JP7736657B2 - Cross-sectional shape data generating method and cross-sectional shape data generating device - Google Patents

Description

The present invention relates to a cross-sectional shape data generation method, a cross-sectional shape data generation device, and a program.

In recent years, there has been a growing need for 3D printers as a means of production, and research and development is being conducted in industries such as the aircraft industry with a view to commercializing their use with metallic materials. 3D printers that use metallic materials use a heat source such as a laser or arc to melt metal powder or metal wire, and then layer the molten metal to create an object.

Patent Document 1 discloses a manufacturing technology that defines a three-dimensional model of a workpiece product, creates a second data file consisting of a set of continuous relative spatial coordinates that depict the path of the tool in this three-dimensional model, and positions and manipulates the welding head relative to the processing table so that its relative movement follows the path in the second data file.

U.S. Patent No. 6,274,839

When additively manufacturing a model, it is considered to build from cross sections in various directions due to the high degree of freedom that additive manufacturing offers. In this case, from the perspective of modeling quality, it is required to have many slice cross sections that are easy to manufacture, and from the perspective of productivity, it is required to have a small number of torch passes.

Therefore, taking these conditions into account and slicing a complex object in the appropriate layering direction to obtain cross-sectional data often requires know-how and trial and error, placing a heavy burden on designers and other users.

The present invention aims to provide a cross-sectional shape data generation method, cross-sectional shape data generation device, and program that can easily generate cross-sectional shape data suitable for additive manufacturing of an object when manufacturing the object, thereby reducing the burden on the user.

The present invention comprises the following configurations.
(1) A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing the shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
Including,
Cross-sectional shape data generation method.
(2) A cross-sectional shape data generation device that generates cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
having
Cross-sectional shape data generator.
(3) A program for generating cross-sectional shape data of a shaped object used when manufacturing the shaped object by repeatedly stacking molten metal in a stacking direction, the program comprising:
On the computer,
an information acquisition function for acquiring three-dimensional shape information of the object;
an identification function for identifying a surface of the object in the three-dimensional shape information;
a generation function of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation function for calculating the area distribution of the cut surface;
a determination function of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output function of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
In order to realize this,
program.

The present invention makes it possible to easily generate cross-sectional shape data suitable for additive manufacturing of an object when manufacturing the object, thereby reducing the burden on the user.

FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system. FIG. 2 is a functional block diagram of the shaping control device. FIG. 3 is a perspective view of an example of a shaped object. FIG. 4 is a flowchart showing a processing procedure performed by the cross-sectional shape data generating device. FIG. 5A is a schematic diagram showing a model made up of three-dimensional shape information of a shaped object. FIG. 5B is a schematic diagram showing a model made up of three-dimensional shape information of a shaped object. FIG. 5C is a schematic diagram showing a model formed from three-dimensional shape information of a shaped object. FIG. 6 is a schematic diagram showing an image of zebra analysis. FIG. 7A is a schematic diagram illustrating the generation of a cutting plane based on the identified plane. FIG. 7B is a schematic diagram illustrating the generation of a cutting plane based on the identified plane. FIG. 7C is a schematic diagram illustrating the generation of a cutting plane based on the identified plane. FIG. 8A is a graph showing the area distribution of the generated cut surfaces. FIG. 8B is a graph showing the area distribution of the generated cut surfaces. FIG. 8C is a graph showing the area distribution of the generated cut surfaces. FIG. 9 is a schematic diagram showing a cut surface at the overhang portion. FIG. 10 is a schematic side view of a shaped object illustrating a case where the stacking direction is determined by dividing the region. FIG. 11A is a schematic side view of a shaped object having an overhang portion. FIG. 11B is a schematic side view of a shaped object having an overhang portion. FIG. 11C is a schematic side view of a shaped object having an overhang portion. FIG. 12 is a schematic perspective view of a shaped object having an overhang and having the same area of the cut surface.

Embodiments of the present invention will be described in detail below with reference to the drawings. The additive manufacturing system shown here uses a heat source device to melt a filler material (welding wire) held by a manipulator to form a weld bead, and then repeatedly stacks the formed weld beads into a desired shape to form a molded object made of stacked weld beads. The cross-sectional shape data generation device generates cross-sectional shape data to be used by the additive manufacturing device that manufactures such a molded object.

<Configuration of additive manufacturing system>
An example of the configuration of an additive manufacturing system that is operated by the control information generated by the control information modifying device described above will be described.
FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system.
The additive manufacturing system 100 includes a manufacturing control device 15, a manipulator 17, a filler material supply device 19, a manipulator control device 21, and a heat source control device 23.

The manipulator control device 21 controls the manipulator 17 and the heat source control device 23. A controller (not shown) is connected to the manipulator control device 21, allowing the operator to instruct any operation of the manipulator control device 21 via the controller.

The manipulator 17 is, for example, an articulated robot, and the torch 11 attached to the tip shaft supports a continuous supply of filler material M. The torch 11 holds the filler material M protruding from its tip. The position and orientation of the torch 11 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm that constitutes the manipulator 17. Preferably, the manipulator 17 has six or more degrees of freedom, and is capable of arbitrarily changing the axial direction of the heat source at the tip. The manipulator 17 may take various forms, such as the articulated robot with four or more axes shown in Figure 1, or a robot equipped with angle adjustment mechanisms on two or more orthogonal axes.

The torch 11 has a shield nozzle (not shown), through which shielding gas is supplied. The shielding gas blocks the atmosphere and prevents oxidation and nitridation of the molten metal during welding, thereby reducing welding defects. The arc welding method used in this configuration may be either a consumable electrode method such as shielded metal arc welding or carbon dioxide gas arc welding, or a non-consumable electrode method such as TIG (Tungsten Inert Gas) welding or plasma arc welding, and is selected appropriately depending on the object to be created. Here, gas metal arc welding will be used as an example. In the case of a consumable electrode method, a contact tip is placed inside the shield nozzle, and a filler material M, to which current is supplied, is held by the contact tip. While holding the filler material M, the torch 11 generates an arc from the tip of the filler material M in a shielding gas atmosphere.

The filler material supply device 19 supplies filler material M toward the torch 11. The filler material supply device 19 includes a reel 19a around which filler material M is wound, and a payout mechanism 19b that pays out the filler material M from the reel 19a. The filler material M is fed to the torch 11 by the payout mechanism 19b while being sent in the forward or reverse direction as needed. The payout mechanism 19b is not limited to a push type that is located on the filler material supply device 19 side and pushes out the filler material M, but may also be a pull type or push-pull type that is located on a robot arm or the like.

The heat source control device 23 is a welding power source that supplies the power required for welding by the manipulator 17. The heat source control device 23 adjusts the welding current and welding voltage supplied when forming a bead by melting and solidifying the filler material M. In addition, the filler material supply speed of the filler material supply device 19 is adjusted in conjunction with the welding conditions, such as the welding current and welding voltage, set by the heat source control device 23.

The heat source for melting the filler material M is not limited to the arc described above. Other heat sources may also be used, such as a heating method that combines an arc and a laser, a heating method that uses plasma, or a heating method that uses an electron beam or laser. Heating with an electron beam or laser allows for more precise control of the amount of heat, maintaining the state of the formed bead more appropriately and contributing to further improving the quality of the laminated structure. Furthermore, the material of the filler material M is not particularly limited; the type of filler material M used may vary depending on the characteristics of the object W, such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, or nickel-based alloy.

The molding control device 15 controls all of the above-mentioned parts.

The additive manufacturing system 100 configured as described above operates in accordance with a manufacturing program created based on a manufacturing plan for the object W. The manufacturing program is composed of numerous command codes and is created based on an appropriate algorithm depending on various conditions, such as the shape, material, and heat input of the object. According to this manufacturing program, the torch 11 is moved while the supplied filler material M is melted and solidified, forming a linear weld bead, which is the molten solidified body of the filler material M, on the base material 13. In other words, the manipulator control device 21 drives the manipulator 17 and heat source control device 23 based on a predetermined program provided by the manufacturing control device 15. In response to commands from the manipulator control device 21, the manipulator 17 moves the torch 11 while melting the filler material M with an arc to form a weld bead. By sequentially forming and stacking weld beads in this manner, a manufactured object W of the desired shape is obtained.

Figure 2 is a functional block diagram of the shaping control device 15. The shaping control device 15 includes an information acquisition unit 31, an identification unit 33, a generation unit 35, a calculation unit 37, a determination unit 39, and an output unit 41, and functions as a cross-sectional shape data generation device.

The above-mentioned modeling control device 15 is configured with hardware using an information processing device such as a PC (Personal Computer). Each function of the modeling control device 15 is realized by a control unit (not shown) reading and executing a program with a specific function stored in a storage device (not shown). Examples of storage devices include RAM (Random Access Memory), which is a volatile storage area, ROM (Read Only Memory), which is a non-volatile storage area, and storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive). Examples of the control unit include a processor such as a CPU (Central Processing Unit) or MPU (Micro Processor Unit), or a dedicated circuit. In addition to the above configurations, the modeling control device 15 may be another computer remotely connected to the additive manufacturing system 100 via a network, etc.

<Sculpture>
Next, a description will be given of an example of the object W manufactured by the above-described additive manufacturing system 100. Fig. 3 is a perspective view of the object W, showing an example of the object W.

As shown in Figure 3, the object W has multiple block parts BL1, BL2, BL3, and BL4. These block parts BL1, BL2, BL3, and BL4 are each formed in a rectangular parallelepiped shape, with block part BL2 stacked on block part BL1, and block part BL3 stacked on block part BL2, and block part BL4 is formed on the side of block part BL3. Block part BL2 is joined to block part BL1, block part BL3 is joined to block part BL2, and block part BL4 is joined to block part BL3.

<Control information generation procedure>
Next, a process for generating cross-sectional shape data for the above-mentioned shaped object W will be described.
FIG. 4 is a flowchart showing a processing procedure performed by the cross-sectional shape data generating device.

(Information acquisition process)
The information acquisition unit 31 acquires three-dimensional shape information of the object W to be formed (step S1). The acquired three-dimensional shape information may be, for example, information on the object W generated by commercially available CAD editing software or the like, or may be point cloud data acquired by three-dimensionally measuring the shape of the object W using a shape measurement sensor.

Figures 5A to 5C are schematic diagrams showing models made up of 3D shape information that represent the shaped object W in various orientations. Figure 5A shows orientation PA in which block portions BL1, BL2, and BL3 are arranged so that they overlap in order from below, with block portion BL4 extending laterally. Figure 5B shows orientation PB in which block portions BL1, BL2, and BL3 are arranged laterally in order, with block portion BL4 extending downward. Figure 5C shows orientation PC in which block portions BL3, BL2, and BL1 are arranged so that they overlap in order from below, with block portion BL4 extending laterally from block portion BL3.

(Identification process)
The identification unit 33 identifies the surfaces of the object W in the three-dimensional shape information (step S2). To distinguish and identify the surfaces in the model of the object W, surface analysis means such as zebra analysis, curvature analysis, and gradient analysis can be used.

When using zebra analysis, the continuity between two surfaces can be evaluated and identified. Specifically, for two surfaces, if the position, tangent, and curvature are continuous, if the position and tangent are continuous, or if only the position is continuous, the two surfaces can be identified as separate surfaces.

Figure 6 is a schematic diagram showing an image of zebra analysis. As shown in Figure 6, parallel lines are projected onto the surface of the object W to create a striped pattern (zebra line) Z. For example, the point where the continuity of this striped pattern Z changes is used as a boundary, and the two surfaces are identified as separate, adjacent surfaces.

(Generation process)
The generation unit 35 generates cut planes A _i,j (j = 1 to N) parallel to the identified plane A _i at intervals (step S3). The cut planes A _i,j can be generated, for example, by extracting a plurality of sufficiently large planes that are parallel to the identified plane A _i and intersect with the object W. At this time, the spacing between the generated cut planes A _i,j may be arbitrarily specified by the designer, but it is preferable that the spacing be approximately the height of the weld beads that are planned to be layered when forming the object W. This series of cut planes A _i,j is generated for each identified plane A _i , and a corresponding index j (j = 1 to N) is assigned.

7A to 7C are schematic diagrams illustrating the generation of cut surfaces A _i,j based on the identified surfaces A _i . FIG. 7A shows a case where cut surfaces A i,j parallel to the surface A i formed by the bottom surface of block portion BL1 are generated at intervals for a structure W in orientation PA, where block portions BL1, BL2, and BL3 are arranged overlapping from below. FIG. 7B shows a case where cut surfaces A _{2 ,j} parallel to the surface A ₂ formed by the side surface of block portion BL1 are generated at intervals for a structure W in orientation PB, where block portions BL1, BL2, and BL3 are arranged laterally. FIG. 7C shows a case where cut surfaces A 3 _, j parallel to the surface A ₃ formed by the top surface of block portion BL3 are generated at intervals for a structure W in orientation PC, where block portions BL3 _{, BL2, and BL1} are arranged overlapping from below. Cut surfaces A _i,j are generated for each identified surface A _i in this way.

(calculation process)
The calculation unit 37 calculates the area S _i of the surface A _i and the area S _i,j of each of the generated cross-sections A _i, j, and calculates the area distribution, which is the transition thereof (step S4). This area distribution is calculated for each surface A _i identified when the cross-sections A _i,j are generated. When calculating the area distribution, the areas S _i,j are calculated in order of proximity to the surface A _i identified when the cross-sections A _i,j are generated, and the trend is output. When calculating this area distribution, in addition to the area, the perimeter of each cross-section A _i,j may be calculated and the distribution of this perimeter may also be calculated.

8A to 8C are graphs showing the area distribution of each of the generated cross-sections A _i,j , where the areas are displayed in the order of the index j (j = 1 to N) assigned to the cross-sections A _i,j . FIG. 8A shows the area distribution of the object W in orientation PA. FIG. 8B shows the area distribution of the object W in orientation PB. FIG. 8C shows the area distribution of the object W in orientation PC. Note that in FIGS. 8A to 8C, the areas S i _{,j of the cross-sections A i ,j} may be displayed in the order of the distance from the identified plane A _i .

(Decision process)
The determining unit 39 extracts a feature value for each calculated area distribution and determines the layering direction of the weld beads based on the feature value (step S5). Specifically, for each area distribution, the number of layers that satisfy the following formula (1) is counted, and the area distribution with the largest number of layers is extracted.

S _i,j ≧S _i,(j+1) …(1)

Here, when the area distribution satisfies formula (1), and in particular when S _i,j > S _i,(j+1) , the area of the lower layer of the cut surface A _i,j is larger. In contrast, when formula (1) is not satisfied, the area of the upper layer of the cut surface A _i,j is larger, resulting in an overhang. Therefore, by extracting, as a feature, the area distribution in which the number of layers satisfying formula (1) is the largest, it is possible to easily and smoothly stack weld beads when forming the object W. Note that the number of cut surfaces A _i,j varies depending on the identified surface A _i , and therefore, the ratio of the number of layers for which formula (1) above applies to the total number of cut surfaces A _i,j may be calculated and compared.

The surface _Ai in the area distribution where the number of layers satisfying the formula (1) is the maximum is set as the bottom surface to be placed on the base material 13, and the orientation direction of each cut surface Ai _,j is set as the stacking direction. Note that the direction of movement of the center of gravity or central position of each cut surface Ai _,j may also be considered as the orientation direction.

8A to 8C , among the number of layers of the cut surface A _i,j that are adjacent to each other and satisfy the above formula (1), the number of layers Ls whose area on the side of the identified surface A _i is larger than that on the side opposite to the identified surface A _i is three layers in the orientation PA (see FIG. 8A ), two layers in the orientation PB (see FIG. 8B ), and one layer in the orientation PC (see FIG. 8C ), with the number being the largest in the orientation PA. In other words, among these three examples of orientations PA, PB, and PC, by selecting the orientation PA, it is possible to suppress the occurrence of overhanging portions and easily and smoothly stack weld beads to form the object W.

(Output process)
The output unit 41 outputs a cut surface corresponding to the determined stacking direction or installation surface as cross-sectional shape data (step S6). In the three examples of orientations PA, PB, and PC, the cut surface (A1,j in FIG. 7A) corresponding to the stacking direction or installation surface (A1 in FIG. 7A) of the orientation PA determined and selected in the determination step is output as the cut shape data. Then, by using the additive manufacturing system 100 to form the object W by stacking weld beads based on this output cross-sectional shape data, the object W can be smoothly formed while suppressing the occurrence of overhanging portions.

If the stacking direction and installation surface were to be determined without performing the processing of this configuration example, it would be necessary, for example, to examine the area of the surface that would serve as the bottom surface while rotating the model of the object W around an axis multiple times. Considering the combinations possible when rotating the model of the object W around three rotation axes, the number of combinations would be enormous, requiring time for search and placing a heavy burden on users such as designers.

In contrast, according to the cross-sectional shape data generation method of this configuration example, the layering direction of the molten metal or the installation surface for placing the object W on the base material 13 can be mechanically determined based on information about the surface _Ai of the object W to be formed. In other words, since the layering direction or installation surface is determined by limiting _it to the surface Ai of the object W, verification with a finite number of patterns is sufficient compared to a search performed by rotating the model of the object W about three rotation axes, thereby reducing the burden on users such as designers. Moreover, since the area distribution of the cross-sections Ai _,j (j = 1 to N) parallel to the identified surface _Ai is taken into consideration, the layering direction and installation surface can be determined by taking into account the presence or absence and amount of overhanging portions.

When determining the installation surface and stacking direction to be installed on base material 13, an area distribution where _Si ≧ _{Si ,j} is satisfied _may be extracted in the relationship between the area Si of the specified surface Ai and the area Si _{, j of the cut surface Ai,} j, and the specified surface _Ai at that time may be set as the installation surface in contact with base material 13, and the orientation direction of the multiple cut surfaces Ai _,j may be set as the stacking direction. By determining the installation surface and stacking direction in this way, the layer with a relatively large amount of deposition can be placed on the bottom when stacking weld beads, and the amount of sagging of the stacked metal can be reduced.

The average value of the area distribution may also be used as a feature value when determining the placement surface and layering direction. Here, the larger the average value of the area distribution, the fewer layers the object W needs to be layered on. Therefore, by selecting the distribution with the largest average value of the area distribution, it is possible to extract a layering direction and placement surface that minimizes the number of layers and the number of weld bead passes.

Also, if there are multiple area distributions extracted from the features, any one of them may be selected arbitrarily.

Even in the orientation PA shown in FIG. 5A , the portion where block portion BL4 protrudes laterally from block portion BL3 does not satisfy S _i,j ≧ S _i,(j+1) in the area distribution (see FIG. 8A ) in equation (1), resulting in an overhang portion. In such a case, the object W may be divided into multiple regions based on the area distribution of the cut surface A _i,j . It is preferable to set a threshold value for the area change rate in advance, taking into account the effect of the overhang portion on the area distribution. This makes it easy to identify the layer to be extracted as the overhang portion.

9, for example, the cross section A _i(j+1) is divided into a region having the same shape as the region R1 of the cross section A _i,j and an remaining region R2. After that, the processes from the identification step (step S1) to the determination step (step S5) are executed for each of the regions R1 and R2.

As shown in Figure 10, by extracting the stacking direction (arrow D1 in Figure 10) of the main region (blocks BL1, BL2, BL3) and the stacking direction (arrow D2 in Figure 10) of the remaining region (block BL4) individually, it becomes possible to create a model that is not restricted by the installation surface of the object W, significantly reducing the difficulty of creation. At this time, the dot product of the main stacking direction (arrow D1 in Figure 10) and the secondary stacking direction (arrow D2 in Figure 10) can be calculated to identify the rotation angle required to create the overhang portion of the positioner that supports the base material 13.

Here, an example of a case where a stacking direction is determined by dividing a shaped object having an overhang portion into a plurality of regions will be described.
11A to 11C are schematic side views of a shaped object having an overhang portion.
11A, the object W1 has multiple block parts BL11, BL12, BL13, BL14, and BL15. Block part BL12 is stacked on top of block part BL11, and block parts BL13 and BL14 extend laterally from block part BL12, and further block part BL15 extends upward from block part BL14.

When this object W1 is additively manufactured using the bottom surface of block portion LB11 as the installation surface for base material 13, the portions of block portions BL13 and BL14 that are wider than the lower layers in the stacking direction D11 become overhanging regions. Therefore, as shown in FIG. 11B, this object W1 is divided into the region of block portions BL11 and BL12 and the region of block portions BL13 and BL14 and BL15, which become overhanging regions. The processes from the identification process (step S1) to the determination process (step S5) are then performed for each of the region of block portion BL13 and the region of block portions BL14 and BL15 to set the stacking directions D12 and D13.

Furthermore, in the region of block portions BL14 and BL15, the portion of block portion BL15 that is wider than the lower layer in the stacking direction D13 becomes an overhanging region. Therefore, as shown in Figure 11C, the region of block portions BL14 and BL15 is divided into the region of block portion BL14 and the region of block portion BL15 that becomes an overhanging region, and the processes from the identification process (step S1) to the determination process (step S5) are performed for the region of block portion BL15 to set the stacking direction D14.

In this way, when there are areas that are wider than the lower layer, dividing them into smaller parts and setting individual stacking directions can reduce the occurrence of overhanging areas and enable smooth and successful molding.

12, in an obliquely inclined columnar object W2, the bottom surface _Ai and the cross-sections Ai _,j (j = 1 to N) parallel to the bottom surface _Ai may have the same area. That is, in this object W2, even though the area of the upper layer is the same as that of the lower layer at the cross-section Ai _,j , the upper layer always overhangs the lower layer. In such an object W2, for example, the direction of movement of the center of gravity or central position of each cross-section Ai _,j may be regarded as the orientation direction, and this orientation direction may be set as the stacking direction.

As such, the present invention is not limited to the above-described embodiments, and the invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the disclosures in the specification and well-known technology, and these modifications and applications are within the scope of the protection sought.

As described above, the present specification discloses the following:
(1) A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing the shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
A cross-sectional shape data generation method including:
According to this cross-sectional shape data generation method, the layering direction of the molten metal or the installation surface for placing the object on the base material can be mechanically determined based on information about the surfaces of the object to be formed, thereby reducing the burden on the user. Moreover, since the area distribution of the cut surfaces parallel to the identified surfaces is taken into consideration, the layering direction and the installation surface can be determined taking into account the presence or absence and amount of overhanging portions.

(2) The cross-sectional shape data generating method according to (1), wherein in the determining step, the feature amounts for the respective area distributions are compared to determine the bottom surface of the shaped object.
This cross-sectional shape data generation method checks the area distribution of the cross section for each surface of the object to be formed, making it possible to comprehensively search for surfaces suitable for the bottom surface of the object. Furthermore, since the feature values are compared only for identified surfaces, the comparison range can be limited to a finite number, eliminating the need for cumbersome processing such as rotating the object three-dimensionally to search for the bottom surface.

(3) The cross-sectional shape data generating method according to (1) or (2), wherein the feature amount is the area of the identified surface, which is the maximum area in the area distribution.
According to this cross-sectional shape data generation method, the surface with the largest area is set as the bottom surface, which not only ensures the most stable placement on the base material, but also reduces the amount of dripping when the molten metal is layered.

(4) The cross-sectional shape data generation method according to (1) or (2), wherein the feature amount is the number of layers that satisfy a relationship that the area of the cut surface on the identified surface side is equal to or greater than the area of the cut surface on the opposite side of the identified surface, in the adjacent cut surfaces.
According to this cross-sectional shape data generation method, it is possible to search for a stacking direction or installation surface that avoids stacking of overhanging portions as much as possible.

(5) the feature amount is a mean value of the area distribution,
The cross-sectional shape data generation method according to (1) or (2), wherein in the determining step, the stacking direction or the installation surface is determined based on the value that maximizes the average value.
According to this cross-sectional shape data generation method, the stacking direction or the installation surface is determined based on the value that maximizes the average value of the area distribution. Here, the number of layers of molten metal that are stacked on the molded object can be reduced as the average value of the area distribution increases. Therefore, if the stacking direction or the installation surface is determined based on the value that maximizes the average value of the area distribution, the total number of passes required can be easily reduced.

(6) The method further includes a dividing step of dividing a layer subsequent to the cut surface adjacent to the identified surface on the opposite side into a plurality of regions when a rate of change in area between the cut surface on the identified surface side and the cut surface adjacent to the identified surface on the opposite side is greater than a preset threshold in the area distribution,
A cross-sectional shape data generation method according to any one of (1) to (5), wherein the identification step to the determination step are performed for each of the divided regions, and the stacking direction corresponding to each of the regions is determined.
According to this cross-sectional shape data generating method, when an overhang clearly occurs, the part can be divided and the stacking direction suitable for the overhang part can be extracted separately.

(7) A cross-sectional shape data generation device that generates cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
A cross-sectional shape data generating device having the above structure.
This cross-sectional shape data generation device can mechanically determine the layering direction of the molten metal or the installation surface for placing the object on the base material based on information about the surfaces of the object to be formed, thereby reducing the burden on the user. Moreover, since it takes into account the area distribution of cut surfaces parallel to the identified surfaces, it can determine the layering direction and installation surface taking into account the presence or absence and amount of overhanging portions.

(8) A program for generating cross-sectional shape data of a shaped object used when manufacturing the shaped object by repeatedly stacking molten metal in a stacking direction, the program comprising:
On the computer,
an information acquisition function for acquiring three-dimensional shape information of the object;
an identification function for identifying a surface of the object in the three-dimensional shape information;
a generation function of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation function for calculating the area distribution of the cut surface;
a determination function of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output function of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data;
A program to make this happen.
This program can mechanically determine the layering direction of the molten metal or the installation surface for placing the object on the base material based on information about the surfaces of the object to be formed, thereby reducing the burden on the user. Moreover, since it takes into account the area distribution of cut surfaces parallel to the identified surfaces, it can determine the layering direction and installation surface taking into account the presence or absence and amount of overhanging portions.

13 Base material 15 Forming control device (cross-sectional shape data generating device)
31 Information acquisition unit 33 Identification unit 35 Generation unit 37 Calculation unit 39 Determination unit 41 Output unit 100 Layered manufacturing system A _i- plane A _i,j -cutting plane W Modeled object

Claims (8)

1. A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data ,
In the determining step, the feature amounts for the respective area distributions are compared, and a surface from which the area distribution with the maximum feature amount is extracted is determined as the installation surface, which is a bottom surface of the object;
the feature amount is the area of the identified surface, which is the maximum area in the area distribution;
Cross-sectional shape data generation method. 1. A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
In the determining step, the feature amounts for the respective area distributions are compared, and a surface from which the area distribution with the maximum feature amount is extracted is determined as the installation surface, which is a bottom surface of the object;
The feature amount is the number of layers that satisfy a relationship that the area of the cut surface on the identified surface side is equal to or greater than the area of the cut surface on the opposite side to the identified surface, in the adjacent cut surfaces .
Cross-sectional shape data generation method. 1. A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
In the determining step, the feature amounts for the respective area distributions are compared, and a surface from which the area distribution with the maximum feature amount is extracted is determined as the installation surface, which is a bottom surface of the object;
the feature amount is a mean value of the area distribution,
In the determining step, the stacking direction or the installation surface is determined based on the value that maximizes the average value .
Cross-sectional shape data generation method. 1. A cross-sectional shape data generation method for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the method comprising:
an information acquisition step of acquiring three-dimensional shape information of the object;
an identification step of identifying a surface of the object in the three-dimensional shape information;
a generating step of generating cut surfaces of the object parallel to the identified surface at intervals;
a calculation step of calculating an area distribution of the cut surface;
a determination step of determining the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution;
an output step of outputting the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
In the determining step, the feature amounts for the respective area distributions are compared, and a surface from which the area distribution with the maximum feature amount is extracted is determined as the installation surface, which is a bottom surface of the object;
a dividing step of dividing a layer subsequent to the cut surface adjacent to the identified surface on the opposite side into a plurality of regions when a rate of change in area between the cut surface on the identified surface side and the cut surface adjacent to the identified surface on the opposite side is greater than a preset threshold in the area distribution,
performing the identifying step to the determining step for each of the divided regions, and determining the stacking direction corresponding to each of the regions ;
Cross-sectional shape data generation method. 1. A cross-sectional shape data generation device for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross - sectional shape data,
the determining unit compares the feature amounts for the respective area distributions, and determines a surface from which the area distribution having the maximum feature amount is extracted as the installation surface, which is a bottom surface of the object;
the feature amount is the area of the identified surface, which is the maximum area in the area distribution;
Cross-sectional shape data generator. 1. A cross-sectional shape data generation device for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
the determining unit compares the feature amounts for the respective area distributions, and determines a surface from which the area distribution having the maximum feature amount is extracted as the installation surface, which is a bottom surface of the object;
The feature amount is the number of layers that satisfy a relationship that the area of the cut surface on the identified surface side is equal to or greater than the area of the cut surface on the opposite side to the identified surface, in the adjacent cut surfaces.
Cross-sectional shape data generator. 1. A cross-sectional shape data generation device for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
the determining unit compares the feature amounts for the respective area distributions, and determines a surface from which the area distribution having the maximum feature amount is extracted as the installation surface, which is a bottom surface of the object;
the feature amount is a mean value of the area distribution,
the determining unit determines the stacking direction or the installation surface based on the value that maximizes the average value.
Cross-sectional shape data generator. 1. A cross-sectional shape data generation device for generating cross-sectional shape data of a shaped object used in manufacturing a shaped object by repeatedly stacking molten metal in a stacking direction, the device comprising:
an information acquisition unit that acquires three-dimensional shape information of the object;
an identification unit that identifies a surface of the object in the three-dimensional shape information;
a generation unit that generates cut surfaces of the object parallel to the identified surface at intervals;
a calculation unit for calculating an area distribution of the cut surface;
a determination unit that determines the stacking direction or a placement surface on which the object is to be placed on a base material, based on the feature amount of the area distribution; and
an output unit that outputs the cut surface corresponding to the determined stacking direction or the determined installation surface as cross-sectional shape data,
the determining unit compares the feature amounts for the respective area distributions, and determines a surface from which the area distribution having the maximum feature amount is extracted as the installation surface, which is a bottom surface of the object;
a dividing unit that divides a layer subsequent to the cut surface adjacent to the identified surface on the opposite side into a plurality of regions when a rate of change in area between the cut surface on the identified surface side and the cut surface adjacent to the identified surface on the opposite side is greater than a preset threshold in the area distribution,
determining the stacking direction corresponding to each of the divided regions;
Cross-sectional shape data generator.