Additive Manufacturing Powder Supply Module capable of drying powder

Abstract

A module (2) for supplying additive manufacturing powder comprises a main hopper (29) for storing additive manufacturing powder, the main hopper (29) being designed to be connected to a manufacturing module (4), the manufacturing module (4) being configured to manufacture objects by additive manufacturing from the powder in the main hopper (29), an inlet of the supply module (2) being designed to be connected to the manufacturing module (4) and to receive the powder in the manufacturing module (4), a glove box (25) being designed to accommodate a container (28), the glove box (25) being suitable for being sealed and closed, a supply line being configured to divert the powder in the glove box (25) to the main hopper (29), a circulation system being designed to move the powder in a closed circulation loop, the circulation system comprising a suction system (21) remote from the main hopper (29), the suction system (21) being designed to remove gas present in the circulation loop, the circulation loop passing through the main hopper (29) and the suction system (21).

Description

Technical Field

[0001] The present invention relates to the general field of additive manufacturing equipment, and more particularly to the field of powder drying in additive manufacturing equipment. Background Art

[0002] Selective additive manufacturing builds three-dimensional objects by consolidating selected areas in successive layers of powdered material (metal powder, ceramic powder, etc.).

[0003] If the AM powder loaded into the AM machine has high moisture levels, parts made from this powder will be of lower quality and often have defects.

[0004] To this end, the AM equipment can include a drying system. Conventional drying systems include heating elements to increase the powder temperature. Others use vacuum systems to extract moisture from the powder. Another solution involves using mechanical elements that are immersed in the reservoir containing the powder to agitate or stir the powder. These various solutions can be implemented individually or in combination. However, some are not sufficiently efficient or significantly interfere with the proper operation of the AM equipment. Summary of the Invention

[0005] The object of the present invention is to propose an additive manufacturing apparatus that is capable of drying powder more efficiently without interfering with the correct operation of the additive manufacturing apparatus.

[0006] In the context of the present invention, this object is achieved by a module for supplying powder for additive manufacturing, comprising:

[0007] a main hopper for storing additive manufacturing powder, the main hopper being designed to be connected to a manufacturing module configured to additively manufacture an object from the powder located in the main hopper,

[0008] - an inlet of the supply module, the inlet being designed to be connected to the manufacturing module and to receive the powder located in the manufacturing module,

[0009] a glove box designed to accommodate the container, said glove box being closable in a leaktight manner,

[0010] - a supply line configured to transfer the powder located in the glove box to the main hopper,

[0011] A circulation system designed to move the powder according to a self-closed circulation loop, comprising a suction system remote from the main hopper, designed to evacuate the gases present in the circulation loop passing through the main hopper and the suction system.

[0012] On the one hand, the circulation system allows the wet powder to move, and on the other hand, the suction system extracts moisture from the powder's gaseous environment, resulting in faster and more efficient drying of the powder overall. The absence of moving mechanical elements (e.g., mixers) immersed in the reservoir containing the powder means that the drying device does not interfere with the correct operation of the additive manufacturing equipment.

[0013] Advantageously, such a device is supplemented by the following characteristics or steps, considered alone or in combination:

[0014] The circulation loop comprises:

[0015] - a reservoir located below the main hopper and comprising an outlet designed to be connected to the manufacturing module through a manufacturing pipe,

[0016] a return line configured to redirect the additive manufacturing powder located in the reservoir to the inlet of the supply module,

[0017] The circulation system is designed to draw powder from the outlet of the reservoir to the inlet of the supply module,

[0018] Dry inert gas supply system, which is designed to supply dry inert gas to the circulation loop below the main hopper,

[0019] Humidity sensors, which are designed to measure the humidity level in the circulation loop,

[0020] A sieve located above the reservoir,

[0021] The powder passing through the circulation loop passes through the main hopper, sieve, storage, return line and suction system in sequence. The first moisture sensor is designed to measure the moisture level in the main hopper.

[0022] a second humidity sensor placed on the gas exhaust line of the pumping system and a third humidity sensor connected to the dry inert gas supply system,

[0023] an extraction line, distinct from the supply line and configured to transfer additive manufacturing powder from an inlet of the supply module to the container when the container is housed in the glove box, the extraction line comprising a flow divider,

[0024] a bypass line connecting the diverter to the reservoir and designed to transfer powder directly from the diverter to the reservoir, said diverter being configurable:

[0025] - an extraction configuration, in which additive powder from the inlet of the supply module is selectively redirected to the glove box,

[0026] - a loop-back configuration, in which additive powder from the inlet of the supply module is selectively redirected to a bypass line,

[0027] The flow splitter is configured in a loop-back configuration as the circulation system moves powder from the outlet of the reservoir toward the inlet of the manufacturing module.

[0028] The present invention also relates to an additive manufacturing device, comprising:

[0029] - a supply module for supplying additive manufacturing powder as described above, and

[0030] A manufacturing module configured to additively manufacture an object from powder located in a main hopper, the main hopper being connected to the manufacturing module and the inlet of the supply module being connected to the manufacturing module.

[0031] Advantageously, but optionally, the manufacturing module of the device may be supplemented by a recycling system for recovering powder that has not consolidated during the additive manufacturing of the object and for redirecting the recovered powder towards the inlet of the supply module.

[0032] The invention also relates to a method for drying additive manufacturing powder using a supply module as described above, the method comprising the step of circulating the powder in a circulation loop using a circulation system when the powder is present in a main hopper.

[0033] Advantageously, but optionally, the method may be supplemented by the following steps, taken alone or in combination:

[0034] - Steps for measuring the humidity level in the circulation loop,

[0035] - a step of comparing the measured humidity level to a threshold level,

[0036] - a step of stopping the powder circulation, the step of stopping the circulation being performed according to the result of the comparing step;

[0037] A step for screening the powder entering the circulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features and advantages of the present invention will become more apparent from the following description, which is intended to be illustrative and non-limiting only and should be read in conjunction with the accompanying drawings, in which:

[0039] Figure 1 Schematic diagram of an additive manufacturing apparatus according to one embodiment of the present invention.

[0040] Figure 2 Schematic diagram of a powder drying method for additive manufacturing according to one embodiment of the present invention. DETAILED DESCRIPTION

[0041] Figure 1 An additive manufacturing apparatus 1 is shown comprising a powder supply module 2 and a manufacturing module 4 .

[0042] Supply Module

[0043] The supply module 2 includes a suction system 21 at the top, connected to a first gas exhaust line 23. The suction system 21 has an inlet 211 and an outlet 213 located at the bottom of the suction system 21. The suction system 21 is designed to generate suction at the inlet 211 that is directed into the interior of the suction system 21. The first gas exhaust line 23 may include a vacuum pump for generating the suction. The suction system 21 is designed to receive additive manufacturing powder from the inlet 211 and store it. The stored powder is located at the bottom of the suction system 21 and can be extracted via the outlet 213. The suction system 21 may include a powder filter to prevent the powder from entering the first exhaust line 23. The suction system 21 includes a device capable of separating powder from the gas, such as a circulation filter 22. Other devices for separating powder from the gas exist, such as a filter chamber including a filter, a cyclone separator, or an exhaust box.

[0044] Supply module 2 includes a housing 25 positioned below suction system 21. Housing 25 includes walls defining a chamber. Housing 25 can be enclosed, so that the chamber is a three-dimensional object that is hermetically sealed from the exterior of the device. The housing is designed to allow for the movement and processing of objects within the housing. Specifically, the housing includes tools for moving and processing objects within the chamber when the chamber is enclosed.

[0045] Housing 25 can specifically be a glove box. In this case, the housing has two holes in which gloves 251 are placed, thereby maintaining the housing's fluid-tightness. Gloves 251 are used to move and handle objects within the chamber while it is sealed. By wearing gloves 251, an operator can handle objects within glove box 25 from outside the glove box. One wall of the glove box may be transparent to allow the operator to observe the objects being handled.

[0046] In particular, the object may be a container or canister 28 designed to contain additive manufacturing powder. The container and canister may be closed with a lid.

[0047] The housing's tooling is designed to move and seal the container or canister 28 within the chamber when the chamber is closed.

[0048] One of the walls of the housing 25 has a first door 253. The first door 253 is movable between an open position, in which a container can be moved from outside the device into the chamber or from the chamber to outside the device, and a closed position, in which the chamber is sealed from the outside of the device. The first door 253 can be closed to seal the housing from the outside. A lid can also be moved in and out to close the container or can.

[0049] The housing 25 may include a transfer area 255 in which one or more containers may be temporarily stored and stacked.

[0050] The housing 25 may include an oxygen sensor 257. The sensor 257 is designed to measure the oxygen content within the housing.

[0051] The housing 25 may comprise a supply line 259 for supplying air and a supply line 2511 for supplying an inert gas. The inert gas may in particular be nitrogen or argon.

[0052] The housing 25 may include a second gas exhaust line 2513 which may include a vacuum pump for generating suction.

[0053] The assembly of the supply line 259 for supplying air, the supply line 2511 for supplying an inert gas and the second gas exhaust line 2513 defines a gas flow control system which makes it possible to control the oxygen content and the inert gas content in the chamber.

[0054] The supply module 2 comprises a metering system 27 located below the suction system 21. The metering system 27 is connected to an outlet 213 of the suction system 21. Powder stored in the suction system 21 and located at the bottom of the suction system 21 can be extracted to the metering system 27 via the outlet 213.

[0055] The valve 24 is located between the suction system 21 and the metering system 27. In the open configuration, the valve 24 allows the passage of powder, while in the closed configuration, the valve 24 allows the suction system 21 to be sealed from the metering system 27. When the suction system 21 draws in powder, the valve 24 closes so that the suction occurs only at the inlet 211 and is directed to the interior of the suction system 21. The closing of the valve 24 can be automatically triggered by starting the suction of powder into the suction system 21.

[0056] The metering system 27 can isolate a precise amount of powder from the powder stored in the metering system. This precise amount can be delivered to an outlet 271 of the metering system 27. The outlet 271 is located within the housing 25 and has a valve 28. The valve 28 in an open configuration allows powder to pass from the metering system 27 to the interior of the housing 25, and the valve 28 in a closed configuration can isolate the metering system 27 from the interior of the housing 25 in a sealed manner.

[0057] The valve 28 is in particular closed when the first door 253 of the housing 25 is in the open position.

[0058] For example, the metering system can be a metering screw. The metering screw is contained in a barrel extending in a generally horizontal direction. When the screw moves and the powder is poured from the suction system 21 into the metering system 27 through the open valve 24, the powder is transported by the screw along the direction of the barrel extension toward the outlet 271.

[0059] The metering system can also be an airlock comprising two valves. The airlock has a predetermined volume and, when filled with powder via a first valve located on the side of the suction system 21, can isolate a precise volume of powder. This volume of powder can then be transferred to the housing 25 via a second valve located on the side of the housing 25.

[0060] The housing 25 may include a refill area designed to receive a powder container within the housing 25 below the outlet 271 of the metering system 27 .

[0061] The supply module 2 includes a main hopper 29 located below the housing 25. The main hopper 29 is a container capable of storing additive manufacturing powder.

[0062] The main hopper 29 has a frustoconical volume and is designed to store a large amount of manufacturing powder. The main hopper 29 is oriented so that the axis of the frustoconical shape is vertical, and the frustoconical volume has a smaller horizontal cross-section at the bottom of the hopper. The main hopper 29 has an outlet 293 located at the bottom of the main hopper.

[0063] The housing 25 comprises a second door 291 arranged between the chamber and the main hopper 29, said second door 291 being movable between an open position, in which the powder located in the chamber can be transferred to the main hopper 29, and a closed position, in which the chamber is separated from the main hopper 29 in a sealed manner.

[0064] The second door 291 or isolation door 291 is, for example, an isolation valve 291. The second door 291 defines a passage between the housing and the main hopper that can be opened or sealed in a controlled manner. The passage can be vertically oriented and wide enough to allow an operator to empty the contents of the powder canister from the housing 25 into the main hopper 29.

[0065] The supply module 2 comprises a flow splitter, which comprises an inlet and two outlets.

[0066] The inlet of the flow splitter is the inlet of the metering system 27 and is connected to the outlet 213 of the suction system 21. The first outlet of the flow splitter is the outlet 271 of the metering system 27.

[0067] The second outlet of the diverter passes through the metering system 27 in a vertical direction. The second outlet can be a continuation of the direction in which the powder poured from the suction system 21 reaches the metering system 27. The second outlet is connected to a bypass line 31. The bypass line 31 directly connects the second outlet of the diverter and the main hopper 29. The bypass channel 31 can be oriented vertically and pass through the glove box. The powder passing through the bypass line 31 does not reach any wall of the housing 25 and does not come into direct contact with the atmosphere of the housing 25. In particular, if the valve 28 is closed, the powder passing through the bypass line 31 does not come into contact with the atmosphere of the housing 25.

[0068] The second outlet is controlled by a valve 30. The valve 30 in an open configuration allows powder to pass from the metering system 27 to the bypass channel 31 and the valve 30 in a closed configuration prevents powder from passing from the metering system 27 to the bypass channel 31.

[0069] The flow diverter can be configured in an extraction configuration in which powder at the metering system outlet is selectively directed to the glove box 25. In this configuration, the valve 30 is in a closed configuration and the metering screw operates to deliver powder to the outlet 271 of the metering system.

[0070] The flow splitter can be configured as a loop-back configuration in which powder at the outlet of the metering system 21 is selectively directed to a second outlet of the flow splitter. In this configuration, the valve 30 is in an open configuration and the metering screw is at rest.

[0071] The flow divider can therefore be considered to be composed of the metering system 27 and the valve 30 .

[0072] The supply module 2 includes a metering device 33 located below the main hopper 29. The metering device 33 can adjust the flow rate of the powder delivered to the sieve 35 so as not to damage the mesh contained in the sieve 35. The metering device 33 is connected to the outlet 293 of the main hopper. The metering device 33 has an outlet 331 located at the bottom of the metering device 33.

[0073] The supply module 2 includes a sieve 35 located below the metering device 33. The sieve 35 is connected to the outlet 331 of the metering device 33. The sieve can filter agglomerated powder lumps and isolate them from the remaining powder in the receiver 351. The sieve includes a third discharge circuit 353, which can include a vacuum pump for generating suction.

[0074] Supply module 2 includes a reservoir 37 located below screen 35. Reservoir 37 can be a hopper having a frusto-conical volume designed to store a large amount of manufacturing powder. The hopper can be oriented so that the axis of the frusto-conical shape is vertical and the frusto-conical volume has a smaller horizontal cross-section at the bottom of the hopper. Reservoir 37 has an outlet 371 located at the bottom of the reservoir.

[0075] When the second door 291 is in the open position, powder can be transferred from the glove box 25 to the reservoir 37. The powder can then pass from the glove box 25 to the main hopper 29, the metering device 33, the sieve 35, and finally to the reservoir 37 in sequence. In this way, a supply line configured to transfer powder located in the glove box 25 to the main hopper 29 or the further reservoir 37 can be defined. The second door 291, which defines a passage between the housing and the main hopper (which can be opened or sealed in a controlled manner), can open or close the supply line.

[0076] Supply module 2 includes a dry inert gas supply system 36. Supply system 36 can provide a flow of dry inert gas in a conduit 352 connected to sieve 35. The dry inert gas flow through conduit 352 is directed upward from the bottom so as to encounter the powder passing upward from the bottom of the sieve. The inert gas flow reaching sieve 35 via conduit 352 also diffuses into the upper portion of reservoir 37.

[0077] The pipe 352 and the third exhaust line 353 may be aligned in the same direction so that the inert gas flow may sequentially pass through the pipe 352 in the same direction, encounter the powder passing through the sieve, and finally pass through the third exhaust line 353 .

[0078] The supply system 36 may also provide a flow of dry inert gas in a conduit 372 connected to the bottom of the reservoir 37 , for example to the outlet 371 .

[0079] The outlet 371 of the reservoir is connected to a return line 391. The return line 391 connects the outlet 371 of the reservoir 37 and the inlet 211 of the suction system 21. The return line 391 connects the outlet 371 of the reservoir 37 and the housing 25. Powder can be transported from the reservoir 37 to the powder housing 25 via the suction system 21. The suction system 21 can draw powder from the reservoir 37 toward the suction system 21 via the return line 391.

[0080] The outlet 371 of the reservoir is also connected to a manufacturing conduit 392. The manufacturing conduit 392 connects the outlet 371 of the reservoir 37 and the manufacturing module 4 so that the powder contained in the reservoir 37 can be transferred to the manufacturing module 4.

[0081] The sieve 35 is located just above the reservoir 37 so that the powder contained in the reservoir 37 and transferred to the production module 4 is sieved as late as possible before being conveyed to the production module 4 .

[0082] The reservoir 37 may have a smaller volume than the main hopper 29. The purpose of the reservoir 37 is to store powder before it is conveyed to the manufacturing module 4 or the suction system 21. The reservoir 37 may be referred to as a buffer hopper.

[0083] Main hopper 29 is designed to contain the majority of the manufacturing powder required for additive manufacturing of one or more three-dimensional objects. The powder contained in main hopper 29 is intended to be transferred to manufacturing module 4. To this end, main hopper 29 is designed to be connected to manufacturing module 4, which is configured to additively manufacture objects from the powder contained in main hopper 29. Main hopper 29 is connected to the manufacturing module via a circulation of powder through metering device 33, sieve 35, reservoir or buffer hopper 37, and finally manufacturing conduit 392.

[0084] The supply module 2 comprises a controller 39 which allows the powder to be diverted from the outlet 371 to a return line 391 or a production pipe 392 .

[0085] The supply module 2 may comprise a humidity sensor 201 located on the first gas exhaust line 23. This humidity sensor 201 may know the humidity level of the gas exhausted by the suction system 21, ie the humidity level upstream of the inlet 211 of the suction system 21.

[0086] The supply module 2 may include a humidity sensor 202 located above the main hopper 29. This humidity sensor 202 may be aware of the humidity level in the main hopper 29 and directly provide information about the humidity level of the powder that may be present in the main hopper 29.

[0087] The supply module 2 may include a humidity sensor 203 connected to the dry inert gas supply system 36. The humidity sensor 203 may be aware of the humidity level of the dry inert gas delivered to the sieve 35 or the reservoir 37.

[0088] The supply module 2 comprises a circulation system including a suction system 21 .

[0089] The suction system 21 can draw powder from the reservoir 37 toward the suction system 21 via the return line 391 .

[0090] Manufacturing Module

[0091] The manufacturing module 4 includes a second suction system 41 at the top, connected to a fourth gas exhaust line 43. The second suction system 41 has an inlet 411 and an outlet 413 located at the bottom of the second suction system 41. The second suction system 41 is designed to generate suction at the inlet 411 that is directed into the interior of the second suction system 41. The inlet 411 of the second suction system 41 is connected to the manufacturing pipeline 392. The fourth gas exhaust line 43 may include a vacuum pump for generating suction. The second suction system 41 may include a powder filter to prevent powder from entering the fourth gas exhaust line 43. The second suction system 41 includes a device capable of separating powder from the gas, such as a cyclone separator. Other devices for separating powder from the gas include a filter chamber including a filter, a recirculation filter, or an exhaust tank. The second suction system 41 is designed to receive additive manufacturing powder from the inlet 411 and store it. The stored powder is located at the bottom of the second suction system 41 and can be withdrawn via the outlet 413.

[0092] The manufacturing module 4 comprises an airlock 45 located below the second suction system 41. The airlock 45 makes it possible to transfer powder without the printer chamber being in communication with the second suction system 41, thus avoiding damage to the printing enclosure in terms of inertness and pressure.

[0093] The manufacturing module 4 includes a diverging screw 47 and a converging screw 51, which are located on both sides of a housing 49 for manufacturing a three-dimensional object. The housing 49 is a printer chamber.

[0094] The manufacturing module 4 comprises a powder recovery system for recovering powder that has been scattered and not solidified at the end of manufacturing.

[0095] The recovery system may include a suction pipe 53 designed to draw in powder. The suction pipe 53 includes a suction nozzle 533 that forms the inlet of the suction pipe. The powder is drawn in at the nozzle and transferred to the other end of the pipe, which forms the outlet of the suction pipe 53. The manufacturing apparatus 1 may include a first recovery conduit 531 connecting the outlet of the suction pipe 53 and the inlet 211 of the suction system 21.

[0096] The recovery system may include an excess airlock 55 designed to recover powder from the converging screw 51 .

[0097] The manufacturing apparatus 1 may include a second recovery pipe 551 connecting the excess airlock 55 and the inlet 211 of the suction system 21 .

[0098] The excess airlock 55 makes it possible to transfer powder without the printer chamber being in communication with the second recovery duct 551 , thus avoiding damage to the printing enclosure in terms of inertness and pressure.

[0099] The manufacturing plant 1 may also comprise a second controller designed to circulate the powder from the recovery system to the suction system 21 in a controlled manner.

[0100] In this respect, the inlet 211 may be referred to as an inlet of the supply module 2 , which inlet is designed to be connected to the manufacturing module 4 and to receive the powder located in the manufacturing module 4 .

[0101] It should be noted that the manufacturing apparatus 1 includes sufficient valves at the intersections of the conduits 391 , 392 , 531 and 551 to allow the powder circulation mentioned in the description.

[0102] It should also be noted that powder can be transferred from the inlet 211 to the glove box 25. The powder passes sequentially through the suction system 21, the outlet 213 of the suction system 21, the metering system 27, the diverters 27 and 30 configured for its extraction, and finally the glove box 25. More specifically, the powder arriving in the glove box 25 can be poured into a container housed in the glove box 25. Therefore, there is an extraction line, separate from the supply line, configured to transfer the additive manufacturing powder from the inlet 211 of the supply module 2 to the container when the container is housed in the glove box 25, and the extraction line includes the diverters 27 and 30.

[0103] Methods for drying additive manufacturing powders

[0104] Initially, the wet powder is in the main reservoir 37 .

[0105] During a first step E1 , a circulation system circulates the wet powder in a circulation loop.

[0106] A circulation loop may be defined in the supply module 2. The circulation loop passes through the main hopper 29, the screen 35, the reservoir 37, the return line 391, the suction system 21, the bypass channel 31 and then passes through the main hopper 29 again.

[0107] The inert gas supply line 372, connected to the top and bottom of the reservoir, is activated to drive unused powder into the return line 391. The suction system 21 is activated to generate a suction force at the inlet 211 directed into the interior of the suction system 21. This movement can be performed according to various possible transport modes: dense phase mode, dilute phase mode, etc. For this purpose, the powder concentration and gas flow rate in the circulation pipe can be controlled.

[0108] While the circulation system allows wet powder to move, the suction system extracts moisture from the powder's gaseous surroundings, resulting in faster and more efficient drying of the powder overall. During powder circulation, the moisture-laden air is exhausted and dry gas is injected into the circulation loop.

[0109] In particular, air containing moisture can be discharged via the first discharge line 23 or the third discharge line 353 .

[0110] As a result, the wet gas is extracted from the circulation loop and replaced by dry gas. The humidity of the gas and powder contained in the circulation loop tends to decrease. Furthermore, since the powder is in motion, there is dynamic contact between the powder particles and the drying gas, which tends to accelerate the drying of the powder.

[0111] The absence of moving mechanical elements (e.g. mixers) immersed in a reservoir containing the powder means that the drying device does not interfere with the correct operation of the additive manufacturing equipment.

[0112] During a second step E2 , one or more humidity sensors acquire measurements to measure the humidity level in the circulation circuit.

[0113] The sensor 202 can measure the humidity level in the circulation loop directly at the main hopper 29. In case of a large amount of powder contained in the main hopper, the humidity sensor 202 gives an indication that changes relatively slowly over time.

[0114] Sensors 201 and 203 can respectively obtain humidity measurements on the first discharge line 23 of the suction system 21 and humidity measurements on the inlet channel of the dry inert gas supply system 36. The combination of these measurements makes it possible to assess the humidity level in the circulation loop. The humidity sensors 201 and 203 can be used in combination to then provide an indication of the humidity of the powder that has circulated in the powder. This indication changes relatively quickly over time. On the other hand, in the case where a large amount of powder is contained in the supply module (especially the main hopper 29), the humidity sensors 201 and 203 only provide an indication of the humidity of the volume fraction of the powder that has been moved, and only provide indirect information about the overall humidity of the powder.

[0115] The second step E2 makes it possible to monitor the evolution of the humidity level in the circulation circuit over time and to assess whether it is necessary to continue the drying process.

[0116] During the third step E3, the measured humidity level is compared with a threshold level. Typically, the threshold level is the humidity level of the powder's gaseous environment, at which the powder moving in the circulation loop has a sufficiently low humidity level to be useful for manufacturing. The threshold level can typically be equal to 5% relative humidity at a temperature of 25 degrees Celsius.

[0117] The step of comparing the measured moisture level with the threshold level can be performed by an operator or automatically by the control unit.Depending on the result of the comparison step, the powder is moved or not.

[0118] During the fourth step E4, the sieve sieves the powder circulating in the circulation loop. More specifically, the circulating powder reaches the sieve, which sieves the incoming powder.

[0119] The sieving step allows the powder to move and separate it in a dry gas atmosphere, which can further accelerate the drying of the powder.

[0120] During the fifth step E5, the circulation system terminates the movement of the powder through the circulation loop. Once the powder is deemed sufficiently dry, the circulation of the powder is stopped. Therefore, the result of the third comparison step E3 is used to initiate the fifth step. The third and fifth steps E3 and E5 allow for precise quantitative thresholds to be used to terminate the drying process.

Claims

1. Additive manufacturing equipment (1), including: A supply module (2) for supplying additive manufacturing powder, the supply module (2) comprising: - a main hopper (29) for storing additive manufacturing powder, - an inlet (211) of the supply module (2), a glove box (25) designed to accommodate the container (28), said glove box (25) being closable in a leaktight manner, - a supply line configured to transfer the powder located in the glove box (25) to the main hopper (29), A manufacturing module (4) is separated from the supply module (2) and is configured to additively manufacture an object from powder located in a main hopper (29), wherein the main hopper (29) is connected to the manufacturing module (4) via a manufacturing pipe (392), and an inlet (211) of the supply module (2) is connected to the manufacturing module (4) via a first recovery pipe (531), wherein the inlet is configured to receive the powder located in the manufacturing module (4). The device (1) is characterized in that the supply module (2) further comprises a circulation system, the circulation system being designed to move the powder according to a self-closed circulation loop, the circulation system comprising a suction system (21) remote from the main hopper (29), the suction system (21) being designed to exhaust the gas present in the circulation loop, the circulation loop passing through the main hopper (29) and the suction system (21), the suction system (21) being configured to suck the powder from the main hopper (29) towards the suction system (21) via a return line (391); Wherein, the circulation loop comprises: - a reservoir (37) situated below the main hopper (29) and comprising an outlet (371) designed to be connected to the manufacturing module (4) through said manufacturing conduit (392), - said return line (391) configured to redirect the additive manufacturing powder located in the reservoir (37) towards the inlet (211) of the supply module (2), The circulation system is designed to draw powder from the outlet (371) of the reservoir (37) toward the inlet (211) of the supply module (2), The suction system (21) includes a gas exhaust line (23), and the gas exhaust line (23) includes a vacuum pump for generating suction to discharge air containing moisture in the circulation loop. The supply module (2) further includes a dry inert gas supply system (36), and the dry inert gas supply system (36) is designed to supply dry inert gas to the circulation loop below the main hopper (29).

2. The device (1) according to claim 1, wherein The supply module (2) comprises humidity sensors (201, 202, 203) designed to measure the humidity level in the circulation loop.

3. The device (1) according to any one of claims 1 to 2, wherein The supply module (2) comprises a screen (35) located above a reservoir (37).

4. The device (1) according to claim 3, wherein The powder passing through the circulation loop passes through the main hopper (29), the sieve (35), the storage (37), the return line (391) and the suction system (21) in sequence. The first moisture sensor (202) is designed to measure the moisture level in the main hopper (29).

5. The device (1) according to claim 1, wherein The supply module (2) comprises a second humidity sensor (201) placed on the gas exhaust line (23) and a third humidity sensor (203) connected to the dry inert gas supply system (36).

6. The device (1) according to any one of claims 1 to 5, wherein The supply module (2) comprises: an extraction line, distinct from the supply line and configured to transfer additive manufacturing powder from the inlet (211) of the supply module (2) to the container when the container is housed in the glove box (25), said extraction line comprising a flow divider (27, 30), - a bypass line (31) connecting the diverter (27, 30) to the reservoir (37) and designed to transfer powder directly from the diverter (27, 30) to the reservoir (37), said diverter (27, 30) being able to be configured as follows: - an extraction configuration, wherein additive powder coming from the inlet (211) of the supply module (2) is selectively redirected to the glove box (25), - a loop-back configuration, wherein additive powder coming from the inlet (211) of the supply module (2) is selectively redirected into a bypass line (31), The flow diverters (27, 30) are arranged in a loop configuration as the circulation system moves powder from the outlet (371) of the reservoir to the inlet (211) of the manufacturing module (2).

7. The device (1) according to claim 1, wherein The manufacturing module (4) comprises a recovery system (53, 55) for recovering powder that has not solidified during the additive manufacturing of the object and redirecting the recovered powder to an inlet (211) of the supply module (2).

8. Method (P) for drying powder for additive manufacturing using a supply module (2) of an apparatus (1) according to any one of claims 1 to 7, comprising a step (E1) of circulating the powder in a circulation loop using a circulation system when the powder is present in a main hopper (29).

9. Drying method (P) according to claim 8, using the supply module (2) of the device (1) according to claim 3, comprising the following steps: - a step (E2) of measuring the humidity level in the circulation loop, - a step (E3) of comparing the measured humidity level with a threshold level, - a step (E5) of stopping the circulation of the powder, the step (E5) of stopping the circulation being carried out according to the result of the comparison step (E3).

10. Drying method according to claim 8 or 9, using a supply module (2) of a device (1) according to claim 4, comprising a step (E4) of sieving the powder entering the circulation.

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