Modular tray for additive manufacturing of a part having an axis of revolution on a powder bed

Abstract

The invention relates to a modular tray (12) for additive manufacturing of a part having an axis of revolution on a powder bed, characterized in that it comprises: - a circular shaft module (13) comprising a shaft provided at one of its ends with a circular tray, the shaft and the circular tray being concentric; and - a main support module (16) having a cavity (17) in one face, the cavity being configured to receive the circular shaft module (13), the shaft being fully inserted into the cavity; the assembly of the circular shaft module and the main support module defining a flat upper surface formed at least partly by the circular tray of the circular shaft module. A modular tray (12) for additive manufacturing of a part having an axis of revolution on a powder bed, characterized in that it comprises: a circular shaft module (13) comprising a shaft provided at one of its ends with a circular tray, the shaft and the circular tray being concentric; and a main support module (16) having a cavity (17) in one face, the cavity being configured to receive the circular shaft module (13), the shaft being fully inserted into the cavity; the assembly of the circular shaft module and the main support module defining a flat upper surface formed at least partly by the circular tray of the circular shaft module.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing of parts having a rotation axis on a powder bed, and more specifically to a tray for implementing this manufacturing technique (also known as 3D manufacturing). Background Technology

[0002] Manufacturing rotary parts via additive manufacturing in a powder bed first requires the use of support elements, and secondly, it requires separating the blank from the tray on which it is manufactured. This separation is carried out by sawing, electro-erosion (or electrical discharge machining (EDM)), etc. The powder used can be metal, ceramic, or polymer (e.g., PEEK). In the context of this application, the term "metal" includes pure metals and alloys.

[0003] Similar to the parts, these support elements are formed during part formation by localized melting or sintering of powder (using laser or electron beams). These support elements enable the support of parts requiring support and / or the connection of parts together. These support elements are intended to be destroyed after the blank is formed.

[0004] Parts with certain geometries require a large number of support elements. This is the case for parts with tiers of different diameters, such as the outer ring located in the middle of the hub in the case of a sprocket.

[0005] As an example, Figure 1 The diagram illustrates the support elements required to manufacture a sprocket via additive manufacturing on a steel powder bed on a conventional pallet 6. For simplicity, only half of the image is shown; the other half is symmetrical with respect to the plane of symmetry indicated by dashed line A, which also represents the axis of rotation 1 of the part to be manufactured. Specifically, the sprocket includes a main hub 26 on one side of its outer ring 5 (which includes the sprocket's rim and teeth) and an inner hub 2 and an outer hub 3 on the other side; the sprocket also includes a web 4. In gears (e.g., sprockets), the web is the component that connects the rim (on which the teeth are positioned) to the hub.

[0006] The sprocket is manufactured on an additive manufacturing tray 6 (typically square or rectangular), and the manufacture of the sprocket requires the use of a support element 7 (which includes holes 8 for removing powder from the part) for supporting the web 4 and the outer ring 5, a support element 9 for supporting the outer hub 3, and a support element 10 that itself supports the support element 7.

[0007] Therefore, the number of support elements required to manufacture parts with a rotation axis can be large, which can significantly affect the amount of powder used and the time for laser treatment of the parts.

[0008] In addition, separating the parts from the trays (usually square or rectangular) on which they are formed requires specialized operations using saws, electro-etching machines, or other equipment.

[0009] The blank must then be machined to remove the support elements from it. Summary of the Invention

[0010] The object of the present invention is to optimize the duration (melting / sintering and machining) of parts with a rotation axis by additive manufacturing on a powder bed (particularly by SLM (selective laser melting), EBM (electron beam melting) and SLS (selective laser sintering)), particularly for the production of sprockets, especially for the production of parts with a significantly increased diameter, such as sprockets with a web located in the middle of the hub.

[0011] The object of the present invention is particularly to provide a simple and effective solution to the above-mentioned problems.

[0012] Therefore, the present invention proposes a modular tray for additive manufacturing of parts with a rotation axis on a powder bed, characterized in that the modular tray comprises:

[0013] - A shaft-mounted circular module, comprising a shaft, wherein a circular tray is disposed at one end of the shaft, and the shaft and the circular tray are concentric; and

[0014] - Main support module, the main support module including a cavity in one surface, the cavity being configured to receive a shaft-mounted circular module, the shaft being fully inserted into the cavity;

[0015] The components of the shaft-mounted circular module and the main support module define a flat top surface, at least partially formed by the circular tray of the shaft-mounted circular module.

[0016] The main support module can be, for example, a tray. The main support module can be square, rectangular, or circular.

[0017] According to a variation of the invention, the modular tray further includes an annular module, and the main support module further includes an annular cavity configured to receive the annular module. According to this variation, the annular cavity and the cavity of the shaft-mounted circular module are concentric. Furthermore, once assembled with the shaft-mounted circular module and the main support module, the annular module forms part of the flat top surface of the assembly.

[0018] According to a variation of the invention, the shaft-mounted circular module and the optional annular module are preferably machined by turning.

[0019] Advantageously, the shaft of the shaft-mounted circular module is a preform at one end of the part to be manufactured.

[0020] The present invention also proposes a method for manufacturing parts having a rotation axis, the method comprising:

[0021] - A blank with a rotation axis and at least one support element supporting the blank are produced by partially melting or sintering powder on a modular tray as described above, wherein the melted or sintered powder contacts the modular tray only at the following locations:

[0022] On the circular tray of the shaft-mounted circular module, a part is thus formed, along with optional support elements that support the part; and

[0023] Alternatively, additional support elements for supporting the parts can be formed on the annular module;

[0024] The axis of rotation of the blank is coaxial with the axis of the shaft of the shaft-mounted circular module;

[0025] - Remove the components formed by the blank, shaft-mounted circular module and optional ring module from the main support module;

[0026] - Remove powder from the component;

[0027] - Place the components on a lathe, an equipment used for machining by turning;

[0028] - Machining is performed by turning (B) the first part of the blank;

[0029] - If the component includes an annular module, the blank is separated from the annular module by turning, the cutting is performed on a support element along a cutting plane (C) perpendicular to the axis of rotation of the blank, the support element connecting the blank to the annular module;

[0030] - Machining is performed by turning (D) the second part of the blank, so that:

[0031] The optional support elements left after the separation step were completely removed;

[0032] The optional support elements for connecting the blank to the shaft-mounted circular module have been completely eliminated; and

[0033] The shaft-mounted circular module was partially removed, and the remaining portion of the shaft-mounted circular module was integrated into the blank.

[0034] The machining steps via turning (B) and (D) and the optional separation steps via turning are performed by rotating the blank about the axis of the shaft of the shaft-mounted circular module.

[0035] This results in a part with a rotation axis.

[0036] According to one embodiment, the shaft of the shaft-mounted circular module is pre-machined to form a preform of one end of the part to be manufactured.

[0037] Preferably, the shaft-mounted circular module is made of the same material as the part to be produced.

[0038] According to a variation of the invention, the method further includes at least one step of hardening heat treatment of the part, which is performed between the step of removing powder from the assembly and the step of placing the assembly on a lathe for machining by turning, and / or after the step of machining by turning a second portion of the blank.

[0039] The solution proposed according to the present invention has many advantages.

[0040] According to the invention, the melting or sintering of parts and support elements on the modular tray occurs only on removable modules that can be removed from the main support module; therefore, the melting or sintering of powder occurs on shaft-mounted circular modules and optional annular modules, but not on the main support module. Since these removable modules are coaxial, the machining of parts and the removal of support elements can be performed by positioning the assembly formed by the parts and one or more removable modules on a lathe. Therefore, blanks obtained after additive manufacturing (SLM, EBM, etc.) can be directly machined by placing them on a lathe without the need for a first step of separating the blank from the additive manufacturing tray. This eliminates operations that could expose the blank to corrosion problems.

[0041] Furthermore, since the shaft of the shaft-mounted circular module can be a preform of one end of the part to be manufactured, and since the shaft can be pre-machined, the method according to the invention can greatly limit the number of support elements required during part manufacturing. This ultimately limits the time spent on laser treatment and machining of the part, and also limits the amount of powder used. Laser treatment is mentioned here, but naturally, an electron beam can be used instead. Attached Figure Description

[0042] The invention will be better understood by reading the description given by way of non-limiting example with reference to the accompanying drawings, which illustrate:

[0043] - Figure 1 (As detailed above), it is a schematic diagram of the cross-section of a blank with a rotation axis and its supporting elements obtained by additive manufacturing on a powder bed on a prior art tray.

[0044] - Figure 2aIt is a three-dimensional schematic diagram showing how the item is removed from a conventional tray. Figure 1 The rear face of the assembly formed by the blank and its supporting elements shown;

[0045] - Figure 2b It is a three-dimensional schematic diagram showing the front face of the component;

[0046] - Figure 3 It is an exploded schematic diagram of the modules of a modular tray according to a variant of the present invention;

[0047] - Figure 4 , it is Figure 3 A schematic diagram of the cross-section of the modular pallet shown;

[0048] - Figure 5 This is an exploded schematic diagram of a modular tray according to another variation of the present invention;

[0049] - Figure 6 , it is Figure 5 A schematic diagram of the cross-section of the modular pallet shown;

[0050] - Figure 7a It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0051] - Figure 7b It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0052] - Figure 7c It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0053] - Figure 7d It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0054] - Figure 7e It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0055] - Figure 7f It is used Figure 6 An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0056] - Figure 7g It is used Figure 6An explanatory diagram showing the steps of a manufacturing method for a modular pallet according to a first embodiment of the present invention;

[0057] - Figure 8 It is through in Figure 5 A schematic diagram of the cross-section of a blank with a rotation axis and its support elements obtained by additive manufacturing on a powder bed on a modular tray (the main support module has been removed).

[0058] - Figure 9 It is through in Figure 3 A schematic diagram of the cross-section of a blank with a rotation axis and its supporting elements obtained by additive manufacturing on a powder bed on a modular pallet. Detailed Implementation

[0059] According to the invention, the additive manufacturing tray is formed of one or more removable modules placed in cavities in the face of a main support module to define a flat surface on which a powder bed can be spread; the powder will be melted or sintered only on these removable modules, such that once the part has been formed, the assembly formed by the part and the removable modules can be mounted on a lathe after the powder is removed, thereby inserting the operation of separating the part and the removable modules from the tray into the operation of turning the blank and finishing the part.

[0060] like Figure 3 As shown, the modular tray 12 includes at least a shaft-mounted circular module 13 and a main support module 16, the main support module having a cavity 17 in its top surface to accommodate the shaft-mounted circular module 13.

[0061] like Figure 4 As shown, a cross-sectional view of the assembly of the main support tray 16 and the shaft-mounted circular module 13 is shown. The shaft-mounted circular module 13 is an integral assembly including a shaft 14, at one of its ends, with a circular tray 15 disposed thereon.

[0062] Preferably, the shaft is pre-machined into a preform of one end of the part to be produced. Figure 4 In the first example shown, the shaft is a preform of the main hub 26 of the part. Figure 6 In another example shown, the shaft is a preform of the inner hub 2 and the outer hub 3 of the part.

[0063] Modular tray 12 may also include an annular module 18, which is designed to be housed within the main support module 16. Figure 5 and Figure 6 It is located in the annular cavity 19 (annular groove) on the top surface of the ).

[0064] exist Figure 3 and Figure 5 In this design, the main support module is circular, but it can also have another form, such as a square or rectangular shape.

[0065] The first embodiment of the method according to the present invention will now be described using the following methods: Figure 6 The modular tray shown is used to manufacture parts with a rotation axis.

[0066] The shaft-mounted circular module 13 and the annular module 18 are placed in their respective cavities 17 and 19 of the main support module 16. Figure 7a ).

[0067] Next, blank 20 is manufactured by selective melting or selective sintering of the powder. Figure 7b The powder used can be metal, ceramic, or polymer. The preform 20 is produced layer by layer using conventional additive manufacturing methods. Figure 1 As shown, and for simplicity, only half of the image is shown, the other half being symmetrical with respect to the plane of symmetry indicated by dashed line A, which also shows the axis of rotation 1 of the part to be produced.

[0068] In the step of producing blanks 20 and support elements 7 on modular tray 12, the parts and support elements are constructed layer by layer by selective melting or selective sintering of powder 21, for example by means of laser beam 22 (the average particle size of powder 21 is between 10 μm and 50 μm) or by means of electron beam 22 (the average particle size of powder 21 is between 50 μm and 100 μm).

[0069] In this exemplary embodiment ( Figure 7b In the circular module 13, the molten or sintered powder on the circular tray 15 forms part of the component, while the molten or sintered powder on the annular module 18 first forms support element 7 and then forms part of the component.

[0070] Once the part is completed, it is removed from the main support module 16, along with the shaft-mounted circular module 13 and the annular module 18 (hereinafter referred to as the removable module). Figure 7c ) into one.

[0071] Then, remove the powder from the parts. Figure 7d Powder removal can be achieved by suction, blowing, vibration, or by flipping the workpiece to allow the powder to escape by gravity. After powder removal, the desired product is obtained as follows: Figure 8 The components shown.

[0072] Then, the assembly formed by the blank and the removable module is mounted on a lathe, and the first part of the part (here referred to as the front face of the part) is turned. Figure 7eTurning is accomplished by rotating the component around the axis 14 of the shaft-mounted circular module (which corresponds to the rotation axis 1 of the part). The support for the part / removable module assembly on the lathe is indicated by component 23 and the component shown by arrow 24 (e.g., a clamping chuck). The machining of the front face is indicated by dashed line B.

[0073] Next, the blank is separated from the annular module 18 by cutting at the support element 7 along a cutting plane C perpendicular to the axis of rotation of the part (which is also the axis of rotation of the lathe and the axis of shaft 14). Figure 7f Turning can be performed, for example, by means of a slotted tool. Therefore, among the separate components, there is first a component 11 as part of the support component 7, and then a component 25 formed by another part of the support component 7 and the annular module 18.

[0074] It should be noted that one or more heat treatments can be performed on the parts during manufacturing. For example, once powder removal has been performed... Figure 7d If this is not possible, the blank can be subjected to stress-relieving heat treatment before proceeding to step 7e, for example, by heating the part to a temperature below the sintering temperature of the powder for a given time. After step 7g, the part can be subjected to hardening heat treatment.

[0075] These same steps of the method according to the invention can also be used according to the second embodiment by using, for example Figure 3 and Figure 4 Implemented using the modular pallet shown, to achieve, as Figure 9 The parts shown.

[0076] In the first embodiment ( Figure 8 In the first embodiment, powder is melted or sintered on the shaft-mounted circular module 13 and on the annular module 18. In the second embodiment, however, powder is melted or sintered only on the shaft-mounted circular module 13 to form a portion of the part and the support element 27 of the web. Therefore, after the powder removal step, instead of... Figure 8 The components shown obtained Figure 9 The components shown. Machining will allow for the removal of support element 27 and remachining of all precise dimensions of the part.

[0077] Comparison of production needs Figure 1 All the support elements shown (as reference parts) are manufactured using conventional techniques, and are produced according to the first embodiment of the invention (obtained) Figure 8 The blank shown is manufactured from and obtained according to the second embodiment of the present invention. Figure 9 The table below shows the mass of laser-treated powder required to manufacture the same part with a rotation axis from the blank shown.

[0078]

[0079] Table: Comparison between conventional techniques and two embodiments according to the present invention.

[0080] In order to manufacture parts by additive manufacturing on a powder bed using a conventional pallet, three types of support elements will be required (i.e., support element 7 for supporting the web 4 and the outer ring 5, support element 9 for supporting the outer hub 3, and support element 10 for supporting support element 7).

[0081] By using the first embodiment (in) Figure 8 Modular pallets (shown in the image) Figure 5 and Figure 6 Now only two types of support elements are needed, and support element 9 and support element 10 are omitted.

[0082] By using the second embodiment (in) Figure 9 Modular pallets (shown in the image) Figure 3 and Figure 4 Now only a hybrid support element 27 is needed, which supports both the web and the outer ring, but is much smaller in height than in the first embodiment.

[0083] Therefore, it was found that compared with conventional techniques, Example 1 saved 27% of the laser-treated mass and laser treatment time; for Example 2, it saved 38% of the laser-treated mass and laser treatment time.

Claims

1. A modular tray (12) for additive manufacturing of parts with a rotation axis on a powder bed, characterized in that, The modular tray includes: - A shaft-mounted circular module (13), the shaft-mounted circular module comprising a shaft (14), wherein a circular tray (15) is provided at one end of the shaft, the shaft and the circular tray being concentric; and - Main support module (16), the main support module including a cavity (17) in one face, the cavity being configured to receive the shaft-mounted circular module (13), the shaft (14) being fully inserted into the cavity; The assembly of the shaft-mounted circular module and the main support module defines at least a flat top surface formed by the circular tray (15) of the shaft-mounted circular module; and The shaft (14) of the shaft-mounted circular module (13) is a preform of one end of the part to be manufactured.

2. The modular pallet according to claim 1, wherein, The modular tray also includes an annular module (18), wherein the main support module (16) further includes an annular cavity (19) configured to receive the annular module (18); The annular cavity (19) and the cavity (17) of the shaft-mounted circular module are concentric; and Once assembled with the shaft-mounted circular module and the main support module, the annular module (18) forms part of the flat top surface of the assembly.

3. The modular pallet according to claim 2, wherein, The shaft-mounted circular and annular modules are machined by turning.

4. A method for manufacturing a part having a rotation axis, the method comprising: - A blank having a rotation axis and at least one support element (7; 27) supporting the blank are produced by partially melting or sintering the powder on the modular tray (12) according to claim 2 or 3, wherein the melted or sintered powder contacts the modular tray only at the following locations: On the circular tray (15) of the shaft-mounted circular module, a part of the part and a support element (27) supporting the part are thus formed; and On the annular module (18), other support elements (7) are thus formed to support the part; The rotation axis (1) of the blank is coaxial with the axis of the shaft (14) of the shaft-mounted circular module; - Remove the assembly formed by the blank, the shaft-mounted circular module (13) and the annular module (18) from the main support module (16); - Remove powder from the component; - Place the component on a lathe for machining by turning; - Machining is performed by turning (B) the first part of the blank; - If the component includes an annular module (18), the blank is separated from the annular module by turning, the cutting is performed on the support element (7) along a cutting plane (C) perpendicular to the axis of rotation of the blank, the support element connecting the blank to the annular module; - Machining is performed by turning (D) the second part of the blank, such that: The support elements (7) left after the separation step were completely removed; The support element (27) connecting the blank to the shaft-mounted circular module was completely removed; and The shaft-mounted circular module was partially removed, and the remaining portion of the shaft-mounted circular module was integrated into the blank. The machining steps by turning (B) and separation steps by turning are performed by rotating the blank about the axis of the shaft-mounted circular module. This results in a part with a rotation axis.

5. The manufacturing method according to claim 4, wherein, The shaft (14) of the shaft-mounted circular module is pre-machined to form a preform of one end of the part to be produced.

6. The manufacturing method according to claim 4 or claim 5, wherein, The shaft-mounted circular module is made of the same material as the part to be produced.

7. The manufacturing method according to claim 4 or claim 5, wherein, The method further includes at least one step of hardening heat treatment of the part, which is performed between the step of removing powder from the component and the step of placing the component on a lathe for machining by turning, and / or after the step of machining by turning a second portion of the blank.

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