Apparatus and method for additive manufacturing with dusting of powder distribution carriages

Abstract

The present invention relates to an additive manufacturing apparatus (1) comprising an enclosure (3) and a conveyor (5A, 5B, 29A, 29B) configured to recirculate a production powder, the enclosure (3) comprising: - a work-holding platform (7), a carriage (13) configured to sprinkle powder onto the work-holding platform (7); a dusting device (23A, 23B, 33) included in the carriage (13) and configured to trigger an impact or vibration of the carriage to remove powder from the carriage; - an inlet for a conveyor (5A, 5B, 29A, 29B), The apparatus is configured to feed powder (42) removed from the carriage (13) to an inlet of a conveyor (5A, 5B, 29A, 29B), the inlet (6A, 6B) being located between a work-holding platform (7) and an end-of-travel position of the carriage, relative to the additive manufacturing apparatus (1).

Description

[Technical Field]

[0001] The present invention relates to additive manufacturing, where additive manufacturing powder needs to be spread, for example by a powder spreading carriage. [Background technology]

[0002] Additive manufacturing systems that require powder spreading require the use of a system that can transport and spread powder across a manufacturing area, such as a powder spreading carriage, for example, a manufacturing workpiece holding platform.

[0003] Powder moved by the carriage, as well as unconsolidated powder at the end of the manufacturing process, can spread inside the enclosure. In particular, the spreading carriage can become covered with an undesired layer of powder. As the spreading carriage moves over the work-holding platform, it generates a prospective working surface of the powder layer before consolidation. The good condition of this working surface is important for the quality of the parts manufactured. There is a risk that parts of the undesired powder layer will fall from the carriage onto this working surface. This will cause the surface condition of the powder layer to deteriorate just before consolidation, which will reduce the quality of the manufactured part or object.

[0004] Therefore, there is a need for better control of powder contamination that occurs during the powder application step. Summary of the Invention

[0005] One object of the present invention is to better control powder contamination that occurs during the powder application step.

[0006] This object is achieved within the scope of the present invention by an additive manufacturing apparatus comprising an enclosure and a conveyor configured to recycle the manufacturing powder, the enclosure comprising: a work holding platform; a carriage configured to spread powder onto a work-holding platform; a dusting device configured to remove powder from the carriage; a conveyor inlet; The apparatus is configured to feed powder removed from the carriage into a conveyor inlet or into a storage area, the storage area including at least one wall extending into the enclosure and separate from the walls of the enclosure.

[0007] Such a device may have the following various features, either alone or in combination: the conveyor entrance or storage area is located opposite the end-of-travel position of the carriage, and the dusting device is configured to be triggered when the carriage is at the end of its travel so that the powder falls by gravity into the conveyor entrance or storage area; the device is configured to feed powder removed from the carriage to a conveyor inlet, the inlet being located between the work holding platform and an end-of-travel position of the carriage, the dusting implement being attached to the carriage and configured to be triggered when the carriage is level with the inlet; the apparatus is configured to supply powder removed from the carriage to a conveyor inlet, the inlet being located between the work holding platform and an end-of-travel position of the carriage, the apparatus further comprising a displacement member separate from the conveyor and configured to move powder removed from the carriage to the inlet; the displacement member is a scraper mounted on the carriage and configured to have an active configuration in which the scraper contacts the bench in the enclosure and a passive configuration in which the scraper is positioned above the bench; Advantageously and optionally completed by the displacement member being a rotatable flap configured to be in an active configuration inclined towards the conveyor entrance and in a passive configuration being horizontal.

[0008] The present invention also provides an additive manufacturing method comprising: - spreading production powder by a carriage onto a work-holding platform within the enclosure; removing the powder from the carriage; - recycling the removed powder by a conveyor or storing the removed powder in a storage area, the storage area extending into the enclosure and comprising at least one wall separate from the enclosure wall.

[0009] Such a method may comprise the following various features, either alone or in combination: - powder removal is triggered after the step in which the carriage is moved to the end of its travel, so that once the powder is removed, the removed powder falls by gravity into the conveyor entrance or storage area; - after a step in which the carriage is moved vertically between the work holding platform and the carriage movement end position at the same height as the conveyor entrance, powder removal is triggered, so that during powder removal, the removed powder falls into the conveyor entrance by gravity; - the method includes, after powder removal, intermediately moving the removed powder into a conveyor inlet; the intermediate movement is provided by a scraper attached to the carriage and configured to come into contact with the bench; The intermediate movement is advantageously and optionally completed by being provided by a flap that is rotatable and configured to tilt towards the conveyor entrance. [Brief explanation of the drawings]

[0010] Further characteristics and advantages of the invention will become apparent from the following description, which is purely illustrative and non-limiting, and which should be read in conjunction with the accompanying drawings, in which: [Figure 1] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 2] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 3] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 4]1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 5] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 6] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; [Figure 7] 1A-1D are schematic illustrations of details of additive manufacturing apparatus according to different embodiments of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0011] Additive Manufacturing Equipment Referring to Figures 1 to 7, an additive manufacturing apparatus 1 comprises an enclosure 3 in which an object can be manufactured by consolidating an additive manufacturing powder.

[0012] The enclosure 3 comprises various walls that define a working chamber therein. The enclosure 3 is sealed. The gas environment inside the enclosure 3 can be controlled; in particular, the enclosure 3 can be filled with an inert gas that does not alter the additive manufacturing powder.

[0013] Before being consolidated, the powder is placed on a work-holding platform 7. The work-holding platform 7 has a horizontal upper surface. With reference to FIGS. 1-7, the x-axis and y-axis define a horizontal plane, and the z-axis is oriented vertically upward. The work-holding platform is rectangular oriented along the x-axis and y-axis. The work-holding platform has a major length along the x-axis and a lateral length along the y-axis. The direction of the x-axis is defined as the major direction, and the direction of the y-axis is defined as the lateral direction.

[0014] The object is fabricated layer by layer; that is, a first layer of powder spread on the work-holding platform is selectively consolidated, then a second layer of powder is spread on the first layer and then consolidated and fused to the previous layer. As the fabrication process progresses, multiple layers 9 are stacked on top of the work-holding platform 7. The work-holding platform 7 can translate vertically. As each new layer is laid, the work-holding platform 7 can move vertically downward along the z-axis a distance corresponding to the layer's thickness. In this way, the last layer, designated 11 in the figure, is always at the same height within the enclosure 3.

[0015] The enclosure includes a bench 10 extending around the workholding platform 7. The bench 10 is a single component that surrounds the entire workholding platform 7. The bench 10 vertically separates the production line above the bench 10 from the lower portion of the production machine. The upper edge of the bench 10 defines a wall that seals the production line and the lower portion from the production powder. This also ensures airtightness. The bench 10 reduces the number of joints and / or gaskets required for sealing. The bench 10 defines a wall whose maximum vertical position is close to or coincides with the vertical position of the last spreading layer 11. In this way, the bench 10 and the last spreading layer 11 form a continuous horizontal surface when there is no vertical gap between them, or a quasi-continuous horizontal surface when there is a small vertical gap between them.

[0016] The powder is supplied into the enclosure 3 by a delivery system 5A, 5B. This system comprises, for example, two slide trays extending laterally along the y-axis over the entire lateral length of the work-holding platform. The slide trays are capable of lateral translation and have an upper surface on which a continuous bead of production powder is deposited. Two beads may thus be positioned in the main direction on either side of the work-holding platform 7, each bead extending over the entire lateral length of the work-holding platform. The delivery systems 5A, 5B thus bring the powder close to the work-holding platform.

[0017] The slide tray occupies a volume defined by a recess in bench 10. The upper surface of bench 10 has a recess in which the slide tray is accommodated. The upper surface on which the powder is placed has a vertical position that approaches or coincides with the maximum vertical position of bench 10. In this way, the upper surfaces of the slide trays of delivery systems 5A, 5B and bench 10 form a continuous or substantially continuous horizontal surface.

[0018] The delivery systems 5A, 5B also include a recycle path that automatically recycles powder entering the inlets 6A, 6B of the systems 5A, 5B. For example, the recycle path of the delivery systems 5A, 5B may include a gutter located below the inlets 6A, 6B that can receive the powder and an auger screw that can convey the received powder, for example, to a reservoir extending outside the enclosure, to a recycle circuit, or to a suction and filtration system that returns the powder to the main hopper of the additive manufacturing device. This recycled powder can be spread onto the workpiece-holding platform at a later date.

[0019] Delivery systems 5A, 5B are configured to deliver powder near workholding platform 7 so that slide tray and inlets 6A and 6B are located near workholding platform 7. In a main direction parallel to the x-axis, slide tray and inlets 6A and 6B have positions 18A, 18B that are between the workholding platform and carriage end-of-travel positions 17 and 19.

[0020] The additive manufacturing apparatus 1 comprises a carriage 13 configured to spread powder onto (or above) the work-holding platform 7. The carriage 13 is movably mounted inside an enclosure and moves in a main direction parallel to the x-axis. More precisely, the carriage 13 can move translationally along a ramp 15 oriented in the main direction. The carriage 13 is configured to move along a defined stroke 21 between a first end-of-travel position 17 and a second end-of-travel position 19. The stroke 21 corresponds to the length of the ramp 15 in the main direction.

[0021] The carriage 13 is configured to move over the workholding platform 7 along the entire major length of the workholding platform. The stroke 21 of the carriage covers the major length of the workholding platform 7 along the x-axis.

[0022] The lower part of the carriage 13 comprises a member 14 configured to contact the powder and distribute it in a horizontal plane. For example, the member can be a roller or a squeegee.

[0023] To this end, carriage 13 and member 14 each extend laterally over a length equal to or greater than the lateral length of the work-holding platform.

[0024] The carriage 13 is configured to travel over the slide trays of the delivery systems 5A, 5B to dispense powder onto the workpiece holding platform 7.

[0025] The carriage 13 is configured to move continuously over the powder feed point and the workpiece holding platform, in other words, the carriage 13 is configured to move over the bench 10.

[0026] As the carriage moves and comes into contact with the powder, it may become covered with an unwanted layer of powder, and the apparatus includes a dusting implement configured to remove at least some of the powder that accumulates on the carriage in this manner.

[0027] Dusting equipment Different embodiments of this dusting device are possible.

[0028] 1, 2, and 5, a first embodiment of the dusting implement uses stops 23A and 23B on the carriage 13. Stops 23A and 23B are located at the ends of the ramp 15, so that when the carriage reaches the end of its travel, it contacts one of these stops. The dusting implement can be created by applying an impact 40 between the carriage and stops 23A and 23B. In particular, the carriage can be urged against the stops. In this first embodiment, the dusting implement is fixedly attached to the apparatus 1. When impact 40 occurs, a quantity of powder 42 falls from the carriage 13 in a movement indicated by arrow 44.

[0029] Referring to Figures 3 and 4, the dusting tool of the second embodiment uses a dusting tool 33 attached to the carriage 13. In this case, the dusting tool 33 is part of the carriage 13 and moves with it. The dusting tool 33 can be, for example, a striker with a spring that can be compressed under the action of pressurized inert gas supplied to the striker's cylinder. When a trigger signal is received, the compressed inert gas can be released from the cylinder, releasing a spring carrying a component for striking the body of the carriage 13. Alternatively, the dusting tool 33 can be a vibration system that begins to vibrate upon receiving a trigger signal and agitates the carriage to which the vibration system is attached. The dusting tool is configured to trigger an impact or vibration within the carriage. The dusting tool is an active component that is supplied with energy to deliver the impact or vibration to the carriage. During the impact or vibration 40, a certain amount of powder 42 falls from the carriage 13 in a movement indicated by arrow 44. The amount of powder 42 that falls from the carriage 13 is hereinafter referred to as "removed powder." The impact or vibration can be triggered at will, so that it is possible to select the dusting position, ie the position where the powder is removed from the carriage.

[0030] Delivery point for powder removed from carriage The device 1 is configured to deliver the powder 42 removed from the carriage to one of two positions presented below and corresponding to two options:

[0031] According to a first option, the powder removed from the carriage is fed to a storage area, the storage area comprising at least one wall extending into the interior of the enclosure and separate from the walls of the enclosure.

[0032] FIG. 1 illustrates this first option. In this first option, the device 1 comprises at least one of two storage areas 25A, 25B. If the device 1 comprises two storage areas, they are advantageously located symmetrically on either side of the workpiece-holding platform 7 in a main direction parallel to the x-axis. The storage areas 25A, 25B extend inside the enclosure 3. The storage areas 25A, 25B are defined by walls 27A, 27B. These walls 27A, 27B are separate from the walls of the enclosure 3. The storage areas 25A, 25B define a storage volume adapted to receive powder, which is integrally contained within the working chamber defined by the enclosure 3. As shown, the storage area can be a recessed or concave volume defined within the bench 10. In other words, the upper surface of the bench 10 can present a recess or indentation from its maximum vertical position. This recess corresponds to walls 27A, 27B extending downward from the maximum vertical position of bench 10. The recess defines a storage volume below the maximum vertical position of bench 10. In this case, the walls of the storage area are all below the maximum vertical position of bench 10, and the storage area is open at the top. This opening allows for the acceptance of powder. In this case, the storage volume may be defined by the walls and a virtual closure provided by the vertical position of bench 10.

[0033] Advantageously, the storage volume is chosen to be equal to or greater than 4 liters.

[0034] According to a second option, the powder removed from the carriage is fed to the inlet of a conveyor configured to recycle the production powder.

[0035] The conveyor may be configured, for example, to receive the removed powder and transport it to a powder circulation system for distribution so that the removed powder is re-distributed onto the workpiece-holding platform. The conveyor may be configured to transport the powder received at the inlet and then distribute the powder onto the workpiece-holding platform. For example, the conveyor may transport the removed powder to a reservoir, to a recycle circuit, or to a suction and filtration system that returns the powder to the main hopper of the additive manufacturing device.

[0036] In a first variant, the conveyor can be a recycling path for the delivery system 5A, 5B described above.

[0037] In a second variant shown in FIG. 2, the conveyor can be separate from the recycling path of the delivery systems 5A, 5B. In this case, the conveyor is a collection bin 29A, 29B connected to a powder suction system. The collection bin 29A, 29B extends into the interior of the enclosure 3. The collection bin 29A, 29B is defined by walls separate from the walls of the enclosure 3. The collection bin 29A, 29B defines a volume suitable for receiving powder entirely within the working chamber defined by the enclosure 3. As shown, the collection bin can define a recessed or hollow volume within the bench 10. In other words, the bin walls extend downward from the bench's maximum vertical position and define a volume below this maximum vertical position of the bench 10. In this case, the collection bin has its walls all the way below the vertical position of the bench 10 and is open at the top. This opening allows the powder to be received. The storage bin is provided with a hole at its lowest point, i.e., at the bottom of the bin, which hole is connected to a powder suction system via ducts 31A, 31B. The powder suction system is configured to direct the powder received in the collection bin via an orifice and ducts 31A, 31B to a reservoir, a recycling circuit, or a powder circulation system for distribution, so that the removed powder is re-distributed onto the work-holding platform.

[0038] As shown in FIG. 2, the device 1 can comprise two conveyors positioned on either side of the workpiece-holding platform 7, advantageously symmetrically, with the main direction parallel to the x-axis.

[0039] Similar to the first and second options described above, the device may be configured in the following first configuration, i.e. the conveyor entrance or storage area is located opposite the end of travel position of the carriage, and the dusting device is configured to be triggered when the carriage is at the end of its travel so that the powder falls by gravity into the conveyor entrance or storage area.

[0040] This first configuration is shown in FIGS.

[0041] End of travel positions 17 and 19 have already been described. When the carriage reaches one of these positions and therefore contacts one of the stops 23A, 23B, the conveyor entrance or storage area is located vertically below the carriage 13.

[0042] In this first configuration, the conveyor can be a collection bin 29A, 29B connected to a powder suction system. Conversely, the conveyor cannot be a recycling path for the delivery systems 5A, 5B, since the inlets 6A, 6B have positions 18A, 18B that are different from the carriage end positions 17 and 19.

[0043] The various types of dusting implements mentioned above are compatible with this first configuration.

[0044] In relation to the second option shown, the apparatus may be configured for a second configuration as follows: the conveyor entrance is located between the work holding platform and the end of travel position of the carriage, and the dusting implement is mounted on the carriage and configured to be triggered when the carriage is aligned with the entrance, in this manner the dusting implement dusts the carriage when the carriage is aligned with the entrance.

[0045] This second configuration is shown in FIG.

[0046] In this second configuration, the conveyor can be a recycle path for the delivery systems 5A, 5B, as the inlets 6A, 6B have positions 18A, 18B that are different from the end-of-travel positions 17 and 19 of the carriage 13.

[0047] When carriage 13 is aligned with the conveyor entrance, carriage 13 is a distance from stops 23A, 23B, so that a dusting implement using stops 23A and 23B of carriage 13 cannot be used to dust carriage 13. Therefore, the dusting implement of the second embodiment attached to carriage 13 is used in this second configuration.

[0048] Displacement member Also, in relation to the second option shown, the apparatus may be configured for a third configuration below, namely, the conveyor inlet is located between the work holding platform and the end of travel position of the carriage, and the apparatus further comprises a displacement member separate from the conveyor and configured to move powder removed from the carriage to the inlet.

[0049] This third configuration is shown in a first variant in FIGS. 4 and 5 and in a second variant in FIGS.

[0050] In this third configuration, the conveyor can be a recycle path for the delivery systems 5A, 5B, as the inlets 6A, 6B have positions 18A, 18B that are different from the end-of-travel positions 17 and 19 of the carriage 13.

[0051] This third configuration does not require the carriage 13 to be aligned with the conveyor entrance for dusting to be triggered.

[0052] This third configuration is compatible with the various embodiments of dusting implements described above, with Figure 4 showing a second type of dusting implement 33 and Figure 5 showing a first embodiment of dusting implement 23A.

[0053] The additive manufacturing apparatus 1 in this third configuration comprises displacement members 34A, 34B, 35A, 35B that are separate from the conveyor and configured to move powder removed from the carriage to the conveyor inlet.

[0054] Different embodiments of this displacement member are possible.

[0055] In a first embodiment of the displacement member shown in Figures 4 and 5, the member is a scraper 34A, 34B mounted on a carriage and configured in an active configuration in which the scrapers 34A, 34B contact the bench 10, and in a passive configuration in which the scrapers are positioned above the bench 10.

[0056] The carriage 13 includes scrapers 34A, 34B protruding from the carriage 13 in a main direction. The carriage may include a first scraper 34A on one side relative to the main direction and a second scraper 34B on the other side. The scrapers 34A, 34B extend laterally over a length equal to or greater than the length of the carriage in this same lateral direction. The scrapers 34A, 34B include deformable portions forming their lowermost portions. The scrapers 34A, 34B are mounted so as to be movable relative to the carriage 33, in particular so as to be vertically translatable along the z-axis. The scrapers are configured to switch from an active configuration to a passive configuration and vice versa.

[0057] In the active configuration, the scrapers 34A, 34B are in a lower position so that the deformable portions are in contact with the bench 10.

[0058] In the passive configuration, the scrapers 34A, 34B are in a raised position such that the deformable portions are not in contact with the bench 10 but are above the bench 10.

[0059] The scraper can be moved vertically from an active configuration to a passive configuration by a cylinder mounted on a carriage, with the scraper mounted on the cylinder.

[0060] In Figures 4 and 5, the carriage 13 is equipped with two scrapers 34A, 34B, scraper 34A being shown in its active configuration and scraper 34B being shown in its passive configuration.

[0061] When the carriage is dusted by the impact 40, the dislodged powder 42 falls onto the bench 10.

[0062] In its active configuration, the scraper is in contact with the bench 10. By moving the carriage when the scraper is in its active configuration, the scraper can be moved while maintaining contact with the bench 10. It is possible to bring the scraper into contact with the removed powder and move the powder relative to the scraper. In this way, an intermediate powder displacement is achieved, which serves to transport the removed powder to the conveyor inlet.

[0063] It should be noted that if the additive manufacturing apparatus comprises a displacement member in the form of a scraper 34A, 34B attached to the carriage via a cylinder, the scraper can function as a dusting device configured to mechanically excite the carriage and remove powder deposited on the carriage, after which impact energy is generated by the actuator cylinder when it stops.

[0064] In a second embodiment of the displacement member shown in Figures 6 and 7, the member is a rotatable flaps 35A, 35B configured to be in an active configuration in which the flaps 35A, 35B are tilted towards the conveyor entrance, and in a passive configuration in which the flaps are horizontal.

[0065] Flaps 35A and 35B are included in the enclosure 3. The flaps 35A and 35B are located adjacent to the conveyor entrance in the main direction, with the conveyor entrance being located between the flaps 35A and 35B and the work-holding platform. The flaps 35A and 35B are mounted to rotate about horizontal rotation axes 36A and 36B. The horizontal rotation axes are parallel to the lateral direction indicated by the y-axis in Figures 6 and 7. The rotation axes pass through the flap 35A and are located adjacent to the conveyor entrance.

[0066] The flaps 35A, 35B extend in the main direction from the horizontal axis of rotation to the stops 23A, 23B.

[0067] The flaps 35A, 35B are configured to switch from an active configuration to a passive configuration and vice versa.

[0068] In the active configuration, the flaps 35A, 35B are inclined relative to the horizontal plane such that the flaps 35A, 35B are elevated above the vertical position of the bench 10. The flaps 35A, 35B are inclined towards the conveyor entrance in the sense that an object positioned on the top surface of the flaps will be pulled by gravity towards the conveyor entrance.

[0069] In the passive configuration, the flaps 35A, 35B are oriented in a horizontal plane so that the top surfaces of the flaps 35A, 35B are aligned with the bench 10. The carriage 13 can move above the flaps 35A, 35B and stop above them.

[0070] The apparatus may comprise two flaps 35A, 35B located on either side of the workpiece holding platform if the delivery system 5A, 5B comprises two slide trays and therefore two conveyor inlets 6A, 6B.

[0071] Additive Manufacturing Methods Additive manufacturing devices such as the one presented herein make it possible to implement the method according to the invention in order to better control powder contamination occurring during the powder spreading step.

[0072] The different steps of this method are presented below.

[0073] In a first step, the carriage 13 is used to spread manufacturing powder onto the workpiece holding platform 7 within the enclosure 3 .

[0074] This first step can be done, for example, by - providing powder beads on the slide trays of the delivery systems 5A, 5B; - positioning the carriage 13 so that the slide tray is located between the work-holding platform 7 and the carriage 13 before applying the bead; - moving the carriage 13 in a scattering direction towards the slide tray and the workpiece holding platform 7, so that the powder deposited on the slide tray is carried towards the workpiece holding platform by the members 14 of the carriage; -spreading dusting powder onto the work holding platform via the member 14 as the carriage moves along the first length of the work holding platform.

[0075] In a second step, powder that undesirably covers the carriage 13 is removed. This second step is also called dusting the carriage.

[0076] This second step is carried out after the first step. Advantageously, before this second step, the carriage 13 continues its movement in the spreading direction beyond the work-holding platform. In this way, the removed powder is not deposited on the layer of powder just deposited.

[0077] The dusting device according to one of the embodiments described above is triggered to generate an impact or vibration 40 on the carriage 13 , which causes the powder 42 to be removed from the carriage 13 following a movement 44 .

[0078] In the third step, the removed powder is - recycled by conveyor according to the first option above, or or are kept in a storage area according to the second option described above.

[0079] This third step is also called separation of the removed powder, in the sense that the risk of contamination of the newly deposited layer by this removed powder is greatly reduced.

[0080] In all cases, the removed powder is kept away from the work-holding platform to prevent it from contaminating the newly deposited layer and, more generally, the manufacturing process, thus providing better control of powder contamination occurring during the powder spreading step.

[0081] Advantageously, the last two steps mentioned above can be carried out after each planned application of powder during the manufacturing method, or they can be carried out at a lower application frequency, for example after each group of two consecutive application operations, or after each group of a larger number of consecutive application operations.

[0082] If the removed powder is stored in a storage area, it is advantageous for the storage area to have a volume of 4 liters or more. In this way, multiple carriage dustings can be performed before the storage area becomes full. This reduces the frequency of manual intervention to empty the storage area.

[0083] Similar to the first and second options described above, the method may be adapted such that in the first method, powder removal is triggered after the step in which the carriage moves to the end of its travel, so that during powder removal, the removed powder falls by gravity into the conveyor entrance or storage area.

[0084] A first adaptation of this method corresponds to the first configuration of the device described above and shown in FIGS.

[0085] This first adaptation corresponds to the carriage 13 continuing its movement in the spreading direction beyond the work-holding platform after spreading powder to the end of its movement, so that powder that undesirably covers the carriage is removed as far as possible from the work-holding platform, further limiting the risk of contamination of the spread layer.

[0086] After the impact 40 generated by the dusting implement on the carriage 13, the removed powder 42 falls by gravity to the conveyor entrance or storage area, so that there is no need to provide intermediate movement of the powder towards the conveyor entrance or storage area.

[0087] If the apparatus is equipped with a conveyor entrance or storage area at the end of each carriage stroke, it is possible to dust and separate the removed powder after each pass of the carriage over the work holding platform 7.

[0088] In relation to the second option described above, according to a second adaptation, the method can be adapted so that powder removal is triggered after a step in which the carriage is moved vertically at the same height as the conveyor entrance between the work holding platform and the carriage movement end position, so that during powder removal the removed powder falls by gravity into the conveyor entrance.

[0089] A second adaptation of the method corresponds to the second configuration of the device described above and shown in Figure 3. This second adaptation relates to the dusting implement of the second embodiment.

[0090] This second adaptation can be implemented using the delivery systems 5A, 5B already present in the device, without the need to add a storage area or collection bin and powder suction system to the device.

[0091] This second adaptation corresponds to the carriage 13 continuing its movement in the spreading direction after spreading powder beyond the work-holding platform to the inlet 6A, 6B of the recycling path of the delivery system 5A, 5B. Powder that undesirably covers the carriage is removed far enough from the work-holding platform to limit, in a satisfactory manner, the risk of contamination of the spread layer.

[0092] After the impact 40 or vibration generated on the carriage 13 by the dusting tool, the removed powder 42 falls by gravity into the conveyor inlets 6A, 6B, so that there is no need to provide intermediate movement of the powder towards the conveyor inlets.

[0093] If the apparatus is provided with an inlet to the recycling path of the delivery system 5A, 5B on both sides of the work holding platform, it is possible to dust and separate the removed powder every time the carriage passes over the work holding platform 7.

[0094] Furthermore, in relation to the second option recalled above, according to a third adaptation, the method may comprise, after powder removal, a step of intermediately transferring the removed powder to a conveyor inlet.

[0095] This third adaptation is shown in a first variant in FIGS. 4 and 5 and in a second variant in FIGS.

[0096] A third adaptation of the method corresponds to the third configuration of the device described above and is shown in the first variant in Figures 4 and 5 and in the second variant in Figures 6 and 7. This third adaptation is compatible with the various embodiments of the dusting implement described above.

[0097] This third adaptation can be implemented using the delivery systems 5A, 5B already present in the device, without the need to add a storage area or collection bin and powder suction system to the device.

[0098] This third adaptation does not require the carriage 13 to be positioned at a specific point in its stroke for dusting to be triggered. There is more freedom in carriage position. Furthermore, the intermediate transfer step of the removed powder can be used to provide a larger amount of removed powder to the conveyor inlet.

[0099] A first variant of the third adaptation corresponds to the case where the intermediate movement is provided by scrapers 34A, 34B attached to the carriage 13 and arranged to come into contact with the bench 10.

[0100] In this second variant, the scrapers 34A, 34B are by default in their passive configuration, i.e. in a raised position so as not to come into contact with the bench 10 or the last layer of spread powder 11. In particular, during the step of spreading powder on the work-holding platform, the scrapers 34A, 34B are in their passive configuration.

[0101] Unwinding can be triggered when the carriage 13 passes over the work-holding platform and the conveyor entrance, i.e., when the conveyor entrance is located between the carriage and the work-holding platform. Note that the impact 40 can be generated by the dusting implement selected in the first or second embodiment. In the first embodiment, the carriage 13 is positioned at the end of its travel before dusting is triggered. In the second embodiment, the carriage 13 is freely positioned between the end of its travel and the conveyor entrance before dusting is triggered.

[0102] When the dusting tool causes an impact 40 on the carriage 13, the removed powder falls by gravity onto the bench 10. The scrapers 34A, 34B are placed in their active configuration. This situation is shown in Figure 4, where the dusting tool corresponds to the second embodiment 33, and in Figure 5, where the dusting tool corresponds to the first embodiment 23A.

[0103] The carriage 13 is moved so that the scraper 34A moves the removed powder 42 into the conveyor inlets 6A, 6B.

[0104] Once the removed powder 42 is inside the conveyor, the scraper 34A can be placed in a passive configuration.

[0105] If the carriage 13 is equipped with two scrapers 34A, 34B on either side of the carriage in the main direction, the scraper furthest from the conveyor inlet is placed in its active configuration and is used to move the removed powder to the conveyor inlet.

[0106] A second variant of the third adaptation corresponds to the case where the intermediate movement is provided by flaps 35A, 35B that are rotatable and configured to tilt towards the conveyor entrance.

[0107] In this second variant, the flaps 35A, 35B are by default in their passive configuration, i.e., horizontally oriented, particularly during the step of spreading powder onto the work-holding platform.

[0108] Unwinding can be triggered when the carriage 13 passes over the work-holding platform and the conveyor entrance, i.e., when the conveyor entrance is located between the carriage and the work-holding platform. Note that the impact 40 can be generated by the dusting implement selected in the first or second embodiment. In the first embodiment, the carriage 13 is positioned at the end of its travel before dusting is triggered. In the second embodiment, the carriage 13 is freely positioned between the end of its travel and the conveyor entrance before dusting is triggered.

[0109] Unwinding can be triggered when the carriage 13 is positioned above the flaps 35A, 35B, which are oriented in their passive configuration, i.e. horizontally.

[0110] When an impact 40 is generated on the carriage 13 by the dusting tool, the dislodged powder 42 falls by gravity onto the flaps 35A, 35B, as shown in FIG.

[0111] The carriage 13 is then moved towards the work holding platform so that it is no longer above the flaps 35A, 35B.

[0112] The flaps 35A, 35B are placed in their active configuration. This situation is shown in Figure 7. The flap 35A rotates about the rotation axis 36A and thus rises above the axial position of the bench 10. The flap 35A is inclined at an angle 37, forming a sloped surface toward the conveyor inlet 6A. The removed powder 42 located on this sloped surface is then drawn by gravity to the bottom of this surface, i.e., into the conveyor inlet 6A.

[0113] Once the removed powder 42 is inside the conveyor, the flap 35A may be placed in a passive configuration.

[0114] It should be noted that at the end of part production, some of the residual powder present on the bench and removed, for example, from a carriage on the bench, may be sprinkled onto the last layer of a powder bed previously lowered below the surface of the bench. This powder is extracted from the enclosure when the work-holding platform is removed and then processed by a dusting machine, which frees the produced part from the surrounding unconsolidated powder.

Claims

1. 1. An additive manufacturing apparatus (1) comprising an enclosure (3) and a conveyor (5A, 5B, 29A, 29B) configured to recirculate a production powder, said enclosure (3) comprising: - a work-holding platform (7), a carriage (13) configured to sprinkle powder onto said workpiece holding platform (7); a dusting device (23A, 23B, 33) included in said carriage (13) and configured to trigger an impact or vibration of said carriage to remove powder from said carriage; an inlet for said conveyor (5A, 5B, 29A, 29B), The apparatus is configured to feed powder (42) removed from the carriage (13) to 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.

2. 2. The apparatus of claim 1, configured to supply removed powder (42) from the carriage (13) to the inlet (6A, 6B) of the conveyor, the apparatus being separate from the conveyor and further comprising a displacement member (34A, 34B, 35A, 35B) configured to move the removed powder (42) from the carriage (13) to the inlet (6A, 6B).

3. 3. The device according to claim 2, wherein the displacement members (34A, 34B) are scrapers (34A, 34B) attached to the carriage (13) and configured to have an active configuration in which the scrapers (34A, 34B) are in contact with the bench (10) in the enclosure (3) and a passive configuration in which the scrapers (34A, 34B) are positioned above the bench (10).

4. 3. The apparatus of claim 2, wherein the displacement members are rotatable flaps (35A, 35B) configured to have an active configuration in which the flaps (35A, 35B) are inclined towards the conveyor entrance (6A, 6B), and a passive configuration in which the flaps (35A, 35B) are horizontal.

5. 1. An additive manufacturing method comprising: - Spreading production powder onto the workpiece holding platform (7) in the enclosure (3) by means of a carriage (13); - removing the powder from said carriage (13) by triggering an impact or vibration in said carriage by means of a dusting device (23A, 23B, 33) contained in said carriage; - recycling the removed powder by a conveyor (5A, 5B, 29A, 29B), the entrance (6A, 6B) of which is located between the work holding platform (7) and the end of travel position of the carriage, i.e. the position of powder removal.

6. 6. The method of claim 5, wherein the powder removal is triggered after the step of moving the carriage in line with the entrance (6A, 6B), whereby, once the powder is removed, the removed powder (42) falls by gravity into the entrance (6A, 6B) of the conveyor.

7. 6. The method of claim 5, further comprising the step of intermediately transferring the removed powder into said conveyor inlets (6A, 6B) after powder removal.

8. 8. The method of claim 7, wherein the intermediate movement is provided by scrapers (34A, 34B) mounted on the carriage (13) and configured to contact the bench (10).

9. 8. The method of claim 7, wherein the intermediate movement is provided by flaps (35A, 35B) that are rotatable and configured to tilt towards the conveyor entrance (6A, 6B).

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