Classifications

• • 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
  • B22F10/40—Structures for supporting workpieces or articles during manufacture and removed afterwards
  • B22F10/47—Structures for supporting workpieces or articles during manufacture and removed afterwards characterised by structural features
• • 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
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/40—Structures for supporting workpieces or articles during manufacture and removed afterwards
  • B22F10/43—Structures for supporting workpieces or articles during manufacture and removed afterwards characterised by material
• • 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
  • B22F10/60—Treatment of workpieces or articles after build-up
  • B22F10/62—Treatment of workpieces or articles after build-up by chemical means
• • 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
  • B29C64/40—Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• • 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
  • B33Y40/20—Post-treatment, e.g. curing, coating or polishing
• • 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
  • 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
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1103—Making porous workpieces or articles with particular physical characteristics
• • 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
  • B33Y80/00—Products made by additive manufacturing
• • 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 invention relates to an intermediate assembly for manufacturing a mechanical part using an additive manufacturing process.
• the invention also relates to a method for manufacturing a part using such an intermediate assembly.
• a method is known in the art which consists in manufacturing at least one part, in particular one or more metal part(s), by melting successive layers of powder by means of a laser beam controlled by a processing system of the information in which the three-dimensional coordinates of the points of the successive layers to be produced to form said parts have been recorded.
• FIG. 1 illustrates a manufacturing device 1 intended to implement such a method.
• the manufacturing device 1 comprises a reservoir 3 containing a metal powder 5 and whose bottom 7 is movable, movable in translation vertically by a rod 9 of a jack, and an adjacent tank 11, substantially parallelepiped, whose bottom is constituted by a movable plate 13, movable in translation vertically by a rod 15 of a second jack.
• the manufacturing device 1 further comprises a scraper 17 for bringing powder from the reservoir 3 to the tank 11, the scraper 17 being movable in translation along a horizontal plane A substantially parallel to the plate 13.
• the device for manufacturing 1 further comprises means 18 for generating a laser beam 19, coupled to a device 20 for moving said laser beam 19 allowing it to be oriented and/or moved to reach any point of the tank 11 .
• a first layer of powder is placed in the tank 11, substantially in the horizontal plane A, using the scraper 17.
• the layer then has a lower surface corresponding to the surface of the plate 13 and an upper surface on which the laser beam 19 is directed and moved.
• the energy supplied by this beam causes the local fusion of the powder which, on solidifying, forms a first layer of the or each part 21.
• the plate 13 After formation of this first layer, the plate 13 is lowered by a distance corresponding to the thickness of a layer of powder, while the bottom 7 of the reservoir 3 is raised by a corresponding height, so that a certain quantity of powder 22 is located above the horizontal plane A. Then, this quantity of powder 22 is brought by a blade 23 of the scraper 17, from the tank 3 into the tank 11, to form a second layer over the previous layer. In the same way as before, a second layer of each piece 21 is formed using the laser beam 19. The quantity of powder and the positions of the bottom 7 and the plate 13 are determined so as to form layers of powder of a chosen and constant thickness.
• This method allows complex parts to be manufactured quickly and fully automatically, resulting in significant savings in time and resources.
• the overhanging lower surfaces of the parts 21 cannot form angles greater than approximately 45° with the vertical direction Z to be manufactured according to such a method.
• More sloping bottom surfaces are not sufficiently supported during powder layer stacking, and their manufacture requires the addition of support parts to the design model of part 21. These support parts must be manually removed after the additive manufacturing step, which requires long and specific machining work.
• the invention aims to remedy these drawbacks, by providing a method of additive manufacturing of a metal part comprising overhanging surfaces, without requiring machining steps subsequent to the additive manufacturing.
• the subject of the invention is an intermediate manufacturing assembly comprising a part, the part comprising an overhanging part, the intermediate assembly further comprising a support structure for the overhanging part, the support structure comprising:
• Such an intermediate assembly allows the manufacture of a part comprising overhanging parts thanks to the support structure, this support part being easily removable a posteriori by taking advantage of the step of surface treatment by chemical dissolution.
• the intermediate assembly and the part are made of a metallic material.
• the overhanging part comprises at least one lower surface forming with a vertical direction an angle strictly greater than 45°.
• the connecting part may have a porosity greater than or equal to 50%.
• the porosity of a medium comprising a solid part and an interstitial part is defined as the ratio of the volume of the interstitial part to the total volume.
• the connecting part may have a porosity greater than or equal to 70%.
• the porosity of the connecting part can for example be substantially equal to 75%.
• Such porosity values allow significant embrittlement of the bonding part during a surface treatment step by chemical dissolution.
• the sole comprises a plurality of pillars defining between them the channels, the channels emerging opposite the connecting part.
• Each pillar may comprise an upper surface bearing the connecting part, a gap separating the upper surfaces of the pillars from each other being less than 1 millimeter.
• the upper surfaces of the pillars can have, for example, a hexagonal shape, or a square shape.
• the invention also relates to a method for manufacturing a metal part, the method comprising the following steps:
• the mechanical rupture of the connecting part can be implemented by applying a transverse force to a distal end of the column.
• the transverse force is oriented substantially perpendicular to the main extension direction of the column.
• Such a removal method is made possible by the geometry of the support structure and allows easy removal of the support structure, in particular manually.
• the dissolution of the outer surface can take place over a thickness of between 0.05 millimeter and 0.2 millimeter.
• Dissolution of the outer surface can reduce a mechanical strength of the bonding part by at least 90%.
• Such a feature allows easy removal of the support structure, in particular manually.
• the mechanical resistance is here defined as the value of mechanical stress that must be exerted on the connecting part to achieve its complete rupture.
• the chemical dissolution solution is in particular an acid solution, capable of “eating away” metallic materials.
• Such a solution allows surface dissolution to a small thickness, which improves the surface condition of the part and weakens the connecting part, without removing too much material from the part.
• Figure 1 is a schematic view of an additive manufacturing device
• Figure 2 is a front view of a part comprising an overhanging part
• Figure 3 is a front view of an intermediate assembly according to the invention, intended for the manufacture of the part of Figure 2, and
• figure 4 is a detail view of a support structure of the intermediate assembly of figure 3.
• FIG. 2 represents a part 21 which it is desired to manufacture by an additive manufacturing process according to the invention.
• Part 21 comprises an overhanging part 30, which comprises a lower surface 32 extending in a plane P forming an angle greater than 45° with a vertical direction Z.
• the lower surface 32 of the overhanging part 30 extends in a substantially horizontal plane P, that is to say forming an angle of 90° with the vertical direction Z.
• the vertical direction Z considered here relates to the previous additive manufacturing device 1, during an additive manufacturing step, and does not necessarily correspond to the vertical direction in the environment in which the part 21 is intended to be implemented.
• the method of manufacturing part 21 includes a step of manufacturing an intermediate assembly 34, represented in FIG. 3, according to a method by additive manufacturing by selective laser melting or selective sintering, as described above.
• the intermediate assembly 34 is a manufacturing intermediate which includes the part 21 as well as a support structure 36 shaped to support the overhanging part 30.
• the support structure 36 includes a connecting part 38 extending from the overhanging part 30, a sole 40 carrying the connecting part 38 and a column 42 carrying the sole 40 and extending so as to rest on the plate 13 by its distal end 44.
• the connecting part 38 is manufactured at the same time as the rest of the intermediate assembly 34 by additive manufacturing.
• the connecting part 38 is fusible, i.e. it is intended to be destroyed to separate the support structure 36 from the part 21.
• the connecting part 38 extends below the entire bottom surface 32, so as to support it during the additive manufacturing step.
• the sole 40 extends between the connecting part 38 and the column 42, relative to the vertical direction Z, so as to carry the connecting part 38.
• the sole 40 comprises a plurality of pillars 46 having flared shapes, defining between them channels 48 for the circulation of fluid.
• the column 42 is dense and extends substantially in the vertical direction Z, from the sole 40 to its distal end 44 intended to be in contact with the plate 13 during manufacture.
• the column 42 has, in the example shown, a shape which becomes progressively thinner from the sole 40 to the distal end 44, while retaining lateral flanks forming with the vertical direction Z angles less than 45°, and preferably less than 30°. This shape makes it possible to reduce the quantity of material necessary for the manufacture of the column 42 and facilitates its gripping, without constraining the manufacturability of the intermediate assembly 32.
• Figure 4 is a detail view showing the sole 40 and the upper part of the column 42.
• each pillar 46 comprises an upper end 50, opposite the column 42 with respect to the vertical direction Z. Said upper end 50 forms a flat surface carrying the connecting part 38.
• Each upper end 50 has a substantially square shape, in a horizontal plane.
• the upper ends can have rectangular or hexagonal shapes.
• a spacing E separating the upper ends 50 of each pillar 46 is less than or equal to 1 mm, in order to allow the manufacture of the connection part 38 over the sole
• the channels 48 defined between the pillars 46 open between the upper ends 50, over an entire lower surface of the connecting part 38, which makes it possible to bring the entire connecting part into contact with the liquid circulating in the channels 48.
• the process for manufacturing part 21 includes, after the additive manufacturing step, a step of immersing the intermediate assembly 34 in a dissolution solution.
• the chemical dissolution solution is for example an acid solution, capable of “eating away” the metallic materials.
• the intermediate assembly 34 is immersed in the bath of dissolution solution for an immersion time of between 15 minutes and 1 hour, preferably between 15 and 45 minutes.
• the dissolution solution flows through the channels 48 and permeates the entire connecting part 38.
• an outer surface of the intermediate assembly 32 is dissolved by the dissolution solution, to a small thickness.
• the dissolution thickness is in particular between 0.05 millimeter and 0.2 millimeter.
• Such a surface immersion and dissolution step is standard in additive manufacturing processes by selective melting on a powder bed, and makes it possible to improve the surface condition of the manufactured parts.
• This step also makes it possible here to significantly weaken the connecting part 38, since its high porosity makes the dissolution thickness non-negligible relative to its structure.
• the connecting part 38 loses for example at least 90% of its mechanical strength during the step of immersion and surface dissolution.
• the method then comprises a step of removing the support structure 36, during which a transverse force, that is to say oriented along a direction in a horizontal plane, is applied to the distal end 44 of the column 42.
• This transverse force applied manually or by means of a tool depending on the dimensions involved, allows the mechanical rupture of the connecting part 38 and the withdrawal of the support structure 36.
• the invention can be generalized to any part having an overhanging part 30 whose lower surface 32 forms an angle greater than 45° with the vertical direction Z, by changing the shape of the column 42 and/or the orientation of the sole 40 , to have suitable support during the additive manufacturing stage.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (2)

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• 2022
  • 2022-02-09 FR FR2201129A patent/FR3132449B1/fr active Active
• 2023
  • 2023-02-08 EP EP23707145.1A patent/EP4476014A1/de active Pending
  • 2023-02-08 WO PCT/FR2023/050171 patent/WO2023152449A1/fr not_active Ceased
  • 2023-02-08 US US18/837,389 patent/US20250144711A1/en active Pending
  • 2023-02-08 CN CN202380019349.7A patent/CN118647476A/zh active Pending

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