Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/24—Generating plasma
  • H05H1/48—Generating plasma using an arc
  • H05H1/50—Generating plasma using an arc and using applied magnetic fields, e.g. for focusing or rotating the arc
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
  • B22F12/10—Auxiliary heating means
  • B22F12/17—Auxiliary heating means to heat the build chamber or platform
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
  • B22F12/70—Gas flow means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K10/00—Welding or cutting by means of a plasma
  • B23K10/02—Plasma welding
  • B23K10/027—Welding for purposes other than joining, e.g. build-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/001—Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material
• • 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
  • B29C64/10—Processes of additive manufacturing
  • B29C64/141—Processes of additive manufacturing using only solid materials
  • B29C64/153—Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• • 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
  • B29C64/20—Apparatus for additive manufacturing; Details thereof or accessories therefor
  • B29C64/295—Heating elements
• • 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
• • 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
  • B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
• • 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
  • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/64—Burning or sintering processes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/02—Arrangements for confining plasma by electric or magnetic fields; Arrangements for heating plasma
  • H05H1/10—Arrangements for confining plasma by electric or magnetic fields; Arrangements for heating plasma using externally-applied magnetic fields only, e.g. Q-machines, Yin-Yang, base-ball
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/24—Generating plasma
  • H05H1/2406—Generating plasma using dielectric barrier discharges, i.e. with a dielectric interposed between the electrodes
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/24—Generating plasma
  • H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
  • H05H1/4645—Radiofrequency discharges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/20—Direct sintering or melting
  • B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/50—Inorganic materials other than metals or composite materials
  • B23K2103/52—Ceramics
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
  • C04B2235/602—Making the green bodies or pre-forms by moulding
  • C04B2235/6026—Computer aided shaping, e.g. rapid prototyping
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
  • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
  • C04B2235/666—Applying a current during sintering, e.g. plasma sintering [SPS], electrical resistance heating or pulse electric current sintering [PECS]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• the present invention relates to the general field of selective additive manufacturing.
• a general object of the invention is to overcome the disadvantages of the configurations proposed so far.
• an object of the invention is to propose a solution that allows heating without loading and lifting of powder.
• Another object is to propose a heating solution (performed before or after a selective melting step) operating at very low pressure, so as to optimize the performance of the powder melting device.
• Yet another purpose is to provide a solution that can reduce costs and times of preheating or post-treatment by heating in manufacturing cycles.
• Another object of the invention is to propose a simple construction solution.
• Another aim is also to provide an effective heating solution, over a wide range of pressures, while remaining at low pressure ( ⁇ 0.1 mbar).
• a plasma generating device said device being adapted to be arranged and moved above the powder bed, at a distance from the powder bed enabling the plasma to be generated thereon,
• control unit for controlling the supply and the displacement of the plasma generating device
• the plasma generating device comprises a magnetic confinement assembly of the plasma.
• the plasma is confined and located in a restricted area, optimizing the preheating of the powder bed.
• the energy efficiency of the heating cycle is thus improved, thereby decreasing the duration and cost of a preheating or heating cycle.
• the magnetron device comprises a magnet arrangement configured to confine electrons in a linear pattern
• the magnetron type device comprises an ion source slot, the slot being formed through the electrode and opening opposite the powder bed;
• the plasma generating device is adapted to be displaced with a main displacement component perpendicular to the direction in which it extends;
• the unit for the power supply of said plasma generating device comprises a continuous high voltage source and / or radiofrequency and / or pulse.
• the invention proposes an apparatus for manufacturing a three-dimensional object by selective additive manufacturing comprising in an enclosure: a support for the deposition of successive layers of additive manufacturing powder,
• At least one power source suitable for the selective consolidation of a layer of powder applied by the distribution arrangement
• This apparatus may include a dispensing arrangement having a squeegee or layering roll, the plasma generating device extending proximate to or movable with said squeegee or roll, or placed on an independent movable device like a robot arm for example.
• the invention proposes a manufacture of a three-dimensional object by selective additive manufacturing, said method comprising the steps:
• At least one heating step is carried out before and / or after the consolidation step.
• FIG. 1 is a schematic representation of an additive manufacturing apparatus comprising a heating device according to a possible embodiment of the invention
• FIG. 2 is a block diagram of a plasma generating device heating a bed of powder according to the invention
• FIG. 3 is a schematic sectional view of a magnetron plasma generation device according to the invention.
• FIG. 4 is a diagram of the structure of a magnet arrangement of a magnetron device according to the invention
• FIG. 5 is a 3D block diagram, seen from below, showing the operation of a magnetron cathode device in accordance with the invention
• FIG. 6 is a diagrammatic sectional view showing an embodiment of a magnetron cathode device in accordance with the invention optionally equipped with a rotating electrode (cathode);
• FIG. 7 is a 3D representation, seen from below, of a second embodiment of a magnetic confinement plasma generation device generating an ion beam according to the invention (also known as inverted magnetron) );
• FIG. 8 is a schematic representation of a powder bed heated by means of a heating device according to the invention.
• the selective additive manufacturing apparatus 1 of FIG. 1 comprises:
• a support such as a horizontal plate 3 on which are deposited successively the various layers of additive manufacturing powder (metal powder, ceramic powder, etc.) making it possible to manufacture a three-dimensional object (object 2 in the shape of a fir tree in FIG. )
• additive manufacturing powder metal powder, ceramic powder, etc.
• this arrangement 4 comprising for example a squeegee 5 or a layering roll for spreading the different successive layers of powder (displacement along the double arrow A),
• control unit 9 which controls the various components of the apparatus 1 according to pre-stored information (memory M), a mechanism 10 for enabling the support of the plate 3 to be lowered as the layers are deposited (displacement along the double arrow B).
• the set 8 comprises two sources of consolidation:
• the assembly 8 may comprise only one source, for example a source of energy located under vacuum or at very low pressure ( ⁇ 0.1 mbar): electron gun, laser source, etc.
• the assembly 8 may also include several sources of the same type, such as for example several electron guns and / or laser sources, or means for obtaining several beams from the same source.
• At least one galvanometric mirror 14 makes it possible to orient and move the laser beam coming from the source 12 with respect to the object 2 as a function of the information sent by the imaging unit. control 9.
• the assembly 8 comprises several sources 12 of the laser type and the displacement of the different laser beams is obtained by moving the different sources 12 of the laser type above the layer of powder to be fused.
• Deflection and focusing coils 15 and 16 locally deflect and focus the electron beam on the layer areas to be sintered or fused.
• a heat shield T can be interposed between the source or sources of the assembly 8.
• the components of the apparatus 1 are arranged within a sealed enclosure 17 connected to at least a vacuum pump 18 which maintains a high vacuum inside said chamber 17 (typically about 10 2/10 -3 mbar or even 10 4/10 -6 mbar).
• the apparatus further comprises a heating device 19 disposed above the bed of powder and able to move linearly with respect thereto.
• This heating device 19 can be placed behind the squeegee 5 or the layering roller on the same sliding carriage. It can also be mounted on an independent trolley or on a robot arm. In the latter case (not shown) the pattern described by the magnetic trap of the magnetron cathode can be of any other shape than linear, allowing for example a localized heating.
• the displacement of said heating device 19, its power supply and its residence time in front of the powder bed that is to be heated or preheated are also controlled by the unit 9.
• the heating device 19 comprises a plasma generation device 20 that is moved above the metal powder bed (solid or granular surface 21, made up of micro- or nanoparticles). powder).
• the source 22 allows the application of a high voltage (> 0.2 kV) between the plasma generating device 20 and the surface 21 of the powder bed.
• the supply thus made by the source 22 can be direct current, low frequency, radio frequency (RF), or pulse.
• RF radio frequency
• the plasma generating device 20 generates, under the effect of said source 22, electric discharges between the plasma generating device 20 and the surface 21 and creates a plasma, which provides the heating of the surface 21.
• the plasma generating device 20 extends substantially parallel to the surface 21. It is moved parallel to said surface 21, perpendicular to the direction in which it extends. Such a configuration allows homogeneous heating on a surface of the powder bed corresponding to the length of the plasma generating device 20 and its displacement distance.
• the surface 21 of the powder bed is for example connected to ground.
• the heating can be performed before the consolidation step, thus constituting a preheating step, so as to avoid powder splashes.
• a heating step can be performed after the consolidation step, thus constituting a post-heating step, so as to anneal the material or limit the quenching effect by the working atmosphere, or to control the evolution of the cooling temperature so as to obtain a particular crystalline structure.
• this device comprises a magnetic plasma confinement system.
• FIG. 3 shows a plasma confinement assembly comprising a linear plasma generation magnetron device 23.
• It comprises an electrode 24, preferably polarized negatively (and playing, in this case, the role of cathode).
• Magnets can be permanent or electromagnets, or a combination of both.
• the electrode 24 can be powered (source 22) in direct current (DC), in Radio Frequency (RF) or in high power pulse mode (HiPIMS - High Power Impulse). Magnetron Sputtering, but usually receiving a negative voltage.
• DC direct current
• RF Radio Frequency
• HiPIMS High Power Pule
• the constituent material of the electrode 24 may be an electrical conductor, an insulator or a semiconductor.
• a circulation 26 of a cooling fluid (for example water, glycol, etc.) is provided in the electrode 24, powered by an external system.
• the refrigerant may for example be injected through orifices in one of the walls of the carriage 27, and may for example be circulated between the rows of magnets of the magnet arrangement 25, the fluid thus also being contact with the electrode 24 and cooling thereof.
• the refrigerant can then be extracted through a second orifice in the carriage 27.
• Such a magnetron device 23 is mounted inside the enclosure 17 on a carriage 27 disposed above the bed of powder and able to move linearly relative thereto (double arrow in the figure).
• This carriage 27 is for example that of the layering roller, the magnetron device 23 being disposed behind said roller (with respect to the direction of advance thereof).
• an example of a magnet arrangement 25 comprises two rows of magnets arranged to form a linear track 28.
• the magnets of opposite polarities are thus arranged on either side of the track 28.
• the magnetic field generated by the magnets traps the electrons around the magnetic field lines, on the side of the electrode 24 facing the powder bed, and thus increases the ionization of the gas along a linear pattern 29 along the magnetic field. runway 28, as shown in FIG.
• This magnetic configuration concentrates the electrons and along the pattern 29, forming a plasma along said pattern 29.
• an alternating arrangement (north and south to center, or vice versa) is generally made to provide a closed magnetic track 28 as illustrated in FIG.
• the arrangement of magnets 25 is therefore configured to generate a magnetic field that will concentrate the electrons in a determined area.
• it is a linear pattern, but the magnets could be arranged to form any other geometric model, such as a circle or a curve.
• the concentration of electrons in a given zone makes it possible to promote local ionization of the gas in the zone, and the presence of a magnetic trap makes it possible to confine the plasma in a precise zone, even at very low pressure.
• a low operating pressure implies a lower density of the atmosphere. surrounding and therefore less shock between the electrons emitted by the source 12 and the surrounding gas.
• the presence of a magnetic field makes it possible to concentrate the electrons in an area and thus to promote the formation of a plasma despite the low density of the surrounding atmosphere.
• the width of the heated zone is then reduced, which improves the heating accuracy.
• the decrease in the operating pressure limits the surrounding oxygen level, which limits the formation of oxides and fumes.
• the molten material is therefore less polluted by fumes and oxides.
• the denudation phenomenon which consists of a depletion of the metal powders in the zone surrounding the solidified track due to the blowing of these powders by a flow of metal vapor generated by the melting of the powders during the laser heating, is also strongly limited by reducing the surrounding pressure.
• the metal vapors produced during the melting of the powders are then less dense and the flow of these vapors does not blow the powders.
• the magnetic field B is configured to trap only the electrons, without altering the behavior of the ions.
• the mass ratio between the electrons and the ions generates a similar ratio between their respective magnetic gyration radii (Larmor rays).
• the plasma thus created is confined between the electrode 24 and the free surface 21 of the powder bed.
• a magnetron device 23 By placing such a magnetron device 23 with the homogeneous part (plasma or ion beam) towards the powder bed, it is possible to effectively transfer energy from the plasma species to the powder and thus to heat it.
• the energy is transmitted to the powder by several biases simultaneously coexisting in a plasma. These are charged species, electrons and ions, but also neutral energy species, including atomized neutral atoms of the electrode (cathode), non-radiative excited states (metastable), and photons.
• the surface (powder) receives the two charged species, the charge effects (Coulomb repulsion) are reduced or even eliminated.
• the denser the plasma the greater the energy transmitted to the surface.
• the amount of energy in the case of ions but more generally for any type of plasma, can easily be adjusted by the ionic acceleration voltage or the power injected into the plasma. Better control can be achieved by the pulsed operation of the plasma, alternating heating phases (active plasma - ON, in English) and thermal expansion phases (plasma OFF). Changing the ON / OFF period, also known as the duty cycle, makes it easy to adjust the temperature.
• the magnet arrangement 25 is fixedly mounted relative to the magnetron device 23, the electrode 24 being rotatably mounted along the axis along which it extends.
• the position and orientation of the magnetic field with respect to the magnetron device 23 does not change during operation, making it possible to control the plasma formation zone.
• the electrode 24 is rotated. In this way, the part of the electrode 24 which is exposed to the plasma changes regularly, limiting the heating of a particular zone, the plasma being always confined to the magnetic trap generated by the magnet arrangement 25 which has a fixed orientation relative to the magnetron device 23, in particular to the surface 21 of the powder bed, as illustrated in FIG.
• Variations of magnetron cathodes also make it possible to obtain a linear and homogeneous plasma.
• the electrode 24 is a plane electrode.
• the magnetron device may comprise an electrode 24 in which a slot 30 is formed.
• the slot 30 is arranged opposite the track 28, the track 28 being formed by a cavity extending between the rows of the magnet arrangement 25.
• An injection port 31 is formed in a wall of the carriage 27, at the bottom of the cavity formed by the track 28 and the slot 30.
• a gas is injected into the cavity through the injection orifice 31. During the excitation of the cathode 24, the gas is then strongly ionized by the electrons effectively trapped by the magnetic field B generated by the magnet arrangement. 25.
• the gas injected through the injection orifice 31 is the gas forming the working atmosphere, making it possible to simplify the apparatus.
• the cavity formed by the track 28 and the slot 30 thus forms an ion source.
• the magnetic barrier generated by the magnet arrangement increases the electrical resistance of the plasma, thereby generating a potential difference in the Hall effect plasma.
• a charge movement generated by the magnetic field B and an electric field generated by the excitation of the cathode 24 causes a circulation of electrons along the track 28, facing the slot 30, leading to the homogenization of the plasma.
• the ions, not magnetized, are projected by the electric field through the slot 30.
• the slot 30 is ideally located opposite the powder bed, so as to project the plasma jet on the surface 21 to be heated.
• the plasma generating device 20 is of any other shape than linear and is adapted to be moved with a robot.
• this plasma generating device 20 By moving this plasma generating device 20 it is possible to scan the surface 21 of the powder bed. Keeping the plasma lit and performing a full scan of the surface 21 of the powder bed, thereby superficially heating the bed of powder.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Optics & Photonics (AREA)
• Ceramic Engineering (AREA)
• Electromagnetism (AREA)
• Analytical Chemistry (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Plasma Technology (AREA)
• Powder Metallurgy (AREA)
• Discharge Heating (AREA)
• Furnace Details (AREA)

Applications Claiming Priority (2)

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Citations (2)

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• 2018
  • 2018-04-06 FR FR1853031A patent/FR3079775B1/fr active Active
• 2019
  • 2019-04-05 EP EP19720981.0A patent/EP3774132A1/de not_active Withdrawn
  • 2019-04-05 US US17/045,710 patent/US20210086286A1/en not_active Abandoned
  • 2019-04-05 WO PCT/FR2019/050809 patent/WO2019193299A1/fr not_active Ceased
  • 2019-04-05 KR KR1020207031706A patent/KR20210112236A/ko not_active Ceased
  • 2019-04-05 JP JP2021503214A patent/JP2021520310A/ja not_active Ceased
  • 2019-04-05 CN CN201980036631.XA patent/CN112823071A/zh active Pending

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