EP4110588A1

EP4110588A1 - Modular tray for the additive manufacturing of a part with an axis of revolution on a powder bed

Info

Publication number: EP4110588A1
Application number: EP21721154.9A
Authority: EP
Inventors: Arnaud Georges NIFENECKER; Jérémi Christophe Benjamin ADOR; Frédéric AYCAGUER; Frédéric Jacques DUFAU; Gilles Gaston Jacques Gouin; Jean-Pierre WILMES; Werner ARGUEL
Original assignee: Safran Transmission Systems SAS; Safran Helicopter Engines SAS
Current assignee: Safran Transmission Systems SAS; Safran Helicopter Engines SAS
Priority date: 2020-04-06
Filing date: 2021-03-31
Publication date: 2023-01-04
Also published as: WO2021205096A1; FR3108870B1; US20230173584A1; CN115397650A; FR3108870A1

Abstract

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

Description

MODULAR TRAY FOR ADDITIVE POWDER BED MANUFACTURING

OF A PIECE WITH AXIS OF REVOLUTION

TECHNICAL AREA

The present invention relates to the field of additive manufacturing on a powder bed of a part with an axis of revolution, and more particularly to a plate used for the implementation of this manufacturing technique, also called 3D manufacturing.

PRIOR TECHNIQUE

The manufacture of a revolution part by additive manufacturing on a powder bed requires, on the one hand, the use of support elements, and on the other hand, the separation of the raw part from the plate on which it has been placed. manufactured, this separation being done by saw cutting, electroerosion (or EDM for "Electrical Discharge Machining" in English), and so on. The powder used can be metallic, ceramic or polymer (for example PEEK). It is specified that in the context of the present application, the term “metallic” includes pure metals and alloys.

These support elements are created, like the part, by localized melting or localized sintering (using a laser beam or an electron beam) of the powder during the formation of the part. They are used to prop up parts of the part requiring support and / or to connect parts of the part to each other. These support elements are intended to be destroyed after the formation of the blank.

Some part geometries require a very large amount of support elements. This is the case, for example, with parts having steps with different diameters, for example an outer ring positioned at mid-height of the hub, in the case of a pinion. By way of example, FIG. 1 illustrates the support elements necessary for the manufacture of a pinion in additive manufacturing on a steel powder bed on a conventional plate 6. For the sake of simplification, only half of the image has been produced. shown, the other half being symmetrical with respect to the plane of symmetry illustrated by the line A in broken lines, which also represents the axis of revolution 1 of the part to be produced. The pinion comprises in particular, on either side of an outer ring 5 (which comprises the rim and the teeth of the pinion), a main hub 26 on one side, and on the other, an inner hub 2 and a external medium 3; it also comprises a web 4. It will be recalled that in a gear, for example a pinion, the web is the part connecting the rim, on which the teeth are located, to the hub.

The pinion is manufactured on an additive manufacturing plate 6 (generally square or rectangular in shape) and its manufacture requires the use of a support element 7 to support the web 4 and the outer ring 5 (support element 7 comprising holes 8 facilitating the dusting of the part), a support element 9 to support the outer hub 3, and a support element 10 which will itself support the support element 7.

Thus, the quantity of support elements necessary for the manufacture of a part with an axis of revolution can be large, which has a significant impact on the quantity of powder used and the time of lasing of the part.

In addition, the separation of the part from the plate (conventionally square or rectangular) on which it has been formed requires a dedicated operation using a saw, an EDM machine or the like.

The blank must then undergo machining in order to free it from the supporting elements.

DISCLOSURE OF THE INVENTION

The sought-after objective of the invention is to optimize the production in terms of duration (melting / sintering and machining) of parts with an axis of revolution by additive manufacturing on a powder bed (in particular by SLM (for “Selective Laser Melting”). in English), by EBM (for "Electron Beam Melting" in English) and by SLS (for "Selective Laser Sintering" in English)), in particular for the production of pinions, in particular for the production of parts with steps of increasing diameters of great amplitude, like pinions with sails halfway up the hub.

The object of the invention is in particular to provide a simple and effective solution to the problems raised above.

To this end, the invention proposes a modular platform for the additive manufacturing on a powder bed of a part with an axis of revolution, characterized in that it comprises:

- A shaded circular module comprising a shaft provided with a circular plate at one of its ends, the shaft and the circular plate being concentric; and

a main support module comprising, in one face, a cavity configured to receive the circular shafted module, the shaft fitting completely into the cavity; the assembly of the shaded circular module and the main support module defining a planar upper surface which is formed at least in part by the circular plate of the shaded circular module.

The main support module can for example be a tray. It can be square, rectangular or even circular.

According to a variant of the invention, the modular plate further comprises an annular module and the main support module further comprises an annular cavity configured to receive the annular module. According to this variant, the annular cavity and the cavity of the shaded circular module are concentric. Further, the annular module, when assembled to the circular shafted module and the main support module, forms a portion of the flat top surface of the assembly.

According to a variant of the invention, the shaved circular module and the optional annular module are machined, preferably by turning.

Advantageously, the shaft of the shaded circular module is a preform of one end of the part to be manufactured. The invention also provides a method of manufacturing a part with an axis of revolution, comprising:

- The production, by localized melting or localized sintering of a powder on a modular plate as described above, of a raw part with an axis of revolution and at least one support element of this raw part, the powder merged or sintered and the modular plate being in contact only: on the circular plate of the shaved circular module, thus forming a portion of the part and a possible support element of the part; and possibly on the annular module, thus forming a possible other support element for the part; the axis of revolution of the blank being coaxial with the axis of the shaft of the shaved circular module;

- the withdrawal, from the main support module, of the assembly formed by the blank, the shaved circular module and any annular module;

- dusting of this assembly;

- Placement of the assembly on a lathe of a turning machining device;

- machining by turning of a first portion (B) of the blank;

- if the assembly comprises an annular module, the separation of the raw part from said annular module by cutting by turning, the cutting being carried out at the level of the support element connecting the raw part to the annular module according to a cutting plane (C ) perpendicular to the axis of revolution of the blank;

- machining by turning of a second portion (D) of the blank, by means of which: the possible support element remaining at the end of the separation step is completely eliminated; the possible support element connecting the blank to the shaded circular module is completely eliminated; and the shaded circular module is partially removed, the non-deleted portion of said shaved circular module being integrated into the blank; the steps of machining by turning (B) (D) and the optional step of separating by turning being carried out by rotating the blank about the axis of the shaft of the shaved circular module; whereby we obtain the part with an axis of revolution.

According to one embodiment, the shaft of the shaved circular module is pre-machined so as to form a preform of one end of the part to be produced.

Preferably, the shaded circular module is made of the same material as that of the part to be produced.

According to a variant of the invention, the method further comprises at least one step of heat treatment of hardening of the part, this step being carried out between the steps of depouding the assembly and placing this assembly on a turn of the device. machining by turning, and / or after the step of machining by turning the second portion of the blank.

The solution proposed in accordance with the invention has many advantages.

According to the invention, the melting or sintering of the part and of the support elements on the modular plate is carried out only on removable modules which can be removed from the main support module; the melting or sintering of the powder is therefore carried out on the shaved circular module and on the possible annular module, but not on the main support module. As these removable modules are coaxial, it is possible to proceed with the machining of the part and the withdrawal of the support elements by positioning the assembly formed by the part and this or these removable modules on a lathe. Thus, the raw part obtained at the end of additive manufacturing (SLM, EBM, etc.) can be directly machined, by being placed on a lathe, without first requiring a step to separate the raw part from the production plate. additive. This saves an operation during which the blank could be exposed to corrosion problems. On the other hand, since the shaft of the shaved circular module can be a preform of one end of the part to be manufactured and that this shaft can be pre-machined, the method according to the invention makes it possible to greatly limit the quantity of support elements necessary during the manufacture of the part, which ultimately limits the time of lasing and machining of the part, and also limits the amount of powder used. We are talking about lasing here, but it is understood that we can also use an electron beam instead of a laser beam.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other details, characteristics and advantages of the invention will emerge on reading the description given by way of non-limiting example with reference to the appended drawings, which illustrate:

- Figure 1 (already detailed above), a schematic sectional view of a blank part with an axis of revolution and its support elements obtained by additive manufacturing on a powder bed on a plate of the prior art;

- Figure 2a, a schematic 3-dimensional view showing the rear face of the assembly formed of the blank and its support elements as illustrated in Figure 1, once detached from the conventional plate;

- Figure 2b, a schematic 3-dimensional view showing the front face of this assembly;

FIG. 3, an exploded schematic view of the modules of the modular platform according to a variant of the invention;

- Figure 4, a schematic sectional view of the modular plate illustrated in Figure 3;

FIG. 5, an exploded schematic view of the modules of the modular platform according to another variant of the invention;

- Figure 6, a schematic sectional view of the modular plate illustrated in Figure 5; FIG. 7a, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7b, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7c, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7d, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7e, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7f, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 7g, an explanatory diagram of a step of the manufacturing process according to a first embodiment of the invention using the modular plate of FIG. 6;

FIG. 8, a schematic sectional view of a blank part with an axis of revolution and of its support elements obtained by additive manufacturing on a powder bed on the modular plate of FIG. 5 (the main support module having already been removed );

- Figure 9, a schematic sectional view of a blank part with an axis of revolution and its support elements obtained by additive manufacturing on a powder bed on the modular plate of Figure 3.

DETAILED DESCRIPTION OF EMBODIMENTS

According to the invention, the additive manufacturing platform is formed from one or more removable modules, placed in cavities in one face of a main support module so as to define a flat surface on which the powder bed will be able to be spread out; the powder will be fused or sintered only on these removable modules so that the part once formed, the assembly formed by the part and the removable modules will be able to be assembled - after depouding - on a lathe and thus insert the workpiece / removable modules separation operation from the table top among the roughing and workpiece finishing operations.

As illustrated in FIG. 3, the modular platform 12 comprises at least a circular shafted module 13 and a main support module 16, having a cavity 17 in its upper face to house the circular shafted module 13 therein.

As illustrated in FIG. 4, which represents a sectional view of the assembly of the main support plate 16 and of the shaved circular module 13, the shaved circular module 13 is a one-piece assembly comprising a shaft 14 provided at one of its ends of a circular plate 15.

Preferably, the shaft is pre-machined to be a preform of one end of the part to be produced. In a first example illustrated in FIG. 4, the shaft is a preform of the main hub 26 of the part. In another example illustrated in FIG. 6, the shaft is a preform of the internal hub 2 and of the external hub 3 of the part.

The modular plate 12 can also include an annular module 18, intended to be housed in an annular cavity 19 (annular groove) present in the upper face of the main support module 16 (FIGS. 5 and 6).

In Figures 3 and 5, the main support module is circular, but it could also have had another shape, for example square or rectangular.

We will now describe the manufacture of a part with an axis of revolution according to a first embodiment of the method according to the invention using the modular plate as illustrated in FIG. 6.

The shaded circular module 13 and the annular module 18 are placed in their respective cavities 17 and 19 of the main support module 16 (FIG. 7a).

The blank part 20 is then manufactured by selective melting or selective sintering of a powder (FIG. 7b). The powder used can be metallic, ceramic or polymer. The blank 20 is produced layer by layer by a conventional additive manufacturing process. As in Figure 1 and for the sake of simplicity, only one half of the image has been shown, the other half being symmetrical with respect to the plane of symmetry illustrated by line A in broken lines, which also represents the axis of revolution 1 of the part to be produced.

In the step of producing the blank 20 and the support element 7 on the modular plate 12, the part and the support element are for example constructed layer by layer by selective melting or selective sintering of the powder 21 using a laser beam 22, the powder 21 having an average particle size between 10 and 50 μm, or using an electron beam 22, the powder 21 having an average particle size between 50 and 100 pm.

In this exemplary embodiment (FIG. 7b), the powder fused or sintered on the circular plate 15 of the shaved circular module 13 forms a portion of the part, while the powder fused or sintered on the annular module 18 firstly forms the part. support element 7, then a portion of the part.

Once the part is finished, it is removed from the main support module 16, the part being integral with the circular shafted module 13 and the annular module 18 (hereinafter called removable modules) (FIG. 7c).

Then, the part is powdered (FIG. 7d). Depoding can be done by suction, blowing, vibration or even by overturning the blank so that the powder escapes by gravity. At the end of the dusting, the assembly is obtained as illustrated in figure 8.

Then, the assembly formed by the blank and the removable modules is installed on a lathe and a first portion of the part (here called the front face of the part) is turned (FIG. 7e). The turning is done by rotation around the axis of the shaft 14 of the shaved circular module (which corresponds to the axis of revolution 1 of the part). The supports of the part / removable module assembly on the lathe are represented by the member 23 and the member represented by the arrow 24 (for example a clamping mandrel. The machining of the front face is symbolized by line B in broken lines.

The blank part is then separated from the annular module 18 by cutting along a section plane C perpendicular to the axis of revolution of the part (which is also the axis of rotation of the lathe and the axis of the shaft 14) at the level of the support element 7 (FIG. 7f). It is for example possible to carry out a turning using a groove tool. Among the detached elements, there is thus, on the one hand, an element 11 which is a portion of the support element 7 and, on the other hand, an element 25 which is formed from the other portion of the element. support 7 and the annular module 18.

It should be noted that it is possible to carry out one or more heat treatments of the part during its manufacture. For example, once depolding has been carried out (Figure 7d), it is possible to subject the blank to a stress release heat treatment before proceeding to step 7e, for example by heating the part to a temperature lower than the sintering temperature of the powder, for a determined period of time. Following step 7g, the part can be subjected to a hardening heat treatment.

These same steps of the method according to the invention can also be carried out according to a second embodiment using the modular plate as illustrated in Figures 3 and 4 to obtain the part as illustrated in Figure 9.

While in the first embodiment (Figure 8), the powder was fused or sintered both on the shaved circular module 13 and on the annular module 18, in this second embodiment the powder will be fused or sintered only on the shaft. circular shaded module 13 to form both a portion of the part, as well as the support element 27 of the veil. Thus, at the end of the depolding step, instead of the assembly illustrated in FIG. 8, the assembly illustrated in FIG. 9 is obtained. The machining will make it possible to remove the support element. 27 and resume all the precise dimensions of the piece.

We compared the mass of lased powder, as well as the lasing time required to produce the same part with an axis of revolution manufactured by the conventional technique requiring all of the support elements described in FIG. 1 (part serving as reference), by the first embodiment according to the invention (obtaining the blank part illustrated in FIG. 8) and by the second mode of embodiment according to the invention (obtaining the blank part illustrated in FIG. 9). The results are shown in the table below.

Table: comparison between the conventional technique and two embodiments according to the invention To manufacture the part by additive manufacturing on a powder bed using a conventional plate, we will need three types of support elements (namely the support member 7 to support the web 4 and to support the outer ring 5, the support member 9 to support the outer hub 3 and the support member 10 to support the support member 7). By using the modular tray (Figures 5 and 6) according to the first embodiment (shown in Figure 8), only two types of support members are required, the support member 9 and the support member 10 being removed.

Using the modular platform (Figures 3 and 4) according to the second embodiment (shown in Figure 9), all that is needed is a hybrid support member 27, which supports both the web and the web. 'outer ring, but at a much lower height than in the first embodiment.

Thus, it can be seen that embodiment 1 allows a saving of 27% on the lasing mass and on the lasing time compared to the conventional technique; embodiment 2, for its part, allows a saving of 38% on the lased mass and on the lasing time.

Claims

1. Modular platform (12) for the additive manufacturing on a powder bed of a part with an axis of revolution, characterized in that it comprises:

- a shaded circular module (13) comprising a shaft (14) provided with a circular plate (15) at one of its ends, the shaft and the circular plate being concentric; and

- a main support module (16) comprising, in one face, a cavity (17) configured to receive the shaded circular module (13), the shaft (14) fitting completely into the cavity; the assembly of the shaded circular module and the main support module defining a planar upper surface which is formed at least in part by the circular plate (15) of the shaded circular module.

2. The modular platform according to claim 1, further comprising an annular module (18) and wherein the main support module (16) further comprises an annular cavity (19) configured to receive the annular module (18); the annular cavity (19) and the cavity (17) of the shaved circular module being concentric; and the annular module (18), when assembled to the circular shafted module and the main support module, forming a portion of the flat upper surface of the assembly.

3. Modular plate according to claim 1 or claim 2, wherein the shaved circular module and the optional annular module are machined, preferably by turning.

4. Modular tray according to claim 3, wherein the shaft (14) of the shaded circular module (13) is a preform of one end of the part to be manufactured.

5. A method of manufacturing a part with an axis of revolution, comprising: - The production, by localized melting or localized sintering of a powder on a modular plate (12) according to any one of claims 1 to 4, of a blank with an axis of revolution and at least one support element (7; 27) of this raw part, the fused or sintered powder and the modular plate being in contact only: on the circular plate (15) of the shaved circular module, thus forming a portion of the part and a possible support element ( 27) of the room; and possibly on the annular module (18), thus forming a possible other support element (7) of the part; the axis of revolution (1) of the blank being coaxial with the axis of the shaft (14) of the shaved circular module;

- the withdrawal, from the main support module (16), of the assembly formed by the blank, the shaved circular module (13) and any annular module (18);

- dusting of this assembly;

- Placement of the assembly on a lathe of a turning machining device;

- machining by turning of a first portion (B) of the blank;

- if the assembly comprises an annular module (18), the separation of the raw part from said annular module by cutting by turning, the cut being made at the level of the support element (7) connecting the blank to the annular module according to a section plane (C) perpendicular to the axis of revolution of the blank;

- machining by turning of a second portion (D) of the blank, by means of which: the possible support element (7) remaining at the end of the separation step is completely eliminated; the possible support element (27) connecting the blank to the shaded circular module is completely eliminated; and the shaded circular module is partially deleted, the non-deleted portion of said shaved circular module being integrated into the blank; the steps of machining by turning (B) (D) and the optional step of separating by turning being carried out by rotating the blank about the axis of the shaft of the shaved circular module; whereby we obtain the part with an axis of revolution.

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

7. The manufacturing method according to claim 5 or claim 6, wherein the shaved circular module is made of the same material as that of the part to be produced.

8. The manufacturing method according to any one of claims 5 to 7, further comprising at least one step of heat treatment of hardening of the part, this step being carried out between the steps of depouding the assembly and placing this. together on a lathe of a turning machining device, and / or after the step of machining by turning the second portion of the blank.