at least three different scaling factors comprising a first scaling factor, a second scaling factor, and a third scaling factor, such that: (i) a first portion of the at least three portions is rescaled along the direction in accordance with the first scaling factor; (ii) a second portion of the at least three portions is rescaled along the direction in accordance with the second scaling factor that is different from the first scaling factor; and (iii) a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling
  • the at least three scaling factors can be determined based on a linear function with respect to positioning (e.g., the layer number) of the at least three portions along the direction.
  • the at least three scaling factors can be determined based on a non-linear function with respect to positioning (e.g., the layer number) of the at least three portions along the direction.
  • the nonlinear function can be polynomial (e.g., 2 nd , 3 rd , 4 th , or 5 th order polynomial).
  • the nonlinear function can be higher order polynomial (e.g., 3 rd , 4 th , or 5 th order polynomial).
  • the scaling factor along the first direction can be varied following a scale factor curve from the first slice to m th slice wherein m is greater than 1 but less than n (the total number of slices) and following an additional scale factor curve from the m th slice to the n th slice.
  • the n slices can be divided to a plurality of group of slices wherein the plurality of group of slices can have a plurality of scale factors following a plurality of scale factor curves, wherein the plurality of scale factor curves can be different or same.
  • one scale factor curve of the plurality of scale factor curves can have a constant value.
  • the first portion can be usable by the 3D printer to be printed prior to the second portion, and wherein the first scaling factor can be greater than the second scaling factor.
  • the second portion can be usable by the 3D printer to be printed prior to the third portion, and wherein the second scaling factor can be greater than the third scaling factor.
  • the first portion, the second portion, and the third portion can be adjacent. In some embodiments, the first portion, the second portion, and the third portion may not be adjacent.
  • the direction can be a printing direction of the 3D printer. In some embodiments, the direction may not be a printing direction of the 3D printer. In some embodiments, the direction may be substantially orthogonal to the printing direction. In some embodiments, the direction may be any one of X, Y, or Z axes.
  • the rescaling can be performed on the digital model and the rescaled digital model can be subsequently sliced to a plurality of slices for printing. In some embodiments, the rescaling can be performed on the plurality of slices after the generation of the plurality of slices from the digital model.
  • the method can further comprise generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a first digital slice corresponding to the first portion, a second digital slice corresponding to the second portion, and a third digital slice corresponding to the third portion, and wherein the rescaling in (b) is performed to the plurality of digital slices.
  • the method can further comprise generating, subsequent to (b) and by the computer processor, a first digital slice corresponding to the rescaled portion, a second digital slice corresponding to the second rescaled portion, and a third digital slice corresponding to the third rescaled additional portion.
  • a digital slice of the plurality of digital slices can correspond to a grid of voxels or a grid or pixels.
  • the method can further comprise rescaling by the computer processor, the first portion, the second portion, and the third portion along an additional direction in accordance with three additional different scaling factors.
  • the additional direction can be the printing direction. In some embodiments, the additional direction may not be the printing direction. In some embodiments, the additional direction can be substantially orthogonal to the direction. In some embodiments, the direction and the additional direction can be any two of the X, Y, and Z axes.
  • the at least three different scaling factors can be determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • the present disclosure provides a method for processing a 3D object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured to be printed by the 3D printer using a same source of resin; (b) rescaling, by the computer processor, the portion along a direction in accordance with a first scaling factor; and (c) rescaling, by the computer processor, the additional portion along the direction in accordance with a second scaling factor that is different from the first scaling factor, wherein, subsequent to the rescaling in (b) and (c), the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • the portion can be configured to be printed using a first resin from the same source.
  • the additional portion can be configured to be printed using a second resin from the same source.
  • a material composition of the first resin can be different from that of the second resin by at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • a material composition of the first resin can be substantially same to the second resin.
  • the first resin can have a different particle loading in comparison to the second resin.
  • the first resin can have a particle loading different from the second resin by at most about 30%, at most about 20%, at most about 10%, at most about 5%, at most about 1%, or less. In some embodiments, the first resin can have a particle loading different from the second resin by at least about 1%, at least about 2%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, or more.
  • the portion is usable by the 3D printer to be printed prior to the additional portion, and wherein the portion is rescaled along the direction via a scaling factor that is greater than that for rescaling the additional portion along the direction.
  • the portion is further rescaled along a second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction.
  • the direction can be a printing direction of the 3D printer. In some embodiments, the direction may not be a printing direction of the 3D printer. In some embodiments, the direction may be substantially orthogonal to a printing direction of the 3D printer. In some embodiments, the direction can be any one or X, Y, or Z axes.
  • the scaling factor along the first direction and/or the second direction can be varied from the first slice to the last slice. In some embodiments, the scaling factor along the first direction can be varied following a scale factor curve from the first slice to the last slice. In some embodiments, the scale factor curve can be linear. In some embodiments, the scale factor curve can be nonlinear. In some embodiments, the scaling factor can be polynomial (e.g., 2 nd , 3 rd , 4 th , or 5 th order polynomial). In some embodiments, the scale factor curve can be higher order polynomial (e.g., 3 rd , 4 th , or 5 th order polynomial).
  • the scaling factor along the first direction can be varied following a scale factor curve from the first slice to m th slice wherein m is greater than 1 but less than n (the total number of slices) and following an additional scale factor curve from the m th slice to the n th slice.
  • the n slices can be divided to a plurality of group of slices wherein the plurality of group of slices can have a plurality of scale factors following a plurality of scale factor curves, wherein the plurality of scale factor curves can be different or same.
  • one scale factor curve of the plurality of scale factor curves can have a constant value.
  • the rescaling can be performed on the digital model and the rescaled digital model can be subsequently sliced to a plurality of slices for printing. In some embodiments, the rescaling can be performed on the plurality of slices after the generation of the plurality of slices from the digital model.
  • the method can further comprise generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) and (c) is performed to the plurality of digital slices.
  • the method can further comprise generating, subsequent to (b) and by the computer processor, a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion.
  • a digital slice of the plurality of digital slices can correspond to a grid of voxels or a grid of pixels.
  • the first and the second scaling factors can be determined based on one or more of resin composition of the source of resin, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • the present disclosure provides a system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion; and (b) rescale the portion along at least two directions and the additional portion along the at least two directions, such that: (i) the portion and the additional portion are rescaled along a first direction of the at least two directions in accordance with a first set of different scaling factors; and (ii) the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding
  • the computer processor can be further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) is performed to the plurality of digital slices.
  • the computer processor can be further configured to generate, subsequent to (b), a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion.
  • the computer processor can be further configured to rescale the portion along a third direction and the additional portion along the third direction, such that: the portion and the additional portion are rescaled along the third direction in accordance with a third set of different scaling factors.
  • the present disclosure provides a system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising at least three portions; and (b) rescale the at least three portions along a direction in accordance with at least three different scaling factors comprising a first scaling factor, a second scaling factor, and a third scaling factor, such that: (i) a first portion of the at least three portions is rescaled along the direction in accordance with the first scaling factor; (ii) a second portion of the at least three portions is rescaled along the direction in accordance with the second scaling factor that is different from the first scaling factor; and (iii) a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling factor,
  • the computer processor can be further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a first digital slice corresponding to the first portion, a second digital slice corresponding to the second portion, and a third digital slice corresponding to the third portion, and wherein the rescaling in (b) is performed to the plurality of digital slices.
  • the computer processor can be further configured to generate, subsequent to (b), a first digital slice corresponding to the rescaled portion, a second digital slice corresponding to the second rescaled portion, and a third digital slice corresponding to the third rescaled additional portion.
  • the computer processor can be further configured to rescale by the computer processor, the first portion, the second portion, and the third portion along an additional direction in accordance with three additional different scaling factors.
  • the present disclosure provides a system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured to be printed by the 3D printer using a same source of resin; (b) rescale the portion along a direction in accordance with a first scaling factor; and (c) rescale the additional portion along the direction in accordance with a second scaling factor that is different from the first scaling factor, wherein, subsequent to the rescaling in (b) and (c), the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object.
  • a computer processor in digital communication with computer memory, configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object, the digital model comprising a portion and an additional portion that are configured to
  • the computer processor can be further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) and (c) is performed to the plurality of digital slices.
  • the computer processor can be further configured to generate, subsequent to (b), a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion.
  • the thickness of the slices can be consistent. In some embodiments, the thickness of the slices can be varied. In some embodiments, the variation in thickness is less than a specified z layer height tolerance. In some embodiments, the variation in thickness is less than 1 particle diameter. In some embodiments, the variation in thickness is at least about 1%, at least about 2%, at least about 3%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, or more of the thickness of a slice.
  • the variation in thickness is at most about 20%, at most about 15%, at most about 10%, at most about 5%, at most about 4%, at most about 3%, at most about 2%, at most about %, or less of the thickness of a slice.
  • slices can be scaled from the global slice center and then cropped back to standard printer resolution.
  • layer heights can be adjusted in the print settings file.
  • dynamic scale factor can work in conjunction with any method disclosed in the present disclosure.
  • the present disclosure provides a method for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital model corresponding to at least a portion of the 3D object; (b) generating, by the computer processor, a scaled digital model by scaling the digital model based on a plurality of scaling factors, wherein the plurality of scale factors comprises a first scale factor for a first axis and a second scale factor for a second axis, wherein the first scale factor and the second scale factor are varied along the first axis or second axis; and (c) slicing, by the computer processor, the scaled digital model to generate a plurality of digital slices corresponding to the scaled digital model, wherein the plurality of digital slices are usable to produce a computer instruction for printing by the 3D printer.
  • the plurality of scale factors comprises a third scale factor for a third axis.
  • the third scale factor can be varied in the first or second axis.
  • each of the plurality of scale factors can be different.
  • the first axis is the X axis
  • the second axis is the Z axis
  • the third axis is the Y axis.
  • the plurality of scale factors can be varied along the Z axis.
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or pixels.
  • a voxel/pixel of the grid of voxels/pixels can have a first size along the first axis and a second size along the second axis, wherein the first size and second size are different.
  • a size of the voxel along a z- axis is different than that along a x-axis or a y-axis.
  • the method can further comprise assigning a light intensity level for a voxel/pixel of the grid of voxels/pixels based on a portion of the voxel/pixel that is contained within the scaled digital model.
  • the light intensity level can be modified by at least 1%, at least 2%, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, or more.
  • the light intensity level can be modified by at most about 50%, at most about 40%, at most about 30%, at most about 20%, at most about 10%, at most about 5%, or less.
  • the method can further comprise selectively modifying a subpopulation of the plurality of digital slices.
  • the computer instruction is usable by the 3D printer to print at least a portion of the 3D object from a photoactive resin at sub -pixel precision.
  • the method can be combined with any method provided in the present disclosure.
  • the present disclosure provides a system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with a computer memory, wherein the computer processor is configured to: (a) obtain a digital model corresponding to at least a portion of the 3D object; (b) generate a scaled digital model by scaling the digital model based on a plurality of scale factors, wherein the plurality of scale factors comprises a first scale factor for a first axis and a second scale factor for a second axis, wherein the first scale factor and second scale factor are varied along the first axis or second axis; and (c) slice the scaled digital model to generate a plurality of digital slices corresponding to the scaled digital model, wherein the plurality of digital slices are usable to produce a computer instruction for printing by the 3D printer.
  • a computer processor in digital communication with a computer memory, wherein the computer processor is configured to: (a) obtain a digital model corresponding to at least
  • printing with dynamic scaling factor can increase the accuracy of the printing (e.g., reducing difference between the dimension of the printed 3D object and the dimension of the desired 3D object).
  • printing with dynamic scaling factor can increase the accuracy of printing by at least about 1%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, in comparison to printing without rescaling and/or rescaling with constant scaling factors.
  • printing with dynamic scaling factor can reduce the error (e.g., difference between the dimension of the printed 3D object and the dimension of the desired 3D object) by at least about 1%, at least about 5%, at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more, in comparison to printing without rescaling and/or rescaling with constant scaling factors.
  • error e.g., difference between the dimension of the printed 3D object and the dimension of the desired 3D object
  • FIG. 6 shows an example of a 3D printing system 600.
  • the system 600 includes a vat 602 to hold a mixture 604, which includes a polymeric precursor.
  • the vat 602 includes a window 606 in its bottom through which illumination is transmitted to cure a 3D printed structure 608.
  • the 3D printed structure 608 is shown in FIG. 6 as a block, however, in practice a wide variety of complicated shapes can be 3D printed. In some cases, the 3D printed structure 608 includes entirely solid structures, hollow core prints, lattice core prints and generative design geometries. Additionally, a 3D printed structure 608 can be partially cured such that the 3D printed structure 608 has a gel-like or viscous mixture characteristic.
  • the 3D printed structure 608 is 3D printed on a build head 610, which is connected by a rod 612 to one or more 3D printing mechanisms 614.
  • the 3D printing mechanisms 614 can include various mechanical structures for moving the build head 610 within and above the vat 602. This movement is a relative movement, and thus moving pieces can be the build head 610, the vat 602, or both, in various cases.
  • the 3D printing mechanisms 614 include Cartesian (xyz) type 3D printer motion systems or delta type 3D printer motion systems.
  • the 3D printing mechanisms 614 include one or more controllers 616 which can be implemented using integrated circuit technology, such as an integrated circuit board with embedded processors and firmware. Such controllers 616 can be in communication with a computer or computer systems 618.
  • the 3D printing system 600 includes a computer 618 that connects to the 3D printing mechanisms 614 and operates as a controller for the 3D printing system 600.
  • a computer 618 can include one or more hardware (or computer) processors 620 and a memory 622.
  • a 3D printing program 624 can be stored in the memory 622 and run on the one or more processors 620 to implement the techniques described herein.
  • the controller 618, including the one or more hardware processors 620, may be individually or collectively programmed to implement methods of the present disclosure.
  • Multiple devices emitting various wavelengths and/or intensities of light can be positioned below the window 606 and in communication to the computer 618 (or other controller).
  • the multiple devices include the light projection device 626 and the light sources 628.
  • the light sources 628 can include greater than or equal to about 2, 3, 4, 5, 6, 7, 8, 9, 10, or more light sources.
  • the light sources 628 may include less than or equal to about 10, 9, 8 7, 6, 5, 4, 3, 2 or less light sources.
  • a single light source may be used.
  • the light projection device 626 directs a first light having a first wavelength into the mixture 604 within the vat 602 through window 606.
  • the first wavelength emitted by the light projection device 626 is selected to produce photoinitiation and is used to create the 3D printed structure 608 on the build head 610 by curing the photoactive resin in the mixture 604 within a photoinitiation layer 60630.
  • the light projection device 626 is utilized in combination with one or more projection optics 62632 (e.g., a projection lens for a digital light processing (DLP) device), such that the light output from the light projection device 626 passes through one or more projection optics 62632 prior to illuminating the mixture 604 within the vat 602.
  • DLP digital light processing
  • the light projection device 626 is a DLP device including a digital micro-mirror device (DMD) for producing patterned light that can selectively illuminate and cure 3D printed structures 608.
  • DMD digital micro-mirror device
  • the light projection device 626 in communication with the computer 618, can receive instructions from the 3D printing program 624 defining a pattern of illumination to be projected from the light projection device 626 into the photoinitiation layer 60630 to cure a layer of the photoactive resin onto the 3D printed structure 608.
  • the light projection device 626 and projection optics 632 are a laser and a scanning mirror system, respectively (e.g., stereolithography apparatus). Additionally, in some cases, the light source includes a second laser and a second scanning mirror system. Such light source may emit a beam of a second light having a second wavelength. The second wavelength may be different from the first wavelength. This may permit photoinhibition to be separately controlled from photoinitiation. Additionally, in some cases, the platform 638 is separately supported on adjustable axis rails 640 from the projection optics 632 such that the platform 638 and the projection optics 632 can be moved independently.
  • the relative position (e.g., vertical position) of the platform 638 and the vat 602 may be adjusted.
  • the platform 638 is moved and the vat 602 is kept stationary.
  • the platform 638 is kept stationary and the vat 602 is moved.
  • both the platform 638 and the vat 602 are moved.
  • the light sources 628 direct a second light having a second wavelength into the mixture 604 in the vat 602.
  • the second light may be provided as multiple beams from the light sources 628 into the build area simultaneously.
  • the second light may be generated from the light sources 628 and provided as a single beam (e.g., uniform beam) into the beam area.
  • the second wavelength emitted by the light sources 628 is selected to produce photoinhibition in the photoactive resin in the mixture 604 and is used to create a photoinhibition layer 634 within the mixture 604 directly adjacent to the window 606.
  • the light sources 628 can produce a flood light to create the photoinhibition layer 634, the flood light being a non-pattemed, high-intensity light.
  • the light sources 628 are light emitting diodes (LEDs) 336.
  • the light sources 628 can be arranged on a platform 638.
  • the platform 638 is mounted on adjustable axis rails 640.
  • the adjustable axis rails 640 allow for movement of the platform 638 along an axis.
  • the platform 638 additionally acts as a heat-sink for at least the light sources 628 arranged on the platform 638.
  • the respective thicknesses of the photoinitiation layer 630 and the photoinhibition layer 634 can be adjusted by computer 618 (or other controller). In some cases, this change in layer thickness(es) is performed for each new 3D printed layer, depending on the desired thickness of the 3D printed layer, and/or the type of 3D printing process being performed.
  • the thickness(es) of the photoinitiation layer 630 and the photoinhibition layer 634 can be changed, for example, by changing the intensity of the respective light emitting devices, exposure times for the respective light emitting devices, the photoactive species in the mixture 604, or a combination thereof.
  • the overall rate of polymerization can be controlled. This process can thus be used to prevent polymerization from occurring at the resin-window interface and control the rate at which polymerization takes place in the direction normal to the resin-window interface.
  • an intensity of the light sources 628 emitting a photoinhibiting wavelength to create a photoinhibition layer 634 is altered in order to change a thickness of the photoinhibition layer 634.
  • Altering the intensity of the light sources 628 can include increasing the intensity or decreasing the intensity of the light sources 628.
  • the intensity of the light sources 628 can be achieved by increasing a power input to the light sources 628 by controllers 616 and/or computer 618. Decreasing the intensity of the light sources 628 (e.g., LEDs) can be achieved by decreasing a power input to the light sources 628 by controllers 616 and/or computer 618. In some cases, increasing the intensity of the light sources 628, and thereby increasing the thickness of the photoinhibition layer 634, will result in a decrease in thickness of the photoinitiation layer 630. A decreased photoinitiation layer thickness can result in a thinner 3D printed layer on the 3D printed structure 608.
  • the intensities of all of the light sources 628 are altered equally (e.g., decreased by a same level by reducing power input to all the light sources by an equal amount).
  • the intensities of the light sources 628 can also be altered where each light source of a set of light sources 628 produces a different intensity. For example, for a set of four LEDs generating a photoinhibition layer 634, two of the four LEDs can be decreased in intensity by 10% (by reducing power input to the LEDs) while the other two of the four LEDs can be increased in intensity by 10% (by increasing power input to the LEDs).
  • Setting different intensities for a set of light sources 628 can produce a gradient of thickness in a cured layer of the 3D printed structure or other desirable effects.
  • the computer 618 adjusts an amount of a photoinitiator species and/or a photoinhibitor species in the mixture 604.
  • the photoinitiator and photoinhibitor species can be delivered to the vat 602 via an inlet 646 and evacuated from the vat 602 via an outlet 648.
  • one aspect of the photoinhibitor species is to prevent curing (e.g., suppress cross-linking of the polymers) of the photoactive resin in the mixture 604.
  • one aspect of the photoinitiation species is to promote curing (e.g., enhance cross-linking of the polymers) of the photoactive resin in the mixture 604.
  • the 3D printing system 600 includes multiple containment units to hold input/output flow from the vat 602.
  • the intensities of the light sources 628 are altered based in part on an amount (e.g., volumetric or weight fraction) of the one or more photoinhibitor species in the mixture and/or an amount (e.g., volumetric or weight fraction) of the one or more photoinitiator species in the mixture. Additionally, the intensities of the light sources 628 are altered based in part on a type (e.g., a particular reactive chemistry, brand, composition) of the one or more photoinhibitor species in the mixture and/or a type (e.g., a particular reactive chemistry, brand, composition) of the one or more photoinitiator species in the mixture.
  • a type e.g., a particular reactive chemistry, brand, composition
  • an intensity of the light sources 628 for a mixture 604 including a first photoinhibitor species of a high sensitivity can be reduced when compared to the intensity of the light sources 628 for a mixture 604 including a second photoinhibitor species of a low sensitivity (e.g., a low reactivity or conversion ratio to a wavelength of the light sources 628).
  • the changes to layer thickness(es) is performed during the creation of the 3D printed structure 608 based on one or more details of the 3D printed structure 608 at one or more points in the 3D printing process.
  • the respective layer thickness(es) can be adjusted to improve resolution of the 3D printed structure 608 in the dimension that is the direction of the movement of the build head 610 relative to the vat 602 (e.g., z-axis) in the layers that require it.
  • the 3D printing system 600 is described in FIG. 6 as a bottom-up system where the light projection device 626 and the light sources 628 are located below the vat 602 and build head 610, other configurations can be utilized.
  • a top-down system where the light projection device 626 and the light sources 628 are located above the vat 602 and build head 610, can also be employed.
  • FIGS. 7 and 8 show additional examples of a 3D printing system.
  • the system 700 includes a platform 701 comprising an area (i.e., a print surface, such as a film 770) configured to hold the mixture 704 or a film of the mixture 704, which includes a photoactive resin.
  • the mixture 704 may include a plurality of particles (e.g., metal, intermetallic, and/or ceramic particles).
  • the platform 701 comprises a print window 703.
  • the system 700 further comprises a film transfer unit 772 that is configured to hold the film 770.
  • the film transfer unit is operatively coupled to one or more actuators to dispose the film 770 onto the print window 703.
  • the platform 701 comprises a plurality of first coupling units 750.
  • the platform 701 is an open platform, wherein the mixture 704 is self-supporting on or adjacent to the film 770 without requiring support or being supported by any wall.
  • the plurality of first coupling units 750 are not in contact with the mixture 704 during 3D printing.
  • the system 700 includes a build head 710 configured to move relative to the platform 701.
  • the build head 710 is movable by an actuator 712 (e.g., a linear actuator) operatively coupled to the build head 710.
  • the platform 701 may comprise one or more actuators to move the platform 701 relative to the build head 710.
  • the build head 710 comprises a surface 711 configured to hold at least a portion of a 3D object 708a (e.g., a previously printed portion of the 3D object) or a different object onto which the at least the portion of the 3D object is to be printed.
  • the surface 711 of the build head 710 may be a portion of a surface of the build head 710.
  • the surface 711 may be a surface of an object (e.g., a film or a slab) that is disposed on or adjacent to a surface of the build head 710.
  • the build head 710 comprises a plurality of second coupling units 760.
  • One of the plurality of second coupling units 760 of the build head 710 is configured to couple to one of the plurality of the first coupling units 750 of the platform 701 to provide an alignment of film 770 relative to the surface 711 of the build head 710 during 3D printing.
  • the plurality of first coupling units 750 e.g., three first coupling units
  • the plurality of second coupling units 760 may couple to generate a kinematic coupling between the build head 710 and the film 770, to provide an alignment between the build head 710 and the film 770.
  • the relative movement between the build head and the platform may continue until each of the plurality of first coupling units 750 is coupled to its respective second coupling unit from the plurality of second coupling units 760 (or vice versa).
  • One or more of the plurality of first coupling units 750 of the platform 701 may comprise one or more sensors 752.
  • one or more of the plurality of second coupling units 760 of the build head 710 may comprise one or more sensors 762.
  • the one or more sensors 752 and/or the one or more sensors 762 may be configured to at least detect coupling of the first coupling unit(s) 750 and the second coupling unit(s) 760.
  • the plurality of first coupling units 750 of the platform 701 may be operatively coupled to one or more actuators 754 (e.g., one or more z-axis telescopic actuators) configured to adjust a height (or protrusion) of the plurality of first coupling units 750 relative to the platform 701 (or relative to a surface of the film 770 disposed adjacent to the platform 701).
  • actuators 754 e.g., one or more z-axis telescopic actuators
  • the one or more actuators 754 may comprise one or more fasteners 756 (e.g., one or more shaft clamps) configured to fasten, hold on to, or stabilize a movement of the plurality of first coupling units 750 relative to the actuators 754.
  • fasteners 756 e.g., one or more shaft clamps
  • the plurality of second coupling units 760 of the build head 710 may be operatively coupled to one or more actuators (e.g., one or more z-axis telescopic actuators) configured to adjust a height (or protrusion) of the plurality of second coupling units 760 relative to a surface 711 of the build head 710 (or relative to a surface of the object 708a disposed on the build head 710).
  • the one or more actuators may comprise one or more fasteners (e.g., one or more shaft clamps) configured to fasten, hold on to, or stabilize a movement of the plurality of second coupling units 760 relative to the actuators.
  • One or more optical sources 726 directs one or more lights to the mixture 704 to cure the photoactive resin in the at least the portion of the mixture 704, thereby to print at least a portion of the 3D object on the surface of the build head 710 or a surface of the object 708a disposed on the surface of the build head 710.
  • the optical source(s) 726 may direct the light(s) through the print surface 702 of the platform 701 and to the at least the portion of the mixture for 3D printing.
  • the 3D printing system 800 comprises a mixture deposition zone 810 and a printing zone 820 that are (i) connected to a same platform 701 or (ii) coupled to the same platform 701.
  • the system 800 further comprises a deposition head 705 configured to deposit a mixture 704 to the platform 701, print window 703, and/or film 770 configured to hold a mixture.
  • the deposition head is configured to deposit the mixture 704 onto the film 770.
  • the deposition head 705 comprises a nozzle 707 that is in fluid communication with a source of the mixture 704 and at least one wiper 706 configured to (i) reduce or inhibit flow the mixture 704 out of the deposition head 705, (ii) flatten the mixture 704 into a film or layer of the mixture 704, and/or (iii) remove any excess of the 704 from the film 770.
  • the system 800 further comprises a mixture sensor 830 (e.g., a camera, a densitometer, etc.) configured to detect one or more qualities of the mixture 704 that is deposited onto the film 770.
  • the mixture sensor comprises a mixture sensor light source 832 and a mixture sensor detector 834.
  • the mixture sensor light source 832 is disposed beneath the film 770, and the mixture sensor detector 834 is disposed above the film 770. Alternatively or in addition to, the mixture sensor light source 832 and the mixture sensor detector 834 may be disposed inversely or on the same side of the film 770. Subsequent to depositing a layer of the mixture 704 on the film 770, the mixture sensor light source 832 may emit a sensor light (e.g., infrared light) through at least the film 770 and towards the layer of mixture 704 on or adjacent to the film 770, and the mixture sensor detector 834 may capture or detect any of the infrared light that is transmitted through the layer of the mixture 704. Measurements by the mixture sensor 830 can help determine whether a quality of the layer of the mixture 704 is sufficient to proceed with printing at least a portion of the 3D object.
  • the printing zone 820 can comprise one or more components of the 3D printing system 700 provided in FIG. 7.
  • the film 770 is coupled to a film transfer unit 772.
  • the film transfer unit 772 is configured to move 860 at least between and/or over the mixture deposition zone 810 and the printing zone 820.
  • the system may comprise one or more sensor stations comprising (i) a pre-print inspection station configured to receive a feedstock film on the transparent substrate from the recoating station and to inspect the feedstock film before sending the feedstock film on the transparent substrate onto the printing station, and (ii) a post-print inspection station configured to receive a waste film on the transparent substrate from the printing station and to inspect the waste film before sending the waste film on the transparent substrate onto the recoating station.
  • a pre-print inspection station configured to receive a feedstock film on the transparent substrate from the recoating station and to inspect the feedstock film before sending the feedstock film on the transparent substrate onto the printing station
  • a post-print inspection station configured to receive a waste film on the transparent substrate from the printing station and to inspect the waste film before sending the waste film on the transparent substrate onto the recoating station.
  • a sensor as disclosed herein may be configured to provide a feedback (e.g., light absorption spectroscopy, image, video, etc.) indicative of the film of the mixture disposed on or adjacent to at least a portion of the platform (e.g., a print window of the platform, a film disposed on or adjacent to the at least the portion of the platform, etc.).
  • the sensor may be operatively coupled to a controller (e.g., a computer) that controls one or more operations (e.g., depositing the film of the mixture onto the at least the portion of the platform) of the 3D printing.
  • the controller may adjust the one or more operations of the 3D printing, based on the feedback provided by the sensor.
  • the controller may adjust the operation(s) during the 3D printing, and thus such feedback may be a closed loop feedback.
  • the sensor may provide the feedback (i) during calibration of the 3D printing system, (ii) prior to, during, and/or subsequent to depositing the film of the mixture to be used for 3D printing, and/or (iii) prior to, during, or subsequent to solidifying (curing) at least a portion of the film of the mixture to print at least a portion of the 3D object.
  • the sensor may provide the feedback pre-fabrication or postfabrication of the 3D object.
  • the 3D printing may use at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sensors.
  • the 3D printing may use at most about 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 sensor(s).
  • Examples of the sensor configured to provide such feedback indicative of the film of the mixture may comprise a detector, vision system, computer vision, machine vision, imager, camera, electromagnetic radiation sensor (e.g., IR sensor, color sensor, etc.), proximity sensor, densitometer (e.g., optical densitometer), profilometer, spectrometer, pyrometer, force sensor (e.g., piezo sensor for pressure, acceleration, temperature, strain, force), motion sensor, magnetic field sensor (e.g., microelectromechanical systems), electric field sensor, chemical sensor, structured-light sensor, etc.
  • electromagnetic radiation sensor e.g., IR sensor, color sensor, etc.
  • proximity sensor e.g., densitometer (e.g., optical densitometer), profilometer, spectrometer, pyrometer, force sensor (e.g., piezo sensor for pressure, acceleration, temperature, strain, force), motion sensor, magnetic field sensor (e.g., microelectromechanical systems), electric field sensor, chemical sensor, structured-light
  • the sensor may be capable of detecting and/or analyzing one or more profiles of various components of the 3D printing system.
  • the various components may be used (e.g., the print window) and/or generated (e,g., the film of mixture or mixture) during the 3D printing process.
  • the sensor may capture profiles of a print surface (e.g., a portion of the platform, i.e., a print area, the film 170), a surface of the build head that is configured to hold at least a portion of the 3D object during printing, or a surface of a previously deposited layer of the 3D object adjacent to the build head.
  • a print surface e.g., a portion of the platform, i.e., a print area, the film 170
  • a surface of the build head that is configured to hold at least a portion of the 3D object during printing, or a surface of a previously deposited layer of the 3D object adjacent to the build head.
  • the feedback from the sensor may be one or more images of the film of the mixture or any excess mixture remaining on the print surface after printing at least a portion of the 3D object.
  • the feedback from the sensor may be one or more videos (e.g., for a duration of time) of the film of the mixture or the excess mixture remaining on the print surface.
  • the feedback provided by the sensor may comprise one or more internal or external features (e.g., temperature, transparency or opacity, surface texture, thickness, shape, size, length, area, pattern, density of one or more particles embedded in the film of the mixture, defects, etc.) of the film of the mixture deposited on or adjacent to the print surface.
  • the sensor provides such feedback of the film of the mixture prior to solidifying (e.g., curing, polymerizing, cross-linking) a portion of the film of the mixture into at least a portion of the 3D object.
  • the senor provides such feedback of any excess mixture remaining on the print surface after the portion of the film of the mixture is solidified (e.g., cured, polymerized, cross-linked) into the at least a portion of the 3D object and removed from the print surface (e.g., by the build head).
  • the feedback may comprise the one or more internal or external features of at least a portion of a 3D object printed on the build head, or a portion of a non-printed 3D object on the build head onto which at least a portion of a 3D object is to be printed.
  • the sensor may be capable of measuring an energy that is emitted, reflected, or transmitted by a medium (e.g., the film of the mixture on the build surface).
  • the sensor may be capable of measuring an energy density, comprising: electromagnetic energy density, optical energy density, reflectance density, transmittance density, absorbance density, spectral density, luminescence (fluorescence, phosphorescence) density, and/or electron density.
  • energy density may be indicative of an amount, concentration, and/or density of one or more components (e.g., one or more particles) within one or more points, lines, or areas within the film of the mixture.
  • the sensor may be operatively coupled to a source of energy for sensing, wherein at least a portion of energy for sensing is measured by the sensor as a feedback indicative of the 3D printing process.
  • energy for sensing may be electromagnetic radiation (e.g., from ambient light or from an electromagnetic radiation source) and/or electrons (e.g., from an electron beam).
  • the sensor may be an IR sensor (e.g., an IR camera), and the source of energy may be an IR light source.
  • the IR sensor may detect at least a portion of the IR light from the IR optical source that is being reflected by or transmitted from (i) the film of the mixture adjacent to the print surface, or (ii) any excess mixture remaining on the print surface.
  • the IR light being reflected by or transmitted from the film of the mixture or any excess mixture may be zero-dimensional (a point), ID (a line), or 2D (a plane).
  • a single sensor may be operatively coupled to a single source of energy for sensing.
  • a single sensor may be operatively coupled to at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sources of energy for sensing that are the same or different.
  • a single sensor may be operatively coupled to at most 10, 9, 8, 7, 6, 5, 4, 3, or 2 sources of energy for sensing that are the same or different.
  • a single source of energy for sensing may be operatively coupled to at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sensors that are the same or different.
  • a single source of energy for sensing may be operatively coupled to at most 10, 9, 8, 7, 6, 5, 4, 3, or 2 sensors that are the same or different.
  • One or more sensors and one or more sources of energy for sensing may be part of a same system (e.g., a single enclosed unit) or different systems.
  • the one or more sensors may be disposed below, within, on, and/or over the build surface.
  • the one or more sensors and the one or more sources of energy for sensing may be on a same side or opposite sides of a component of the 3D printing system (e.g., the print window or film comprising the print surface, the film of the mixture adjacent to the print surface, etc.).
  • the one or more sensors and the one or more sources of energy may be in contact with the print surface, the film of the mixture adjacent to the print surface, and/or any excess mixture remaining on the print surface subsequent to printing a layer of the 3D object. In some examples, the one or more sensors and the one or more sources of energy may not be in contact with the print surface, the film of the mixture adjacent to the print surface, and/or any excess mixture remaining on the print surface subsequent to printing a layer of the 3D object.
  • the sensor may not be in contact with the film of the mixture while generating the feedback.
  • the sensor may be in contact with the film of the mixture while generating the feedback.
  • the sensor and/or the source of energy for sensing may be stationary with respect to the print surface (e.g., the print window or the film disposed on or adjacent to the platform).
  • the sensor and/or the source of energy for sensing may be movable with respect to the print surface. Such movement may be a relative movement, and thus the moving piece may be the sensor, the source of energy for sensing, and/or the print surface.
  • the one or more sensors may be operatively coupled to a controller (e.g., a computer) capable of employing artificial intelligence (e.g., one or more machine learning algorithms) to analyze a database comprising a plurality of feedbacks indicative of various components of the 3D printing system, such as the film of the mixture on the print surface or of any excess mixture remaining on the print surface after printing a portion of the 3D object.
  • a controller e.g., a computer
  • Artificial intelligence e.g., one or more machine learning algorithms
  • One or more machine learning algorithms of the artificial intelligence may be capable of distinguishing or differentiating profiles (e.g., features) of a film of the mixture on or adjacent to the print surface based on the database.
  • Such features may comprise the film quality, film thickness, density of one or more components (e.g., one or more particles, etc.) in the film of the mixture, or one or more defects (e.g., bubbles, wrinkles, pre-polymerized particulates, etc.).
  • the database may further comprise a plurality of training data sets that comprise example feedback indicative of the features of the film of the mixture.
  • the plurality of training data sets may allow the machine learning algorithm(s) to learn a plurality of parameters to generate one or more models (e.g., mathematical models, classifiers) that can be used to distinguish or differentiate the features of a new film of the mixture received from the one or more sensors during the 3D printing.
  • the feedback from a sensor may be an optical (e.g., IR) densitometry profile of the film of the mixture.
  • the trained machine learning algorithm may be used to distinguish (i) a variation in optical density due to a height defect across the film of the mixture, (ii) a variation in optical density due to voids (e.g., bubbles, streaks, etc.) in the film of the mixture, and (iii) a variation in optical density due to a difference in the density of one or more particles (e.g., metal or ceramic particles) in the film of the mixture.
  • a series of machine learning algorithms may be connected as an artificial neural network to better recognize, categorize, and/or classify each feature of the film of the mixture or each feature of any excess mixture remaining on the print surface from the feedback of the one or more sensors.
  • An artificial intelligence system capable of acquiring, processing, and analyzing image and/or video feedbacks from the one or more sensors, and such system may be referred to as computer vision.
  • the one or more machine learning algorithms may use deep learning algorithms.
  • the deep learning algorithms may be capable of generating new classifications (e.g., categories, sub-categories, etc.) of one or more features of the mixture or the film of the mixture, based on a new feedback and a database comprising a plurality of previous feedbacks and example feedbacks.
  • the deep learning algorithms may use the new classifications to distinguish or differentiate the features of the mixture or the film of the mixture.
  • the mixture may be used for printing the at least the portion of the 3D object.
  • the mixture may comprise a photoactive resin to form a polymeric material.
  • the photoactive resin may comprise a polymeric precursor of the polymeric material.
  • the photoactive resin may comprise at least one photoinitiator that is configured to initiate formation of the polymeric material from the polymeric precursor.
  • the photoactive resin may comprise at least one photoinhibitor that is configured to inhibit formation of the polymeric material from the polymeric precursor.
  • the mixture may comprise a plurality of particles for forming the at least the portion of the 3D object.
  • the mixture may be the photoactive resin.
  • the viscosity of the photoactive resin may range between about 1 cP to about 2,000,000 cP.
  • the viscosity of the photoactive resin may be at least about 1 cP, 5 cP, 10 cP, 50 cP, 100 cP, 500 cP, 1000 cP, 5,000 cP, 10,000 cP, 50,000 cP, 100,000 cP, 500,000 cP, 1,000,000 cP, 2,000,000 cP, or more.
  • the viscosity of the photoactive resin may be at most about 2,000,000 cP, 1,000,000 cP, 500,000 cP, 100,000 cP, 50,000 cP, 10,000 cP, 5,000 cP, 1,000 cP, 500 cP, 100 cP, 50 cP, 10 cP, 5 cP, 1 cP, or less.
  • the mixture may be a non-Newtonian fluid.
  • the viscosity of the mixture may vary based on a shear rate or shear history of the mixture. As an alternative, the mixture may be a Newtonian fluid.
  • the mixture may comprise the photoactive resin and the plurality of particles.
  • the viscosity of the mixture may range between about 4,000 cP to about 2,000,000 cP.
  • the viscosity of the mixture may be at least about 4,000 cP, 10,000 cP, 20,000 cP, 30,000 cP, 40,000 cP, 50,000 cP, 60,000 cP, 70,000 cP, 80,000 cP, 90,000 cP, 100,000 cP, 200,000 cP, 300,000 cP, 400,000 cP, 500,000 cP, 600,000 cP, 700,000 cP, 800,000 cP, 900,000 cP, 1,000,000 cP, 2,000,000 cP, or more.
  • the viscosity of the mixture may be at most about 2,000,000 cP, 1,000,000 cP, 900,000 cP, 800,000 cP, 700,000 cP, 600,000 cP, 500,000 cP, 400,000 cP, 300,000 cP, 200,000 cP, 100,000 cP, 90,000 cP, 80,000 cP, 70,000 cP, 60,000 cP, 50,000 cP, 40,000 cP, 30,000 cP, 20,000 cP, 10,000 cP, 4,000 cP, or less.
  • the photoactive resin may be present in an amount ranging between about 5 volume % (vol%) to about 80 vol% in the mixture.
  • the photoactive resin may be present in an amount of at least about 5 vol%, 6 vol%, 7 vol%, 8 vol%, 9 vol%, 10 vol%, 11 vol%, 12 vol%, 13 vol%, 14 vol%, 15 vol%, 16 vol%, 17 vol%, 18 vol%, 19 vol%, 20 vol%, 21 vol%, 22 vol%, 23 vol%, 24 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, or more in the mixture.
  • the photoactive resin may be present in an amount of at most about 80 vol%, 75 vol%, 70 vol%, 65 vol%, 60 ol%, 55 vol%, 50 vol%, 45 vol%, 40 vol%, 35 vol%, 30 vol%, 25 vol%, 24 vol%, 23 vol%, 22 vol%, 21 vol%, 20 vol%, 19 vol%, 18 vol%, 17 vol%, 16 vol%, 15 vol%, 14 vol%, 13 vol%, 12 vol%, 11 vol%, 10 vol%, 9 vol%, 8 vol%, 7 vol%, 6 vol%, 5 vol%, or less in the mixture.
  • the polymeric precursor in the photoactive resin may comprise monomers to be polymerized into the polymeric material, oligomers to be cross-linked into the polymeric material, or both.
  • the monomers may be of the same or different types.
  • An oligomer may comprise two or more monomers that are covalently linked to each other.
  • the oligomer may be of any length, such as at least 2 (dimer), 3 (trimer), 4 (tetramer), 5 (pentamer), 6 (hexamer), 7, 8, 9, 10, 20, 30, 40, 50, 100, 200, 300, 400, 500, or more monomers.
  • the polymeric precursor may include a dendritic precursor (monodisperse or polydisperse).
  • the dendritic precursor may be a first generation (Gl), second generation (G2), third generation (G3), fourth generation (G4), or higher with functional groups remaining on the surface of the dendritic precursor.
  • the resulting polymeric material may comprise a monopolymer and/or a copolymer.
  • the copolymer may be a linear copolymer or a branched copolymer.
  • the copolymer may be an alternating copolymer, periodic copolymer, statistical copolymer, random copolymer, and/or block copolymer.
  • Examples of monomers include one or more of hydroxy ethyl methacrylate; n-Lauryl acrylate; tetrahydrofurfuryl methacrylate; 2 , 2, 2 - trifluoroethyl methacrylate; isobomyl methacrylate; polypropylene glycol monomethacrylates, aliphatic urethane acrylate (i.e., Rahn Genomer 1122); hydroxy ethyl acrylate; n-Lauryl methacrylate; tetrahydrofurfuryl acrylate; 2 , 2, 2 - trifluoroethyl acrylate; isobornyl acrylate; polypropylene glycol monoacrylates; trimethylpropane triacrylate; trimethylpropane trimethacrylate; pentaerythritol tetraacrylate; pentaerythritol tetraacrylate; triethyleneglycol diacrylate; triethylene
  • Polymeric precursors may be present in an amount ranging between about 3 weight % (wt%) to about 90 wt% in the photoactive resin of the mixture.
  • the polymeric precursors may be present in an amount of at least about 3 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or more in the photoactive resin of the mixture.
  • the polymeric precursors may be present in an amount of at most about 90 wt%, 85 wt%, 80 wt%, 75 wt%, 70 wt%, 65 wt%, 60 wt%, 55 wt%, 50 wt%, 45 wt%, 40 wt%, 35 wt%, 30 wt%, 25 wt%, 20 wt%, 15 wt%, 10 wt%, 5 wt%, 4 wt%, 3 wt%, or less in the photoactive resin of the mixture.
  • Photopolymerization of the polymeric precursors into the polymeric material may be controlled by one or more photoactive species, such as the at least one photoinitiator and the at least one photoinhibitor.
  • the at least one photoinitiator may be a photon-absorbing compound that (i) is activated by a first light comprising a first wavelength and (ii) initiates photopolymerization of the polymeric precursors.
  • the at least one photoinhibitor may be another photon-absorbing compound that (i) is activated by a second light comprising a second wavelength and (ii) inhibits the photopolymerization of the polymeric precursors.
  • the first wavelength and the second wavelength may be different.
  • the first light and the second light may be directed by the same optical source.
  • the first light may be directed by a first optical source and the second light may be directed by a second optical source.
  • the first light may comprise wavelengths ranging between about 420 nm to about 510 nm.
  • the second light may comprise wavelengths ranging between about 350 nm to about 410 nm.
  • the first wavelength to induce photoinitiation is about 460 nm.
  • the second wavelength to induce photoinhibition is about 365 nm.
  • Relative rates of the photoinitiation by the at least one photoinitiator and the photoinhibition by the at least one photoinhibitor may be controlled by adjusting the intensity and/or duration of the first light, the second light, or both.
  • an overall rate and/or amount (degree) of polymerization of the polymeric precursors into the polymeric material may be controlled.
  • Such process may be used to (i) prevent polymerization of the polymeric precursors at the print surface-mixture interface, (ii) control the rate at which polymerization takes place in the direction away from the print surface, and/or (iii) control a thickness of the polymeric material within the film of the mixture.
  • Examples of types of the at least one photoinitiator include one or more of benzophenones, thioxanthones, anthraquinones, benzoylformate esters, hydroxyacetophenones, alkylaminoacetophenones, benzil ketals, dialkoxyacetophenones, benzoin ethers, phosphine oxides acyloximino esters, alphahaloacetophenones, trichloromethyl-S-triazines, titanocenes, dibenzylidene ketones, ketocoumarins, dye sensitized photoinitiation systems, maleimides, and mixtures thereof.
  • Examples of the at least one photoinitiator in the photoactive resin include one or more of 1-hydroxy-cyclohexyl-phenyl-ketone (IrgacureTM 184; BASF, Hawthorne, NJ); a 1 : 1 mixture of 1-hydroxy-cyclohexyl-phenyl-ketone and benzophenone (IrgacureTM 500; BASF); 2- hydroxy-2-methyl-l -phenyl- 1 -propanone (DarocurTM 1173; BASF); 2-hydroxy-l-[4-(2- hydroxyethoxy)phenyl]-2-methyl-l -propanone (IrgacureTM 2959; BASF); methyl benzoylformate (DarocurTM MBF; BASF); oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy- ethoxy]-ethyl ester; oxy-phenyl-acetic 2-[2-hydroxy-
  • the at least one photoinitiator may be present in an amount ranging between about 0.1 wt% to about 10 wt% in the photoactive resin.
  • the at least one photoinitiator may be present in an amount of at least about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, or more in the photoactive resin.
  • the at least one photoinitiator may be present in an amount of at most about 10 wt%, 9 wt%, 8 wt%, 7 wt%, 6 wt%, 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.9 wt%, 0.8 wt%, 0.7 wt%, 0.6 wt%, 0.5 wt%, 0.4 wt%, 0.3 wt%, 0.2 wt%, 0.1 wt%, or less in the photoactive resin.
  • the at least one photoinhibitor in the photoactive resin may comprise one or more radicals that may preferentially terminate growing polymer radicals, rather than initiating polymerization of the polymeric precursors.
  • types of the at least one photoinitiator include: one or more of sulfanylthiocarbonyl and other radicals generated in photoiniferter polymerizations; sulfanylthiocarbonyl radicals used in reversible addition-fragmentation chain transfer polymerization; and nitrosyl radicals used in nitroxide mediate polymerization.
  • Non-radical species that can be generated to terminate growing radical chains may include the numerous metal/ligand complexes used as deactivators in atom-transfer radical polymerization (ATRP).
  • ATRP atom-transfer radical polymerization
  • additional examples of the types of the at least one photoinhibitor include: one or more of thiocarbamates, xanthates, dithiobenzoates, hexaarylbiimidazoles, photoinitiators that generate ketyl and other radicals that tend to terminate growing polymer chains radicals (i.e., camphorquinone (CQ) and benzophenones), ATRP deactivators, and polymeric versions thereof.
  • CQ camphorquinone
  • benzophenones i.e., camphorquinone (CQ) and benzophenones
  • Examples of the at least one photoinhibitors in the photoactive resin include one or more of zinc dimethyl dithiocarbamate; zinc diethyl dithiocarbamate; zinc dibutyl dithiocarbamate; nickel dibutyl dithiocarbamate; zinc dibenzyl dithiocarbamate; tetramethylthiuram disulfide; tetraethylthiuram disulfide (TEDS); tetramethylthiuram monosulfide; tetrabenzylthiuram disulfide; tetraisobutylthiuram disulfide; dipentamethylene thiuram hexasulfide; N,N'-dimethyl N,N'-di(4-pyridinyl)thiuram disulfide; 3-Butenyl 2- (dodecylthiocarbonothioylthio)-2-methylpropionate; 4-Cyano-4- [(dodecylcyl
  • the mixture may comprise the plurality of particles for forming the at least the portion of the 3D object.
  • the amount of the plurality of particles in the mixture may be sufficient to minimize shrinking of the green body during sintering.
  • the plurality of particles may comprise any particulate material (a particle) that can be melted or sintered (e.g., not completely melted).
  • the particulate material may be in powder form.
  • the particular material may be inorganic materials.
  • the inorganic materials may be metallic, intermetallic, ceramic materials, or any combination thereof.
  • the one or more particles may comprise at least one metallic material, at least one intermetallic material, at least one ceramic material, at least one polymeric material, or any combination thereof.
  • powdered metals alone may be a severe safety hazard and may explode and/or require extensive safety infrastructures
  • using powdered metals that are dispersed in the mixture may avoid or substantially reduce the risks relevant to using the powdered metals that are not dispersed in a liquid medium.
  • photopolymer-based 3D printing using the mixture comprising the photoactive resin and the powdered metals may be performed without using heat, thereby avoiding or substantially reducing thermal distortion to the at least the portion of the 3D object during printing.
  • the metallic materials for the particles may include one or more of aluminum, calcium, magnesium, barium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, niobium, molybdenum, ruthenium, rhodium, silver, cadmium, actinium, and gold.
  • the particles may comprise a rare earth element.
  • the rare earth element may include one or more of scandium, yttrium, and elements of the lanthanide series having atomic numbers from 57-71.
  • An intermetallic material may be a solid-state compound exhibiting metallic bonding, defined stoichiometry and ordered crystal structure (i.e., alloys).
  • the intermetallic materials may be in prealloyed powder form. Examples of such prealloyed powders may include, but are not limited to, brass (copper and zinc), bronze (copper and tin), duralumin (aluminum, copper, manganese, and/or magnesium), gold alloys (gold and copper), rose-gold alloys (gold, copper, and zinc), nichrome (nickel and chromium), and stainless steel (iron, carbon, and additional elements including manganese, nickel, chromium, molybdenum, boron, titanium, silicon, vanadium, tungsten, cobalt, and/or niobium).
  • the prealloyed powders may include superalloys.
  • the superalloys may be based on elements including iron, nickel, cobalt, chromium, tungsten, molybdenum, tantalum, niobium, titanium, and/or aluminum.
  • the ceramic materials may comprise metal (e.g., aluminum, titanium, etc.), non- metal (e.g., oxygen, nitrogen, etc.), and/or metalloid (e.g., germanium, silicon, etc.) atoms primarily held in ionic and covalent bonds.
  • metal e.g., aluminum, titanium, etc.
  • non- metal e.g., oxygen, nitrogen, etc.
  • metalloid e.g., germanium, silicon, etc.
  • the ceramic materials include, but are not limited to, an aluminide, boride, beryllia, carbide, chromium oxide, hydroxide, sulfide, nitride, mullite, kyanite, ferrite, titania zirconia, yttria, and magnesia.
  • the mixture may comprise a pre-ceramic material.
  • the pre-ceramic material may be a polymer that can be heated (or pyrolyzed) to form a ceramic material.
  • the pre-ceramic material may include polyorganozirconates, polyorganoaluminates, polysiloxanes, polysilanes, polysilazanes, polycarbosilanes, polyborosilanes, etc.
  • pre-ceramic material examples include zirconium tetramethacrylate, zirconyl dimethacrylate, or zirconium 2- ethylhexanoate; aluminum III s-butoxide, aluminum III diisopropoxide-ethylacetoacetate; 1,3- bis(chloromethyl) l,l,3,3-Tetrakis(trimethylsiloxy)disiloxane; l,3-bis(3- carboxypropyl)tetramethyldisiloxane; l,3,5,7-tetraethyl-2,4,6,8-tetramethylcyclotetrasilazane; tris(trimethylsilyl)phosphate; tris(trimethylsiloxy)boron; and mixtures thereof.
  • a cross-sectional dimension of the plurality of particles may range between about 1 nanometers (nm) to about 500 pm.
  • the cross-sectional dimension of the plurality of particles may be at least about 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm, 7 pm, 8 pm, 9 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, 100 pm, 200 pm, 300 pm, 400 pm, 500 pm, 2
  • the cross-sectional dimension of the plurality of particles may be at most about 500 pm, 400 pm, 300 pm, 200 pm, 100 pm, 90 pm, 80 pm, 70 pm, 60 pm, 50 pm, 40 pm, 30 pm, 20 pm, 10 pm, 9 pm, 8 pm, 7 pm, 6 pm, 5 pm, 4 pm, 3 pm, 2 pm, 1 pm, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, 9 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm, 1 nm, or smaller.
  • the plurality of particles may be present in an amount ranging between about 5 vol% to about 90 vol% in the mixture.
  • the plurality of particles may be present in an amount of at least about 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%,
  • the plurality of particles may be present in an amount of at most about 90 vol%, 85 vol%, 80 vol%, 75 vol%,
  • the mixture may comprise an anti-settling component to prevent settling of the plurality of particles and keep them suspend in the mixture.
  • the anti-settling component may sterically limit the plurality of particles from moving closer to each other.
  • the anti-settling component may not scatter light (e.g., the first light and/or the second light) to avoid negatively affecting the penetration depth of the light into the mixture.
  • the anti-settling component may be present in an amount ranging between about 5 vol% to about 90 vol% in the mixture.
  • the anti-settling component may be present in an amount of at least about 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or more in the mixture.
  • the anti-settling component may be present in an amount of at most about 90 vol%, 85 vol%, 80 vol%, 75 vol%, 70 vol%, 65 vol%, 60 vol%, 55 vol%, 50 vol%, 45 vol%, 40 vol%, 35 vol%, 30 vol%, 25 vol%, 20 vol%, or less in the mixture.
  • Examples of the anti-settling component include, but are not limited to, one or more additional particles and a thixotropic additive.
  • the one or more additional particles may be configured to prevent settling of the plurality of particles in the mixture.
  • the one or more additional particles may decrease free space and increase the overall packing density within the mixture, thereby preventing the plurality of particles from settling towards the window during printing.
  • the one or more additional particles include micronized and/or dispersed waxes such as paraffin, carnuba, montan, Fischer tropsch wax, ethylene bis stearamide, and lignin; micronized polymers such as cellulose, high density polyethylene, polyethylene, polypropylene, oxidized polyethylene (PE), paraformaldehyde, polyethylene glycol, phenolics, and melamine-formaldehyde based materials; and microspheres made from crosslinked polystyrene, polymethyl methacrylate, and/or other copolymers.
  • An example of the one or more additional particles is Byk Ceraflour 929 (micronized, modified polyethylene wax).
  • the thixotropic additive may be a gel-like or static material that becomes fluid-like when physically disturbed. Such property may be reversible.
  • the thixotropic additive may be configured to create a network to prevent settling of the plurality of particles.
  • the network of the thixotropic additive may be easily disturbed by shearing (e.g., dispensing through the nozzle) the mixture to allow flow.
  • shearing e.g., dispensing through the nozzle
  • the thixotropic additive may form another network within the mixture to prevent settling of the plurality of particles during printing.
  • the thixotropic additive include castor wax, oxidized polyethylene wax, amide wax, modified ureas, castor oil derivatives, fumed silica and alumina, Bentonite clays, and mixtures thereof.
  • the anti-settling component of the mixture may be the one or more additional particles, the thixotropic additive, or both.
  • the mixture may comprise at least one additional additive that is configured to prevent foaming (or induce deaeration) of the mixture. Preventing foaming of the mixture may improve quality of the resulting 3D object.
  • the at least one additional additive may be an amphiphilic material.
  • the at least one additional additive may be a low surface energy material to allow association with each other within the mixture. Such association of the at least one additional additive may trap air bubbles present inside the mixture, migrate towards the mixture-air interface, and release the air bubbles.
  • the at least one additional additive may polymerize and/or cross-link with the polymeric precursor. Examples of the one additional additive include silcones, modified silicones, lauryl acrylates, hydrophobic silicas, and modified ureas.
  • An example of the one additional additive may be Evonik Tegorad 2500 (silicon acrylate).
  • the mixture may comprise an extractable material.
  • the extractable material may be soluble in the polymeric precursor and/or dispersed throughout the mixture.
  • curing of the polymeric precursor of the photoactive resin of the at least the portion of the mixture may create a first solid phase comprising the polymeric material and a second solid phase comprising the extractable material within the at least the portion of the 3D object.
  • Such process may be a polymerization-induced phase separation (PIPS) process.
  • PIPS polymerization-induced phase separation
  • At least a portion of the plurality of particles may be encapsulated by the first solid phase comprising the polymeric material.
  • the at least the portion of the 3D object may be a green body that can be heated to sinter at least a portion of the plurality of particles and burn off at least a portion of other components (i.e., organic components).
  • the green body Prior to sintering the plurality of particles, the green body may be treated (e.g., immersed, jetted, etc.) with a solvent (liquid or vapor) to generate a brown body.
  • the solvent may be an extraction solvent.
  • the extractable material may be soluble in the solvent.
  • a first solubility of the extractable material in the solvent may be higher than a second solubility of the polymeric material in the solvent.
  • the solvent may be a poor solvent for the polymeric material.
  • treating the green body with the solvent may solubilize and extract at least a portion of the extractable material out of the green body into the solvent, and create one or more pores in the at least the portion of the 3D object.
  • the one or more pores may be a plurality of pores.
  • the green body may be treated with the solvent and heat at the same time.
  • the one or more pores may create at least one continuous porous network in the at least the portion of the 3D object.
  • Such process may be a solvent de-binding process.
  • the system may comprise the optical source that provides the light through the print window for curing the at least the portion of the film of the mixture.
  • the light of the optical source may comprise a first wavelength for curing the photoactive resin in a first portion of the film of the mixture.
  • the first wavelength may activate the at least one photoinitiator of the photoactive resin, thereby initiating curing of the polymeric precursors into the polymeric material.
  • the light may be a photoinitiation light, and the first portion of the film may be a photoinitiation layer.
  • the optical source may provide an additional light having a second wavelength for inhibiting curing of the photoactive resin in a second portion of the film of the mixture.
  • the first wavelength and the second wavelength may be different.
  • the second wavelength may activate the at least one photoinhibitor of the photoactive resin, thereby inhibiting curing of the polymeric precursors into the polymeric material.
  • the additional light may be a photoinhibition light
  • the second portion of the film of the mixture may be a photoinhibition layer.
  • a dual -wavelength projector e.g., a dual -wav elength laser
  • the light of the optical source may comprise a first wavelength for curing the photoactive resin in a first portion of the film of the mixture.
  • the first wavelength may activate the at least one photoinitiator of the photoactive resin, thereby initiating curing of the polymeric precursors into the polymeric material.
  • the light may be a photoinitiation light, and the first portion of the film may be a photoinitiation layer.
  • the light may be a patterned light.
  • the system may further comprise an additional optical source comprising an additional light having a second wavelength for inhibiting curing of the photoactive resin in a second portion of the film of the mixture. The first wavelength and the second wavelength may be different.
  • the second wavelength may activate the at least one photoinhibitor of the photoactive resin, thereby inhibiting curing of the polymeric precursors into the polymeric material.
  • the additional light may be a photoinhibition light, and the second portion of the film of the mixture may be a photoinhibition layer.
  • the additional light may be a flood light.
  • the present disclosure provides computer systems that are programmed to implement methods of the disclosure.
  • Computer systems of the present disclosure may be used to regulate various operations of 3D printing, such as, for example, (i) directing movement of one or more platforms (for holding a film of mixture) relative to a deposition unit and/or a building unit or (ii) directing movement of a plurality of wipers for mixing, collecting, and reusing any excess mixture for 3D printing.
  • FIG. 13 shows a computer system 1301 that is programmed or otherwise configured to communicate with and regulate various aspects of a 3D printer of the present disclosure.
  • the computer system 1301 can communicate with, for example, the optical sources, build head, one or more deposition heads, one or more sources of one or more mixtures of the present disclosure, one or more first coupling units of the platform, one or more second coupling units of the build head, one or more actuators coupled to one or more of the coupling units, one or more fixtures coupled to the one or more coupling units, one or more film transfer units, one or more actuators operatively coupled to the film transfer units, one or more sensors for detecting the layer of the mixture prior to, during, and subsequent to printing at least a portion of the 3D object, a vacuum unit, and/or a laminator unit.
  • the computer system 1301 may also communicate with the 3D printing mechanisms or one or more controllers of the present disclosure.
  • the computer system 1301 can be an electronic device of a user or a computer system that is remotely located with respect to the electronic device.
  • the electronic device can be a mobile electronic device.
  • the computer system 1301 includes a central processing unit (CPU, also “processor” and “computer processor” herein) 1305, which can be a single core or multi core processor, or a plurality of processors for parallel processing.
  • the computer system 1301 also includes memory or memory location 1310 (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 1315 (e.g., hard disk), communication interface 1320 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 1325, such as cache, other memory, data storage and/or electronic display adapters.
  • the memory 1310, storage unit 1315, interface 1320 and peripheral devices 1325 are in communication with the CPU 1305 through a communication bus (solid lines), such as a motherboard.
  • the storage unit 1315 can be a data storage unit (or data repository) for storing data.
  • the computer system 1301 can be operatively coupled to a computer network (“network”) 1330 with the aid of the communication interface 1320.
  • the network 1330 can be the Internet, an internet and/or extranet, or an intranet and/or extranet that is in communication with the Internet.
  • the network 1330 in some cases is a telecommunication and/or data network.
  • the network 1330 can include one or more computer servers, which can enable distributed computing, such as cloud computing.
  • the network 1330 in some cases with the aid of the computer system 1301, can implement a peer-to-peer network, which may enable devices coupled to the computer system 1301 to behave as a client or a server.
  • the CPU 1305 can execute a sequence of machine-readable instructions, which can be embodied in a program or software.
  • the instructions may be stored in a memory location, such as the memory 1310.
  • the instructions can be directed to the CPU 1305, which can subsequently program or otherwise configure the CPU 1305 to implement methods of the present disclosure. Examples of operations performed by the CPU 1305 can include fetch, decode, execute, and writeback.
  • the CPU 1305 can be part of a circuit, such as an integrated circuit.
  • a circuit such as an integrated circuit.
  • One or more other components of the system 1301 can be included in the circuit.
  • the circuit is an application specific integrated circuit (ASIC).
  • the storage unit 1315 can store files, such as drivers, libraries and saved programs.
  • the storage unit 1315 can store user data, e.g., user preferences and user programs.
  • the computer system 1301 in some cases can include one or more additional data storage units that are external to the computer system 1301, such as located on a remote server that is in communication with the computer system 1301 through an intranet or the Internet.
  • the computer system 1301 can communicate with one or more remote computer systems through the network 1330.
  • the computer system 1301 can communicate with a remote computer system of a user.
  • remote computer systems include personal computers (e.g., portable PC), slate or tablet PC’s (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personal digital assistants.
  • the user can access the computer system 1301 via the network 1330.
  • Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 1301, such as, for example, on the memory 1310 or electronic storage unit 1315.
  • the machine executable or machine readable code can be provided in the form of software.
  • the code can be executed by the processor 1305.
  • the code can be retrieved from the storage unit 1315 and stored on the memory 1310 for ready access by the processor 1305.
  • the electronic storage unit 1315 can be precluded, and machine-executable instructions are stored on memory 1310.
  • the code can be pre-compiled and configured for use with a machine having a processer adapted to execute the code, or can be compiled during runtime.
  • the code can be supplied in a programming language that can be selected to enable the code to execute in a precompiled or as-compiled fashion.
  • aspects of the systems and methods provided herein can be embodied in programming.
  • Various aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of machine (or processor) executable code and/or associated data that is carried on or embodied in a type of machine readable medium.
  • Machine-executable code can be stored on an electronic storage unit, such as memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk.
  • “Storage” type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server.
  • another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links.
  • a machine readable medium such as computer-executable code
  • a tangible storage medium such as computer-executable code
  • Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the databases, etc. shown in the drawings.
  • Volatile storage media include dynamic memory, such as main memory of such a computer platform.
  • Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system.
  • Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications.
  • RF radio frequency
  • IR infrared
  • Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and/or data.
  • Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.
  • the computer system 1301 can include or be in communication with an electronic display 1335 that comprises a user interface (UI) 1340 for providing, for example, (i) activate or deactivate a 3D printer for printing a 3D object, (ii) determining when to clean the deposition head, (iii) determine any defects in the film of the mixture, (iv) determining a pathway of a platform to move from a deposition unit to a building unit, or vice versa, (v) determining a type of multi-wiper configuration to utilize for removing, collecting, and/or flattening any excess mixture, and/or (vi) controlling movement of a belt system (e.g., continuous belt, roll-to-roll belt) of the 3D printing system disclosed herein.
  • UI user interface
  • GUI graphical user interface
  • web-based user interface web-based user interface
  • Methods and systems of the present disclosure can be implemented by way of one or more algorithms.
  • An algorithm can be implemented by way of software upon execution by the central processing unit 1305. The algorithm can, for example, determine a volume of the mixture that must be dispensed into a pool of excess mixture for a subsequent printing step.
  • Methods and systems of the present disclosure may be combined with or modified by other methods and systems for 3D printing and further processing thereof (e.g., debinding, sintering, etc.), such as, for example, those described in U.S. Patent Publication No. 2016/0067921 (“THREE DIMENSIONAL PRINTING ADHESION REDUCTION USING PHOTOINHIBITION”), U.S. Patent Publication No.
  • 2018/0348646 (“MULTI WAVELENGTH STEREOLITHOGRAPHY HARDWARE CONFIGURATIONS”), Patent Cooperation Treaty Patent Publication No. 2018/213356 (“VISCOUS FILM THREE- DIMENSIONAL PRINTING SYSTEMS AND METHODS”), Patent Cooperation Treaty Patent Publication No. 2018/232175 (“METHODS AND SYSTEMS FOR STEREOLITHOGRAPHY THREE-DIMENSIONAL PRINTING”), Patent Cooperation Treaty Patent Application No. PCT/US2019/068413 (“SENSORS FOR THREE-DIMENSIONAL PRINTING SYSTEMS AND METHODS”), Patent Cooperation Treaty Patent Application No.
  • FIG. 14A shows an exemplary 3D object 1400 for printing.
  • FIG. 14B shows the perimeter of the 3D object 1400 in the x-y plane.
  • the 3D object 1400 comprises a flattened cylinder with two flattened vertical surfaces (e.g., 1401) and a total height of 10.00 mm.
  • the perimeter has an outer diameter (OD) of 7.00 mm with 6.50 mm from flats to opposing radius in both X and Y axis.
  • the 3D object 1400 has holes (e.g., 1402) in the vertical surfaces spacing 1.33 mm between holes starting 1.00 mm from the base on X axis and 1.50 mm from the base on Y axis.
  • X-scale factor and Y-scale factor started at 1.407 and decreased linearly to 1.385 at 6.00 mm height.
  • X-scale factor and Y-scale factor were then constant at 1.385 after 6.00 mm to the end.
  • Z-scale factor started at 1.574 and decreased linearly to 1.492 at 2.50 mm.
  • Z-scale factor was then constant at 1.492 after 2.50 mm to the end.
  • Active setters were used during sintering. The setter is a disk with 9 mm OD and 0.75 mm thickness. The setter’s contacts the starting side (base) of the printed 3D object and the contact with starting side of the 3D object was reduced to minimize drag.
  • FIG. 15A shows the comparison of the start OD (base of the printed 3D object, first printed side) and end OD (end of the printed 3D object, last printed side) by printing with constant scale factors.
  • Lower CL and upper CL refer to lower and upper control limits denoting 0.05 mm below or above the desired OD (6.50 mm).
  • FIG. 15B shows the difference between the start OD and end OD (start OD-End OD) for the printed 3D objects.
  • the start OD was less than end OD, with an average of about 113 pm.
  • End OD in both X and Y axis for items 10 to 20 were significantly larger than the desired OD. Data split into two groups depending on sintering orientation.
  • OD X and OD Y varied little on free end (e.g., start side) but large on the end side which was in contact with the setter.
  • FIG. 16A shows the comparison of the start OD and end OD by printing with dynamic scale factors in one example.
  • FIG. 16B shows the Z position error (desired position - actual position). The differences in start OD and end OD in both X and Y axis were smaller than printing with constant scale factors. In some items, the start OD were larger than the end OD. In some items, the start OD was larger than the desired dimension and the end OD was smaller than the desired dimension, indicating the starting scale factor was relatively higher and the ending scale factor was relatively lower than the optimum values (e.g., printing to the desired dimensions). Sintering with the setter resulted in asymmetric dimensions in the X and Y axis, indicating the asymmetric setter drag during the sintering. No significant change in Z position error was observed.
  • FIG. 17A shows the Z position error (desired - actual) by printing with the constant scale factors in one example.
  • FIG. 17B shows the Z position error by printing with the dynamic scale factors in one example.
  • Z position error of print with constant scale factors at the beginning of the printing was eliminated by printing with dynamic scale factors.
  • Z position error in printing with dynamic scale factors increased slightly after transition to constant scale factor value after 2.50 mm, indicating the scale factors of 1.492 was lower than the optimal value.
  • Increasing the scale factor for a late stage printing may reduce the Z position error.
  • the scale factor values can be further optimized to further reduce the errors in printing.
  • FIG. 18A shows a side view of an exemplary 3D object 1800.
  • FIG. 18B shows a perspective view of the exemplary 3D object 1800.
  • the 3D object 1800 has a flat base to print without supports. It has flat flags and one vertical surface for X measurement. It further has holes in the vertical surface.
  • the printed 3D parts are sintered on flat active setter.
  • the data shown are average of 5 measurements.
  • Embodiment 1 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising:
  • mapping by the computer processor, the digital model on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model
  • mapping by the computer processor, the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of sub-pixels or sub-voxels, to generate an additional image containing a set of sub-pixels or sub-voxels of the additional grid that overlap with at least a portion of the digital model;
  • the method further comprises calculating a difference rate between the image and the additional image;
  • the method further comprises applying a light intensity scaling factor to a subset of the set of pixels or voxels, and an additional light intensity scaling factor to an additional subset of the set of pixels or voxels, wherein the subset of the set of pixels or voxels has a different difference rate from the additional subset of the set of pixels or voxels, optionally wherein the method further comprises applying a Gaussian filter to a light corresponding to the subset of the set pixels and an additional Gaussian filter to a light corresponding to the additional subset of the set pixels, wherein a standard deviation of the Gaussian filter and a standard deviation of the additional Gaussian filter are different; and/or
  • each pixel or voxel of the set of pixels or voxels is fully contained in the at least a portion of the digital model
  • each sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels is fully contained in the at least a portion of the digital model;
  • the individual pixel or voxel has mxm sub-pixels or sub-voxels
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 2 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; map the digital model on a grid of pixels or voxels, to generate an image containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; map the digital model on an additional grid of pixels or voxels, wherein an individual pixel or voxel of the additional grid of pixels or voxels comprises a plurality of subpixels or sub-voxels, to generate an additional image containing a set of sub-pixels or subvoxels of the additional grid that overlap with at least a portion of the digital model; generate a difference image by subtracting the image from the additional image; and modify a light intensity of the set of pixels or voxels based on the difference image, optionally
  • the computer processor is further configured to calculate a difference rate between the image and the additional image;
  • the computer processor is further configured to apply a light intensity scaling factor to a subset of the set of pixels or voxels, and an additional light intensity scaling factor to an additional subset of the set of pixels or voxels, wherein the subset of the set of pixels or voxels has a different difference rate from the additional subset of the set of pixels or voxels, optionally wherein the computer processor is further configured to apply a Gaussian filter to a light corresponding to the subset of the set pixels and an additional Gaussian filter to a light corresponding to the additional subset of the set pixels, wherein a standard deviation of the Gaussian filter and a standard deviation of the additional Gaussian filter are different; and/or
  • each pixel or voxel of the set of pixels or voxels is fully contained in the at least a portion of the digital model
  • each sub-pixel or sub-voxel of the set of sub-pixels or sub-voxels is fully contained in the at least a portion of the digital model;
  • the individual pixel or voxel has mxm sub-pixels or sub-voxels, optionally wherein m is an integer larger than 1;
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the system further comprises the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 3 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising:
  • each of the first pixel or voxel and the second pixel or voxel corresponds to at least a portion of a boundary region of the slice;
  • the first light intensity value and the second light intensity value are assigned based on a degree of containment of the first pixel or voxel and the second pixel or voxel, respectively, by the slice; and in (c), the modifying comprises adjusting (i) a first degree of containment of the first pixel or voxel relative to (ii) a second degree of containment of the second pixel or voxel, or vice versa; and/or
  • the modifying comprises modifying the first light intensity value but not the second light intensity value;
  • the modifying comprises applying different degrees of a light intensity scaling factor to the first pixel or voxel and the second pixel or voxel;
  • the modifying comprises applying different light intensity scaling factors to the first pixel or voxel and the second pixel or voxel;
  • the additional slice is directly adjacent to the slice in the digital model.
  • the grid and the additional grid are usable by the 3D printer to print the slice and the additional slice, respectively, and wherein the slice is to be printed prior to the additional slice;
  • the method further comprises, subsequent to (c), generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • the method further comprises, applying a Gaussian filter to a light source, optionally wherein (c) comprising applying a first standard deviation of the Gaussian filter for the first pixel or voxel and a second standard deviation of the Gaussian filter for the second pixel or voxel, optionally wherein the first standard deviation is larger than the second standard deviation; and/or
  • a pixel or voxel of the plurality of grids is a pixel
  • a pixel or voxel of the plurality of grids is a voxel
  • the method further comprises comprising generating printing instructions corresponding to the slice, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 4 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: provide a plurality of grids of pixels or voxels corresponding to a plurality of slices of a digital model of the 3D object, the plurality of grids comprising: a grid comprising a set of pixels or voxels that correspond to a slice of the plurality of slices, wherein a pixel or voxel of the set is assigned with a light intensity value based on an overlap between the set and the slice; and an additional grid comprising an additional set of pixels or voxels that correspond to an additional slice of the plurality of slices, wherein the additional slice is adjacent to the slice in the digital model; identify, by the computer processor, (i) a first pixel or voxel of the set that does not overlap with the additional set and (ii) a second pixel or voxel of the set that overlaps with
  • the first pixel or voxel or the second pixel or voxel corresponds to at least a portion of a boundary region of the slice; and/or optionally wherein each of the first pixel or voxel and the second pixel or voxel corresponds to at least a portion of a boundary region of the slice; and/or
  • the first light intensity value and the second light intensity value are assigned based on a degree of containment of the first pixel or voxel and the second pixel or voxel, respectively, by the slice; and the modifying comprises adjusting (i) a first degree of containment of the first pixel or voxel relative to (ii) a second degree of containment of the second pixel or voxel, or vice versa; and/or
  • the modifying comprises modifying the first light intensity value but not the second light intensity value
  • the modifying comprises applying different degrees of a light intensity scaling factor to the first pixel or voxel and the second pixel or voxel;
  • the modifying comprises applying different light intensity scaling factors to the first pixel or voxel and the second pixel or voxel;
  • the additional slice is directly adjacent to the slice in the digital model; and/or (7) the grid and the additional grid are usable by the 3D printer to print the slice and the additional slice, respectively, and wherein the slice is to be printed prior to the additional slice; and/or
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • the computer processor is further configured to apply a Gaussian filter to a light source, optionally wherein the computer processor is configured to apply a first standard deviation of the Gaussian filter for the first pixel or voxel and a second standard deviation of the Gaussian filter for the second pixel or voxel, optionally wherein the first standard deviation is larger than the second standard deviation; and/or
  • (10) pixel or voxel of the plurality of grids is a pixel
  • a pixel or voxel of the plurality of grids is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to the slice, optionally wherein the system further comprises the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 5 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising:
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model;
  • the distance threshold is less than or equal to about 10 pixels or voxels
  • the distance threshold is less than or equal to about 8 pixels or voxels
  • the distance threshold is less than or equal to about 5 pixels or voxels
  • the distance threshold is selected by a user of the 3D printer.
  • the distance threshold is determined based at least in part on a shape, a dimension, or a complexity of the at least the portion of the digital model.
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 6 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises:
  • the first light intensity is sufficient for curing of a resin during the printing, and wherein the first pixel or voxel is near a boundary of the at least the portion of the digital model, optionally wherein the first light intensity is substantially a maximum light intensity of a light directed from an optical source; and/or
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model;
  • the distance threshold is less than or equal to about 10 pixels or voxels
  • the distance threshold is less than or equal to about 8 pixels or voxels
  • the distance threshold is less than or equal to about 5 pixels or voxels
  • the distance threshold is selected by a user of the 3D printer.
  • the distance threshold is automatically determined based at least in part on a shape of the at least the portion of the digital model
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the system further comprises the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 7 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises:
  • the first light intensity is sufficient for curing of a resin during the printing, and wherein the first pixel or voxel is near a boundary of the at least the portion of the digital model, optionally wherein the first light intensity is substantially a maximum light intensity of a light directed from an optical source; and/or
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model;
  • the threshold intensity level is less than or equal to about 50%;
  • the threshold intensity level is less than or equal to about 40%
  • the threshold intensity level is less than or equal to about 30%;
  • the threshold intensity level is less than or equal to about 20%;
  • the threshold intensity level is selected by a user of the 3D printer.
  • the threshold intensity level is determined based at least in part on a shape, a dimension, or a complexity of the at least the portion of the digital model.
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel; and/or (13) the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 8 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain, by a computer processor, a grid of pixels or voxels corresponding to at least a portion of a digital model of the 3D object, wherein the grid of pixels or voxels comprises:
  • the first light intensity is sufficient for curing of a resin during the printing, and wherein the first pixel or voxel is near a boundary of the at least the portion of the digital model, optionally wherein the first light intensity is substantially a maximum light intensity of a light directed from an optical source; and/or
  • the reducing comprises changing the second light intensity of the second pixel or voxel to substantially zero intensity
  • the second light intensity is assigned to the second pixel or voxel based on a degree of containment of the second pixel or voxel by the at least the portion of the digital model;
  • the threshold intensity level is less than or equal to about 50%;
  • the threshold intensity level is less than or equal to about 40%
  • the threshold intensity level is less than or equal to about 30%;
  • the threshold intensity level is less than or equal to about 20%;
  • the threshold intensity level is selected by a user of the 3D printer; and/or (9) the threshold intensity level is automatically determined based at least in part on a shape of the at least the portion of the digital model; and/or
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the system further comprises the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 9 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising:
  • mapping by the computer processor, a slice of the plurality of slices on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels;
  • the re-mapping comprises moving the slice within the grid of pixels or voxels by a distance, wherein the distance is less than a dimension of a pixel of the grid of pixels or voxels;
  • the re-mapping comprises rotating the slice within the grid of pixels or voxels by an angle of less than 360 degrees;
  • the method further comprises automatically selecting, by the computer processor, the slice from the plurality of slices; and/or
  • the method further comprises (i) determining a degree of containment of a pixel or voxel of the additional grid of pixels or voxels that overlap with at least a portion of the additional slice; (ii) assigning a light intensity for the pixel or voxel; and (iii) generating a light intensity profile of the additional slice corresponding to the additional grid of pixels or voxels, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object; and/or
  • (6) (c) comprises calculating an average pixel or voxel intensity
  • (c) comprises calculating a weighted pixel or voxel intensity
  • (c) comprises calculating a pixel-value entropy
  • a pixel of the grid of pixels or voxels comprises a plurality of sub-pixels or sub -voxels;
  • (10) (c) further comprises (i) determining a degree of containment of a pixel or voxel of the grid of pixels or voxels that overlaps with at least a portion of the slice, (ii) assigning a light intensity for the pixel or voxel, and (iii) generating a light intensity profile of the slice corresponding to the grid of pixels or voxels; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the method further comprises generating printing instructions corresponding to the plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 10 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a plurality of slices of a digital model corresponding to at least a portion of the 3D object; map a slice of the plurality of slices on a grid of pixels or voxels at a relative alignment position between the slice and the grid of pixels or voxels; generate an alignment score between the slice and the grid of pixels or voxels at the relative alignment position; determining an alignment of the slice with the grid of pixels or voxels; determin if the alignment score meets a quality threshold; and map an additional slice of the plurality of slices onto an additional grid of pixels or voxels at the relative alignment position if the alignment score meets the quality threshold, or re-mapping the slice on the grid of pixels or voxels at a different relative alignment position if the alignment score does not meet the quality threshold, optionally wherein:
  • the re-mapping comprises moving the slice within the grid of pixels or voxels by a distance, wherein the distance is less than a dimension of a pixel of the grid of pixels or voxels;
  • the re-mapping comprises rotating the slice within the grid of pixels or voxels by an angle of less than 360 degrees;
  • the computer processor is further configured to automatically select the slice from the plurality of slices;
  • the computer processor is further configured to (i) determine a degree of containment of a pixel or voxel of the additional grid of pixels or voxels that overlap with at least a portion of the additional slice; (ii) assign a light intensity for the pixel or voxel; and (iii) generate a light intensity profile of the additional slice corresponding to the additional grid of pixels or voxels, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object; and/or
  • the alignment score is based on an average pixel or voxel intensity
  • the alignment score is based on a weighted pixel or voxel intensity
  • the alignment score is based on a pixel-value entropy
  • a pixel of the grid of pixels or voxels comprises a plurality of sub-pixels or sub -voxels;
  • the computer processor is further configured to (i) determine a degree of containment of a pixel or voxel of the grid of pixels or voxels that overlaps with at least a portion of the slice, (ii) assign a light intensity for the pixel or voxel, and (iii) generate a light intensity profile of the slice corresponding to the grid of pixels or voxels; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to the plurality of slices of the digital model.
  • the method further comprises the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 11 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object;
  • mapping by the computer processor, the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model;
  • the light intensity of the interior pixel or voxel is sufficient for curing of a resin during the printing
  • (2) (d) comprises moving the exterior pixel or voxel by a distance, wherein the distance is less than a dimension of a pixel or voxel, optionally wherein the distance is l/6 th of the dimension of the pixel or voxel; or the distance is l/5 th of the dimension of the pixel or voxel; or the distance is l/4 th of the dimension of the pixel or voxel; or the distance is l/3 rd of the dimension of the pixel or voxel; or the distance is l/2 nd of the dimension of the pixel or voxel; or the distance is 2/3 rd of the dimension of the pixel or voxel; or the distance is 3/4 th of the dimension of the pixel or voxel; and/or
  • (d) comprises moving the exterior pixel or voxel in a direction parallel to a side of the exterior pixel or voxel, optionally wherein (d) comprises moving the exterior pixel or voxel in an additional direction orthogonal to the side of the exterior pixel or voxel;
  • (e) further comprises (i) determining a degree of containment of the exterior pixel or voxel and (ii) assigning the light intensity for the exterior pixel or voxel, optionally wherein the modifying comprises applying a light intensity scaling factor to the exterior pixel or voxel; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 12 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain a digital image corresponding to at least a portion of the 3D object; map the digital model on a grid of pixels or voxels, to generate a pattern containing a set of pixels or voxels of the grid of pixels or voxels that overlap with at least a portion of the digital model; identify an exterior pixel or voxel, the exterior pixel or voxel partially overlaps with the digital image; adjust a position of the exterior pixel or voxel; modify a light intensity of the exterior pixel or voxel such that the light intensity is lower than a light intensity of an interior pixel or voxel; and generate a modified pattern of the digital image, wherein the modified pattern is usable by the 3D printer to print the at least the portion of the 3D object, optionally wherein:
  • the light intensity of the interior pixel or voxel is sufficient for curing of a resin during the printing
  • the adjusting comprising moving the exterior pixel or voxel by a distance, wherein the distance is less than a dimension of a pixel or voxel, optionally wherein the distance is l/6 th of the dimension of the pixel or voxel; and/or the distance is l/5 th of the dimension of the pixel or voxel; or the distance is l/4 th of the dimension of the pixel or voxel; or the distance is 1 /3 rd of the dimension of the pixel or voxel; or the distance is l/2 nd of the dimension of the pixel or voxel; or the distance is 2/3 rd of the dimension of the pixel or voxel; or the distance is 3/4 th of the dimension of the pixel or voxel; and/or
  • the adjusting comprises moving the exterior pixel or voxel in a direction parallel to a side of the exterior pixel or voxel, optionally wherein the adjusting comprises moving the exterior pixel or voxel in an additional direction orthogonal to the side of the exterior pixel or voxel;
  • the computer processor is further configured to (i) determine a degree of containment of the exterior pixel or voxel and (ii) assign the light intensity for the exterior pixel or voxel, optionally wherein the modifying comprises applying a light intensity scaling factor to the exterior pixel or voxel; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the system further comprises further comprising the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 13 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising:
  • the light intensity corresponds to a containment level of the at least one interior pixel or voxel
  • the light intensity is 90% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 80% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 70% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 60% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 50% of a containment level of the at least one interior pixel or voxel; and/or (8) the at least one interior pixel or voxel is cured at a degree higher than the at least one exterior pixel or voxel; and/or
  • the method further comprises determining a duration of exposure needed to cure the at least one exterior pixel or voxel at the light intensity to a degree of curing; and/or
  • the method further comprises generating a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the exterior pixel or voxel is a pixel
  • a pixel or voxel of the exterior pixel or voxel is a voxel
  • a pixel or voxel of the interior pixel or voxel is a pixel
  • a pixel or voxel of the interior pixel or voxel is a voxel
  • the method further comprises generating printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the method further comprises using the printing instructions to print the 3D object by the 3D printer.
  • Embodiment 14 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to: obtain digital image corresponding to at least a portion of the 3D object; identify (i) at least one interior pixel or voxel of the digital image and (ii) at least one exterior pixel or voxel of the digital image; assign (i) a light intensity of the at least one interior pixel or voxel and (ii) an additional light intensity of the at least one exterior pixel or voxel, to generate a light intensity profile of the digital image, wherein the light intensity profile is usable by the 3D printer to print the at least the portion of the 3D object, wherein the light intensity is higher than the additional light intensity; and assign a duration of exposure for printing, wherein the duration of exposure is sufficient to cause the exterior pixel or voxel to cure, optionally wherein:
  • the light intensity corresponds to a containment level of the at least one interior pixel or voxel
  • the light intensity is 90% of a containment level of the at least one interior pixel or voxel; and/or (4) the light intensity is 80% of a containment level of the at least one interior pixel or voxel; and/or
  • the light intensity is 70% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 60% of a containment level of the at least one interior pixel or voxel
  • the light intensity is 50% of a containment level of the at least one interior pixel or voxel
  • the at least one interior pixel or voxel is cured at a degree higher than the at least one exterior pixel or voxel;
  • the computer processor is further configured to determine a duration of exposure needed to cure the at least one exterior pixel or voxel at the light intensity to a degree of curing;
  • the computer processor is further configured to generate a light intensity profile of the grid, wherein the light intensity profile is usable by the 3D printer to print at least a portion of the 3D object;
  • a pixel or voxel of the exterior pixel or voxel is a pixel
  • a pixel or voxel of the exterior pixel or voxel is a voxel
  • a pixel or voxel of the interior pixel or voxel is a pixel
  • a pixel or voxel of the interior pixel or voxel is a voxel
  • the computer processor is further configured to generate printing instructions corresponding to a plurality of slices of the digital model, optionally wherein the 3D printer configured to print the 3D object according to the printing instructions.
  • Embodiment 15 A method for printing a three-dimensional (3D) object by a 3D printer with a plurality of lights, comprising:
  • a light of the plurality of lights comprises a pattern corresponding to a portion of the at least one 3D object, wherein the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern;
  • (c) generating a modified pattern for the printing optionally wherein: (1) the method further comprises identifying a center of the overlapped region and an edge of the overlapped region, optionally wherein the modifying comprising applying a higher light intensity scaling factor at the edge of the overlapped region than at the center of the overlapped region, optionally wherein a scaling factor at the center is substantially 1; and/or
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the light is directed through the surface and towards the resin;
  • the resin comprises a plurality of particles
  • the plurality of particles comprises a plurality of metal particles or a plurality of ceramic particles.
  • Embodiment 16 A system for printing a three-dimensional (3D) object by a 3D printer, comprising: a plurality of optical sources configured to provide a plurality of lights to a resin disposed adjacent to a surface, wherein a light of the plurality of lights (i) comprises a pattern corresponding to a portion of the at least one 3D object, the pattern is mapped to a grid of pixels or voxels, (ii) overlaps with an additional light of the plurality of lights, and (iii) is sufficient to cause a domain of the resin to solidify based on the pattern; a computer processor in digital communication with computer memory, configured to modify a light intensity profile of an overlapped region of the pattern with the additional light and generate a modified pattern for the printing, optionally wherein:
  • the computer processor is further configured to identify a center of the overlapped region and an edge of the overlapped region;
  • the modifying comprising applying a higher light intensity scaling factor at the edge of the overlapped region than at the center of the overlapped region, optionally wherein a scaling factor at the center is substantially 1; and/or (3) the light is configured to overlap with the additional light by at least 4 pixels; and/or
  • the light is configured to overlap with the additional light by 10 pixels;
  • the light is configured to overlap with the additional light by 9 pixels;
  • the light is configured to overlap with the additional light by 8 pixels;
  • the light is configured to overlap with the additional light by 7 pixels;
  • the light is configured to overlap with the additional light by 6 pixels;
  • the light is configured to overlap with the additional light by 4 pixels;
  • a pixel or voxel of the grid is a pixel
  • a pixel or voxel of the grid is a voxel
  • the light is directed through the surface and towards the resin;
  • the resin comprises a plurality of particles
  • the plurality of particles comprises a plurality of metal particles or a plurality of ceramic particles.
  • Embodiment 17 A method for printing at least one three-dimensional (3D) object, comprising:
  • (1) (c) comprises detecting (i) a remaining portion of the solidified domain on the surface;
  • (c) comprises detecting (ii) the at least the portion of the solidified domain that is removed from the surface;
  • (c) comprises detecting (iii) an excess of the resin remaining on the surface; and/or (4) the modifying comprises removing at least a portion of the additional pattern of the additional light, optionally wherein the at least the portion of the additional pattern comprises a substantially continuous boundary; and/or
  • the at least one 3D object comprises a plurality of 3D objects, wherein:
  • the pattern of the light corresponds to a plurality of cross-sections of the plurality of 3D objects from a common plane
  • the additional pattern of the additional light corresponds to an additional plurality of cross-sections of the plurality of 3D objects from an additional common plane
  • the modifying comprises removing at least a portion of the additional pattern that corresponds to a cross-section of the additional plurality of crosssections
  • the method further comprises identifying the cross-section of the additional plurality of cross-sections by analyzing the detected member in (c), optionally wherein the identifying is based on using a two-dimensional (2D) projection of a 3D object of the plurality of 3D objects, optionally wherein the 2D projection comprises a substantially continuous boundary, optionally wherein the common plane and the additional common plane are substantially parallel to each other; and/or
  • the method further comprises subsequent to (d), directing the additional light to an additional resin for printing the additional cross-sectional layer of the at least one 3D object;
  • the removing comprises directing a relative movement between (1) a build head configured to hold the at least the portion of the solidified domain and (2) the surface; and/or
  • the light is directed through the surface and towards the resin;
  • the resin comprises a plurality of particles, optionally wherein the plurality of particles comprises a plurality of metal particles or a plurality of ceramic particles.
  • Embodiment 18 A system for printing at least one three-dimensional (3D) object, comprising: an optical source configured to provide a light to a resin disposed adjacent to a surface, wherein the light (i) comprises a pattern corresponding to a cross-section of the at least one 3D object and (ii) is sufficient to cause a domain of the resin to solidify based on the pattern; a sensor configured to detect, subsequent to removal of at least a portion of a solidified domain from the surface, (i) a remaining portion of the solidified domain on the surface, (ii) the at least the portion of the solidified domain that is removed from the surface, or (iii) an excess of the resin remaining on the surface; and a computer processor in digital communication with computer memory and configured to modify an additional pattern of an additional light from the optical source, wherein the additional light is usable to print an additional cross-section of the at least one 3D object, optionally wherein:
  • the senor is configured to detect (i) a remaining portion of the solidified domain on the surface;
  • the sensor is configured to detect (ii) the at least the portion of the solidified domain that is removed from the surface;
  • the sensor is configured to detect (iii) an excess of the resin remaining on the surface;
  • the senor is configured to detect (i) and (ii); and/or
  • the senor is configured to detect (i) and (iii); and/or
  • the senor is configured to detect (ii) and (iii); and/or
  • the senor is configured to detect (i), (ii), and (iii); and/or
  • the modification comprises removing at least a portion of the additional pattern of the additional light, optionally wherein the at least the portion of the additional pattern comprises a substantially continuous boundary;
  • the at least one 3D object comprises a plurality of 3D objects, wherein:
  • the pattern of the light corresponds to a plurality of cross-sections of the plurality of 3D objects from a common plane
  • the additional pattern of the additional light corresponds to an additional plurality of cross-sections of the plurality of 3D objects from an additional common plane;
  • the modifying comprises removing at least a portion of the additional pattern that corresponds to a cross-section of the additional plurality of cross-sections, optionally wherein the computer processor is further configured to identify the cross-section of the additional plurality of cross-sections by analyzing the detected member of (i), (ii), or (iii), optionally wherein the identifying is based on using a two- dimensional (2D) projection of a 3D object of the plurality of 3D objects, optionally wherein the 2D projection comprises a substantially continuous boundary; and/or
  • the common plane and the additional common plane are substantially parallel to each other; and/or (12) the optical source is further configured to direct the additional light to an additional resin for printing the additional cross-sectional layer of the at least one 3D object; and/or
  • the system further comprises an actuator to direct a relative movement between (1) a build head configured to hold the at least the portion of the solidified domain and (2) the surface for the removal of the at least a portion of a solidified domain from the surface; and/or
  • the resin comprises a plurality of particles, optionally wherein the plurality of particles comprises a plurality of metal particles or a plurality of ceramic particles.
  • Embodiment 19 A method for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising:
  • the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object, optionally wherein:
  • the portion is usable by the 3D printer to be printed prior to the additional portion, and wherein the portion is rescaled along the first direction via a scaling factor that is greater than that for rescaling the additional portion along the first direction, optionally wherein the portion is rescaled along the second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction;
  • one of the first direction and the second direction is a printing direction of the 3D printer optionally wherein the first direction is the printing direction of the 3D printer, or the second direction is the printing direction of the 3D printer;
  • the method further comprises generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) is performed to the plurality of digital slices; and/or
  • the method further comprises generating, subsequent to (b) and by the computer processor, a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion; and/or
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid of pixels
  • the method further comprises rescaling by the computer processor, the portion along a third direction and the additional portion along the third direction, such that: the portion and the additional portion are rescaled along the third direction in accordance with a third set of different scaling factors; and/or
  • the first set and the second set of different scaling factors are determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • Embodiment 20 A method for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising:
  • a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling factor, wherein, subsequent to the rescaling, the at least three portions are usable by the 3D printer to print the at least the portion of the 3D object, optionally wherein: (1) the at least three scaling factors are determined based on a linear function with respect to positioning of the at least three portions along the direction; and/or
  • the at least three scaling factors are determined based on a non-linear function with respect to positioning of the at least three portions along the direction;
  • the first portion is usable by the 3D printer to be printed prior to the second portion, and wherein the first scaling factor is greater than the second scaling factor, optionally wherein the second portion is usable by the 3D printer to be printed prior to the third portion, and wherein the second scaling factor is greater than the third scaling factor;
  • the direction is a printing direction of the 3D printer or the direction is not a printing direction of the 3D printer, optionally wherein the direction is substantially orthogonal to the printing direction;
  • the method further comprises generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a first digital slice corresponding to the first portion, a second digital slice corresponding to the second portion, and a third digital slice corresponding to the third portion, and wherein the rescaling in (b) is performed to the plurality of digital slices; and/or
  • the method further comprises generating, subsequent to (b) and by the computer processor, a first digital slice corresponding to the rescaled portion, a second digital slice corresponding to the second rescaled portion, and a third digital slice corresponding to the third rescaled additional portion; and/or
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid or pixels
  • the method further comprises rescaling by the computer processor, the first portion, the second portion, and the third portion along an additional direction in accordance with three additional different scaling factors; and/or
  • the at least three different scaling factors are determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • Embodiment 21 A method for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising:
  • the portion is configured to be printed using a first resin from the same source and (ii) the additional portion is configured to be printed using a second resin from the same source, wherein a material composition of the first resin is different from that of the second resin by no more than about 30%;
  • the material composition of the first resin is different from that of the second resin by no more than about 10%;
  • the portion is usable by the 3D printer to be printed prior to the additional portion, and wherein the portion is rescaled along the direction via a scaling factor that is greater than that for rescaling the additional portion along the direction, optionally wherein the portion is further rescaled along a second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction;
  • the direction is a printing direction of the 3D printer, or the direction is not a printing direction of the 3D printer, optionally wherein the direction is substantially orthogonal to a printing direction of the 3D printer;
  • the method further comprises generating, prior to (b) and by the computer processor, a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) and (c) is performed to the plurality of digital slices; and/or
  • the method further comprises generating, subsequent to (b) and by the computer processor, a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion; and/or
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid of pixels
  • Embodiment 22 A system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to:
  • the portion and the additional portion are rescaled along a second direction of the at least two directions in accordance with a second set of different scaling factors, wherein, subsequent to the rescaling, the portion and the additional portion are usable by the 3D printer to print the at least the portion of the 3D object, optionally wherein:
  • the portion is usable by the 3D printer to be printed prior to the additional portion, and wherein the portion is rescaled along the first direction via a scaling factor that is greater than that for rescaling the additional portion along the first direction, optionally wherein the portion is rescaled along the second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction;
  • one of the first direction and the second direction is a printing direction of the 3D printer optionally wherein the first direction is the printing direction of the 3D printer, or the second direction is the printing direction of the 3D printer;
  • the computer processor is further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) is performed to the plurality of digital slices; and/or (5) the computer processor is further configured to generate, subsequent to (b), a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion; and/or
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid of pixels
  • the computer processor is further configured to rescale the portion along a third direction and the additional portion along the third direction, such that: the portion and the additional portion are rescaled along the third direction in accordance with a third set of different scaling factors; and/or
  • the first set and the second set of different scaling factors are determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • Embodiment 23 A system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to:
  • a third portion of the at least three portions is rescaled along the direction in accordance with the third scaling factor that is different from the first scaling factor and the second scaling factor, wherein, subsequent to the rescaling, the at least three portions are usable by the 3D printer to print the at least the portion of the 3D object, optionally wherein:
  • the at least three scaling factors are determined based on a linear function with respect to positioning of the at least three portions along the direction;
  • the at least three scaling factors are determined based on a non-linear function with respect to positioning of the at least three portions along the direction; and/or (3) the first portion is usable by the 3D printer to be printed prior to the second portion, and wherein the first scaling factor is greater than the second scaling factor, optionally wherein the second portion is usable by the 3D printer to be printed prior to the third portion, and wherein the second scaling factor is greater than the third scaling factor; and/or
  • the direction is a printing direction of the 3D printer or the direction is not a printing direction of the 3D printer, optionally wherein the direction is substantially orthogonal to the printing direction;
  • the computer processor is further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a first digital slice corresponding to the first portion, a second digital slice corresponding to the second portion, and a third digital slice corresponding to the third portion, and wherein the rescaling in (b) is performed to the plurality of digital slices; and/or
  • the computer processor is further configured to generate, subsequent to (b), a first digital slice corresponding to the rescaled portion, a second digital slice corresponding to the second rescaled portion, and a third digital slice corresponding to the third rescaled additional portion; and/or
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid or pixels
  • the computer processor is further configured to rescale by the computer processor, the first portion, the second portion, and the third portion along an additional direction in accordance with three additional different scaling factors;
  • the at least three different scaling factors are determined based on one or more of resin composition, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • Embodiment 24 A system for processing a three-dimensional (3D) object for printing the 3D object by a 3D printer, comprising: a computer processor in digital communication with computer memory, configured to:
  • the portion is configured to be printed using a first resin from the same source and (ii) the additional portion is configured to be printed using a second resin from the same source, wherein a material composition of the first resin is different from that of the second resin by no more than about 30%;
  • the material composition of the first resin is different from that of the second resin by no more than about 10%;
  • the portion is usable by the 3D printer to be printed prior to the additional portion, and wherein the portion is rescaled along the direction via a scaling factor that is greater than that for rescaling the additional portion along the direction, optionally wherein the portion is further rescaled along a second direction via a scaling factor that is greater than that for rescaling the additional portion along the second direction;
  • the direction is a printing direction of the 3D printer, or the direction is not a printing direction of the 3D printer, optionally wherein the direction is substantially orthogonal to a printing direction of the 3D printer;
  • the computer processor is further configured to generate, prior to (b), a plurality of digital slices corresponding to the at least the portion of the 3D object, the plurality of digital slices comprising a slice corresponding to the portion and an additional slice corresponding to the additional portion, and wherein the rescaling in (b) and (c) is performed to the plurality of digital slices; and/or
  • the computer processor is further configured to generate, subsequent to (b), a digital slice corresponding to the rescaled portion and an additional digital slice corresponding to the rescaled additional portion;
  • a digital slice of the plurality of digital slices corresponds to a grid of voxels or a grid of pixels
  • the first and the second scaling factors are determined based on one or more of resin composition of the source of resin, print area, layer number, resin film thickness, and orientation of printing of the 3D object.
  • Embodiment 25 A method for processing a three-dimensional (3D) object for printing by a 3D printer, comprising: (a) obtaining, by a computer processor, a digital image corresponding to at least a portion of the 3D object;
  • (1) (c) comprises decreasing the exterior intensity level to generate the modified exterior intensity level, optionally wherein the modified exterior intensity level is less than the exterior intensity level by at least about 5% or at least about 10%;
  • (d) comprises increasing the exterior exposure time to generate the modified exterior exposure time, optionally wherein the modified exterior exposure time is longer than the exterior exposure time by at least about 5% or at least about 10%;
  • the method further comprises determining, by the computer processor and based on the digital image, an interior intensity level and an interior exposure time of the light for at least one interior unit of the digital image; and modifying, by the computer processor and based on the modified exterior intensity level, the interior exposure time to generate a modified interior exposure time of the light for the at least one interior unit, optionally wherein the interior exposure time and the exterior exposure time are substantially the same, and/or the modified interior exposure time and the modified exterior exposure time are substantially the same, and/or the interior intensity level remains substantially the same for the light for printing the at least the portion of the 3D object; and/or
  • the exterior unit comprises a pixel or voxel that overlaps partially but not completely with the digital image, optionally wherein the exterior unit further comprises an additional pixel or voxel that is directly adjacent to the pixel or voxel, wherein the additional pixel or voxel overlaps substantially completely with the digital image; and/or (5) the exterior unit comprises a plurality of pixels or voxels along the length of a diagonal dimension of the digital image; and/or
  • the interior unit comprises a plurality of pixels or voxels; and/or;
  • the exterior exposure time is modified to generate the modified exterior exposure time based on the modified exterior intensity level
  • the exterior intensity level is modified to generate the modified exterior intensity level based on the modified exterior exposure time
  • a degree or ratio of change between the exterior exposure time and the modified exterior exposure time is substantially the same as (ii) a degree or ratio of change between the interior exposure time and the modified interior exposure time;
  • Embodiment 26 A system for processing a three-dimensional (3D) object for printing by a 3D printer, comprising a computer processor in digital communication with computer memory, wherein the computer processor is configured to:
  • the computer processor is configured to decrease the exterior intensity level to generate the modified exterior intensity level, optionally wherein the modified exterior intensity level is less than the exterior intensity level by at least about 5% or at least about 10%;
  • the computer processor is configured to increase the exterior exposure time to generate the modified exterior exposure time, optionally wherein the modified exterior exposure time is higher than the exterior exposure time by at least about 5% or at least about 10%;
  • the computer processor is configured to determine, based on the digital image, an interior intensity level and an interior exposure time of the light for at least one interior unit of the digital image; and modify, based on the modified exterior intensity level, the interior exposure time to generate a modified interior exposure time of the light for the at least one interior unit, optionally wherein the interior exposure time and the exterior exposure time are substantially the same, and/or the modified interior exposure time and the modified exterior exposure time are substantially the same, and/or the interior intensity level remains substantially the same for the light for printing the at least the portion of the 3D object; and/or
  • the exterior unit comprises a pixel or voxel that overlaps partially but not completely with the digital image, optionally wherein the exterior unit further comprises an additional pixel or voxel that is directly adjacent to the pixel or voxel, wherein the additional pixel or voxel overlaps substantially completely with the digital image;
  • the exterior unit comprises a plurality of pixels or voxels along the length of a diagonal dimension of the digital image
  • the interior unit comprises a plurality of pixels or voxels
  • the exterior exposure time is modified to generate the modified exterior exposure time based on the modified exterior intensity level
  • the exterior intensity level is modified to generate the modified exterior intensity level based on the modified exterior exposure time
  • a degree or ratio of change between the exterior exposure time and the modified exterior exposure time is substantially the same as (ii) a degree or ratio of change between the interior exposure time and the modified interior exposure time;

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)

Abstract

La présente invention concerne des systèmes et des procédés d'impression d'objets tridimensionnels (3D). Selon un aspect, la présente invention concerne un procédé de détermination d'une complexité d'une partie d'un objet 3D et d'application d'un lissage adaptatif pendant l'impression de la partie de l'objet 3D.
EP24761105.6A 2023-02-24 2024-02-23 Systèmes et procédés d'impression tridimensionnelle par stéréolithographie Pending EP4669511A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US202363448053P 2023-02-24 2023-02-24
PCT/US2024/017155 WO2024178383A2 (fr) 2023-02-24 2024-02-23 Systèmes et procédés d'impression tridimensionnelle par stéréolithographie

Publications (1)

Publication Number Publication Date
EP4669511A2 true EP4669511A2 (fr) 2025-12-31

Family

ID=92501818

Family Applications (1)

Application Number Title Priority Date Filing Date
EP24761105.6A Pending EP4669511A2 (fr) 2023-02-24 2024-02-23 Systèmes et procédés d'impression tridimensionnelle par stéréolithographie

Country Status (2)

Country Link
EP (1) EP4669511A2 (fr)
WO (1) WO2024178383A2 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7706910B2 (en) * 2007-01-17 2010-04-27 3D Systems, Inc. Imager assembly and method for solid imaging
US10780641B2 (en) * 2016-09-29 2020-09-22 Holo, Inc. Enhanced three dimensional printing of vertical edges
CN115043974A (zh) * 2017-06-30 2022-09-13 阿莱恩技术有限公司 通过图案化曝光而用单一树脂制成的3d打印复合物

Also Published As

Publication number Publication date
WO2024178383A3 (fr) 2024-10-31
WO2024178383A2 (fr) 2024-08-29

Similar Documents

Publication Publication Date Title
US11351735B2 (en) Sensors for three-dimensional printing systems and methods
US11161301B2 (en) Viscous film three-dimensional printing systems and methods
EP3625056B1 (fr) Systèmes et procédés d'impression tridimensionnelle de film visqueux
US11400650B2 (en) Methods and systems for stereolithography three-dimensional printing
US20220176622A1 (en) Stereolithography three-dimensional printing systems and methods
EP1894704B1 (fr) Amélioration de la régularité des parois, de la précision des caractéristiques et de la résolution des images projetées par le contrôle des niveaux d'exposition dans l'imagerie solide
US12583178B2 (en) Systems and methods for stereolithography three-dimensional printing
CN107584760B (zh) 用于制造三维制造物体的三维制造方法和装置
CN110997282A (zh) 用于立体光刻三维打印的方法和系统
EP4058265A1 (fr) Compositions et procédés d'impression en trois dimensions
WO2024178383A2 (fr) Systèmes et procédés d'impression tridimensionnelle par stéréolithographie
US20250010550A1 (en) Three-Dimensional Printing Methods and Systems Thereof
WO2024086660A2 (fr) Systèmes et procédés d'impression tridimensionnelle stéréolithographique
EP4121236A1 (fr) Compositions et procédés d'impression tridimensionnelle de particules

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20250714

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR