WO2024126953A1

WO2024126953A1 - Device and method for additive manufacturing with dusting of a powder spreading carriage

Info

Publication number: WO2024126953A1
Application number: PCT/FR2023/052004
Authority: WO
Inventors: Benoît POURCHER; Léopold BARRY; Julien MARCER; Julien CANO
Original assignee: Addup
Priority date: 2022-12-14
Filing date: 2023-12-14
Publication date: 2024-06-20
Also published as: FR3143418A1

Abstract

The invention relates to an additive manufacturing device (1) comprising an enclosure (3) and a conveyor (5A, 5B, 29A, 29B) configured to recirculate manufacturing powder, the enclosure (3) comprising: - a work-holding platform (7); - a carriage (13) configured to spread powder on top of the work-holding platform (7); - a dusting appliance (23A, 23B, 33) included in the carriage (13) and configured to trigger a jolt or a vibration in the carriage and remove powder from the carriage; and - an inlet of the conveyor (5A, 5B, 29A, 29B), the device being configured to feed removed powder (42) from the carriage (13) into the inlet of the conveyor (5A, 5B, 29A, 29B), the inlet (6A, 6B) being located between the work-holding platform (7) and an end-of-travel position of the carriage.

Description

Additive manufacturing device and method with powder removal from a powder spreading cart

FIELD OF THE INVENTION

The invention relates to additive manufacturing which requires spreading of the additive manufacturing powder, for example by a powder spreading cart.

STATE OF THE ART

In additive manufacturing devices which require spreading of the powder, it is necessary to use a system capable of transporting and spreading the powder, such as for example a powder spreading cart, on the manufacturing zone, as by example a manufacturing part-carrying platform.

The powder moved by the carriage as well as the unconsolidated powder at the end of manufacturing can spread inside the enclosure. The spreading cart may in particular be covered with an unwanted layer of powder. When the spreading carriage moves on the part-carrying platform, it produces the expected working surface of the powder layer before consolidation. The good condition of this work surface is necessary for the good quality of the manufactured part. There is a risk that some of the unwanted powder layer will fall from the cart onto this work surface. The surface condition of the powder layer is then deteriorated just before consolidation, and there is a risk of poor quality of the manufactured part or the manufactured object.

There is therefore a need to better control powder pollution generated at the powder spreading stage.

STATEMENT OF THE INVENTION

One aim of the invention is to better control pollution by powder generated at the powder spreading stage.

The aim is achieved in the context of the present invention thanks to an additive manufacturing device comprising an enclosure and a conveyor configured to recycle manufacturing powder, the enclosure comprising:

- a workpiece carrying platform,

- a cart configured to spread powder above the part-carrying platform,

- a powder removal device configured to remove powder from the carriage, and - an entrance to the conveyor, the device being configured to bring powder removed from the carriage into the entrance to the conveyor or into a reserve, the reserve extending inside the enclosure and comprising at least one separate wall of the walls of the enclosure.

Such a device is advantageously and optionally supplemented by the following different characteristics taken alone or in combination:

- the entrance to the conveyor or the reserve is located opposite an end position of the carriage, the powder removal device being configured to be triggered when the carriage is at the end of the stroke so that the powder falls by gravity in the carrier's entrance or in the reserve;

- the device is configured to bring powder removed from the carriage into the inlet of the conveyor, the inlet being located between the part-carrying platform and an end position of the carriage, the powder removal device being mounted on the trolley and configured to be triggered when the trolley is directly above the entrance

- the device is configured to bring powder removed from the carriage into the inlet of the conveyor, the inlet being located between the part-carrying platform and an end position of the carriage, the device further comprising a movement member separate from the conveyor and configured to move the powder removed from the cart into the inlet;

- the moving member is a scraper mounted on the carriage and configured to be in an active configuration in which the scraper is in contact with a bench in the enclosure and in a passive configuration in which the scraper is located above from the bench; And

- the displacement member is a movable flap in rotation and configured to be in an active configuration in which the flap is inclined towards the entrance of the conveyor and in a passive configuration in which the flap is horizontal.

The invention also relates to an additive manufacturing process comprising the following steps

- by means of a trolley, spreading of a manufacturing powder on a part-holding platform included in an enclosure,

- removal of powder from the carriage, and

- recycling of the powder removed by a transporter or conservation of the powder removed in a reserve, the reserve extending inside the enclosure and comprising at least one wall distinct from the walls of the enclosure. Such a process is advantageously and optionally supplemented by the following different characteristics taken alone or in combination:

- the withdrawal of powder is triggered after a step of moving the carriage at the end of the stroke, so that during the withdrawal of powder, the removed powder falls by gravity into the entrance of the conveyor or into the reserve;

- the removal of powder is triggered after a step of moving the carriage directly above the entrance of the conveyor between the part-carrying platform and an end position of the carriage, so that during the removal of powder, the removed powder falls by gravity into the conveyor inlet;

- the method comprises, after removing the powder, a step of intermediate movement of the removed powder into the inlet of the conveyor;

- intermediate movement is ensured by a scraper mounted on the carriage and configured to be in contact with a bench; And

- intermediate movement is ensured by a movable rotating flap configured to tilt towards the entrance of the conveyor.

DESCRIPTION OF FIGURES

Other characteristics and advantages of the invention will emerge further from the description which follows, which is purely illustrative and not limiting, and must be read with reference to the appended drawings in which: Figures 1 to 7 are schematic representations of a detail of an additive manufacturing device according to different embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Additive manufacturing device

With reference to Figures 1 to 7, an additive manufacturing device 1 comprises an enclosure 3 in which an object can be manufactured by consolidating an additive manufacturing powder.

Enclosure 3 includes different walls which define a working chamber inside. Enclosure 3 is waterproof. We can control the gas environment inside enclosure 3, in particular we can fill enclosure 3 with an inert gas which does not alter the additive manufacturing powder.

The manufacturing powder is placed on a part-holding platform 7 before being consolidated. The workpiece platform 7 includes an upper surface which is horizontal. With reference to Figures 1 to 7, the x and y axes define a horizontal plane, the z axis is oriented vertically to the top. The workpiece platform is rectangular oriented along the x and y axes. The workpiece platform has a main length along the x axis and a transverse length along the y axis. We define the direction of the x axis as the main direction and the direction of the y axis as the transverse direction.

The manufacturing of the object is carried out layer by layer: a first layer of powder spread on the part-holding platform is selectively consolidated then a second layer of powder is spread above the first layer before being consolidated at its turn and merged with the previous layer. Above the part-holding platform 7, a plurality of layers 9 are therefore stacked as manufacturing progresses. The part-holding platform 7 can be movable in translation in the vertical direction. With each new layer spread, the part-holding platform 7 can translate vertically, therefore along the z axis, downwards by a distance corresponding to the thickness of a layer. In this way the last spread layer, referenced 11 in the figures, is always at the same height in enclosure 3.

The enclosure includes a bench 10 which extends around the part-holding platform 7. The bench 10 is a single piece which surrounds the entire part-holding platform 7. The bench 10 vertically separates the manufacturing line which is located at -above the bench 10 and the lower part of the manufacturing machine. The bench 10 defines by its upper edge a wall which ensures sealing between the production line and the lower part, with respect to the manufacturing powder. Sealing can also be ensured against gas. The bench 10 makes it possible to reduce the number of junctions and/or joints necessary to ensure watertightness. The bench 10 defines a wall whose maximum vertical position is close to, or even coincides with, the vertical position of the last spread layer 11. In this way, the bench 10 and the last spread layer 11 form a continuous horizontal surface if it there is no vertical gap between the bench 10 and the last spread layer 11, or almost continuous if there is a slight vertical gap between them.

The powder is introduced into enclosure 3 by a conveyor system 5A, 5B. The system includes for example two drawers which extend in the transverse direction, along the y axis, over the entire transverse length of the workpiece platform. The drawers are movable in translation in the transverse direction and comprise an upper surface on which a continuous bead of manufacturing powder is deposited. The two cords can thus be positioned in the main direction on either side of the workpiece-holding platform 7, each cord extending over the entire transverse length of the workpiece-holding platform. The conveyor system 5A, 5B thus makes it possible to bring the powder close to the part-carrying platform. The drawer occupies a volume defined by a hollow or depression of the bench 10. The upper surface of the bench 10 has a hollow in which the drawer is housed. The upper surface on which the powder is placed has a vertical position which is close to, or even coincides with, the maximum vertical position of the bench 10. In this way, the upper surface of the drawers of the conveyor system 5A, 5B and the bench 10 form a continuous or almost continuous horizontal surface.

The conveyor system 5A, 5B also includes a recycling path which makes it possible to automatically recycle powder which enters through an entrance 6A, 6B of the system 5A, 5B. For example, the recycling path of the conveyor system 5A, 5B comprises a gutter located below the inlet 6A, 6B which can receive the powder and an endless screw which can carry the powder received towards a tank which extends by example outside the enclosure, or towards a recycling circuit or even towards a suction and filtering system which replaces the powder in a main hopper of the additive manufacturing device. It is thus possible to subsequently spread this recycled powder on the part-carrying platform.

The conveyor system 5A, 5B is configured to convey the powder near the part-carrying platform 7 so that the drawers and inlets 6A and 6B are located near the part-carrying platform 7. In the main parallel direction on the x axis, the drawers and the inputs 6A and 6B have the positions 18A 18B which are located between the workpiece platform and the end positions 17 and 19 of the carriage.

The additive manufacturing device 1 comprises a carriage 13 configured to spread powder above (or on) the part-carrying platform 7. The carriage 13 is movably mounted inside the enclosure and moves according to the main direction parallel to the x axis. More precisely, the carriage 13 can be moved in translation along a ramp 15 which is directed in the main direction. The carriage 13 is configured to move over a stroke 21 defined between a first end of stroke position 17 and a second end of stroke position 19. The stroke 21 corresponds to the length of the ramp 15 in the main direction.

The carriage 13 is configured to move above the workpiece platform 7 over the entire main length of the workpiece platform. The travel 21 of the carriage covers the main length along the x axis of the part-carrying platform 7.

The carriage 13 comprises in its lower part a member 14 configured to be in contact with the powder and spread it along a horizontal plane. For example, the organ can be a roller or a squeegee.

For this purpose, the carriage 13 and the member 14 each extend in the transverse direction over a length greater than or equal to the transverse length of the part-carrying platform. The carriage 13 is configured to move above the drawers of the conveyor system 5A, 5B in order to be able to distribute the powder above the part-carrying platform 7.

The carriage 13 is configured to move continuously above the powder supply locations and the part-carrying platform. In other words, the carriage 13 is configured to move above the bench 10.

When the carriage moves and comes into contact with the powder, the carriage may become covered with an unwanted layer of powder. The device includes a powder removal device which is configured to remove at least part of the powder which thus accumulates on the carriage.

Powder removal device

Different embodiments of this powder removal device are possible.

With reference to Figures 1, 2 and 5, a first embodiment of the powder removal device uses the stops 23A and 23B of the carriage 13. The stops 23A and 23B are located at the ends of the ramp 15 so that when the carriage is at the end of the stroke it is in contact with one of these stops. A powder removal device can be produced by implementing a shock 40 between the carriage and the stops 23A and 23B. In particular, the carriage can be propelled against the stop. In this first embodiment the powder removal device is fixedly mounted in the device 1. During the impact 40, a quantity of powder 42 falls from the carriage 13 according to the movement illustrated by the arrow 44.

With reference to Figures 3 and 4 a second embodiment of the powder removal device uses a powder removal device 33 mounted on the carriage 13. The powder removal device 33 then forms part of the carriage 13 and moves together with the carriage 13 The powder removal device 33 can for example be a striker comprising a spring which can be compressed under the action of a pressurized inert gas brought into a cylinder of the striker. On receipt of a trigger signal, the compressed inert gas can be released from the cylinder, thus releasing the spring which carries a part which strikes the body of the carriage 13. Alternatively, the powder removal device 33 can be a vibrating system which, upon receipt of a trigger signal, begins to oscillate, shaking the carriage to which the vibrating system is attached. The powder removal device is configured to be able to trigger a shock or vibration in the carriage. The powder removal device is an active component which is supplied with energy to be able to deliver the shock or vibration to the carriage. During the shock or vibration 40, a quantity of powder 42 falls from the carriage 13 according to the movement illustrated by the arrow 44. We speak in the following text of "powder removed" to designate this quantity of powder 42 which falls from the trolley 13. Shock or vibration can be triggered at will so that we can choose the place of depowdering, that is to say the place where powder is removed from the cart.

Places to bring the powder removed from the cart

The device 1 is configured to bring the powder removed 42 from the carriage into one of the two locations presented below and corresponding to the following two options.

According to a first option, the powder removed from the carriage is brought into a reserve, the reserve extending inside the enclosure and comprising at least one wall distinct from the walls of the enclosure.

Figure 1 illustrates this first option. Device 1 includes in this first option at least one of the two reserves 25A, 25B. When the device 1 includes the two reserves, they are located in the main direction, parallel to the x axis, on either side of the part-holding platform 7, advantageously symmetrically. A reserve 25A, 25B extends inside the enclosure 3. A reserve 25A, 25B is defined by walls 27A, 27B. These walls 27A, 27B are distinct from the walls of the enclosure 3. A reserve 25A, 25B defines a storage volume adapted to receive powder, the storage volume being entirely included in the working chamber defined by the enclosure 3 As illustrated, the reserves can be hollow or depressed volumes defined in the bench 10. In other words, the upper surface of the bench 10 can present, from its maximum vertical position, a hollow or a depression. This hollow corresponds to the walls 27A, 27B which extend from the maximum vertical position of the bench 10 downwards. The hollow defines a storage volume which is located below the maximum vertical position of the bench 10. The reserve has in this case walls all located below the maximum vertical position of the bench 10 and the reserve is open upwards. This opening allows you to receive the powder. The storage volume can then be defined by the walls and a virtual closure given by the vertical position of the bench 10.

Advantageously the storage volume is chosen greater than or equal to four liters.

According to a second option, the powder removed from the carriage is brought into the entrance of a conveyor configured to recycle manufacturing powder.

This conveyor is configured for example to receive the removed powder and transport it to the powder circulation system intended to be spread so that the removed powder is spread again on the part-carrying platform. The conveyor is configured to transport the powder received as input so as to subsequently spread the powder on the part-carrying platform. For example, the transporter can take the removed powder to a tank, or to a recycling circuit or even towards a suction and filtering system which replaces the powder in a main hopper of the additive manufacturing device.

The transporter can in a first variant be the recycling route of the convoy system 5A, 5B described previously.

In a second variant illustrated in Figure 2, the transporter can be separate from the recycling path of the convoy system 5A, 5B. The conveyor is then a recovery tank 29A, 29B connected to a powder suction system. The recovery tank 29A, 29B extends inside the enclosure 3. The recovery tank 29A, 29B is defined by walls distinct from the walls of the enclosure 3. The recovery tank 29A, 29B defines a volume adapted to receive powder, entirely included in the working chamber defined by the enclosure 3. As illustrated, the recovery tank can define a hollow or depressed volume in the bench 10. In other words, the walls of the tank extend from the maximum vertical position of the bench downwards and define a volume which is located below this maximum vertical position of the bench 10. The recovery tank in this case has walls all located below the position vertical of the bench 10 and it is open upwards. This opening allows you to receive the powder. The reservation tank comprises in its lowest part, at the bottom of the tank, an orifice which is connected via a conduit 31 A, 31 B to a powder suction system. The powder suction system is configured to send the powder received in the recovery tank via the orifice and the conduit 31 A, 31 B towards a tank, or towards a recycling circuit or even towards the circulation system of the powder intended to be spread so that the powder removed is spread again on the part-holding platform.

As illustrated in Figure 2, the device 1 can comprise two conveyors located in the main direction, parallel to the x axis, on either side of the part-carrying platform 7, advantageously symmetrically.

In common with the first option and the second option that we have presented, the device can be configured in the following first configuration: the entrance to the conveyor or the reserve is located opposite an end position of the carriage, the powder removal device being configured to be triggered when the carriage is at the end of its stroke so that the powder falls by gravity into the entrance of the conveyor or into the reserve.

This first configuration is illustrated in Figures 1 and 2.

End positions 17 and 19 were previously presented. When the carriage reaches one of these positions and is therefore in contact with one of the stops 23A, 23B, then the entrance to the conveyor or the reserve is located vertically below the carriage 13. In this first configuration, the conveyor can be a recovery tank 29A, 29B connected to a powder suction system. On the other hand, the transporter cannot be the recycling path of the conveyor system 5A, 5B because the inputs 6A, 6B have positions 18A 18B different from the end positions 17 and 19 of the carriage.

The different embodiments of the powder removal device presented previously are compatible with this first configuration.

In relation to the second option that has been presented, the device can be configured for the following second configuration: the entrance to the conveyor is located between the part-carrying platform and an end position of the carriage, the device powder removal unit being mounted on the cart and configured to be triggered when the cart is directly above the entrance. The depowdering device thus depowders the trolley when it is directly above the entrance.

This second configuration is illustrated in Figure 3.

In this second configuration, the conveyor can be the recycling path of the conveyor system 5A, 5B because the inputs 6A, 6B have positions 18A, 18B different from the end positions 17 and 19 of the carriage 13.

When the carriage 13 is directly above the entrance to the conveyor, the carriage 13 is distant from the stops 23A, 23B, so that the powder removal device which uses the stops 23A and 23B of the carriage 13 cannot be used to depowder the carriage 13. We therefore use the second embodiment of the depowdering device mounted on the carriage 13 in this second configuration.

Movement member

Still in connection with the second option that we presented, the device can be configured for the following third configuration: the entrance to the conveyor is located between the part-carrying platform and an end position of the carriage, the device further comprising a moving member separate from the conveyor and configured to move the powder removed from the carriage into the inlet.

This third configuration is illustrated in a first variant in Figures 4 and 5 and in a second variant in Figures 6 and 7.

In this third configuration, the conveyor can be the recycling path of the conveyor system 5A, 5B because the inputs 6A, 6B have positions 18A, 18B different from the end positions 17 and 19 of the carriage 13.

This third configuration does not require the carriage 13 to be directly above the entrance to the conveyor for depowdering to be triggered. The different embodiments of the powder removal device presented previously are compatible with this third configuration: Figure 4 illustrates the second embodiment of the powder removal device 33 and Figure 5 illustrates the first embodiment of the device powder removal 23A.

The additive manufacturing device 1 in this third configuration comprises a movement member 34A, 34B, 35A, 35B separate from the conveyor and configured to move the powder removed from the carriage into the inlet of the conveyor.

Different embodiments of this movement member are possible.

In a first embodiment of the displacement member illustrated in Figures 4 and 5, the member is a doctor blade 34A, 34 B mounted on the carriage and configured to be in an active configuration in which the doctor blade 34A, 34 B is in contact with the bench 10 and in a passive configuration in which the doctor blade is located above the bench 10.

The carriage 13 includes the doctor blade 34A, 34B which is located projecting from the carriage 13 in the main direction. The carriage may include a first blade 34A on one side and a second blade 34B on the other side relative to the main direction. The blade 34A, 34B extends in the transverse direction over a length greater than or equal to the length of the carriage in this same transverse direction. The doctor blade 34A, 34B includes a deformable part which constitutes its lowest part. The doctor blade 34 is mounted movable relative to the carriage 33 and in particular it is mounted movable in vertical translation, along the z axis. The doctor blade is configured to switch from an active configuration to a passive configuration and vice versa.

In the active configuration the doctor blade 34A, 34 B is in a low position so that the deformable part is in contact with the bench 10.

In the passive configuration the blade 34A, 34 B is in a high position so that the deformable part is not in contact with the bench 10, it is above the bench 10.

The doctor blade can be moved vertically from the active configuration to the passive configuration by cylinders mounted on the carriage, the blade being mounted on the cylinders.

In Figures 4 and 5, the carriage 13 comprises two blades 34A, 34B, the blade 34A is shown in its active configuration and the blade 34B is shown in its passive configuration.

When the carriage is depowdered by a shock 40, the removed powder 42 falls onto the bench 10. In its active configuration, the doctor blade is in contact with the bench 10. Setting the carriage in motion when the doctor blade is in its active configuration makes it possible to move the doctor blade while maintaining its contact with the bench 10. It is possible to put the doctor blade in contact with the removed powder and move the powder against the doctor blade. An intermediate movement of the powder is thus carried out which serves to place the removed powder at the entrance to the conveyor.

It should be noted that when the additive manufacturing device comprises a movement member in the form of a blade 34A, 34 B mounted on the carriage via cylinders, this blade can play the role of powder removal device configured to mechanically excite the cart and remove any powder deposited on the cart. The shock energy is then produced using the cylinders that set the blade in motion when they reach their stop.

In a second embodiment of the displacement member illustrated in Figures 6 and 7, the member is a flap 35A, 35B movable in rotation and configured to be in an active configuration in which the flap 35A, 35B is inclined towards the 'inlet of the conveyor and in a passive configuration in which the flap is horizontal.

The flap 35A, 35B is included in the enclosure 3. The flap 35A, 35B is located contiguous to the entrance to the conveyor in the main direction so that the entrance to the conveyor is placed between the flap 35A, 35B and the workpiece platform. The shutter 35A, 35B is mounted movable in rotation around a horizontal axis of rotation 36A, 36B. The horizontal axis of rotation is parallel to the transverse direction illustrated by the y axis in Figures 6 and 7. The axis of rotation passes through the flap 35A and is located contiguous to the entrance to the conveyor.

The flap 35A, 35B extends in the main direction from the horizontal axis of rotation to the stop 23A, 23B.

The shutter 35A, 35B is configured to go from an active configuration to a passive configuration and vice versa.

In the active configuration the shutter 35A, 35B is inclined relative to the horizontal plane so that the shutter 35A, 35B rises above the vertical position of the bench 10. The shutter 35A, 35B is inclined towards the entrance of the conveyor in the sense that an object located on the upper surface of the flap is attracted by gravity towards the inlet of the conveyor.

In the passive configuration the shutter 35A, 35B is oriented along a horizontal plane so that an upper surface of the shutter 35A, 35B is located in the extension of the bench 10. The carriage 13 can then move above the shutter 35A, 35B and stop above it. The device can include two flaps 35A, 35B which are located on either side of the part-carrying platform when the conveyor system 5A, 5B comprises two drawers and therefore two conveyor entrances 6A, 6B.

Additive manufacturing process

An additive manufacturing device as just presented makes it possible to implement a process according to the invention to better control pollution by powder generated at the powder spreading stage.

We will present the different stages of the process.

During a first step and by means of the carriage 13, a manufacturing powder is spread on the part-holding platform 7 included in the enclosure 3.

This first step may include, for example:

- the supply of a bead of powder on a drawer of the conveyor system 5A, 5B,

- prior to the supply of the cord, the positioning of the carriage 13 so that the drawer is located between the part-carrying platform 7 and the carriage 13,

- setting the carriage 13 in motion in a spreading direction towards the drawer and the part-holding platform 7, so that the powder deposited on the drawer is carried by the member 14 of the carriage towards the part-holding platform, and as the carriage travels along the first length of the part-holding platform, the spreading of the powder spread on the part-holding platform by the member 14.

During a second step, powder is removed which undesirably covers the carriage 13. We also speak of depowdering the carriage to designate this second step.

This second step is carried out after the first step. Advantageously, and before the powder removal of this second step, the carriage 13 continues its movement in the direction of spreading beyond the part-carrying platform. In this way, the removed powder does not settle on the layer of powder that has just been deposited.

The powder removal device according to one of the modes previously described is triggered and it produces a shock or vibrations 40 on the carriage 13 so that the powder 42 is removed from the carriage 13 according to the movement 44.

During a third step, the removed powder is

- either recycled by the carrier according to the first option already mentioned previously, - either kept in the reserve according to the second option already mentioned previously.

We also speak of isolation of the removed powder to designate this third stage, in the sense that the risk of pollution of the newly deposited layer by this removed powder is greatly reduced.

In fact, the removed powder is, in all cases, kept away from the part-holding platform to prevent it from polluting the newly deposited layer and more generally the manufacturing process. Powder pollution generated undesirably during the powder spreading stage is thus better controlled.

Advantageously, the last two steps described above can be carried out after each planned spreading of the powder during the manufacturing process. We can also choose to perform them at a lower spreading frequency, for example after each group of two successive spreadings, or after each group of a greater number of successive spreadings.

When the removed powder is kept in the reserve, it is advantageous for the reserve to have a volume greater than or equal to four liters. In this way, a large number of powder removals from the cart can be carried out before the reserve is full. This limits the frequency of human intervention on the device to empty the reserve.

In common with the first option and the second option recalled above, the method can be adapted according to a first adaptation so that the withdrawal of powder is triggered after a step of moving the carriage at the end of the stroke, so that when of powder removal, the removed powder falls by gravity into the conveyor inlet or into the reserve.

This first adaptation of the process corresponds to the first configuration of the device mentioned previously and illustrated in Figures 1 and 2.

This first adaptation corresponds to a carriage 13 which, after having spread the powder, continues its movement in the direction of spreading beyond the part-carrying platform until the end of the stroke. The powder which undesirably covers the carriage is removed as far as possible from the part-carrying platform, further limiting the risk of pollution of the spread layer.

After the shock 40 produced on the carriage 13 by the powder removal device, the removed powder 42 falls by gravity into the entrance of the conveyor or into the reserve, so that it is not necessary to provide an intermediate movement of the powder towards the entrance of the transporter or in the reserve. When the device includes at each end of the carriage's stroke an entrance to the conveyor or a reserve, then it is possible to carry out depowdering and isolation of the powder removed after each passage of the carriage above the part-carrying platform 7 .

In relation to the second option recalled above, the method can be adapted according to a second adaptation so that the withdrawal of powder is triggered after a step of moving the carriage directly above the entrance of the conveyor between the carrier platform. part and an end position of the carriage, so that when removing powder, the removed powder falls by gravity into the inlet of the conveyor.

This second adaptation of the process corresponds to the second configuration of the device mentioned previously and illustrated in Figure 3. This second adaptation is linked to the second embodiment of the powder removal device.

This second adaptation can be implemented with the convoy system 5A, 5B already present in the device. It is not necessary to add a reserve or a recovery tank and a powder suction system in the device.

This second adaptation corresponds to a carriage 13 which, after having spread the powder, continues its movement in the direction of spreading beyond the part-carrying platform up to the entrance 6A, 6B of the recycling path of the system of convoy 5A, 5B. The powder which undesirably covers the carriage is removed far enough from the part-carrying platform, to satisfactorily limit the risk of pollution of the spread layer.

After the shock 40 or the vibrations produced on the carriage 13 by the powder removal device, the removed powder 42 falls by gravity into the inlet 6A, 6B of the conveyor, so that it is not necessary to provide a movement intermediate of the powder towards the entrance of the conveyor.

When the device includes on either side of the part-carrying platform an entrance to the recycling path of the conveyor system 5A, 5B, then it is possible to carry out depowdering and isolation of the powder removed after each passage of the carriage above the workpiece platform 7.

Still in connection with the second option recalled above, and according to a third adaptation, the method can comprise, after the removal of powder, a step of intermediate movement of the powder removed into the inlet of the conveyor.

This third adaptation is illustrated in a first variant in Figures 4 and 5 and in a second variant in Figures 6 and 7. This third adaptation of the method corresponds to the third configuration of the device mentioned previously and illustrated in a first variant in Figures 4 and 5 and in a second variant in Figures 6 and 7. This third adaptation is compatible with the different embodiments of the powder removal device presented previously.

This third adaptation can be implemented with the convoy system 5A, 5B already present in the device. It is not necessary to add a reserve or a recovery tank and a powder suction system in the device.

This third adaptation does not require that the carriage 13 be placed at a particular location in its travel for powder removal to be triggered. There is greater freedom in terms of carriage position. Furthermore, the intermediate movement step of the removed powder can make it possible to bring a larger quantity of removed powder to the entrance to the conveyor.

The first variant of the third adaptation corresponds to the case where the intermediate movement is ensured by the scraper 34A, 34B mounted on the carriage 13 and configured to be in contact with the bench 10.

In this second variant, the doctor blade 34A, 34B is by default in its passive configuration, that is to say in a high position so as not to come into contact with the bench 10 or the last layer of spread powder 11. In particular, during the stage of spreading the powder on the workpiece platform, the doctor blade 34A, 34B is in its passive configuration.

Depowdering can be triggered when the carriage 13 is beyond the part-carrying platform and the entrance to the conveyor, that is to say when the entrance to the conveyor is located between the carriage and the work-carrying platform. piece. It should be noted that the shock 40 can be produced by the powder removal device chosen in its first embodiment or in its second embodiment. In the first mode, the carriage 13 is placed at the end of its travel before powder removal is initiated. In the second mode, the carriage 13 is freely placed between this end of travel and the entrance to the conveyor before powder removal is initiated.

Once the shock 40 produced on the carriage 13 by the powder removal device, the removed powder falls by gravity onto the bench 10. The doctor blade 34A, 34B is placed in its active configuration. This situation is illustrated in Figure 4 when the powder removal device corresponds to the second embodiment 33, and in Figure 5 when the powder removal device corresponds to the first embodiment 23A.

The carriage 13 is set in motion so that the scraper 34A moves the removed powder 42 into the inlet 6A, 6B of the conveyor. Once the powder has been removed 42 inside the conveyor, the blade 34A can be placed in passive configuration.

In the case where the carriage 13 comprises two scrapers 34A, 34B on either side of the carriage in the main direction, it is the scrape furthest from the entrance to the conveyor which is placed in its active configuration and used to move the removed powder into the conveyor inlet.

The second variant of the third adaptation corresponds to the case where the intermediate movement is ensured by a flap 35A, 35B movable in rotation and configured to tilt towards the entrance of the conveyor.

In this second variant, the shutter 35A, 35B is by default in its passive configuration, that is to say oriented horizontally. In particular, during the stage of spreading the powder on the part-carrying platform, the shutter 35A, 35B is in its passive configuration.

Powder removal can be triggered when the carriage 13 is located above shutter 35A, 35B which is in its passive configuration, that is to say oriented horizontally.

Once the shock 40 produced on the carriage 13 by the powder removal device, the removed powder 42 falls by gravity onto the shutter 35A, 35B. This situation is illustrated in Figure 6.

The carriage 13 is then moved towards the workpiece platform so that it is no longer above the flap 35A, 35B.

The shutter 35A, 35B is placed in its active configuration. This situation is illustrated in Figure 7. The flap 35A rotates around the axis of rotation 36A and thus rises above the axial position of the bench 10. The flap 35A tilts by an angle 37 and thus forms an inclined plane towards the entrance 6A of the transporter. The removed powder 42 located on this inclined plane is then attracted by gravity to the bottom of the plane, that is to say in the inlet 6A of the conveyor. Once the powder has been removed 42 inside the transporter, the flap 35A can be placed in passive configuration.

It should be noted that at the end of manufacturing the part, part of the residual powder present on the bench, and which has for example been removed from the carriage on the bench, can be spread on the last layer of the powder bed beforehand. lowered below the surface of the bench. This powder is then extracted from the enclosure when the part-holding platform is removed, this powder is then treated by a depowdering machine which frees the manufactured part from the unconsolidated powder which surrounds it.

Claims

1. Additive manufacturing device (1) comprising an enclosure (3) and a conveyor (5A, 5B, 29A, 29B) configured to recycle manufacturing powder, the enclosure (3) comprising:

- a workpiece support platform (7),

- a carriage (13) configured to spread powder above the part-carrying platform (7),

- a powder removal device (23A, 23B, 33) included in the carriage (13) and configured to trigger a shock or vibration in the carriage and remove powder from the carriage, and

- an inlet of the conveyor (5A, 5B, 29A, 29B), the device being configured to bring powder removed (42) from the carriage (13) into the inlet of the conveyor (5A, 5B, 29A, 29B), the inlet (6A, 6B) being located between the workpiece support platform (7) and an end position of the carriage.

2. Device according to claim 1 configured to bring powder removed (42) from the carriage (13) into the inlet (6A, 6B) of the conveyor, the device further comprising a movement member (34A, 34B, 35A, 35B) separate from the conveyor and configured to move the powder removed (42) from the carriage (13) into the inlet (6A, 6B).

3. Device according to claim 2 in which the displacement member (34A, 34B) is a doctor blade (34A, 34B) mounted on the carriage (13) and configured to be in an active configuration in which the doctor blade (34A, 34B ) is in contact with a bench (10) in the enclosure (3) and in a passive configuration in which the doctor blade (34A, 34B) is located above the bench (10).

4. Device according to claim 2 in which the displacement member is a movable flap (35A, 35B) in rotation and configured to be in an active configuration in which the flap (35A, 35B) is inclined towards the inlet (6A , 6B) of the transporter and in a passive configuration in which the flap (35A, 35B) is horizontal.

5. Additive manufacturing process comprising the following steps:

- by means of a carriage (13), spreading of a manufacturing powder on a part-carrying platform (7) included in an enclosure (3), - removal of powder from the carriage by triggering a shock or vibration in the carriage by a powder removal device (23A, 23B, 33) included in the carriage (13), and

- recycling of the powder removed by a conveyor (5A, 5B, 29A, 29B), an inlet (6A, 6B) of the conveyor being located between the part-carrying platform (7) and an end position of the carriage, the powder removal.

6. Method according to claim 5 in which the powder withdrawal is triggered after a step of moving the carriage directly above the inlet (6A, 6B), so that during the powder withdrawal, the powder removed (42 ) falls by gravity into the inlet (6A, 6B) of the transporter.

7. Method according to claim 5 comprising, after removing the powder, a step of intermediate movement of the removed powder into the inlet of the conveyor (6A, 6B).

8. Method according to claim 7 in which the intermediate movement is ensured by a doctor blade (34A, 34B) mounted on the carriage (13) and configured to be in contact with a bench (10).

9. Method according to claim 7 in which the intermediate movement is ensured by a movable flap (35A, 35B) in rotation and configured to tilt towards the entrance of the conveyor (6A, 6B).