Additive manufacturing machine for manufacturing annular parts

Abstract

The invention relates to an additive manufacturing machine (10) for additive manufacturing by deposition of layers of powder and selective consolidation of these layers of powder, the machine (10) comprising a device (18) for depositing layers of powder, a working plane (12), a selective consolidation zone (14), a main jacket (42) of outer contour (Cex), and a secondary jacket (46) arranged inside the main jacket (42) and defining a non-manufacturing zone (48) inside the selective consolidation zone, the device (18) for depositing layers of powder comprising a powder distribution device (22) and a powder spreading device (24), the secondary jacket (42) is closed at the top by a flat closure wall parallel to the working plane (12) of the machine, and the powder spreading device (24) moves in translation above the selective consolidation zone (14) along a rectilinear movement axis (DR).

Description

ADDITIVE MANUFACTURING MACHINE FOR THE MANUFACTURE OF ANNULAR PARTS TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an additive manufacturing machine by depositing layers of powder and selectively consolidating these layers of powder.

[0002] More specifically, the invention aims at additive manufacturing by depositing layers of powder and selectively consolidating large parts with a hollow central part, for example fixed parts of turbojet engines: casing, flow straighteners, etc.; or rotating parts of turbojet engines: turbine discs, etc.

[0003] When manufacturing parts with a hollow central portion with an additive manufacturing machine equipped with a cylindrical or parallelepiped build sleeve, there is a large central volume in the build sleeve in which no part of the part is consolidated. Therefore, this central volume is unnecessarily filled with powder.

[0004] To address this drawback, additive manufacturing machines with annular manufacturing sleeves have been designed. Thanks to the annular shape of their manufacturing sleeve, these machines can manufacture large parts with a hollow central part while limiting powder consumption. DESCRIPTION OF THE PRIOR ART

[0005] Document EP 3300819 relates to a machine for manufacturing annular parts by selective powder melting, this machine comprising a concentric inner annular wall and an outer annular wall and delimiting an annular powder deposition zone. For spreading the powder layers, the machine comprises a powder distributor movable in rotation around the axis of the inner and outer annular walls, this powder distributor comprising a scraper extending between the inner annular wall and the outer annular wall forming a predefined angle with the radial direction of the inner and outer annular walls. Thanks to the angle formed by the scraper with respect to the radial direction, the excess powder is discharged laterally towards the inner side or towards the outer side of the annular zone.

[0006] According to a first drawback, the rotary powder distribution provided in document EP 3300819 offers relatively complex kinematics that will require numerous tests before it can be validated for use in a manufacturing cycle. For example, due to its rotary movement, the speed of the scraper is not identical at all points along its length: it is minimal at its inner end and maximal at its outer end. On the other hand, different additive manufacturing powders have different flow characteristics. Therefore, and for each type of powder, the best compromise must be found between the maximum speed of the scraper at its outer end and the minimum speed of the scraper at its inner end. In addition, the angle of the scraper relative to the radial direction must be adjusted at each powder change. SUMMARY OF THE INVENTION

[0007] The present invention aims to overcome these drawbacks of the prior art by proposing a configuration of an additive manufacturing machine which makes it possible to limit the consumption of powder during the manufacture of parts having a hollow central part and which is easily and quickly exploitable.

[0008] To this end, the subject of the invention is an additive manufacturing machine by depositing layers of powder and selectively consolidating these layers of powder, the machine comprising a device for depositing layers of powder and a source for selectively consolidating the layers of powder, the machine comprising a work surface and a zone for selectively consolidating the layers of powder located in this work surface, the machine comprising a main jacket opening into the work surface through an opening defining the outer contour of the selective consolidation zone, the machine comprising a secondary jacket arranged inside the main jacket and defining a non-manufacturing zone inside the selective consolidation zone, the machine comprising a manufacturing plate moving in translation between the main jacket and the secondary jacket under the effect of an actuator,and the powder layer deposition device comprising a powder distribution device and a powder spreading device, such as a roller or a squeegee, on the selective consolidation zone.,

[0009] According to the invention, the secondary jacket is closed in the upper part by a flat closing wall parallel to the working plane of the machine, and the powder spreading device moves in translation above the selective consolidation zone along a rectilinear axis of movement.

[0010] Advantageously but not necessarily, the invention may also provide that: - the powder spreading device extends in a transverse direction perpendicular to its rectilinear axis of movement, - the length of the powder spreading device in the transverse direction is greater than the maximum dimension of the outer contour of the selective consolidation zone in this transverse direction, - the powder distribution device makes it possible to carry or deposit a bead of powder on the work surface between the selective consolidation zone and the powder spreading device when this powder spreading device is located in a waiting position outside the selective consolidation zone, - the powder distribution device comprises a powder receiving surface movable relative to the work surface and to the selective consolidation zone, - the powder dispensing device comprises a movable powder reservoir above the work surface, - the upper surface of the closing wall of the secondary jacket is located in the same plane as the upper surface of the worktop, - the manufacturing plate includes a closed contour opening crossed by the secondary jacket, - the secondary jacket has a shape identical to the main jacket in a horizontal plane, but reduced homothetically, - the secondary jacket and the main jacket are cylindrical and extend in a vertical direction, - the secondary jacket and the main jacket are coaxial. DESCRIPTION OF DRAWINGS

[0011] Other characteristics and advantages of the invention will appear in the description which follows. This description, given by way of example and not as a limitation, refers to the attached drawings in which: - [Fig.l] represents a schematic top view of a machine according to the invention with a first variant of a powder distribution device, - [Fig.2] represents a schematic side view of a machine according to the invention with a second variant of a powder distribution device. DETAILED DESCRIPTION OF THE INVENTION

[0012] The invention relates to an additive manufacturing machine by depositing layers of powder and selectively consolidating these layers of powder.

[0013] Additive manufacturing by powder layer deposition and selective consolidation is an additive manufacturing process in which one or more parts are manufactured by the selective consolidation of different layers of additive manufacturing powder superimposed on each other. The first layer of powder is deposited on a support such as a plate, then selectively consolidated using at least one consolidation source according to a first section of the part(s) to be manufactured. Then, a second layer of powder is deposited on the first layer of powder which has just been consolidated, and this second layer of powder is selectively consolidated in turn, and so on until the last layer of powder useful for the manufacture of the last section of the part(s) to be manufactured.

[0014] In the context of the invention, an additive manufacturing powder is preferably metallic, but may also be non-metallic.

[0015] A machine 10 for additive manufacturing by powder bed deposition and selective consolidation according to the invention is schematically illustrated in top view by FIG. 1.

[0016] This machine 10 comprises a work surface 12 and a selective consolidation zone 14 for the layers of powder located in this work surface. The work surface 12 and the selective consolidation zone 14 are preferably located in an enclosure 16 which can be closed in a sealed manner. A wall of this enclosure 16 may comprise a door giving access to the work surface 12 and to the selective consolidation zone 14. The work surface 12 and the selective consolidation zone 14 are preferably located in a horizontal plane.

[0017] For the implementation of additive manufacturing, the machine 10 comprises a device 18 for depositing layers of powder and at least one source 20 for selective consolidation of the layers of powder.

[0018] In the example shown in Figure 2, the machine 10 comprises several selective consolidation sources 20. This plurality of selective consolidation sources is suitable for the additive manufacturing of large parts in a large selective consolidation zone 14. Indeed, the machine according to the invention is particularly intended for the manufacturing of large parts and it preferably offers a large selective consolidation zone 14. Large parts are, for example, parts with an outside diameter greater than 35 centimeters and a height greater than 35 centimeters.

[0019] Preferably, each selective consolidation source 20 is a source emitting at least one laser beam making it possible to melt at least a portion of a layer of powder present in the consolidation zone 14. A laser source 20 comprises, for example, a scanning head making it possible to move the spot of the laser beam over at least a portion of the selective consolidation zone 14 and a device for managing the focusing of the laser beam. Each source 20 may also comprise a device for monitoring the emitted laser beam and / or the melt pool created by the emitted laser beam in a layer of powder.

[0020] Alternatively, a selective consolidation source can also be a particle beam, such as an electron gun for example.

[0021] The device 18 for depositing layers of powder comprises a powder distribution device 22 and a powder spreading device 24, such as a roller or a scraper, on the selective consolidation zone 14.

[0022] Preferably, the powder distribution device 22 makes it possible to carry or deposit a bead of powder on the work surface 12 between the selective consolidation zone 14 and the powder spreading device 24 when this powder spreading device 24 is located in a waiting position situated outside the selective consolidation zone, such as that illustrated in FIG. 1 for example.

[0023] In a first variant, the powder distribution device 22 comprises at least one powder distributor 25 and a powder receiving surface 26 movable relative to the work surface 12 and to the selective consolidation zone 14 and relative to the powder distributor 25. For example, the powder distributor 25 comprises a powder reservoir mounted above a screw dispenser. The movable receiving surface 26 moves under the powder distributor 25 so as to receive the powder delivered by the distributor 25 which forms a bead of powder on this movable receiving surface. Then, the receiving surface 26 is positioned with its bead of powder between the spreading device 24 and the selective consolidation zone 14 so that the spreading device 24 can spread the bead of powder over the selective consolidation zone.

[0024] In the example illustrated in Figure 1, the powder distribution device 22 comprises two distributors 25 arranged on either side of the selective consolidation zone 14 and two mobile powder receiving surfaces 26 arranged on either side of the selective consolidation zone. Thus, the powder spreading device 24 can spread a new layer of powder during each of its movements above the selective consolidation zone.

[0025] In a second variant, the powder distribution device 22 comprises at least one mobile powder reservoir 28 above the work surface 12. For example, a mobile powder reservoir 28 is mounted on the powder spreading device 24. Preferably, and in order to deposit a bead of powder in front of the spreading device, a powder reservoir 28 is mounted to move in translation relative to the spreading device 24. The powder distribution device 22 preferably comprises a powder inlet 30 in the enclosure 16 to replenish a mobile powder reservoir 28 with powder.

[0026] In the example illustrated in Figure 2, the powder dispensing device 22 comprises two movable powder reservoirs 28 mounted on the spreading device, one reservoir on each side of the spreading device. Thus, a bead of powder can be deposited on each side of the spreading device, and the powder spreading device 24 can spread a new layer of powder during each of its movements above the selective consolidation zone 14.

[0027] In the first variant of the powder distribution device 22, each movable powder receiving surface 26 is mounted to move in translation in a housing 32 provided in the work surface. Advantageously, this housing 32 makes it possible to recover the excess powder deposited when producing a new layer of powder on the selective consolidation zone.

[0028] In the second variant of the powder distribution device 22, at least one reservoir 34 for collecting excess powder deposited is provided in the work surface 12. Preferably, two reservoirs 34 for collecting excess powder deposited are provided, one on each side of the selective consolidation zone 14.

[0029] Due to the fumes created by the selective melting operations of the powder in the consolidation zone, the machine 10 preferably comprises a device 36 for collecting the fumes created by the selective consolidation. This collection device 36 makes it possible to generate a flow of gas F for evacuating the fumes above the selective consolidation zone. In more detail, the flow of evacuating gas F circulates for example between an inlet ramp 38 located on a first side of the consolidation zone 14 and an outlet ramp 40 located on the other side of the consolidation zone 14. For example, the collection device 36 comprises a device for generating the flow of evacuating gas F and a device for filtering the fumes (not shown in the figures) located in a circuit connected to the inlet and outlet ramps.

[0030] Advantageously, the inlet 38 and outlet 40 ramps can be movable in translation between a position dedicated to selective melting (illustrated in dotted lines in FIG. 1) where they are located as close as possible to the selective consolidation zone and a position dedicated to layering the powder (illustrated in strong lines in FIG. 1) in which they are further away from the selective consolidation zone so as not to prevent the movements of the powder spreading device. SELECTIVE CONSOLIDATION AREA

[0031] According to the invention, and in particular for the purpose of manufacturing large parts having a hollow central part, the machine 10 comprises a main jacket 42 opening into the work plane 12 through an opening 44 defining the external contour Cex of the selective consolidation zone 14, at least one secondary jacket 46 arranged inside the main jacket 42 and defining a non-manufacturing zone 48 inside the selective consolidation zone 14, and a manufacturing plate 50 moving in translation between the main jacket 42 and the secondary jacket 46 under the effect of at least one actuator 52. The non-manufacturing zone 48 is a sub-zone of the selective consolidation zone 14 in which no selective consolidation of powder is carried out.

[0032] In a variant of the selective consolidation zone not illustrated in the figures, the machine 10 may comprise several secondary jackets 46 arranged inside the main jacket 42 and defining several non-manufacturing zones 48 inside the selective consolidation zone 14. In this case, the manufacturing plate 50 moves in translation between the main jacket 42 and the different secondary jackets 46.

[0033] In more detail, the main jacket 42 extends below the worktop 12. For example, the main jacket 42 is removably attached to the worktop 12. Each secondary jacket 46 also extends below the worktop 12. For example, each jacket secondary 46 is removably mounted on a support 54 secured to the frame of the machine 10. The main jacket 42 and the secondary jacket(s) 46 are removably mounted to facilitate their extraction from the machine with the manufactured parts and the manufacturing plate 50, for example via the lower part of the machine.

[0034] The manufacturing plate 50 preferably moves in translation along a vertical axis AV corresponding to the vertical direction in which the different layers of powder are superimposed. Preferably, several actuators 52 are used to move the manufacturing plate 50 relative to the main and secondary jackets. Advantageously, in addition to the actuator(s), the machine 10 may comprise means for guiding the manufacturing plate in translation (not shown).

[0035] According to the invention and in order to limit the consumption of powder during the manufacture of large parts with a hollow central part, each secondary jacket 46 is closed in the upper part by a closing wall 56 which is flat and parallel to the working plane 12 of the machine.

[0036] In addition to the closure in the upper part of each secondary jacket, the powder spreading device 24 moves in translation above the selective consolidation zone 14 along a rectilinear movement axis DR. Coupled with the closure in the upper part of each secondary jacket, the rectilinear movement of the spreading device 24 makes it possible to easily and quickly control the layering of the powder on the selective consolidation zone. Indeed, thanks to the rectilinear movement of the spreading device, the speed of the roller or the scraper of the spreading device is identical over its entire length, and thanks to the closure in the upper part of each secondary jacket, the formation of a layer of powder takes place as if the selective consolidation zone 14 did not include a non-manufacturing zone.

[0037] Preferably, the rectilinear displacement axis DR of the powder spreading device 24 is horizontal. Preferably, the rectilinear displacement axis DR of the powder spreading device 24 is perpendicular to the gas flow F for evacuating the fumes. Preferably, the rectilinear displacement axis DR of the powder spreading device 24 is perpendicular to the vertical translation axis AV of the manufacturing plate 50. SPREADING DEVICE

[0038] Still with a view to easily and quickly controlling the layering of the powder on the selective consolidation zone 14, the powder spreading device 24 extends in a transverse direction DT perpendicular to its rectilinear displacement axis DR. More precisely, the roller or the scraper of the powder spreading device 24 extends in a transverse direction DT perpendicular to its rectilinear displacement axis DR.

[0039] In order to ensure a uniform layering of the powder thickness over the entire surface of the selective consolidation zone 14, the length L24 of the powder spreading device 24 in the transverse direction DT is greater than the maximum dimension DM of the outer contour Cex of the selective consolidation zone 14 in this transverse direction DT. Preferably and in order to avoid moving the inlet 38 and outlet 40 ramps too far away from the consolidation zone 14, the length L24 of the powder spreading device 24 in the transverse direction DT is only a few millimeters greater than the maximum dimension DM of the outer contour Cex of the selective consolidation zone 14 in this transverse direction DT.

[0040] By extending over a length L24 greater than the maximum dimension DM of the external contour Cex of the selective consolidation zone 14 in the transverse direction DT and by moving along a rectilinear displacement axis DR, the powder spreading device 24 offers easy-to-implement layering of the powder and more efficient deposition speed than a rotary powder distribution solution. SHIRTS AND TRAY

[0041] In a first preferred variant of the closure in the upper part of each secondary jacket, the upper surface 58 of the closure wall 56 of a secondary jacket 46 is located in the same plane as the upper surface 60 of the work surface 12. In this first variant, the upper surface 58 of the closure wall 56 of a secondary jacket 46 and the upper surface 60 of the work surface 12 are located a few tenths of a millimeter, 0.5 millimeter for example, below the generatrix of the roller or the scraper of the spreading device 24. This prevents the roller or the scraper from rubbing on the upper surface 58 of the closure wall 56 of a secondary jacket 46 and on the upper surface 60 of the work surface 12.Also, this space between the generator of the roller or the squeegee of the spreading device 24 and the upper surfaces of a closing wall 56 and of the work surface 12 is filled with powder during the first layering of powder and it remains filled with powder until the end of manufacturing.

[0042] In a second variant (not shown), the upper surface 58 of the closing wall 56 of a secondary jacket 46 is located very slightly above the plane of the upper surface 60 of the working plane 12, by a few tenths of a millimeter for example. In this second variant, the upper surface 58 of the closing wall 56 of a secondary jacket 46 is always located below the generatrix of the roller or the scraper of the spreading device 24.

[0043] In a third variant (not shown), the upper surface 58 of the closing wall 56 of a secondary jacket 46 is located very slightly below the plane of the upper surface 60 of the working plane 12, by a few tenths of a millimeter for example. In this third variant, a significant thickness of powder, of several tenths of a millimeter, must be formed by the spreading device 24 above a closing wall 56. It is intended to achieve this significant thickness of powder at the start of the manufacturing cycle during the first layering of powder, by distributing more powder in front of the spreading device 24 with the distribution device 22 than for the subsequent layerings of powder. Advantageously, the first layer of powder to be consolidated in the selective consolidation zone 14 is produced simultaneously with this significant thickness of powder.

[0044] Ideally, a secondary liner 46 is entirely surrounded by the manufacturing plate 50. Also, the manufacturing plate 50 comprises an opening 62 of closed contour CF crossed by the secondary liner 46. In the case where several secondary liners 46 are installed inside the main liner 42, the manufacturing plate 50 comprises several openings 62 of closed contour CF each crossed by one of the secondary liners 46.

[0045] In the example shown in the figures, the secondary jacket 46 has a shape identical to the main jacket 42 in a horizontal plane, but reduced homothetically. For example, the main jacket 42 has a circular outer contour Cex and the inner contour Cl of a secondary jacket 46 is also circular but with a diameter 1.01 to 10 times smaller, the inner contour Cl of a secondary jacket 46 corresponding to the closed contour CF of the opening 62 provided in the plate 50 for this secondary sleeve. However, the main sleeve 42 and the secondary sleeve(s) 46 may take different shapes, for example polygonal.

[0046] For the purpose of manufacturing annular parts, i.e. having an axis of revolution, the secondary jacket 42 and the main jacket 46 are for example cylindrical and extend in a vertical direction DV parallel to the vertical axis AV of translation of the plate 50 and of superposition of the layers of powder. For example, the secondary jacket 46 and the main jacket 42 are coaxial around the same vertical central axis ACV.

[0047] In the present invention, the main 42 and secondary 46 jackets take the form of metal walls several millimeters thick, at least 15 to 20 millimeters thick.

[0048] Advantageously, to prevent powder leaks towards the lower part of the machine 10, sealing means 64, such as seals, can be provided between the manufacturing plate 50 and the main 42 and secondary 46 jackets. VARIANTS

[0049] Alternatively (not shown in the figures), the inlet ramp 38 and the outlet ramp 40 of the smoke collection device 36 may be located along the outer contour Cex of the selective consolidation zone 14 and the inner contour(s) Cl of the secondary jacket(s). In a first example, the inlet ramp 38 is located along the outer contour Cex of the selective consolidation zone 14 and an outlet ramp 40 is located along the inner contour Cl of a secondary jacket 46. In another example, an inlet ramp 38 is located along the inner contour Cl of a secondary jacket 46 and an outlet ramp 40 is located along the outer contour Cex of the selective consolidation zone 14. In such a configuration, and when the selective consolidation zone 14 is annular, gas flows F for evacuating the smoke extend radially above the selective consolidation zone 14.Still in such a configuration, the entry ramps 38 and exit ramps 40 are retractable, for example in the work surface 12 or at a height several centimeters above the work surface 12, so as not to hinder the movements of the powder spreading device.

Claims

CLAIMS 1. Machine (10) for additive manufacturing by depositing layers of powder and selectively consolidating these layers of powder, the machine (10) comprising a device (18) for depositing layers of powder and a source (20) for selectively consolidating the layers of powder, the machine comprising a work surface (12) and a zone (14) for selectively consolidating the layers of powder located in this work surface, the machine comprising a main jacket (42) opening into the work surface through an opening (44) defining the outer contour (Cex) of the selective consolidation zone, the machine comprising a secondary jacket (46) arranged inside the main jacket (42) and defining a non-manufacturing zone (48) inside the selective consolidation zone, the machine (10) comprising a manufacturing plate (50) moving in translation between the main jacket and the secondary jacket under the effect of an actuator (52),the device (18) for depositing layers of powder comprising a powder distribution device (22) and a powder spreading device (24), such as a roller or a scraper, on the selective consolidation zone (14), the machine (10) being characterized in that the secondary jacket (42) is closed in the upper part by a closing wall (56) which is flat and parallel to the working plane (12) of the machine, and in that the powder spreading device (24) moves in translation above the selective consolidation zone (14) along a rectilinear displacement axis (DR)., 2. Additive manufacturing machine according to claim 1, wherein the powder spreading device (24) extends in a transverse direction (DT) perpendicular to its rectilinear displacement axis (DR).

3. Additive manufacturing machine according to claim 2, wherein the length (L24) of the powder spreading device (24) in the transverse direction (DT) is greater than the maximum dimension (DM) of the outer contour (Cex) of the selective consolidation zone (14) in this transverse direction (DT).

4. Additive manufacturing machine according to one of the preceding claims, in which the powder distribution device (22) makes it possible to carry or deposit a bead of powder on the work surface (12) between the selective consolidation zone (14) and the powder spreading device (24) when this powder spreading device is located in a waiting position situated outside the selective consolidation zone (14).

5. Additive manufacturing machine according to claim 4, wherein the powder distribution device (22) comprises a powder receiving surface (26) movable relative to the work surface (12) and to the selective consolidation zone (14).

6. Additive manufacturing machine according to claim 4, wherein the powder dispensing device (22) comprises a powder reservoir (28) movable above the work surface.

7. Additive manufacturing machine according to one of the preceding claims, in which the upper surface (58) of the closing wall (56) of the secondary jacket is located in the same plane as the upper surface (60) of the work plane (12).

8. Additive manufacturing machine according to one of the preceding claims, in which the manufacturing plate (50) comprises an opening (62) of closed contour (CF) crossed by the secondary jacket (46).

9. Additive manufacturing machine according to claim 8, in which the secondary jacket (46) has a shape identical to the main jacket (42) in a horizontal plane, but reduced homothetically.

10. Additive manufacturing machine according to claim 9, wherein the secondary jacket (46) and the main jacket (42) are cylindrical and extend in a vertical direction (DV).

11. Additive manufacturing machine according to claim 10, wherein the secondary jacket (46) and the main jacket (42) are coaxial.

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