Module for supplying powder for additive manufacturing that enables drying of the powder

Abstract

A supply module (2) for supplying additive manufacturing powder, a main hopper (29) for storing powder for additive manufacturing, the main hopper (29) being designed to be connected to a manufacturing module (4) configured to additively manufacture an object from the powder located in the main hopper (29); an inlet (211) of the supply module (2), connected to the production module (4) and designed to receive the powder located in the production module (4); In a supply module (2) comprising: The supply module (2) further comprises: a glove box (25) designed to receive the container (28) and capable of being sealed; a feed circuit configured to transfer powder located within the glove box (25) to a main hopper (29); - a circulation system designed to move powder according to a circulation loop that is closed on itself, including a suction system (21) remote from a main hopper (29), the suction system (21) being designed to exhaust gases present in the circulation loop, the circulation loop passing through the main hopper (29) and the suction system (21); Equipped with.

Description

Technical Field

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

Background Art

[0002] Selective additive manufacturing generates three-dimensional objects by solidifying selected areas in successive layers of powdery materials (such as metal powders, ceramic powders, etc.).

[0003] When the additive manufacturing powder loaded into an additive manufacturing machine has a high level of humidity, the parts made from this powder are often of low quality and have defects.

[0004] For this purpose, an additive manufacturing machine can include a drying system. Conventionally, the drying system includes a heating element for raising the temperature of the powder. There is also a vacuum system for extracting moisture from the powder. Another solution is to use a mechanical element suitable for immersing and stirring or steering the powder inside a reservoir that contains the powder. These different solutions can be implemented individually or collectively. These different solutions are not efficient enough or significantly interfere with the normal operation of the additive manufacturing machine.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to propose an additive manufacturing machine that enables more efficient drying of powder without interfering with the normal operation of the additive manufacturing machine.

Means for Solving the Problems

[0006] An object of the present invention is, within the context of the present invention, a module for supplying additive manufacturing powder, A main hopper for storing additive manufacturing powder, designed to be connected to a manufacturing module configured to additively manufacture an object from the powder located within the main hopper, the main hopper, An inlet of a supply module, designed to be connected to the manufacturing module and receive the powder located in the manufacturing module, the inlet, A glove box designed to receive a container and capable of closing in a sealed state, the glove box, A supply circuit configured to transfer the powder located within the glove box to the main hopper, the supply circuit, A circulation system designed to move the powder according to a self - contained closed circulation loop, including a suction system remote from the main hopper, the suction system being designed to exhaust the gas present in the circulation loop and passing through the main hopper and the suction system, the circulation system, is achieved by a module comprising.

[0007] On the one hand, a circulation system that enables the movement of moist powder, and on the other hand, a suction system that enables the suction of moisture from the gas environment of the powder, enables the powder to be dried more rapidly and effectively overall. For example, movable mechanical elements immersed in a reservoir containing the powder, such as a mixer, are not used, which means that the drying means does not interfere with the normal operation of the additive manufacturing machine.

[0008] Such a device is advantageously complemented by the following various features or steps considered alone or in combination. That is, the circulation loop, includes a reservoir located below the main hopper and designed to be connected to the manufacturing module by a manufacturing conduit, the reservoir having an outlet, a return circuit configured to re - orient the additive manufacturing powder located within the reservoir towards the inlet of the supply module, and includes, the circulation system is designed to suction the powder from the outlet of the reservoir towards the inlet of the supply module, A dry inert gas supply system designed to supply dry inert gas to a circulation loop below the main hopper, A moisture sensor designed to measure the humidity level in the circulation loop, A sieve located above the reservoir, including The powder passing through the circulation loop sequentially passes through the main hopper, sieve, reservoir, return circuit and suction system. The first moisture sensor is designed to measure the humidity level in the main hopper. Including a second moisture sensor placed on the gas exhaust circuit of the suction system and a third moisture sensor connected to the dry inert gas supply system. An extraction circuit different from the supply circuit, configured to transfer additive manufacturing powder from the inlet of the supply module to the container when the container is received in the glove box, the extraction circuit including a diverter. A bypass circuit designed to connect the diverter to the reservoir and transfer powder directly from the diverter to the reservoir. including The diverter An extraction configuration in which the additive manufacturing powder coming from the inlet of the supply module is selectively reoriented towards the glove box, A loop-back configuration in which the additive manufacturing powder coming from the inlet of the supply module is selectively reoriented to the bypass circuit. is configurable to The diverter is configured in a loop-back configuration when the circulation system is moving powder from the outlet of the reservoir towards the inlet of the manufacturing module.

[0009] The present invention also relates to A supply module for supplying powder for additive manufacturing as described above, A manufacturing module configured to additively manufacture an object from the powder located in the main hopper, wherein the main hopper is connected to the manufacturing module and the inlet of the supply module is connected to the manufacturing module. relates to an additive manufacturing machine comprising.

[0010] Advantageously, although optionally, the manufacturing module of the apparatus can be complemented by a recovery system for recovering powder that has not solidified while the object is being additive manufactured and reorienting the recovered powder to the inlet of the supply module.

[0011] The present invention also relates to a method for drying a powder for additive manufacturing using the supply module described above, the method comprising circulating the powder in a circulation loop using a circulation system when the powder is present in the main hopper.

[0012] Advantageously, although optionally, the method may include the following various steps, performed alone or in combination: That is, measuring the humidity level in the circulation loop, comparing the measured humidity level with a threshold value, stopping the circulation of the powder, the step of stopping the circulation according to the result of the comparison step, screening the circulated powder, and can be complemented by.

[0013] Further features and advantages of the present invention will become more apparent from the following description, which is purely illustrative and non-limiting and should be read in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0015] FIG. 1 is a diagram showing an additive manufacturing machine 1 including a powder supply module 2 and a manufacturing module 4.

[0016] (Supply module) At its upper part, the supply module 2 comprises a suction system 21 connected to a first gas discharge circuit 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 a suction force directed towards the inside of the suction system 21 at the inlet 211. The first gas discharge circuit 23 can comprise a vacuum pump for generating the suction force. The suction system 21 is designed to receive and store the additive manufacturing powder from the inlet 211. The stored powder is located at the bottom of the suction system 21 and can be taken out via the outlet 213. The suction system 21 can comprise a powder filter so that the powder does not enter the first gas discharge circuit 23. The suction system 21 comprises a device that enables the separation of the powder from the gas, such as a cyclone filter 22 for example. Other devices for separating the powder from the gas include a filter chamber containing a filter, a cyclone or a discharge box, etc.

[0017] The supply module 2 comprises a housing 25 located below the suction device 21. The housing 25 includes various walls that define a chamber. The housing 25 can be closed so that the chamber is an airtight sealed volume with respect to the outside of the device. The housing is designed to be able to move and handle an object disposed inside the housing. Specifically, the housing comprises a tool for moving and handling an object inside the chamber while the chamber is closed.

[0018] The housing 25 can in particular be a glove box. In this case, the housing has two orifices through which the glove 251 is provided so that the fluid tightness of the housing is maintained. The glove 251 is a device for moving and handling an object within the chamber while the chamber is closed. By wearing the glove 251, an operator can handle an object located inside the glove box 25 from outside the glove box. One wall of the glove box can be made transparent so that the operator can observe the object being handled.

[0019] In particular, the object can be a container or pot 28 designed to contain an additive manufacturing powder. The container or pot can be closed by a lid.

[0020] The device of the housing is designed to move and close the container or pot 28 within the chamber while the chamber is closed.

[0021] One of the walls of the housing 25 has a first door 253. The first door 253 is movable between an open position where the container can move into or out of the chamber from outside the device and a closed position where the chamber is sealed off from outside the device. The first door 253 can be closed so that the housing is airtight separated from the outside. It is also possible to move the lid in and out to close the container or pot.

[0022] The housing 25 can be provided with a passage area 255 where one or more containers can be temporarily stored and stacked.

[0023] The housing 25 can include an oxygen sensor 257. The sensor 257 is designed to measure the oxygen fraction within the housing.

[0024] The housing 25 can include a supply circuit 259 for supplying air and a supply circuit 2511 for supplying an inert gas. The inert gas can be, in particular, dinitrogen or argon.

[0025] The housing 25 can include a second gas discharge circuit 2513 that can be equipped with a vacuum pump for generating a suction force.

[0026] The assembly of the supply circuit 259 for supplying air, the supply circuit 2511 for supplying an inert gas, and the second gas discharge circuit 2513 defines a gas stream control system that enables control of the oxygen fraction and the inert gas fraction within the chamber.

[0027] The supply module 2 includes a metering system 27 located below the suction system 21. The metering system 27 is connected to the outlet 213 of the suction system 21. The powder stored within the suction system 21 and located at the bottom of the suction system 21 can be extracted towards the metering system 27 via the outlet 213.

[0028] A valve 24 is arranged between the suction system 21 and the metering system 27. The valve 24 in the open configuration allows the passage of the powder, and the valve 24 in the closed configuration enables separation of the suction system 21 from the metering system 27 in a sealed state. When the suction system 21 is sucking the powder, the valve 24 is closed, and suction occurs only at the inlet 211 and is directed towards the interior of the suction system 21. The closing of the valve 24 can be automatically triggered by initiating the suction of the powder into the suction system 21.

[0029] The metering system 27 enables separation of an accurate amount of powder from the powder stored within the metering system. This accurate amount can be supplied to the outlet 271 of the metering system 27. The outlet 271 is disposed inside the housing 25 and has a valve 28. The valve 28 in the open configuration can allow the powder to pass from the metering system 27 into the interior of the housing 25, and the valve 28 in the closed configuration can separate the metering system 27 from the interior of the housing 25 in a sealed state.

[0030] The valve 28 is closed, in particular, when the first door 253 of the housing 25 is in the open position.

[0031] The metering system can be, for example, a metering screw. The metering screw is housed in a barrel that extends in a direction that is conventionally horizontal. When the screw is operated and the powder flows from the suction device 21 through the open valve 24 into the metering device 27, the powder is conveyed by the screw towards the outlet 271 in the direction in which the barrel extends.

[0032] Also, the metering system can be an airlock including two valves. The airlock has a predetermined volume and can isolate an accurate amount of powder when the powder is filled through the first valve located on the side of the suction device 21.

[0033] Thereafter, a certain volume of powder can be transferred to the housing 25 through the second valve located on the side of the housing 25.

[0034] The housing 25 can be provided with a transfer area designed to receive a powder container below the outlet 271 of the metering system 27 inside the housing 25.

[0035] The supply module 2 includes a main hopper 29 located below the housing 25. The main hopper 29 is a container that can store additive manufacturing powder.

[0036] The main hopper 29 has a volume with a frustoconical shape and is designed to store a large amount of manufactured powder. The main hopper 29 is oriented such that the axis of the frustoconical shape is vertical and the volume of the frustoconical shape 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.

[0037] The housing 25 is disposed between the chamber and the main hopper 29 and includes a second door 291 movable between an open position allowing the powder located in the chamber to be transferred to the main hopper 29 and a closed position separating the chamber from the main hopper 29 in a sealed state.

[0038] 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 hermetically opened and closed in a controlled manner. The passage can be oriented vertically and made wide enough so that an operator can empty the contents of a powder pot from the housing 25 into the main hopper 29.

[0039] The supply module 2 includes a diverter. The diverter includes one inlet and two outlets.

[0040] The inlet of the diverter 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 diverter is the outlet 271 of the metering system 27.

[0041] The second outlet of the diverter passes vertically through the metering system 27. 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 the bypass circuit 31. The bypass flow path 31 directly connects the second outlet of the diverter and the main hopper 29. The bypass channel 31 is oriented vertically and can pass through the glove box. The powder passing through the bypass circuit 31 does not reach any wall of the housing 25 and does not come into direct contact with the atmosphere of the housing 25. Specifically, when the valve 28 is closed, the powder passing through the bypass circuit 31 does not contact the atmosphere of the housing 25.

[0042] The second outlet is controlled by the valve 30. In the open configuration of the valve 30, it allows the powder to pass from the metering system 27 towards the bypass channel 31, and in the closed configuration of the valve 30, it blocks the passage of the powder from the metering system 27 towards the bypass channel 31.

[0043] It is also possible to configure the diverter in an extraction configuration, in which case the powder at the outlet of the metering system is selectively oriented towards the glove box 25. In this configuration, the valve 30 is in the closed configuration, and the metering screw is operationally set to convey the powder towards the outlet 271 of the metering system.

[0044] It is also possible to configure the diverter in a loop-back configuration, in which case the powder at the outlet of the metering system 21 is selectively oriented towards the second outlet of the diverter. In this configuration, the valve 30 is in the open configuration and the metering screw is in a stationary state.

[0045] Therefore, the diverter can be regarded as being formed by the metering system 27 and the valve 30.

[0046] The supply module 2 includes a metering device 33 disposed below the main hopper 29. The metering device 33 enables adjustment of the flow rate of the powder sent to the sieve 35 so as not to damage the screen contained inside 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.

[0047] 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. This sieve enables filtering of the powder agglomerates and separation of these agglomerates from the remaining powder within the receptacle 351. The sieve includes a third discharge circuit 353 that can be provided with a vacuum pump for generating a suction force.

[0048] The supply module 2 includes a reservoir 37 located below the sieve 35. The reservoir 37 can be a hopper having a volume with a frustoconical shape designed to store a large amount of powder for manufacturing. This hopper can be oriented such that the axis of the frustoconical shape is vertical and the volume of the frustoconical shape has a smaller horizontal cross-section at the bottom of the hopper. The reservoir 37 has an outlet 371 located at the bottom of the reservoir.

[0049] When the second door 291 is in the open position, it is possible to transfer the powder from the glove box 25 to the reservoir 37. Thereafter, the powder can sequentially pass from the glove box 25 through the main hopper 29, the metering device 33, the sieve 35, and finally the reservoir 37. In this way, it is possible to define a supply circuit configured to transfer the powder located within the glove box 25 to the main hopper 29 or further to the reservoir 37. The second door 291, which defines a passage between the housing and the main hopper and can be hermetically opened and closed in a controlled manner, can open and close the supply circuit.

[0050] The supply module 2 includes a dry inert gas supply system 36. The supply system 36 can supply a stream of dry inert gas in a duct 352 connected to the sieve 35. The stream of dry inert gas passing through the duct 352 is oriented upward from below so as to encounter the powder passing through the sieve from bottom to top. The stream of inert gas reaching the sieve 35 via the duct 352 also diffuses to the upper part of the reservoir 37.

[0051] The duct 352 and the third discharge circuit 353 can be aligned in the same direction such that a stream of inert gas can sequentially pass through the duct 352, encounter the powder passing through the sieve, and finally pass through the third discharge circuit 353 in the same direction.

[0052] The supply system 36 can also supply a stream of dry inert gas in a duct 372 connected to the bottom of the reservoir 37, for example, the outlet 371.

[0053] The outlet 371 of the reservoir is connected to a return circuit 391. The return circuit 391 connects the outlet 371 of the reservoir 37 and the inlet 211 of the suction system 21. The return circuit 391 connects the outlet 371 of the reservoir 37 and the housing 25. It is possible to convey the powder from the reservoir 37 through the suction system 21 towards the powder housing 25. The suction system 21 can suction the powder from the reservoir 37 towards the suction system 21 via the return circuit 391.

[0054] Also, the outlet 371 of the reservoir is connected to a production duct 392. The production duct 392 connects the outlet 371 of the reservoir 37 and the production module 4, enabling the powder contained in the reservoir 37 to be transferred to the production module 4.

[0055] The sieve 35 is arranged directly above the reservoir 37 such that the powder stored in the reservoir 37 and transferred to the production module 4 is sieved as slowly as possible before being sent to the production module 4.

[0056] The reservoir 37 can have a volume smaller than that of the main hopper 29. The role of the reservoir 37 is to store the powder immediately before being conveyed to either the manufacturing module 4 or the suction system 21. The reservoir 37 can be referred to as a buffer hopper.

[0057] The main hopper 29 is designed to accommodate most of the manufacturing powder required for the additive manufacturing of one or more three-dimensional objects. The powder contained in the main hopper 29 is intended to be transferred to the manufacturing module 4. To this end, the main hopper 29 is designed to be connected to a manufacturing module 4 configured to additively manufacture an object from the powder located in the main hopper 29. The main hopper 29 is connected to the manufacturing module by the circulation of the powder passing through the weighing device 33, the sieve 35, the reservoir or buffer hopper 37, and finally the manufacturing duct 392.

[0058] The supply module 2 includes a controller 39 that enables the powder to be diverted from the outlet 371 to the return circuit 391 or the manufacturing duct 392.

[0059] The supply module 2 can include a moisture sensor 201 disposed on the first gas discharge circuit 23. This moisture sensor 201 makes it possible to know the humidity level of the gas discharged by the suction system 21, that is, the humidity level upstream of the inlet 211 of the suction system 21.

[0060] The supply module 2 can include a moisture sensor 202 disposed on the upper part of the main hopper 29. This moisture sensor 202 makes it possible to know the humidity level inside the main hopper 29 and can directly provide information regarding the humidity level of the powder that may be present inside the main hopper 29.

[0061] The supply module 2 can include a moisture sensor 203 connected to the dry inert gas supply system 36. This moisture sensor 203 makes it possible to know the humidity level of the dry inert gas sent to the sieve 35 or the reservoir 37.

[0062] The supply module 2 comprises a circulation system including a suction system 21.

[0063] The suction system 21 can suck powder from the reservoir 37 towards the suction system 21 via the return circuit 391.

[0064] (Manufacturing module) At its upper part, the manufacturing module 4 comprises a second suction system 41 connected to a fourth gas discharge circuit 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 a suction force directed towards the inside of the second suction system 41 at the inlet 411. The inlet 411 of the second suction system 41 is connected to the manufacturing duct 392. The fourth gas discharge circuit 43 can comprise a vacuum pump for generating the suction force. The second suction system 41 can comprise a powder filter so that powder does not enter the fourth gas discharge circuit 43. The second suction device 41 can comprise a device capable of separating powder from gas, such as a cyclone for example. Other devices for separating powder from gas include, for example, a filter and a filter chamber, a cyclone filter, or a discharge box. The second suction device 41 is designed to receive and store additional manufacturing powder from the inlet 411. The stored powder is located at the bottom of the second suction device 41 and can be taken out via the outlet 413.

[0065] The manufacturing module 4 comprises an airlock 45 located below the second suction system 41. The airlock 45 enables the transfer of powder without the printer chamber communicating with the second suction system 41 so as to avoid disturbing the printing enclosure in terms of inerting and pressure.

[0066] The manufacturing module 4 includes a diverging screw 47 and a converging screw 51 arranged one on each side of the housing 49 in which the three-dimensional object is manufactured. The housing 49 is a printer chamber.

[0067] The manufacturing module 4 is provided with a powder recovery system for recovering the powder that has not been diffused and solidified at the end of manufacturing.

[0068] The recovery system can be provided with a suction pipe 53 designed to suck the powder. The suction pipe 53 is provided with a suction nozzle 533 that constitutes the inlet of the suction pipe. The powder is sucked by the nozzle and transferred to the other end of the pipe that constitutes the outlet of the suction pipe 53. The manufacturing machine 1 can be provided with a first recovery duct 531 that connects the outlet of the suction pipe 53 and the inlet 211 of the suction system 21.

[0069] The recovery system can be provided with a surplus air lock 55 designed to recover the powder coming from the converging screw 51.

[0070] The manufacturing apparatus 1 can be provided with a second recovery duct 551 that connects the surplus air lock 55 and the inlet 211 of the suction system 21.

[0071] The surplus air lock 55 enables the transfer of the powder without the printer chamber communicating with the second recovery duct 551 so as to avoid disturbing the printing housing in terms of inactivation and pressure.

[0072] The manufacturing apparatus 1 can also be provided with a second controller designed to circulate the powder in a controlled manner from the recovery system towards the suction system 21. In this regard, the inlet 211 can be referred to as the inlet of the supply module 2, and this inlet is connected to the manufacturing module 4 and is designed to receive the powder disposed within the manufacturing module 4.

[0073] It should be noted that the manufacturing apparatus 1 is provided with sufficient valves at the intersections of the ducts 391, 392, 531, 551 in order to enable the circulation of the powder described herein.

[0074] It should be noted that it is also possible to transfer powder from the inlet 211 to the glove box 25. The powder sequentially passes through the suction system 21, the outlet 213 of the suction system 21, the metering system 27, the diverters 27, 30 configured in an extraction configuration, and finally the glove box 25. More specifically, the powder that reaches the glove box 25 can be poured into a container housed in the glove box 25. In this way, there is an extraction circuit different from the supply circuit, and when the container is received in the glove box 25, it is configured to transfer the additive manufacturing powder from the inlet 211 of the supply module 2 to the container, and the extraction circuit includes the diverters 27, 30.

[0075] (Method for drying additive manufacturing powder) In the initial state, the wet powder is in the main reservoir 37.

[0076] During the first step E1, the circulation system circulates the wet powder in the circulation loop.

[0077] It is possible to define a circulation loop within the supply module 2. The circulation loop passes through the main hopper 29, the sieve 35, the reservoir 37, the return circuit 391, the suction system 21, the bypass channel 31, and again the main hopper 29.

[0078] The inert gas supply circuit 372 connected to the upper and lower parts of the reservoir operates to put the unused powder into the return circuit 391. The suction system 21 operates to generate a suction force directed towards the inside of the suction system 21 at the inlet 211. This operating setting can be carried out according to the dense phase mode, the dilute phase mode, and various other possible transfer modes. The powder concentration in the circulation duct and the velocity of the gas stream can be controlled for this purpose.

[0079] On the one hand, a circulation system that enables the movement of wet powder, and on the other hand, a suction system that enables the suction of moisture from the gas environment of the powder, can dry the powder more quickly and effectively as a whole. While the powder is being circulated, within the circulation loop, the exhaust of air containing moisture and the injection of dry gas are carried out.

[0080] The exhaust of air containing moisture can be carried out, in particular, via the first exhaust circuit 23 or the third exhaust circuit 353.

[0081] Therefore, the wet gas is extracted within the circulation loop and replaced with dry gas. For this reason, the humidity of the gas and powder contained within the circulation loop tends to decrease. Also, since the powder is in motion, the powder particles and the dry gas come into dynamic contact, and the drying of the powder tends to be promoted.

[0082] A movable mechanical element such as a mixer immersed in a reservoir containing powder is not used, which means that the drying means does not interfere with the normal operation of the additive manufacturing machine.

[0083] During the second step E2, one or more moisture sensors acquire measurement values so as to measure the humidity level within the circulation loop.

[0084] With the sensor 202, it becomes possible to directly measure the humidity level within the circulation loop at the level of the main hopper 29. When a large amount of powder is contained in the main hopper, the moisture sensor 202 gives an indication that changes relatively slowly over time.

[0085] The sensors 201 and 203 can respectively obtain the humidity measurement value of the first discharge circuit 23 of the suction system 21 and the humidity measurement value of the inlet channel of the dry inert gas supply system 36. By combining these measurement values, it becomes possible to estimate the humidity level in the circulation loop. The moisture sensors 201 and 203 can be used in combination to provide an index of the humidity of the circulated powder. This index changes relatively rapidly over time. On the other hand, when a large amount of powder is stored in the supply module, particularly the main hopper 29, the moisture sensors 201 and 203 only provide an index of the humidity of the fraction of the volume of the moving powder and only provide indirect information regarding the humidity of the powder as a whole.

[0086] By the second step E2, it becomes possible to monitor the change over time of the humidity level in the circulation loop and estimate whether it is necessary to continue the drying process.

[0087] During the third step E3, the measured level of humidity is compared with a threshold value. Typically, the threshold level is the humidity level of the gas environment of the powder having a humidity low enough for the powder moved in the circulation loop to be used in manufacturing. The threshold level can typically be set equal to 5% relative humidity at a temperature of 25 degrees.

[0088] The step of comparing the measured humidity level with the threshold level can be performed manually by the operator or automatically by the control unit. Depending on the result of this comparison step, the powder will either be moved or not.

[0089] During the fourth step E4, the sieve screens the powder that has entered the circulation in the circulation loop. More specifically, the circulating powder reaches the sieve, and the sieve screens the incoming powder.

[0090] This sieving step enables the separation of the powder by moving it in a dry gas atmosphere, and further promotes the drying of the powder. During the fifth step E5, the circulation system ends the movement of the powder within the circulation loop. When it is determined that the powder is 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 step E3 and the fifth step E5 enable working with an exact quantitative threshold for ending the drying process.

Explanation of Signs

[0091] 1 Additive manufacturing machine 2 Powder supply module 4 Manufacturing module 21 Suction system 25 Glove box 29 Main hopper 211 Inlet

Claims

1. An additive manufacturing machine 1, comprising: a supply module (2) for supplying additive manufacturing powder, the supply module (2) comprising: - a main hopper (29) for storing powder for additive manufacturing; - an inlet (211) of the supply module (2); - a glove box (25) designed to receive a container (28) and capable of closing in a sealed state; - a supply circuit configured to transfer the powder located in the glove box (25) to the main hopper (29); a manufacturing module (4) separate from the supply module (2), configured to additively manufacture an object from the powder located in the main hopper (27), the main hopper (29) being connected to the manufacturing module (4) by a manufacturing conduit (392), and the inlet (211) of the supply module (2) being connected to the manufacturing module (4) by a recovery duct (531), the inlet being configured to receive powder within the manufacturing module (4); The additive manufacturing machine 1 comprises a circulation system designed such that the supply module (2) moves the powder according to a self - contained closed loop, the circulation system including a suction system (21) remote from the main hopper (29), the suction system (21) being designed to exhaust gas present in the circulation loop, the circulation loop passing through the main hopper (29) and the suction system (21), and the suction system (21) being configured to suction powder from the main hopper (29) through a return circuit (391) towards the suction system (21). An additive manufacturing machine (1), characterized in that.

2. The circulation loop comprises: - a reservoir (37) located below the main hopper (29) and designed to be connected to the manufacturing module (4) by a manufacturing conduit (392), including an outlet (371); - the return circuit (391) being configured to re - orient the additive manufacturing powder located in the reservoir (37) towards the inlet (211) of the supply module (2); The circulation system is designed to suction the powder from the outlet (371) of the reservoir (37) towards the inlet (211) of the supply module (2). The additive manufacturing machine (1) according to claim 1.

3. The supply module (2) comprises a dry inert gas supply system (36) designed to supply dry inert gas to the circulation loop below the main hopper (29). The additive manufacturing machine (1) according to claim 2.

4. The supply module (2) further comprises moisture sensors (201, 202, 203) designed to measure the humidity level in the circulation loop. The additive manufacturing machine (1) according to claim 2 or 3.

5. The supply module (2) further comprises a sieve (35) located above the reservoir (37). The additive manufacturing machine (1) according to claim 2 or 3.

6. The powder passing through the circulation loop sequentially passes through the main hopper (29), the sieve (35), the reservoir (37), the return circuit (391) and the suction system (21), and the first moisture sensor (202) is designed to measure the humidity level in the main hopper (29). The additive manufacturing machine (1) according to claim 5.

7. The supply module (2) comprises a second moisture sensor (201) placed on the gas exhaust circuit (23) of the suction system (21) and a third moisture sensor (203) connected to the dry inert gas supply system (36). The additive manufacturing machine (1) according to claim 3.

8. The supply module (2) is an extraction circuit different from the supply circuit, and is configured to transfer additive manufacturing powder from the inlet (211) of the supply module (2) to the container when the container is received in the glove box (25). The extraction circuit includes a diverter (27, 30), - A bypass circuit (31) connecting the diverter (27, 30) to the main hopper (29) and designed to directly transfer the powder from the diverter (27, 30) to the main hopper (29). Comprising The diverter (27, 30) - An extraction configuration in which the additive manufacturing powder coming from the inlet (211) of the supply module (2) is selectively redirected towards the glove box (25), - A loop-back configuration in which the additive manufacturing powder coming from the inlet (211) of the supply module (2) is selectively redirected to the bypass circuit (31). Can be configured to The diverters (27, 30) are configured in the loop-back configuration when the circulation system is moving the powder from the outlet (371) of the reservoir towards the inlet (211) of the supply module (2). The additive manufacturing machine (1) according to one of claims 2 to 7.

9. 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 towards the inlet (211) of the supply module (2). The apparatus (1) according to claim 1.

10. A method (P) for drying powder for additive manufacturing using the supply module (2) of the additive manufacturing machine (1) according to one of claims 1 to 9, the method (P) comprising a step (E1) of circulating the powder in the circulation loop using the circulation system when the powder is present in the main hopper (29).

11. The drying method (P) according to claim 10, using the supply module (2) of the additive manufacturing machine (1) according to claim 4, - a step (E2) of measuring the humidity level in the circulation loop; - a step (E3) of comparing the measured humidity level with a threshold value; - a step (E5) of stopping the circulation of the powder; comprising wherein the step (E5) of stopping the circulation is carried out in response to the result of the comparing step (E3). characterized in that it is a drying method (P).

12. Including a step (E4) of sieving the powder introduced into circulation, using the supply module (2) of the additive manufacturing machine (1) according to claim 5. The drying method according to claim 10 or 11.

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