SEPARATE SUPPORT FOR ADDITIVE PRODUCTION OF A PART BY LASER POWDER BED FUSING

Abstract

Support (2) for additive manufacturing of a part (1) by laser powder bed fusion comprising a foot (3) and a body (4) extending from the foot (3), said body (4) comprising at least one bearing surface (5) for the part (1). The bearing surface (5) comprises a series of portions, said portions being in the shape of truncated cones and each comprising a base and a contact surface with the part (1), said contact surface being smaller than the size of the base, the portions of said series being aligned along an axis perpendicular to the foot (3) of the support (2). Figure for the abbreviation: Fig 1

Description

Title of the invention: SEPARATE SUPPORT FOR ADDITIVE MANUFACTURING OF A PART BY LASER POWDER BED FUSION technical field

[0001] The present invention relates to the field of additive manufacturing of parts by laser powder bed fusion.

[0002] Additive manufacturing by laser powder bed fusion, which constitutes an alternative to machining processes by material subtraction, consists of selectively and iteratively depositing and consolidating a layer of powder in order to build up, layer by layer, a three-dimensional object.

[0003] Additive manufacturing of an object by laser powder bed fusion generally involves the use of a build platform that serves as the base for manufacturing the object, a device for spreading powder of a predetermined material onto the platform to a desired thickness, and one or more lasers that scan an area of ​​the deposited powder to transform it into a solid bead. This process is carried out on several successive layers that will form the final object.

[0004] The equipment used in this process is generally controlled from a digital production file resulting from the slicing of an object modeled by CAD (Computer-Aided Design) into layers of a given thickness. This is particularly the case for the spreading device and the laser(s), whose scanning pattern and all laser parameters, such as laser power, scanning speed, spacing between two laser passes, etc., are dictated by the production file.

[0005] Passing the laser over the powder bed raises the powder's temperature above its melting point. This creates a molten bath. As it cools, this bath solidifies, forming a bead of solid metal. Following the laser scan of a powder layer, a two-dimensional cross-section of the desired object is thus obtained.

[0006] A support is used to support certain faces of the part, which may be vertical, inclined or cantilevered, and thus prevent them from breaking or deforming during additive manufacturing due to thermomechanics.

[0007] Such a support is only useful during additive manufacturing and is then removed.

[0008] The supports used today in additive manufacturing are solid, solid volumetric supports and allow, in particular, good adhesion of the part with the build platform. However, once additive manufacturing is complete, removing the supports from the part can prove very complex.

[0009] Today, supports are generally removed from the part by EDM (Electrical Discharge Machining) wire cutting or by mechanical machining. However, these methods of support removal generate significant additional costs and time losses. Description of the invention

[0010] The present invention aims to overcome the aforementioned disadvantages and, in particular, to ensure that the part is held in place during additive manufacturing while facilitating the removal of the supports from the part once manufacturing is complete.

[0011] The invention therefore relates to a support for the additive manufacturing of a part by laser powder bed fusion, comprising a foot and a body extending from the foot, said body comprising at least one bearing surface for the part. The bearing surface comprises a series of portions, said portions being in the shape of truncated cones and each comprising a base and a contact surface with the part, said contact surface being smaller than the size of the base, the portions of said series being aligned along an axis perpendicular to the foot of the support.

[0012] Advantageously, the truncated cone-shaped portions are in the form of truncated pyramids with a rectangular base, each comprising four trapezoidal faces, two faces extending from the length of the rectangular base and two faces extending from the width of the rectangular base.

[0013] The angles of the truncated apex of the faces extending from the length of the base of the pyramid are between 30° and 45°.

[0014] The angles of the truncated apex of the faces extending from the width of the base of the pyramid are between 30° and 45°.

[0015] Advantageously, the contact surface of the truncated cone-shaped portions is a rectangle with a width between 0.001 millimeter and 30 millimeters, and a length between 0.001 millimeter and 30 millimeters.

[0016] Advantageously, the truncated cone-shaped portions are in the shape of cones of revolution.

[0017] In one embodiment, the truncated cone-shaped portions of said series are aligned along a straight axis, said portions being in the shape of truncated pyramids with a rectangular base and / or in the shape of cones of revolution.

[0018] Advantageously, the height of the truncated cone-shaped portions is between 0.5 millimeters and 20 millimeters, and preferably between 0.7 millimeters and 10 millimeters.

[0019] The invention also relates to an assembly comprising a part obtained by laser powder bed fusion and a support as defined above. Brief description of the drawings

[0020] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0021] - Figure [Fig. 1] is a schematic perspective view of a part produced by additive manufacturing by laser powder bed fusion, showing the use of a breakable support;

[0022] - Figure [Fig.2] is a top view of a part produced by manufacturing additive by laser powder bed fusion, showing the use of a breakable support comprising rectangular-based pyramid-shaped portions;

[0023] - Figure [Fig.3] is a side view of a part produced by additive manufacturing by laser powder bed fusion, showing the use of a breakable support comprising rectangular-based pyramid-shaped portions;

[0024] - Figure [Fig.4] is a schematic perspective view of a breakable support including portions in the shape of pyramids with a rectangular base;

[0025] - Figure [Fig. 5] is a top view of a part produced by manufacturing additive by laser powder bed fusion, showing the use of a breakable support comprising portions in the shape of cones of revolution;

[0026] - Figure [Fig. 6] is a side view of a part produced by additive manufacturing by Laser powder bed fusion, demonstrating the use of a breakable support comprising portions in the shape of cones of revolution; and

[0027] - Figure [Fig.7] is a schematic perspective view of a breakable support including portions in the shape of cones of revolution. Detailed description

[0028] In [Fig.1], part 1 is represented in a vertical position, in an orthonormal coordinate system X, Y, Z. The X axis designates the longitudinal direction of part 1, the Y axis designates the direction normal to the longitudinal axis X, and the Z axis designates the vertical direction of part 1.

[0029] As previously stated, a three-dimensional shaping process consists of depositing a layer of powder of a predetermined material onto a manufacturing platform, spreading the layer of powder on the manufacturing platform to a desired thickness, corresponding to the thickness of a slice of an object modeled by CAD and cut into slices, and selectively consolidating the layer of powder by selective scanning of one or more laser beams, these steps being repeated iteratively in order to constitute, layer by layer, a three-dimensional object.

[0030] In [Fig. 1], part 1 shown corresponds to part 1 obtained after implementing the different iterations. It is, for example, made from a bed of metal powder.

[0031] As previously stated, part 1 includes areas that are difficult to manufacture and require supports to prevent said part 1 from breaking or deforming during additive manufacturing.

[0032] In [Fig. 1], part 1 is a rectangular block comprising a base and a tall vertical face extending from the base, supported by a breakable support 2. The assembly comprising part 1 and support 2 is generally positioned on the manufacturing platform.

[0033] The support 2 comprises a foot 3 and a body 4 extending from the foot 3 and having a bearing surface 5 for the part 1. The support 2 is in the form of a right triangular prism comprising two faces in the form of right triangles, equal and parallel, connected by three rectangular faces forming the thickness of the support which extends along the Y axis. An adjacent side of the right angle of the right triangular prism extends perpendicularly to the base of the part 1 in a longitudinal direction along the X axis and the other adjacent side of the right angle extends vertically along the Z axis, in contact with the vertical face of the part 1. The right angle of the support 2 is therefore complementary to the angle formed between the part 1 and the manufacturing platform.

[0034] The bearing surface 5 of part 1 of the support 2 extends vertically along the Z-axis and is positioned against the vertical face of part 1, in order to provide the necessary support to part 1 during its manufacture to prevent deformation. The bearing surface 5 comprises a series of portions generally in the shape of truncated cones, each comprising a base 6 and a contact surface 7 with part 1, said contact surface being smaller than the size of the base 6.

[0035] A cone represents the union of straight lines passing through the same point and intersecting the same curve. The cone can have a circular, triangular, or polygonal base. Here, the cone is truncated to obtain the contact surface 7 with part 1.

[0036] In the embodiment shown in Figures 2, 3, and 4, the bearing surface 5 comprises a double chamfer in which several truncated pyramidal cone-shaped portions are integrated. In other words, the bearing surface 5 comprises a series of truncated pyramid-shaped portions 8 with a rectangular base 6, the portions of said series being aligned along the vertical axis Z perpendicular to the foot 3 of the support 2.

[0037] The truncated pyramid-shaped portions 8 of said series are aligned along a right axis. Each truncated pyramid 8 with a rectangular base 6 comprises a height h extending along the X-axis, a length 1 extending along the Z-axis, and a width L which extends along the Y axis. The height h of pyramid 8 is between 0.5 millimeters and 20 millimeters, and preferably between 0.7 millimeters and 10 millimeters.

[0038] Each truncated pyramid 8 with a rectangular base 6 comprises four trapezoidal faces, two of which extend from the length 1 of the rectangular base 6 and two faces which extend from the width L of the rectangular base 6.

[0039] As illustrated in Figure 2, the bisector ba of the angles aL of the truncated vertex of the faces extending from the width L of the rectangular base 6 of the pyramid 8 divides said angles aL into two angles aL1 and aL2. The angles “L1 and aL2 are between 30° and 45°. Below 30°, the truncated pyramid portions 8 are too thin and too flexible to provide sufficiently rigid support for the part 1, and above 45°, the space separating each truncated pyramid portion 8 is too small, and there is a risk of powder sintering during additive manufacturing.

[0040] As illustrated in Figure 3, the bisector bA of the angles Al of the truncated vertex of the faces extending from the length 1 of the rectangular base 6 of the pyramid 8 divides said angles Al into two angles Ail and A12. The angles Ail and A12 are between 30° and 45°. Below 30°, the truncated pyramid portions 8 are at risk of collapsing during melt manufacturing, and above 45°, the space separating each truncated pyramid portion 8 is too close to the part 1, and there is a risk of powder sintering during additive manufacturing.

[0041] The contact surface 7 of the truncated pyramid 8 with rectangular base 6 is a rectangle of a width L2 between 0.001 millimeter and 30 millimeters, and preferably between 0.05 millimeter and 10 millimeters, and of a length 12 between 0.001 millimeter and 30 millimeters, and preferably between 0.05 millimeter and 10 millimeters.

[0042] The series of truncated pyramids 8 with a rectangular base comprises several truncated pyramids 8 with a rectangular base which represent a repeating pattern whose period is between 0.5 millimeters and 20 millimeters, and preferably between 1 millimeter and 2 millimeters.

[0043] In the embodiment of figures 5, 6 and 7, the support surface 5 comprises a series of portions in the form of cones of revolution 9 which are aligned along the vertical axis Z perpendicular to the foot 3 of the support 2. The cones of revolution 9 are slightly truncated in order to create a contact surface 7 with the part 1.

[0044] Each truncated cone 9 comprises a height h extending along the X axis and a circular base 6 of diameter d. The height h of the pyramid 8 is between 0.5 millimeters and 20 millimeters, and preferably between 0.7 millimeters and 10 millimeters.

[0045] The horizontal and vertical sections shown in Figures 5 and 6 of each cone of revolution 9 extending respectively along a plane X, Y and a plane X, Z are Truncated triangles with a vertex at angle 5. Angle 5 is divided by an angle bisector bd into two angles <51 and 52. Angles <51 and 52 are between 30° and 45°. Below 30°, the cone-shaped portions 9 are at risk of collapsing during melt manufacturing, and above 45°, the space between each cone-shaped portion 9 is too close to part 1, and there is a risk of powder sintering during additive manufacturing.

[0046] The series of revolution cones 9 comprises several truncated revolution cones 9 which represent a repeating pattern whose period is between 0.5 millimeters and 20 millimeters, and preferably between 1 millimeter and 2 millimeters.

[0047] The truncated cone-shaped portion of the support 2 allows for the creation of a pivot with the vertical axis Z as its axis of rotation when the support 2 is detached from the part 1, thus facilitating the manual separation of the support 2 from the part 1.

[0048] The dimensions of the support 2, and in particular of the truncated cone-shaped portion, vary according to several parameters related to the size of the part 1 and the conditions of the three-dimensional forming process. Undesired sintering can occur during additive manufacturing, particularly between the truncated cone-shaped portions. To avoid sintering, the truncated cone-shaped portions are sufficiently spaced and have a sufficiently high height h.

[0049] It is possible to design the bearing surface 5 of the support 2 comprising several series of portions in the shape of truncated cones.

[0050] The architecture of the support 2 thus allows for quick and simple manual detachment of the support 2 from the part 1.

Claims

Demands

1. Support (2) for additive manufacturing of a part (1) by laser powder bed fusion comprising a foot (3) and a body (4) extending from the foot (3), said body (4) comprising at least one bearing surface (5) of the part (1), characterized in that the bearing surface (5) comprises a series of portions, said portions being in the form of truncated cones and each comprising a base (6) and a contact surface (7) with the part (1), said contact surface (7) being smaller in dimension than the base (6), the portions of said series being aligned along an axis perpendicular to the foot (3) of the support (2).

2. Support (2) according to claim 1, wherein the truncated cone-shaped portions are in the form of truncated pyramids (8) with a rectangular base (6) each comprising four trapezoidal faces, two faces extending from the length (1) of the rectangular base (6) and two faces extending from the width (L) of the rectangular base (6).

3. Support (2) according to claim 2, wherein the angles (Ail, A12) of the truncated apex of the faces extending from the length (1) of the base (6) of the pyramid (8) are between 30° and 45°.

4. Support (2) according to any one of claims 2 and 3, wherein the angles (°L 1 and flL2) of the truncated apex of the faces extending from the width (L) of the base (6) of the pyramid (8) are between 30° and 45°.

5. Support (2) according to any one of claims 1 to 4, wherein the contact surface (7) of the truncated cone-shaped portions is a rectangle of a width (L2) between 0.001 millimeter and 30 millimeters, and of a length (12) between 0.001 millimeter and 30 millimeters.

6. Support (2) according to claim 1, wherein the truncated cone-shaped portions are in the shape of cones of revolution (9).

7. Support (2) according to any one of claims 1 to 6, wherein the truncated cone-shaped portions of said series are aligned along a straight axis.

8. Support (2) according to any one of claims 1 to 7, wherein the height (h) of the truncated cone-shaped portions is between 0.5 millimeters and 20 millimeters, and preferably between 0.7 millimeters and 10 millimeters.

9. Assembly comprising a part (1) obtained by laser powder bed fusion and a support (2) according to any one of claims 1 to 8.

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