Method for manufacturing a part provided with a cylindrical hole, by depositing and solidifying successive layers of a powder, and part obtained by this method

Abstract

One aspect of the invention concerns a method for manufacturing a part (10) by depositing and solidifying successive layers of a powder along a deposition axis Z, comprising a cylindrical final hole (30), characterized in that it comprises the following steps: depositing and solidifying successive layers of powder around a predefined zone, the predefined zone forming, after deposition and solidification of a last layer of powder, a construction hole (200), the construction hole (200) comprising a permanent portion (210) and a temporary portion (220), and forming the final hole (30), of axis X perpendicular to the deposition axis Z, by deformation and collapse of the temporary portion (220) of the construction hole (200), the final hole (30) having a section in the shape of a circle C1.

Description

METHOD FOR MANUFACTURED A PART WITH A CYLINDRICAL HOLE BY DEPOSIT AND SOLIDIFICATION OF SUCCESSIVE LAYERS OF POWDER AND THE PART OBTAINED BY THIS METHOD TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of additive manufacturing and particularly to the laser powder bed fusion process.

[0002] The present invention relates more particularly to a method of manufacturing a part having a cylindrical hole by depositing and solidifying successive layers of a powder, and to a part obtained by this method. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Laser beam melting (LBM) or Laser Metal Deposition (LMD) in Anglo-Saxon terminology, is an additive manufacturing technology, also called three-dimensional (3D) printing, involving the use of a 3D printer.

[0004] Powder bed fusion can be used to shape metal or polymer parts, depending on the technology selected. For example, Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) use metal powders such as aluminum, chromium, and cobalt. In contrast, Selective Laser Sintering (SLS) and Multi Jet Fusion (MJF) use polymer powders such as nylon and nylon reinforced with glass or carbon fibers.These various technologies of the laser powder bed fusion process make it possible to manufacture three-dimensional parts by adding material, that is, by depositing and solidifying successive layers of powder. This type of process differs from so-called "conventional" manufacturing processes, in which parts are made either by removing material, called... machining, either by plastic deformation of the material or by assembly of several elements.

[0005] Typically, as shown in Figure 1, the 3D printer used to produce a part 10 by laser powder bed fusion 7 is a machine 2 comprising: - a manufacturing bin 4 comprising a manufacturing platform 42 forming a base for manufacturing part 10, the manufacturing platform 42 being movable in translation along a deposition axis Z, - a powder feed hopper 5 arranged near the manufacturing hopper 4 and comprising a bottom 52 that moves in translation along the Z axis, - a scraper 6 moving in translation along an axis Y, perpendicular to the axis Z, on a first rail 22 of machine 2, and - at least one laser 8 comprising a laser beam 82, the laser 8 being movable in translation along an X axis, perpendicular to the Z axis, and along the Y axis, on a second rail 24 of the machine 2.

[0006] Additive manufacturing of a part 10 requires the prior creation of a digital production file using suitable software including: o a slicing of the 3D model of the part into a plurality of slices with a predetermined thickness, and o the parameters of the laser 8 such as its power, the speed and the scanning pattern of the laser beam 82, the thickness of the slices of the part 10 etc...

[0007] The manufacturing process for part 10 by laser powder bed fusion involves the following successive steps: - translation of the base 52 of the feed tray 5 along the Z axis, upwards, so as to obtain a raised quantity of powder 7, - translation of the bottom 42 of the manufacturing tank 4 along the Z axis, downwards, so as to obtain a free space above the powder bed 7 present in the manufacturing tank 4, - transfer by scraper 6 of a quantity of powder 7 from the feed tray 5 to the manufacturing tray 4 and distribution of the powder 7 uniformly in the manufacturing tray 4 so as to create a new layer of powder 7 whose thickness is substantially equal to that of a slice of the part 10, - selective scanning by the laser beam 82 of the laser 8 of certain areas of the newly deposited powder layer 7 so as to fuse and solidify the powder particles to create a two-dimensional slice of the part 10, and - repetition of the three previous steps until the final three-dimensional piece 10 is obtained.

[0008] However, additive manufacturing using laser powder bed fusion does not allow for the fabrication of an unsupported, or "ceiling," surface because the unsupported surface collapses when the part is subjected to gravity, i.e., when it is completely removed from the powder bed. Consequently, the formation of cylindrical holes, whose axis extends perpendicularly to the Z-axis of deposition (i.e., is essentially horizontal), is not feasible. Indeed, at the highest point of a cylindrical hole, the surface is unsupported and collapses. SUMMARY OF THE INVENTION

[0009] The invention offers a solution to the problems mentioned above, by proposing a method for manufacturing a part by depositing and solidifying successive layers of a powder along a deposition axis Z, the part being provided with a cylindrical hole whose axis extends perpendicularly to the deposition axis Z.

[0010] A first aspect of the invention relates to a method for manufacturing a part by depositing and solidifying successive layers of a powder along a deposition axis Z, comprising a final cylindrical hole. The manufacturing process comprises the following steps: - deposition and solidification of successive layers of powder around a predefined area, the predefined area forming, after deposition and solidification of a final layer of powder, a build hole, the build hole comprising a constant portion and a temporary portion, and - formation of the final hole, with axis X perpendicular to the deposition axis Z, by deformation and collapse of the temporary portion of the construction hole, the final hole having a circular cross-section C1.

[0011] The "predefined zone" is a three-dimensional area that extends along three axes X, Y and Z. This predefined zone corresponds to a volume intended to form the hole for the construction of the part, after the deposition and solidification of all the layers of powder necessary for the construction of the part.

[0012] The manufacturing process according to the invention makes it possible, through the formation of a construction hole during the production of a part made according to the laser powder bed fusion process, to program the production of a final cylindrical hole taking into account the deformation and collapse of the temporary portion of the construction hole.

[0013] Advantageously, the constant portion of the construction hole is arranged below a temporary portion of the construction hole, following the orientation of the deposition axis Z.

[0014] Preferably, the constant portion of the construction hole has a section comprising a lower arc of the circle C1 centered at 01 with radius r1, and the temporary portion of the construction hole has a section comprising an upper arc of a circle C2 centered at 02 with radius r2, and two connecting segments each linking the lower arc of the constant portion to the upper arc of the temporary portion of the construction hole.

[0015] Advantageously, the center 01 of circle C1 and the center 02 of circle 02 are aligned along the Z axis and spaced apart from each other by a distance L1.

[0016] Preferably, the radius r2 of circle C2 is equal to the radius r1 of circle 01.

[0017] Preferably, each connecting segment of the provisional portion is tangent to the lower arc of the constant portion of the construction hole and is tangent to the upper arc of the provisional portion of the construction hole.

[0018] According to a first embodiment of the invention, each connecting section of the temporary portion of the construction hole comprises: - a connecting segment extending substantially along the Z-axis and linked to the lower arc of the constant portion, - an intermediate segment connected to the upper arc of the provisional portion, and - an intermediate arc of a circle C3 with center 03 and radius r3 connecting the connecting segment to the intermediate arc.

[0019] Advantageously, each intermediate segment of each connecting section of the provisional portion of the construction hole is tangent to the intermediate arc and is tangent to the upper arc of the provisional portion of the construction hole.

[0020] Preferably, the center 01 of circle C1 and the center 03 of circle 03 are aligned along the Z axis and spaced apart from each other by a distance L2, and the distance L2 is greater than the distance L1.

[0021] Advantageously, the radius r3 of circle 03 is equal to the radius r1 of circle 01.

[0022] Preferably, each intermediate segment of each connecting section of the provisional portion of the construction hole forms an angle a, between 30° and 45°, with an axis Y passing through the center 02 of the circle 02 and perpendicular to the X axis and the Z axis.

[0023] According to a second embodiment of the invention, each connecting section of the temporary portion of the construction hole comprises a connecting segment extending substantially along the Z axis and linking the lower arc of the constant portion to the upper arc of the temporary portion of the construction hole.

[0024] Advantageously, the step of depositing and solidifying successive layers of powder includes a substep of forming at least one longitudinal wall extending from the lower arc of the permanent portion to the upper arc of the temporary portion of the construction hole, each longitudinal wall extending parallel to an XZ plane. The presence of longitudinal walls allows the temporary portion of the construction hole to be supported.

[0025] Preferably, the step of depositing and solidifying successive layers of powder includes a substep of forming a normal wall extending from the lower arc of the permanent portion to the upper arc of the temporary portion of the construction hole, the normal wall extending parallel to a plane YZ. The presence of a normal wall increases the rigidity of the construction hole.

[0026] Advantageously, the substep of forming at least one wall forms a single normal wall to allow the circulation of a fluid inside the construction hole.

[0027] Preferably, the final hole formation step includes a sub-step of dissolving the longitudinal walls and / or the normal wall of the construction hole.

[0028] A second aspect of the invention relates to a part produced by depositing and solidifying successive layers of a powder along a deposition axis Z. The part is obtained by the manufacturing process according to the invention. The final hole of the part is delimited along the deposition axis Z by a lower surface and an upper surface, the upper surface being unsupported and substantially arranged opposite the lower surface of the final hole.

[0029] Advantageously, the circularity of the lower surface of the final hole is substantially identical to the circularity of the lower surface of the lower arc of the construction hole, and the circularity of the upper surface of the final hole is lower than the circularity of the lower surface of the final hole.

[0030] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0031] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: - Figure 1, already described, is a schematic representation of a machine classically used for the implementation of a laser powder bed fusion process; - Figure 2 is a cross-sectional diagram along a YZ plane of a part being manufactured by a laser powder bed fusion process and comprising a construction hole according to a first embodiment of the invention; - Figure 3 is a cross-sectional diagram along a YZ plane of a part being manufactured by a laser powder bed fusion process and including a construction hole according to a second embodiment of the invention; - Figure 4 is a perspective cross-section along an XY plane of a part being manufactured comprising a construction hole according to the second embodiment of the invention; - Figure 5 is a cross-sectional diagram of a final part produced by a laser powder bed fusion process and comprising a final hole according to the invention. DETAILED DESCRIPTION

[0032] An example of the manufacturing process according to the invention and of a part obtained by this process are described in detail below, with reference to the accompanying drawings. This example illustrates the features and advantages of the invention.

[0033] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0034] For the purposes of understanding the invention, an orthogonal XYZ coordinate system, as shown in the figures, will be adopted, in which the X and Y axes extend in a horizontal plane and the Z axis extends in a vertical plane, following the orientation shown in the figures. A lower portion towards an upper portion of a cylindrical end hole is oriented along the Z axis of the XYZ coordinate system.

[0035] In the description, the terms "lower" and "upper" are defined along the Z axis, for the same element, with the "lower" part being located below the "upper" part.

[0036] Figures 2, 3 and 4 illustrate a 10F part in the process of being manufactured by depositing and solidifying successive layers of a powder, along a deposition axis Z, and having a construction hole 200 extending along an axis X.

[0037] The part 10F being manufactured is delimited between a lower surface 12A and an upper surface 12B and includes the construction hole 200 which is delimited between a low point 202 and a high point 204, along the Z axis.

[0038] More specifically, the 10F coin currently being manufactured includes: - a lower part 14F corresponding to the part of piece 10F located below the construction hole 200, that is to say the part extending from the lower surface 12A of part 10F up to the lowest point 202 of construction hole 200, - a perforated portion 16F corresponding to the part of the piece 10F comprising the final hole 30, that is to say the portion extending from the lowest point 202 of the construction hole 200 to the highest point 204 of the construction hole 200, and - an upper part 18F corresponding to the part of the part 10F located above the construction hole 200, that is to say the part extending from the high point 204 of the construction hole 200 to the upper surface 12B of the part 10F.

[0039] As shown in Figures 2, 3, and 4, the construction hole 200 comprises a permanent portion 210 and a temporary portion 220. A first embodiment of the construction hole 200 is shown in Figure 2, and a second embodiment of the construction hole 200 is shown in Figures 3 and 4. According to the first and second embodiments, the permanent portion 210 of the construction hole 200 is arranged below the temporary portion 220 of the construction hole 200, along the orientation of the Z-axis. The construction hole 200 is configured to form a final hole 30, illustrated in Figure 5, by deformation and collapse of the temporary portion 220 of the construction hole 200. The final hole 30 obtained is substantially identical for the first and second embodiments of the invention.

[0040] Preferably, the construction hole 200 is symmetrical with respect to the Z axis passing through the center 01 of the circle C1 and has a constant cross-section along the X axis. More particularly, the construction hole 200 is delimited along the Z axis by a lower surface 206 and an upper surface 208, the upper surface 208 being unsupported and substantially arranged opposite the lower surface 206 of the construction hole 200.

[0041] The constant portion 210 of the construction hole 200 is identical for the first and second embodiments of the invention. More particularly, the constant portion 210 of the construction hole 200 has a cross-section comprising a lower arc 212 of a circle C1 with center O1 and radius ri, delimited between a first end 212A and a second end 212B. Advantageously, the arc lower 212 forms a semicircle in which the first and second endpoints 212A, 212B are aligned with the center 01 of circle C1, along the Y axis.

[0042] The provisional portion 220 of construction hole 200 has a section comprising: - an upper arc 222 of a circle C2 with center 02 and radius r2, delimited between a first endpoint 222A and a second endpoint 222B, and - a first connecting section 230 linking the first end 212A of the lower arc 212 of the permanent portion 210 to the first end 222A of the upper arc 222 of the temporary portion 220, and - a second connecting section 240 linking the second end 212B of the lower arc 212 of the constant portion 210 to the second end 222B of the upper arc 222 of the temporary portion 220.

[0043] More specifically, the first connecting section 230 of the provisional portion 220 of the construction hole 200 is arranged before the second connecting section 240 of the provisional portion 220 of the construction hole 200, following the orientation of the Y axis.

[0044] As illustrated in Figures 2 and 3, the center O1 of circle C1 and the center O2 of circle C2 are aligned along the Z-axis and separated from each other by a distance L1. More specifically, the distance L1 corresponds to the number of powder layers fused to the last layer spread, i.e., the powder layer being fused, during laser powder bed fusion manufacturing. Advantageously, the distance L1 is between 2 and 5 powder layer thicknesses. Preferably, the radius r2 of circle C2 is equal to the radius r1 of circle C1. For example, the radii r1 and r2 are between 0.6 mm and 1.5 mm.

[0045] According to the first embodiment of the invention as shown in Figure 2: - the first connecting section 230 of the construction hole 200 has a cross-section comprising: o a first connecting segment 232 extending substantially along the Z axis, delimited between a lower end 232A and a upper end 232B and connected to the first end 212A of the lower arc 212 at its lower end 232A, o a first intermediate arc 234 of a circle C3 of center 03 and radius r3, delimited between a lower end 234A and an upper end 234B, and connected to the first connecting segment 232 at its lower end 234A, and o a first intermediate segment 236 delimited between a lower end 236A and an upper end 236B, and connected to the upper end 234A of the first intermediate arc 234 at its lower end 236A, and connected to the first end 222A of the upper arc 222 of the provisional portion 220 at its upper end 236B; - the second connecting section 240 of the construction hole 200 has a cross-section comprising: o a second connecting segment 242, extending substantially along the Z-axis, delimited between a lower end 242A and an upper end 242B and connected to the second end 212B of the lower arc 212 at its lower end 242A, o a second intermediate arc 244 of a circle C3 with center O3 and radius r3, delimited between a lower end 244A and an upper end 244B, and connected to the second connecting segment 224 at its lower end 244A, and o a second intermediate segment 246 delimited between a lower end 246A and an upper end 246B, and connected to the upper end 244A of the second intermediate arc 244 at its lower end 246A and connected to the second end 222B of the upper arc 222 of the provisional portion 220 at its upper end 246B.

[0046] The construction hole 200 according to the first embodiment of the invention has approximately an oblong shape comprising a point formed by the upper arc 222 of the provisional portion 220.

[0047] As illustrated in Figure 2, the center 01 of circle C1 and the center 03 of circle 03 are aligned along the Z-axis and separated from each other by a distance L2 greater than the distance L1. More specifically, the difference between the distance L1 and the distance L2 (L2-L1) corresponds to the number of temporary powder layers, that is, the powder layers intended to collapse during the formation of the final hole 30. Advantageously, the distance L2-L1 is between 1 and 5 powder layer thicknesses. Preferably, the radius r3 of circle 03 is equal to the radius r1 of circle 01.

[0048] According to certain embodiments of the construction hole 200, the first connecting segment 232 of the first connecting section 230 of the temporary portion 220 is tangent to the lower arc 212 of the permanent portion 210 at its lower end 232A and is tangent to the intermediate arc 234 of the first connecting section 230 at its upper end 232B. The first intermediate segment 236 of the first connecting section 230 of the temporary portion 220 is tangent to the intermediate arc 234 of the first connecting section 230 at its lower end 236A, and is tangent to the upper arc 222 of the temporary portion 220 at its upper end 236B. Furthermore, the second connecting segment 242 of the second connecting section 240 of the temporary portion 220 is tangent to the lower arc 212 of the constant portion 210 at its lower end 242A and is tangent to the intermediate arc 244 of the second connecting section 240 at its upper end 242B.The second intermediate segment 246 of the second connecting section 240 of the provisional portion 220 is tangent to the intermediate arc 244 of the second connecting section 240 at its lower end 246A, and is tangent to the upper arc 222 of the provisional portion 220 of the construction hole 200 at its upper end 246B.

[0049] Preferably, each of the first and second intermediate segments 236, 246 of each connecting section 230, 240 of the provisional portion 220 of the construction hole 200 forms an angle a, between 30° and 45°, with the Y axis passing through the center 02 of the circle C2.

[0050] According to the second embodiment of the invention as shown in Figure 3: the first connecting section 230 of the construction hole 200 has a section comprising a first connecting segment 232, extending substantially along the Z axis, delimited between a lower end 232A and an upper end 232B, and connected to the first end 212A of the lower arc 212 at its lower end 232A and connected to the second end 222B of the upper arc 222 of the temporary portion 220 at its upper end 232B, and - the second connecting section 240 of the construction hole 200 has a section comprising a second connecting segment 242, extending substantially along the Z axis, delimited between a lower end 242A and an upper end 242B, and connected to the second end 212B of the lower arc 212 at its lower end 242A and connected to the second end 222B of the upper arc 222 of the temporary portion 220 at its upper end 242B.

[0051] The construction hole 200 according to the second embodiment of the invention has the shape of an oblong hole.

[0052] According to certain embodiments as shown in Figure 3, the construction hole 200 comprises a plurality of temporary longitudinal walls 260. More specifically, the construction hole 200 comprises at least one longitudinal wall 260 extending from the lower arc 212 of the permanent portion 210 to the upper arc 222 of the temporary portion 220 of the construction hole 200. Each longitudinal wall 260 extends parallel to a plane XZ.

[0053] The longitudinal walls 260 are configured to support the temporary portion 220 of the construction hole 200, and more specifically the upper surface 208 of the temporary portion 220 of the construction hole 200. Each longitudinal wall 260 comprises a first wall 262 and a second wall 264 parallel and spaced apart from each other to form the thickness e1 of the longitudinal wall 260. Preferably, the thickness e1 of the longitudinal wall 260 is very small compared to the dimensions of the final hole 30. Preferably, the thickness e1 is between 0.06 mm and 0.12 mm, this value depending directly on the previously parameterized laser power. Indeed, for a thickness value e1 less than 0.06 mm, the manufacturability of the longitudinal wall 260 is very limited, and for a thickness value e1 greater than 0.12 mm, the flow of a fluid inside the manufacturing hole 200 is impaired. According to an exemplary embodiment of the invention such as As shown in Figures 3 and 4, the construction hole comprises three longitudinal walls 260. Preferably, the longitudinal walls 260 are distributed along the Y-axis and spaced from each other by a distance d1 that is very small compared to the dimensions of the final hole 30. Preferably, the distance d1 is between 0.05 mm and 1 mm. Indeed, for a value of the distance d1 less than 0.05 mm, the flow of a fluid inside the fabrication hole 200 is impaired, and for a value of the distance d1 greater than 1 mm, the load-bearing capacity of the upper surface 208 of the temporary portion 220 of the construction hole 200 by the longitudinal walls 260 is insufficient, which can cause collapse of the upper surface 208.

[0054] According to certain embodiments of the invention, the construction hole 200 comprises a temporary normal wall 270 extending from the lower arc 212 of the permanent portion 210 to the upper arc 222 of the temporary portion 220 of the construction hole 200. As shown in Figure 4, the construction hole 200 comprises a single normal wall 270 extending in a median YZ plane of the cylindrical construction hole 200. The presence of a single normal wall 270 prevents the formation of dead cavities between the walls 1260, 270 of the construction hole 200, thus allowing the circulation of a fluid within the construction hole 200.

[0055] The normal wall 270 is configured to reinforce the longitudinal walls 260 and thus improve the rigidity of the construction hole 200. The normal wall 270 comprises a first wall 272 and a second wall 274, parallel and spaced apart to form the thickness e2 of the normal wall 270. Preferably, the thickness e2 of the normal wall 270 is very small compared to the dimensions of the final hole 30. Preferably, the thickness e2 is between 0.06 mm and 0.12 mm, this value depending directly on the previously parameterized laser power. Indeed, for a thickness e2 value less than 0.06 mm, the manufacturability of the normal wall 270 is very limited, and for a thickness e2 value greater than 0.12 mm, the flow of fluid inside the construction hole 200 is impaired.

[0056] According to some embodiments, the first connecting segment 232 of the first connecting section 230 of the temporary portion 220 of the construction hole 200 is tangent to the lower arc 212 of the permanent portion 210 at its lower end 232A and is tangent to the upper arc 222 of the temporary portion 220 of the hole construction hole 200 at its upper end 232B. In addition, the second connecting segment 242 of the second connecting section 240 of the temporary portion 220 of the construction hole 200 is tangent to the lower arc 212 of the permanent portion 210 at its lower end 242A and is tangent to the upper arc 222 of the temporary portion 220 of the construction hole 200 at its upper end 242B.

[0057] The oblong shape of the construction hole 200 according to the second embodiment of the invention eliminates the distance L2, so the number of temporary powder layers corresponds to the distance L1. Consequently, such a geometry requires the presence of longitudinal support walls 260 to limit the collapse of the unsupported upper surface 208 of the temporary portion 220 of the construction hole 200 and thus obtain a final hole 30 with satisfactory circularity.

[0058] As shown in Figure 5, the final part 10 is delimited between a lower surface 12A and an upper surface 12B and includes the final hole 30 delimited between a low point 32 and a high point 34, along the Z axis.

[0059] More specifically, the final piece 10 includes: - a lower part 14 corresponding to the part of the piece 10 located below the final hole 30, that is to say the part extending from the lower surface 12A of the piece 10 to the lowest point 32 of the final hole 30, - a perforated part 16 comprising the final hole 30, that is to say the part extending from the lowest point 32 of the final hole 30 to the highest point 34 of the final hole 30, and - an upper part 18 corresponding to the part of the piece 10 located above the final hole 30, that is to say the part extending from the high point 34 of the final hole 30 to the upper surface 12B of the piece 10.

[0060] The lower portion 14 of the final part 10 is substantially identical to the lower portion 14 of the part 10F currently being manufactured. However, the perforated portion 16 and the upper portion 18 of the final part 10 differ from the perforated portion 16F and the upper portion 18F of the part 10F currently being manufactured because the latter will collapse during the formation of the final hole 30.

[0061] The final hole 30 is in the form of a cylindrical hole with axis X delimited along the Z axis by a lower surface 36 and an upper surface 38, the upper surface 38 being unsupported and substantially arranged opposite the lower surface 36 of the final hole 30. The final hole 30 has a circular cross-section C1 constant along the X axis. Preferably, the final hole 30 is symmetrical with respect to the Z axis passing through the center 01 of the circle C1.

[0062] Advantageously, the circularity of the lower surface 36 of the final hole 30 is substantially identical to the circularity of the lower surface 206 of the lower arc 210 of the construction hole 200. Moreover, the circularity of the upper surface 38 of the final hole 30 is lower than the circularity of the lower surface 36 of the final hole 30. The circularity of a circle corresponds to the value obtained by dividing by 2 the difference between the maximum value of the diameter and the minimum value of the circle, the maximum and minimum values ​​being measured by making 4 to 8 cuts of the circle along its diameter.

[0063] The manufacturing process for a part 10, according to the first and second embodiments of the invention, comprises the following steps: - deposition and solidification of successive layers of powder along the deposition axis Z comprising the following sub-steps: o formation of the lower part 12 of the part 10, o formation of the perforated part 16F of the part 10F being manufactured by deposition and solidification of successive layers of powder around a predefined area, the predefined area forming, after deposition and solidification of a final layer of powder, the constant portion 210 and the temporary portion 220 of the construction hole 200, and o formation of the upper part 18F of the part 10F being manufactured, - formation of the final hole 30 by deformation and collapse of the provisional portion 220 of the construction hole 200 including a sub-step of removal of the part 10F during the manufacture of the powder bed.

[0064] The stage of depositing and solidifying successive layers of powder corresponds to the laser powder bed fusion process, the manufacture of part 10F being carried out in a manufacturing tank of a laser powder bed fusion machine.

[0065] During the final hole formation step 30 of the manufacturing process according to the first embodiment of the invention, the removal of the part 10F being manufactured from the powder bed involves the removal of the unfused powder present inside the construction hole 200. The removal of the unfused powder then causes the sagging and collapse of certain layers of powder of the upper surface 208 of the hole of the temporary portion 220 of the construction hole 200 by gravity these layers corresponding to the temporary layers of powder are no longer supported by the excess of unfused powder then the displacement of the upper surface 208 of the temporary portion 220 of the construction hole 200 downwards to form the upper surface 38 of the final hole 30.More specifically, the upper arc 222 and the intermediate segment 236 of the provisional portion 220 of the construction hole 200 collapse by a distance substantially equal to the distance L2 so that the high point 204 of the construction hole 200 reaches the high point 34 of the final hole 30 to form the upper part 18 of the final piece 10. The connecting segment 232 and the intermediate arc 234 collapse by a distance substantially equal to the distance L1 to form the perforated part 16 of the final piece 10.

[0066] The last layer of powder corresponds to the layer of powder that closes the construction hole 200, that is to say the layer of powder deposited at the high point 204 of the construction hole 200 or above the high point 204 of the construction hole 200.

[0067] The step of depositing and solidifying successive layers of powder in the manufacturing process according to the second embodiment of the invention comprises, before the substep of removing part 10F from the powder bed, the following additional substeps: - formation of at least one longitudinal wall 260, and - formation of a normal wall 270.

[0068] The final hole formation step 30 of the manufacturing process according to the second embodiment of the invention comprises, after the removal substep of part 10F of the powder bed, an additional substep of dissolving the longitudinal walls 260 and / or the normal wall 270 of the build hole 200. The substep of dissolving the longitudinal walls 260 and / or the normal wall 270 is carried out by chemical attack by injecting a fluid, such as a chemical reagent, into the build hole 200. The destruction of the longitudinal walls 260 and / or the normal wall 270 of the build hole will cause the temporary powder layers to collapse and the upper surface 208 of the temporary portion 220 of the build hole 200 to be displaced downwards to form the upper surface 38 of the final hole 30.More specifically, the upper arc 222 and the connecting segment 232 of the provisional portion 220 of the construction hole 200 collapse by a distance substantially equal to the distance L1 so that the high point 204 of the construction hole 200 becomes the high point 34 of the final hole 30 to form the bored part 16 and the high part 18 of the final piece 10.

[0069] The manufacturing process for a part 10 according to the invention offers a solution for forming a final cylindrical hole 30 with axis X perpendicular to the deposition axis Z using laser powder bed fusion technology. Specifically, the formation of a construction hole 200 comprising a temporary portion 220 with a specific geometry, followed by the deformation and collapse of the temporary portion 220, allows for the formation of a final cylindrical hole 30 with satisfactory circularity.

Claims

CLAIMS

1. Method for manufacturing a part (10) by depositing and solidifying successive layers of a powder along a deposition axis Z, comprising a final cylindrical hole (30), characterized in that it comprises the following steps: - deposition and solidification of successive layers of powder around a predefined area, the predefined area forming, after deposition and solidification of a last layer of powder, a construction hole (200), the construction hole (200) comprising a constant portion (210) and a temporary portion (220), and - formation of the final hole (30), with axis X perpendicular to the deposition axis Z, by deformation and collapse of the temporary portion (220) of the construction hole (200), the final hole (30) having a section in the shape of a circle C1.

2. Manufacturing method according to claim 1, characterized in that: - the constant portion (210) of the construction hole (200) has a section comprising a lower arc (212) of the circle C1 with center 01 and radius r1, and - the temporary portion (220) of the construction hole (200) has a section comprising: o an upper arc (222) of a circle C2 with center 02 and radius r2, and o two junction sections (230, 240) each connecting the lower arc (212) of the constant portion (210) to the upper arc (222) of the temporary portion (220) of the construction hole (200).

3. Manufacturing method according to claim 2, characterized in that the center 01 of the circle C1 and the center 02 of the circle C2 are aligned along the Z axis and spaced apart from each other by a distance L1.

4. Manufacturing method according to claim 2 or 3, characterized in that the radius r2 of the circle C2 is equal to the radius r1 of the circle C1.

5. Manufacturing method according to any one of claims 2 to 4, characterized in that each joining section (230, 240) of the temporary portion (220) of the construction hole (200) comprises: - a connecting segment (232, 242) extending substantially along the Z axis and connected to the lower arc (212) of the constant portion (210), - an intermediate segment (236, 246) connected to the upper arc (222) of the temporary portion (220), and - an intermediate arc (234, 244) of a circle C3 with center 03 and radius r3 respectively connecting the connecting segment (232, 242) to the intermediate arc (236, 246).

6. Manufacturing method according to claim 5, characterized in that the center 01 of the circle C1 and the center 03 of the circle 03 are aligned along the Z axis and spaced apart from each other by a distance L2, and in that the distance L2 is greater than the distance L1.

7. Manufacturing method according to claim 5 or 6, characterized in that the radius r3 of the circle 03 is equal to the radius r1 of the circle 01.

8. Manufacturing method according to any one of the preceding claims in combination with claim 5, characterized in that each intermediate segment (232, 242) of each joining section (230, 240) of the temporary portion (220) of the construction hole (200) forms an angle a, between 30° and 45°, with an axis Y passing through the center 02 of the circle C2 and perpendicular to the axis X and to the axis Z.

9. Manufacturing method according to any one of claims 2 to 4, characterized in that each joining section (230, 240) of the temporary portion (220) of the construction hole (200) comprises a connecting segment (232, 242) extending substantially along the Z axis and connecting the lower arc (212) of the constant portion (210) to the upper arc (222) of the temporary portion (220) of the construction hole (200).

10. Manufacturing method according to any one of the preceding claims, characterized in that the step of depositing and solidifying successive layers of powder comprises a sub-step of forming at least one wall longitudinal (260) extending from the lower arc (212) of the constant portion (210) to the upper arc (222) of the temporary portion (220) of the construction hole (200), each longitudinal wall (260) extending parallel to an XZ plane.

11. Manufacturing method according to any one of the preceding claims, characterized in that the step of depositing and solidifying successive layers of powder comprises a sub-step of forming a normal wall (270) extending from the lower arc (212) of the constant portion (210) to the upper arc (222) of the temporary portion (220) of the construction hole (200), the normal wall (270) extending parallel to a YZ plane

12. Manufacturing method according to claim 10 or 11, characterized in that the step of forming the final hole (30) comprises a sub-step of dissolving the longitudinal walls (260) and / or the normal wall (270) of the construction hole (200).

13. Part (10) produced by deposition and solidification of successive layers of a powder along a deposition axis Z, characterized: - in that it is obtained by the manufacturing process according to any one of the preceding claims, - and in that the final hole (30) of the part (10) is delimited along the deposition axis Z by a lower surface (36) and an upper surface (38), the upper surface (38) being unsupported and substantially arranged opposite the lower surface (36) of the final hole (30).

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