UNIT FOR CLEANING PLATES FOR GENERATIVE MANUFACTURING

Description

[0001] The invention lies in the field of powder-based additive manufacturing by sintering or melting the grains of this powder using an electromagnetic radiation energy beam, such as for example a laser beam, and / or a particle beam, such as for example an electron beam.

[0002] More specifically, the invention relates to the cleaning of additive manufacturing trays and parts manufactured on these trays.

[0003] When implementing an additive manufacturing process within an additive manufacturing machine, a first layer of powder is deposited on an additive manufacturing tray mounted to slide inside an enclosure surrounding the manufacturing tray. Then, this first layer of powder is consolidated according to a predetermined pattern using one of the aforementioned energy beams. Then, the manufacturing tray is lowered into its enclosure so as to allow the deposition and consolidation of a second layer of powder. Finally, the steps of lowering the tray and then depositing and consolidating layers of powder follow one another until the deposition and consolidation of the last layer of powder useful for the manufacture of the parts to be produced.

[0004] According to a drawback encountered at the end of this additive manufacturing process, the manufactured part(s) find themselves submerged in the middle of a large quantity of unconsolidated powder which must be removed.

[0005] According to a first method, the manufacturing tray is extracted from the machine, with or without its enclosure, and an operator manually removes the powder grains using tools such as a brush and a compressed air blower or a vacuum cleaner.

[0006] Due to its essentially manual implementation, this first cleaning method is difficult to reconcile with an industrial application.

[0007] Furthermore, this manual cleaning can be dangerous for the operator because the powders used in additive manufacturing generally contain toxic chemical compounds that can be inhaled by operators despite their protective equipment.

[0008] Finally, according to another disadvantage, if the unconsolidated powder is not kept in a protective atmosphere during cleaning, it must undergo several treatments before it can be reused.

[0009] Also, some manufacturers of additive manufacturing machines have modified their machines to better protect the health of operators and to be able to immediately reuse the powder from cleaning the manufactured parts.

[0010] For example, the additive manufacturing machine described in European patent EP1793979 is equipped with means allowing an operator to handle and clean the parts manufactured in the manufacturing enclosure of the machine.

[0011] In more detail, these means include openings made in a wall of the manufacturing enclosure, a robot arm installed in the manufacturing enclosure, and a suction pipe that can be manipulated in this manufacturing enclosure. In addition, the openings are provided with protective gloves allowing an operator to introduce his hands into the manufacturing enclosure to clean the manufactured parts using the suction pipe, and the operator can control the robot arm from outside the machine in order to easily move the heaviest parts.

[0012] Thanks to the means described in European patent EP1793979, the operator is protected and the unconsolidated powder is kept in a protective atmosphere.

[0013] However, cleaning remains a manual operation requiring the work of an operator, and since this manual cleaning takes place in the manufacturing enclosure of the machine, the latter cannot be used to manufacture new parts during the entire cleaning period.

[0014] Also, in European patent EP1192040, it is planned to manufacture the parts in a removable container which can be extracted from the manufacturing enclosure of the additive manufacturing machine and led to a cleaning device independent of this machine.

[0015] In a first embodiment of this cleaning device, a cover provided with two openings facing each other is placed on the top of the container, and a source of compressed air is connected to the first opening while a reservoir is connected to the second opening. Thus, and by gradually raising the manufacturing plate and the manufactured parts towards the top of the container, the flow of compressed air pushes the unconsolidated powder towards the second opening and therefore into the reservoir.

[0016] According to a disadvantage of this first embodiment, there is a risk of polluting the powder with the flow of compressed air used to push the powder towards the reservoir.

[0017] In a second embodiment, the top of the container is equipped with a flared neck comprising a spout allowing the unconsolidated powder to be evacuated when the container is tilted using appropriate means and the manufacturing plate rises gradually.

[0018] In this second embodiment, the unconsolidated powder is advantageously discharged by gravity to a tank. Then, the tank being equipped with a sieve for receiving the manufactured parts, vibrations are used to finish separating the powder grains from the manufactured parts.

[0019] Although this second embodiment of the cleaning device does not use a flow of compressed air which could pollute the unconsolidated powder, it also does not allow the manufactured parts to be perfectly cleaned.

[0020] In fact, under the effect of vibrations, the finest grains of powder are likely to float in the air in the form of a mist and to settle again on the manufactured parts once the vibration has stopped.

[0021] Furthermore, in the case where the manufactured parts are of complex shapes with cavities likely to contain powder agglomerates, simple vibrations are not sufficient to disintegrate the powder clumps that can form in these cavities during additive manufacturing.

[0022] Finally, the simple use of vibrations does not allow all the grains of powder stuck to the manufactured parts to be removed as is possible, for example, with manual brushing.

[0023] Also, the present invention aims to overcome at least one of the drawbacks of the devices described in the documents of the prior art, while making it possible to clean a manufacturing tray alone or with the parts which have been manufactured on this tray and which can be integral with this tray at the end of the additive manufacturing cycle.

[0024] Document US 2014 / 065194 A1 describes an installation for cleaning an additive manufacturing tray using powder and a binding agent by vibration followed by a dry cleaning step.

[0025] To this end, the invention relates to an installation for cleaning an additive manufacturing tray made using powder, the installation comprising an inlet airlock for receiving a tray to be cleaned and an outlet airlock for extracting a cleaned tray from the installation.

[0026] According to the invention, the installation comprises a dry cleaning device according to claim 1, making it possible to clean a tray using vibrations and shocks in a first containment enclosure, a wet cleaning device making it possible to clean a tray using at least one liquid in a second containment enclosure, and at least one conveying device making it possible to transport a tray between the dry cleaning enclosure, the wet cleaning enclosure, and the exit airlock of the installation.

[0027] By using shocks and vibrations to loosen and separate unconsolidated powder grains from the manufactured parts and their build plate, the dry cleaning device allows the powder grains to be recovered without polluting them.

[0028] In addition, the use of shocks helps to break up powder agglomerates that can form in the cavities of certain parts and which would not disintegrate under the effect of simple vibrations.

[0029] Finally, the invention also provides for the use of vibrations during dry cleaning because these vibrations make it possible to quickly remove the grains of unconsolidated powder still present on the manufactured parts and on the manufacturing plate after the application of shocks.

[0030] In more detail, the wet cleaning device comprises in its enclosure at least one station for washing a tray with a washing liquid and at least one station for rinsing a tray with a rinsing liquid.

[0031] Preferably, the washing station takes the form of a tank filled with cleaning liquid and equipped with means for emitting very high frequency ultrasonic waves into this cleaning liquid.

[0032] Advantageously, the wet cleaning device includes a drying station in its enclosure.

[0033] In order to use the facility to supply additive manufacturing machines with clean and / or new trays from outside an additive manufacturing workshop, a conveyor also makes it possible to transport a tray from the facility's exit airlock to the dry cleaning enclosure.

[0034] According to a first alternative of the invention, the installation comprises a first conveyor for transporting a tray from the enclosure of the dry cleaning device to the enclosure of the wet cleaning device and vice versa from the enclosure of the wet cleaning device to the enclosure of the dry cleaning device, and a second conveyor for transporting a tray from the enclosure of the wet cleaning device to the exit airlock and vice versa from the exit airlock to the enclosure of the wet cleaning device.

[0035] According to a second alternative of the invention, the installation comprises a conveyor for transporting a tray from the enclosure of the dry cleaning device to the exit airlock and vice versa from the exit airlock to the enclosure of the dry cleaning device, at least one temporary storage area for trays, and a manipulator arm for moving a tray between the dry cleaning device, the wet cleaning device, the conveyor and each temporary storage area.

[0036] Finally, since the cleaning installation according to the invention is fully automated, the invention provides that the entire installation can be confined in a protective enclosure such as the enclosure of an additive manufacturing workshop comprising a plurality of additive manufacturing machines.

[0037] 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: there figure 1 is a schematic view of an additive manufacturing tray to be cleaned, the tray being equipped with a support and a sleeve, the figure 2 is a schematic top view of a first embodiment of a cleaning installation according to the invention, with arrows illustrating a cleaning cycle of a tray, the figure 3 is a schematic top view of a first embodiment of a cleaning installation according to the invention, with arrows illustrating the use of the installation according to the invention to supply an additive manufacturing workshop with clean and / or new trays, the figure 4 is a schematic top view of a second embodiment of a cleaning installation according to the invention, with arrows illustrating a cleaning cycle of a tray and the use of the installation according to the invention to supply an additive manufacturing workshop with clean and / or new trays, the figure 5 is a schematic top view of a dry cleaning device according to the invention, the figure 6 is a schematic front view of a dry cleaning device according to the invention, this view also illustrating the reception of an additive manufacturing tray to be cleaned by the dry cleaning device, the figure 7 is a detail view of the figure 6 , this view also illustrating the arrival of the tray to be cleaned in the cleaning enclosure of the dry cleaning device, the figure 8 is a schematic side view of the cleaning enclosure of the dry cleaning device according to the invention, this view also illustrating the turning over of the tray to be cleaned provided by the invention, and the figure 9 is also a schematic side view of the cleaning enclosure of the dry cleaning device according to the invention, but this view more particularly illustrates the cleaning of the tray to be cleaned by the dry cleaning device according to the invention.

[0038] The present invention relates to the cleaning of additive manufacturing trays 10.

[0039] An additive manufacturing tray 10 takes the form of a parallelepiped support, generally metallic, and a few centimeters in height and several tens of centimeters in length and width in a plane P10.

[0040] In a known manner, such a tray 10 is used as a manufacturing support for the parts to be manufactured inside the manufacturing chamber of an additive manufacturing machine. In more detail, the tray is mounted inside a manufacturing enclosure surrounding the tray in this manufacturing chamber, and the tray is mounted to move in vertical translation in this manufacturing enclosure so that it can be lowered before each new deposition of a bed of unconsolidated powder.

[0041] As shown in the figure 1 , in the context of the present invention, the plate 10 is preferably surrounded by a jacket 12 acting as a manufacturing enclosure inside an additive manufacturing machine.

[0042] By being assembled together, the tray 10 and the jacket 12 form a container 15. This container 15 is removably mounted inside an additive manufacturing machine so that it can be extracted from the manufacturing chamber of this machine with the manufactured parts 14 and the unconsolidated powder 16 which surrounds them.

[0043] Advantageously, this container 15 makes it possible to facilitate the transport of the manufactured parts 14 and the unconsolidated powder 16 from an additive manufacturing machine to another device present in an additive manufacturing workshop or to a cleaning installation such as that proposed by the present invention.

[0044] For the purpose of automated guidance and transfer, a support 13 equips the plate 10. This support 13 takes the form of a frame onto which a manufacturing plate 10 is fitted. In order to be held in position by studs or other types of retractable axes, this support 13 comprises bores 17. Finally, this support 13 is equipped with a peripheral seal 19 to prevent powder leaks when the plate 10 and its support 13 are moved in translation inside the jacket 12.

[0045] The main objectives of the present invention are to recover, without altering it, the large quantity of unconsolidated powder 16 which surrounds the parts 14 in a container 15 and to rid the manufactured parts 14 and the additive manufacturing trays 10 as best as possible of the grains of unconsolidated powder.

[0046] For this purpose, the invention provides an installation 20 for cleaning additive manufacturing trays as illustrated in figure 2 .

[0047] This installation 20 comprises an inlet airlock 22 for receiving a tray 10 to be cleaned from an additive manufacturing machine, suitable transport means 24 being provided for transporting the container 15, the manufactured parts 14 and the unconsolidated powder 16 in the best possible conditions from an additive manufacturing machine to the inlet airlock 22 of the installation.

[0048] In order to be able to extract a cleaned tray 10 from the installation, the installation 20 also comprises an exit airlock 26. The entire installation 20 is preferably confined in a protective enclosure 28 partially shown in the figures 2 à 4 , the exit airlock 26 is provided through a wall 30 of this enclosure 28.

[0049] As illustrated by the different arrows in figure 3 , the outlet airlock 26 can also be used to supply the installation 20 with new and / or clean trays 10 from outside E of the installation, and the inlet airlock 22 can also be used to extract clean trays 10 from the cleaning installation 20 in order to send them to additive manufacturing machines via the transport means 24.

[0050] In order to ensure optimal cleaning of the trays 10, the installation 20 comprises a dry cleaning device 32 for cleaning a tray 10 using vibrations and shocks in a first containment enclosure E32, a wet cleaning device 34 for cleaning a tray 10 using at least one liquid in a second containment enclosure E34, and at least one conveying device for transporting a tray 10 between the first containment enclosure E32 of the dry cleaning device, the second containment enclosure E34 of the wet cleaning device, and the exit airlock 26 of the installation.

[0051] More specifically, the dry cleaning device 32 aims to recover a maximum quantity of unconsolidated powder without altering it in order to be able to reuse this powder as quickly as possible, without prior drying treatment but only with sieving aimed at controlling the particle size of the powder thus recycled. Subsequently, the wet cleaning device 34 aims to perfectly clean the manufactured parts 14 and the manufacturing trays 10 by removing all the grains of unconsolidated powder which may remain stuck to the parts and the trays after dry cleaning.

[0052] In order to obtain perfect cleaning of the manufactured parts 14 and the manufacturing trays 10, the wet cleaning device 34 comprises in its enclosure E34 at least one washing station 38 for a tray 10 with a cleaning liquid and at least one rinsing station 40 for a tray 10 with a rinsing liquid.

[0053] Preferably, the washing station 38 takes the form of a tank filled with cleaning liquid and equipped with means, such as a transducer, for emitting ultrasonic waves of very high frequencies, preferably 20 kHz and possibly 45 kHz, into this cleaning liquid. Thus, when the plate 10 and the parts 14 to be cleaned are immersed in the cleaning liquid, the ultrasonic waves generate, by a cavitation phenomenon, microscopic bubbles which implode under the effect of these same waves, and these implosions cause turbulence in the cleaning liquid making it possible to detach the last grains of powder still stuck to the manufactured parts 14 and to their manufacturing plate 10. Advantageously, the microscopic size of the bubbles allows them to penetrate into the smallest cavities of the manufactured parts 14.

[0054] Ideally, the cleaning fluid is an aqueous solution and the rinsing fluid is also an aqueous solution.

[0055] In order to facilitate the washing step and improve the quality of the cleaning carried out, the wet cleaning device 34 may include in its enclosure E34 a pre-wash station 42, obviously located upstream of the washing station 38.

[0056] This pre-wash station 42 may take the form of a tank filled with pre-wash liquid and the pre-wash liquid is preferably an aqueous solution.

[0057] The rinsing station 40 can also act as a drying station and include means for drying the cleaned trays and the manufactured parts 14, these drying means taking, for example, the form of a tank equipped with a hot air blower.

[0058] With a view to complete automation of the installation, the wet cleaning device 34 comprises in its enclosure E34 conveying means (not shown) making it possible to convey in an automated manner the trays 10 to be cleaned and the manufactured parts 14 attached to these trays 10 between the different pre-washing 42, washing 38 and rinsing 40 stations.

[0059] In an alternative embodiment not illustrated in the figures, the wet cleaning device 34 may comprise a single working chamber in which the trays 10 can be pre-washed, washed and possibly dried, and different storage chambers for storing the trays 10 before, between and / or after these different steps.

[0060] As illustrated by the figure 3 , the conveying means of the wet cleaning device 34 also make it possible to convey new and / or clean trays 10 through the enclosure E34 of the wet cleaning device 34, without passing through the various washing and rinsing stations.

[0061] In a first embodiment of the installation illustrated by the figures 2 And 3 , the installation comprises a first conveyor 44 for transporting trays 10 being cleaned from the first containment enclosure E32 of the dry cleaning device 32 to the second containment enclosure E34 of the wet cleaning device 34, and a second conveyor 46 for transporting the cleaned trays 10 from the second containment enclosure E34 of the wet cleaning device 34 to the exit airlock 26 of the installation 20.

[0062] For the purpose of using the outlet airlock 26 of the installation to introduce new and / or clean trays 10 into an additive manufacturing workshop via the cleaning installation 20, the second conveyor 46 also makes it possible to transport trays 10 from the outlet airlock 26 of the installation 20 to the second containment enclosure E34 of the wet cleaning device 34, and the first conveyor 44 also makes it possible to transport trays 10 from the second containment enclosure E34 of the wet cleaning device 34 to the first containment enclosure E32 of the dry cleaning device 32.

[0063] In such a case of use of the installation 20 to supply an additive manufacturing workshop with new and / or clean trays 10, provision may be made to carry out wet cleaning of these trays 10 in the wet cleaning device 34. This ensures perfect cleaning and decontamination of these trays 10 before their use within an additive manufacturing machine, these trays 10 having been able to be polluted outside E of the enclosure 28 of the installation 20 during manual handling or during unprotected storage.

[0064] In this first embodiment of the installation 20, the two conveyors 44, 46 can be belt conveyors.

[0065] In a second embodiment of the installation 20 illustrated by the figure 4 , the installation comprises a conveyor 36 for transporting trays 10 from the first containment enclosure E32 of the dry cleaning device 32 to the exit airlock 26 and vice versa from the exit airlock 26 to the first containment enclosure E32 of the dry cleaning device 32, at least one temporary storage area 48, 50 for trays 10, and a manipulator arm 52 for moving a tray 10 between the dry cleaning device 32, the wet cleaning device 34, the conveyor 36 and each temporary storage area 48, 50.

[0066] In more detail, the conveyor 36 can be a belt conveyor, each storage area 48, 50 can take the form of an open storage device such as a shelf, and the manipulator arm 52 is an articulated arm at the end of which is mounted a gripping device 54 for a tray 10 such as for example a clamp.

[0067] Thanks to the presence of at least one storage area 48, 50, the manipulator arm 52 makes it possible, for example, to manage the dry and wet cleaning steps of different trays 10 while the conveyor 36 is used to transfer clean trays 10 from the exit airlock 26 to the dry cleaning device 32.

[0068] Preferably, two temporary storage areas 48 and 50 are provided in order to avoid storing clean trays 10 and trays 10 being cleaned in the same area.

[0069] Still preferably, the manipulator arm 52 is movable in rotation around different horizontal and / or vertical axes in order to move each plate 10 from one point to another as quickly as possible.

[0070] According to a non-illustrated and more economical variant of this second embodiment, the manipulator arm 52 can be removed and the conveyor 36 can be arranged so as to ensure the transport of the trays 10 alone between the first containment enclosure E32 of the dry cleaning device, the second containment enclosure E34 of the wet cleaning device, and the exit airlock 26 of the installation.

[0071] To carry out dry cleaning of the trays 10 using shocks and vibrations, the invention proposes a dry cleaning device 32 for a tray 10.

[0072] As indicated previously, this dry cleaning device 32 comprises a first containment enclosure E32. In order to receive a tray 10 to be cleaned, this first containment enclosure E32 comprises at least one inlet airlock 56, and in order to evacuate a cleaned tray 10, this first containment enclosure E32 also comprises an outlet airlock 58. Advantageously, the inlet airlock 56 of the first containment enclosure E32 of the dry cleaning device 32 is also the inlet airlock 22 of the installation 20.

[0073] The first containment enclosure E32 of the dry cleaning device being formed on the floor S by a front wall 60F, a rear wall 60R, a left side wall 62G, a right side wall 62D and a ceiling P, the inlet airlock 56 is provided through the rear wall 60R of the first containment enclosure E32, and the outlet airlock 58 is provided through the right side wall 62D of the first containment enclosure E32.

[0074] As illustrated by the figure 5 , inside this first containment enclosure E32, the dry cleaning device 32 comprises means 64 for receiving a tray 10 to be cleaned and a dry cleaning station 66 for this tray.

[0075] More precisely, the receiving means 64 make it possible to receive and transport a container 15 formed by a tray 10 to be cleaned, its support 13 and its sleeve 12.

[0076] These receiving means 64 take for example the form of a chain conveyor 72. This chain conveyor 72 extends horizontally inside the first containment enclosure E32 of the dry cleaning device, and in a longitudinal direction DL parallel to the planes of the side walls 62G, 62D of the first containment enclosure E32 and perpendicular to the front 60F and rear 60R walls of this enclosure. Thus, this chain conveyor 72 makes it possible to transport a container 15, and therefore a tray 10 to be cleaned, from the inlet airlock 56 of the first containment enclosure E32 to the dry cleaning station 66.

[0077] In order to facilitate the recovery of the unconsolidated powder 16 contained in a container 15, the dry cleaning device 32 comprises a second cleaning enclosure 68 inside its first containment enclosure E32.

[0078] This second cleaning enclosure 68 takes the form of a bell 70 mounted on a base 74, and this base 74 comprises an opening 76 for receiving a tray 10 to be cleaned.

[0079] More precisely, the base 74 is substantially flat and rectangular, while the bell 70 has a pyramidal shape S70 extending around a central axis A70 perpendicular to the plane P74 of the base 74. At the same time, the opening 76 is of a shape and dimensions adjusted or adjustable to the shape and dimensions of the trays 10 to be cleaned.

[0080] The pyramidal shape of the bell 70 around its central axis A70 facilitates the flow and recovery of the unconsolidated powder 16 when this bell 70 is turned over with a tray 10 to be cleaned.

[0081] In a preferred embodiment illustrated in the figures 6 à 9 , the bell 70 comprises a lower part 70B parallelepiped around its central axis A70 and a upper part 70H pyramidal around its central axis A70, the lower part 70B parallelepiped extending from the base 74, and the upper part 70H pyramidal extending between this lower part 70B and the top 78 of the bell 70.

[0082] In other variants, the bell may also take a fully pyramidal, partially or fully conical, partially or fully frustoconical shape, or any other shape allowing a funnel to be formed when the bell 70 is inverted.

[0083] In order to control the flow of the unconsolidated powder 16 when the bell 70 is turned over in such a way that its base 74 is located above its top 78 as illustrated in figures 8 And 9 , the top 78 of the bell 70 takes the form of a conduit 80 equipped with a valve 82 or any other flow regulation device.

[0084] As has just been indicated, the invention provides for turning the bell 70 and the tray 10 over in order to recover the unconsolidated powder 16 surrounding the manufactured part(s) 14 in a container 15.

[0085] However, initially, it is necessary to take the container 15 comprising the tray 10 to be cleaned and the unconsolidated powder 16 to be recovered to the opening 76 of the base 74 of the cleaning enclosure 68.

[0086] For this purpose, it is provided that the cleaning enclosure 68 is in an initial position corresponding to a non-inverted position in which the bell 70 and its top 78 are located above the base 74. In this initial position of the cleaning enclosure 68, the plane P74 of the base 74 is substantially horizontal, as illustrated in the figures 6 And 7 .

[0087] Then, the receiving means 64 make it possible to transport a container 15, and therefore a tray 10, from the inlet airlock 56 of the first confinement enclosure E32 to opposite the opening 76 of the base 74 of the cleaning enclosure 68 when this cleaning enclosure 68 is in its initial position.

[0088] In addition to the receiving means 64, the dry cleaning device 32 comprises an elevator 84 making it possible to take a tray 10 to be cleaned from the receiving means 64 to the opening 76.

[0089] To this end and as illustrated by the figures 6 And 7, this elevator 84 makes it possible to move the tray 10 to be cleaned and its support 13 in vertical translation T1 inside the jacket 12 of the container 15. More precisely, the jacket 12 extending vertically in height around a central axis A12, the vertical translation T1 of the tray 10 and its support 13 is carried out parallel to the central axis A12 of the jacket 12 and towards the upper edge 86 of the jacket 12.

[0090] In parallel with the vertical translation T1 of the plate 10 and its support 13, the elevator 84 makes it possible to move the jacket 12 in vertical translation T2 parallel to its central axis A12 and towards the base 74 of the cleaning enclosure 68. Thus, the upper edge 86 of the jacket 12 is pressed against the lower edge 88 of the opening 76 of the base 74, which makes it possible to avoid leaks of unconsolidated powder 16 when the plate 10 rises in the jacket 12 and this powder is gradually transferred from the container 15 to the interior volume V68 of the cleaning enclosure 68.

[0091] For the implementation of the vertical translation T1 of the plate 10 and its support 13, the elevator 84 comprises for example a piston 90 guided in translation inside a body 92 and driven in translation by a motor 94 and an endless screw 96.

[0092] For the implementation of the translation T2 of the sleeve 12, the elevator 84 comprises for example a plate 98 guided in translation around the rod 89 of the piston 90 and driven in translation by compression springs 100 bearing on another plate 102 fixed to the body 92.

[0093] Advantageously, the plates 98, 102 and the springs 100 are sized and positioned relative to the body 92 and the piston 90 so that the translation of the piston 90 by the motor 94 also causes the translation of the plate 98 under the effect of the springs 100.

[0094] Once the plate 10 has arrived in the plane P74 of the base 74, the translation T1 of the plate is stopped, and locking elements such as studs 104 immobilize the support 13 in the opening 76 of the base 74, these studs 104 penetrating for this purpose into the bores 17 provided in the support 13.

[0095] Advantageously, in this position of the plate 10 relative to the base 74, the peripheral seal 19 of the support 13 also provides sealing between the support 13 and the base 74, and therefore between the plate 10 and the base 74.

[0096] When the plate 10 is secured to the base 74, the manufactured part(s) 14 and the unconsolidated powder 16 are located in the interior volume V68 of the cleaning enclosure 68, which makes it possible to envisage turning over this cleaning enclosure 68 to recover the unconsolidated powder 16 by gravity and to proceed with the dry cleaning of the plate 10 and the manufactured part(s) 14.

[0097] For this purpose, the cleaning enclosure 68 is pivotally mounted around an axis A68, preferably horizontal.

[0098] As illustrated by the figure 8 , when the cleaning enclosure 68 is in its inverted position, the plane P74 of the base 74 is substantially horizontal. Also, the cleaning enclosure 68 is mounted so as to be able to pivot at least 180° inside the first containment enclosure E32 of the dry cleaning device 32.

[0099] For the purpose of complete automation of the installation, an actuator such as an electric motor 106 makes it possible to drive the enclosure 68 in rotation around its axis A68.

[0100] Advantageously, this actuator 106 makes it possible to control the angle of rotation of the cleaning enclosure 68 around its axis A68, for example in order to modify the inclination of the base 74 and therefore of the plate 10 during the dry cleaning cycle.

[0101] When the cleaning enclosure 68 is turned over, the unconsolidated powder 16 falls by gravity towards the top 78 of the bell 70, which makes it possible to easily recover this powder via the conduit 80.

[0102] Preferably and as illustrated by the figure 5 , means 108 for recovering powder by suction are connected to the conduit 80 at the top of the bell 70 via the valve 82, the suction promoting the flow of the powder in the conduit 80 and therefore making it possible to avoid its clogging.

[0103] In order to suck up the powder grains from the unconsolidated powder mist 16 which forms in the interior volume V68 of the cleaning enclosure when this enclosure 68 is turned over, the bell 70 comprises a suction orifice 110 between its base 74 and its top 78, this orifice 110 being connected to means 109 for recovering a powder mist by suction.

[0104] Preferably, this orifice 110 is provided at mid-height in the bell 70. In a preferred variant and illustrated by the figures 6 à 9 , this orifice 110 is provided in the upper pyramidal part 70H of the bell 70, but close to the lower parallelepiped part 70B.

[0105] In order to collect any grains of powder that could escape from a container 15 during its transport between the inlet airlock 56 of the first containment enclosure E32 and the cleaning enclosure 68, or from the enclosure 68 during its overturning for example, the means 109 for recovering a mist of powder by suction are also connected to the interior volume V32 of the first containment enclosure E32 of the dry cleaning device 32.

[0106] Compared to the means 108 for recovering powder by suction, the means 109 for recovering a powder mist by suction offer a greater suction flow rate.

[0107] To ensure the hermetic closure of the cleaning enclosure 68 after its turning over with the tray 10 to be cleaned, this cleaning enclosure 68 comprises a door 112 making it possible to close the opening 76 of the base 74. This door 112 is pivotally mounted relative to the base 74, and it closes the enclosure 68 just behind the tray 10 and its support 13. With a view to complete automation of the installation, the movement of this door 112 is also fully automated.

[0108] By turning over the cleaning chamber 68 and the tray 10 to be cleaned and the pyramidal part 70H of this chamber 68, a large part of the unconsolidated powder 16 can be simply recovered by gravity via the top 78 of the bell 70, and preferably with the help of suction.

[0109] However, despite this turning and this suction, certain grains of unconsolidated powder 16 may still adhere to the plate 10 and to the manufactured part(s) 14, in particular when these parts 14 comprise cavities and / or hollow shapes.

[0110] Also, in order to cause the grains of powder still adhering to the plate 10 or contained in the hollows or cavities of the manufactured parts 14 to fall, the dry cleaning station 66 of the dry cleaning device 32 comprises means 114 capable of imposing vibrations on the plate 10 to be cleaned and means 116 capable of subjecting this plate 10 to shocks. As shown in figures 8 And 9 , these means 114 capable of imposing vibrations and these means 116 capable of subjecting shocks are supported by the base 74 of the cleaning enclosure 68 and provided next to the opening 76 receiving the tray 10 to be cleaned.

[0111] In more detail, the means 114 capable of imposing vibrations take for example the form of a vibrator 118 with an electric motor, and the means 116 capable of subjecting shocks take for example the form of a pneumatic striker 120.

[0112] In order to prevent the vibrator 118 and the striker 120 from propagating vibrations and shocks in the base 74 and in the entire cleaning enclosure 68, this vibrator 118 and this striker 120 are mounted on a plate 122 mounted on silent blocks opposite an opening 124 made in the base 74. Advantageously, sealing means 126 such as bellows are provided between the base 74 and the plate 122.

[0113] As shown in the figure 9 , the vibrator 118 and the striker 120 come directly into contact with the plate 10, which makes it possible to improve the cleaning efficiency and to optimize the use of vibrations and shocks.

[0114] Since the dry cleaning station 66 is located at a distance from the opening 76 receiving the tray 10 to be cleaned, the cleaning enclosure 68 comprises internal means 128 for conveying a tray 10 between its opening 76 and the means 114, 116 of the dry cleaning station 66.

[0115] In a preferred variant and illustrated on the figures 8 And 9 , these internal means 128 for conveying a tray comprise at least a first guide support 130 movable in translation, a second guide support 132 connected to the plate 122 supporting the means 114, 116 of the dry cleaning station 66, and means 136 for transferring a tray 10 from the first support 130 to the second support 132.

[0116] In more detail, the first support 130 is mounted to move in translation inside the cleaning enclosure 68, opposite the opening 76 of the base 74, and its translation T3 takes place in a direction perpendicular to the plane P74 of the base, for example under the effect of a jack 134.

[0117] In its high position illustrated in figure 8 , the first support 130 makes it possible to receive the tray 10 to be cleaned. The enclosure 68 and the tray 10 having been turned over, the first support 130 makes it possible to receive the turned over tray 10, that is to say with the manufactured part(s) 14 under the tray 10. For this purpose, the first support 130 takes the form of a plurality of fingers 138 spaced apart from each other and a few centimeters in length. Advantageously, the fingers 138 are rounded in order to avoid the retention of powder grains.

[0118] Once the plate 10 is received by the first support 130, this first support is translated from its high position to a low position illustrated in figure 9 authorizing the transfer of the tray 10 to be cleaned to the second guide support 132.

[0119] The second support 132 also taking the form of a plurality of fingers 140 spaced from each other, a few centimeters in length, and preferably rounded in shape, the transfer means 136 of a plate 10 take the form of a fork 142 guided in translation between the first support 130 and the second support 132. The translation T4 of this fork 142 is carried out in a direction parallel to the plane P74 of the base 74, and for example under the effect of a jack 144. This fork 142 makes it possible to grip the plate 10 to be cleaned so as to slide it from the fingers 138 of the first support 130 to the fingers 140 of the second support 132.

[0120] Optionally, an intermediate guide support 146 may also be provided between the first support 130 and the second support 132, this intermediate support 146 also being formed by fingers 148 preferably having a rounded shape.

[0121] Once the plate 10 is present on the second support 132, the dry cleaning by shocks and vibrations provided by the invention can be implemented. However, and prior to the vibration and shocks, the rod 150 of a jack 152 supported by the plate 122 of the dry cleaning station 66 clamps the plate 10 on the second support 132.

[0122] According to the invention, the vibration of a plate 10 consists of making the plate 10 oscillate at frequencies between 40 and 150 Hz, the amplitudes of the oscillations of the plate 10 not exceeding 5 millimeters.

[0123] In the preferred embodiment illustrated in the figures 8 And 9, the vibrations are generated by the vibrator 118 and transmitted to the plate 10 and to the manufactured part(s) 14 via the plate 122 and the second support 132.

[0124] Still according to the invention, the shocks are delivered to a plate 10, and therefore to the manufactured part(s) 14 using a moving body and having a kinetic energy of 20 to 25 Joules when it comes into contact with the plate 10. In addition, a plate 10 undergoes a plurality of shocks at frequencies between 15 and 25 Hz, or from 120 to 600 shocks during a dry cleaning cycle to give an idea.

[0125] In the preferred embodiment illustrated in the figures 8 And 9 , the shocks are delivered to the plate 10 by the rod 154 of the firing pin 120.

[0126] By applying shocks to the plate 10, the clusters of unconsolidated powder grains 16 likely to form in the cavities or hollow shapes of the manufactured parts 14 disintegrate, and by applying vibrations, these powder grains are extracted from the hollow shapes or cavities of the manufactured parts 14 and they fall by gravity towards the top 78 of the bell 70.

[0127] Once the vibration and shock application cycle is complete, the tray 10 is led to the exit airlock 58 of the dry cleaning device 32 where it can, for example, be grasped by the gripping device 54 in order to be extracted from the enclosure E32, as illustrated in figure 5 .

[0128] To return from the dry cleaning station 66 to the exit airlock 58 and more precisely to the reception means 64, the cleaned tray 10 follows the same route as on arrival but in the opposite direction.

[0129] In more detail, after having released the clamping of the rod 154, the fork 142 brings the tray 10 back from the second support 132 towards the first support 130, then the first support 130 returns to the high position so as to bring the tray 10 back into the opening 76 of the base 74. Then, the cleaning enclosure 68 is returned to its initial unturned position, after having taken care to open the door 112, so that the tray 10 is recovered by the elevator 84 and its piston 90 which finish driving the cleaned tray 10 to the chain conveyor 72 of the receiving means 64.

[0130] Thanks to its complete automation, the cleaning installation 20 is particularly suitable for installation in an additive manufacturing workshop comprising a plurality of additive manufacturing machines.

[0131] Advantageously, the installation 20, and more particularly the dry cleaning device 32, can be adapted to carry out the cleaning of a tray 10 alone, that is to say without a jacket 12 forming a container 15 with this tray 10.

[0132] Furthermore, the installation 20 and the trays 10 can also be adapted so as to avoid the use of supports 13 of the trays 10.

[0133] Advantageously, the two containment enclosures E32 and cleaning 68 of the dry cleaning device 32 provide double containment, best protecting people from the toxicity of certain additive manufacturing powders.

[0134] More generally, the present invention also relates to a method for dry cleaning an additive manufacturing tray 10 which can, for example, be implemented with the dry cleaning device 32 which has just been described.

[0135] According to the invention, this method consists of separating the unconsolidated powder 16 from a tray 10 and collecting it by imposing vibrations on the tray and subjecting the tray to shocks.

[0136] As indicated previously, the vibrations applied to the plate 10 have frequencies preferably between 40 and 150 Hz, and the amplitudes of the oscillations of the plate 10 under the effect of the vibrations do not exceed 5 millimeters.

[0137] In addition, a plurality of shocks are delivered to a plate 10 using a moving body having a kinetic energy of 20 to 25 Joules when it comes into contact with the plate 10.

[0138] Preferably, the shocks are given in a direction orthogonal to the plane P10 of the plate 10, and for example using the rod 154 of the striker 120. Indeed, a plate 10 being designed to be particularly rigid in its width and its length, it is more effective to apply these shocks perpendicular to the plate 10 and therefore in its height.

[0139] Preferably, a platen 10 is subjected to 120 to 600 impacts during a dry cleaning cycle, at frequencies between 15 and 25 Hz.

[0140] In order to promote the fall by gravity of the grains of unconsolidated powder 16 from the hollow shapes or cavities of the manufactured part(s) 14, the vibrations are preferably imposed on the plate 10 in directions substantially parallel to the plane P10 of the plate 10, and for example using a vibrator 118.

[0141] Still in order to promote the cleaning of the plate 10 and the manufactured parts, the vibrations can be imposed on the plate 10 in directions substantially parallel to the plane P10 of the plate 10 but different from each other. Preferably, the vibrations are imposed on the plate 10 in two directions parallel to the plane P10 of the plate 10 but perpendicular to each other, and corresponding for example to the directions extending in the length and in the width of the plate 10. This combination of vibrations of different directions is advantageous because it makes it possible to best rid the manufactured parts and their cavities of the grains of unconsolidated powder, and this regardless of the directions in which these parts and these cavities extend parallel to the plane P10 of the plate.

[0142] For optimal dry cleaning, vibration and shock steps are alternated several times.

[0143] Optionally, and to reduce the time of a dry cleaning cycle, vibration and shock stages are carried out simultaneously.

[0144] For example, thanks to the cleaning enclosure 68 and its rotational mounting around a horizontal axis A68, the method comprises a preliminary step consisting of turning the tray 10 over, this turning making it possible to recover a large part of the unconsolidated powder 16 by gravity.

[0145] Still with a view to optimal dry cleaning and to promote the fall by gravity of the grains of unconsolidated powder 16 from the hollow shapes or cavities of the manufactured part(s) 14, the dry cleaning method may provide for varying the inclination of the plate 10 during the steps of vibration and / or the steps of applying shocks to the plate 10.

[0146] For example, thanks to the cleaning enclosure 68, the dry cleaning process takes place in a confined volume V68, and preferably doubly confined thanks to the first confinement enclosure E32 of the dry cleaning device 32.

[0147] By gravity, or using means 108 for recovering powder by suction, the dry cleaning method comprises a step subsequent to the vibration and the application of shocks consisting of evacuating from this confined volume V68 the grains of the unconsolidated powder 16 resulting from the dry cleaning of the tray 10, for example with a view to its storage and reuse.

[0148] Advantageously, the suction intended for the recovery of the unconsolidated powder 16 which has fallen into the top 78 of the bell 70 only operates for a few seconds.

[0149] For example, thanks to the means 109 for recovering a powder mist connected to the dry cleaning enclosure 68, the method provides that the confined volume V68 is subjected to additional suction during cleaning, this additional suction having the aim of eliminating any powder mists that may form inside the dry cleaning enclosure 68 during a dry cleaning cycle.

[0150] Preferably, the additional suction is at least maintained in the enclosure of the dry cleaning enclosure 68 during the vibration of a plate 10 and during the application of shocks to the plate 10.

[0151] Finally, and for example thanks to the means 109 for recovering a powder mist connected to the first containment enclosure E32 of the dry cleaning device 32, the method provides that the containment volume V32 of the dry cleaning device 32 is also subjected to additional suction.

[0152] It is noted that the dry cleaning device 32 only turns over and cleans the plate 10 and the manufactured parts secured to this plate 10. Indeed, it is not useful to turn over and clean the jacket 12 because the translation of the plate 10 with its support 13 and the seal 19 is sufficient to rid the inner walls of the jacket 12 of the grains of unconsolidated powder. In addition, turning over the jacket 12 with the plate 10 would represent an additional and therefore unnecessary energy consumption.

[0153] According to another advantage, the dry cleaning device 32 makes it possible to separate the tray 10 and the manufactured parts from the folder 12 in order to transfer only the tray 10 and the manufactured parts to the wet cleaning device 34. Indeed, wet cleaning of the folders 12 is not necessary.

Claims

1. An installation (20) for cleaning a plate (10) used in powder-based additive manufacturing by sintering or melting grains of this powder using a beam of energy involving electromagnetic radiation, the installation (20) comprising an entry lock (22) for receiving a plate (10) to be cleaned and an exit lock (26) for extracting a cleaned plate (10) from the installation, a dry-cleaning device (32) for cleaning a plate (10) using vibrations and shocks in a first confinement enclosure (E32), a wet-cleaning device (34) for cleaning a plate (10) with at least one liquid in a second confinement enclosure (E34), and at least one conveying device (36, 44, 46) for transporting a plate (10) between the first confinement enclosure (E32) of the dry-cleaning device, the second confinement enclosure (E34) of the wet-cleaning device, and the exit lock (26) of the installation, wherein the installation comprises a first conveyor (44) for transporting a plate (10) from the first confinement enclosure (E32) of the dry-cleaning device (32) to the second confinement enclosure (E34) of the wet-cleaning device (34) and vice versa from the second confinement enclosure (E34) of the wet-cleaning device (34) to the first confinement enclosure (E32) of the dry-cleaning device (32), and a second conveyor (46) for transporting a plate (10) from the second confinement enclosure (E34) of the wet-cleaning device (34) to the exit lock (26) and vice versa from the exit lock (26) to the second confinement enclosure (E34) of the wet-cleaning device (34), or wherein the installation comprises a conveyor (36) for transporting a plate (10) from the first confinement enclosure (E32) of the dry-cleaning device (32) to the exit lock (26) and vice versa from the exit lock (26) to the first confinement enclosure (E32) of the dry-cleaning device (32), at least one storage area (48, 50) for the temporary storage of plates (10), and a manipulator arm (52) for moving a plate (10) between the dry-cleaning device (32), the wet-cleaning device (34), the conveyor (36) and each temporary storage area (48, 50).

2. The installation (20) according to claim 1, wherein the wet-cleaning device (34) comprises, in its enclosure (E34), at least one washing station (38) for washing a plate (10) with a cleaning liquid and at least one rinsing station (40) for rinsing a plate (10) with a rinsing liquid.

3. The installation (20) according to claim 2, wherein the washing station (38) takes the form of a tank filled with cleaning liquid and equipped with means for emitting very high-frequency ultrasonic waves into this cleaning liquid.

4. The installation (20) according to claim 2 or claim 3, wherein the wet-cleaning device (34) comprises a drying station (40) in its enclosure (E34).

5. The installation (20) according to one of the preceding claims, the entire installation (20) being confined in a protective enclosure (28).