Powder bed deposition additive manufacturing system

Abstract

The present invention relates to a powder bed deposition additive manufacturing system (1) comprising a build chamber (2) extending along a vertical axis (Z) and a removable container (10) adapted to be inserted into the build chamber (2) in a build configuration and to be removed from the build chamber (2) in a depowdering configuration. The removable container (10) comprises a side wall (20) extending along the vertical axis (Z) and a bottom wall (30) adapted to move along the vertical axis (Z) inside the side wall (20) and comprising a first perforated wall (31) having first orifices (33) configured to be closed in the build configuration and unclosed in the depowdering configuration. Abstract figure: Figure 2

Description

Title of the invention: Powder bed deposition additive manufacturing system Technical field

[0001] This disclosure relates to the field of additive manufacturing of parts. More specifically, this document concerns a system and a method for additive manufacturing by metal or ceramic powder bed deposition, particularly for the aeronautical field, for example for the manufacture of turbomachine parts. Previous technique

[0002] Additive manufacturing processes using powder bed deposition and binder jetting, commonly referred to as binder jetting, are known because these techniques advantageously allow for the easy and rapid production of complex three-dimensional parts. These techniques are particularly used in the aerospace industry for manufacturing complex metal parts.

[0003] Figures IA and IB schematically illustrate a partial cross-sectional view of a binder jetting additive manufacturing machine with two part manufacturing stages 6, respectively. In particular, the binder jetting additive manufacturing process consists successively of a step of depositing a layer of powder 7 onto a build platform 5, followed by a step of selectively spraying a liquid binder through a nozzle to solidify (by binder polymerization) a section of the part 6 in the build plane. The build plane is substantially perpendicular to a vertical axis Z corresponding to the manufacturing direction. The layer of powder 7 is spread transversely onto the build platform 5 by a scraper. The build platform 5 is then moved downwards along the vertical axis Z into a build hopper 4 to allow the deposition of the next layer of powder.The previous steps are repeated successively to form, layer by layer, at least one piece 6, known as the green piece.

[0004] A "depowdering" step is conventionally performed to remove the unsolidified powder and recover the green parts. Subsequently, a debinding step is performed to remove a large portion of the binder from the green parts. At the end of this step, so-called brown parts are obtained, which contain a network of interconnected pores. This network of pores is the source of the fragility of the brown parts and their lack of mechanical strength, making their handling delicate. The brown parts are then subjected to a treatment. thermal in order to eliminate binder residues and ensure the cohesion of the parts by creating strong bonds between particles by diffusion of matter leading to the elimination of porosity and densification of matter, according to a sintering process leading to the obtaining of a sintered part.

[0005] It is understood that it is only after the sintering stage that the parts acquire good mechanical strength and that the green and brown parts are generally very fragile. The depowdering stage is in particular one of the critical stages and can lead to breakage or deformation of the green parts.

[0006] More specifically, a preliminary step known as free powder unloading is typically performed to remove the powder volume, including the green parts, from the build hopper. This step can potentially cause breakage of the green parts due to the forces exerted by the powder on them. Furthermore, this step can involve prolonged exposure of additive manufacturing machine users to high-risk, suspended, free-floating powders.

[0007] Furthermore, a step is then carried out to remove the excess powder from the green parts, for example by techniques using an airflow or mechanical movements. These techniques can also damage the green parts.

[0008] The present document aims to resolve at least in part the problems mentioned above, by proposing an additive manufacturing system by binder jetting and an associated process to improve the depowdering of the manufactured parts and thus limit the risks of damage to the green parts. Summary

[0009] A binder jetting additive manufacturing system is proposed, comprising a build chamber extending along a vertical axis and a removable container adapted to be inserted into the build chamber in a manufacturing configuration and removed from the build chamber in a depowdering configuration. The removable container includes a side wall extending along the vertical axis. Furthermore, the removable container includes a bottom wall adapted to move along the vertical axis within the side wall and comprising a first perforated wall having first orifices configured to be closed in the manufacturing configuration and unclosed in the depowdering configuration. "Closed" means that a powder flow cannot pass through the orifices, and "unclosed" means that a powder flow can pass freely through the orifices.In other words, in the manufacturing configuration, the removable container is advantageously housed within the manufacturing chamber, with the first openings of the first perforated wall sealed. The bottom wall is notably moved downwards along the vertical axis during manufacturing. In the powder removal configuration, the removable container can then be moved out of the manufacturing chamber. For example, in a dust removal zone, the first openings of the first perforated wall can be unblocked to allow the powder to flow through them. The first perforated wall acts as a sieve, retaining the parts and allowing the powder to flow out of the removable container by gravity.

[0010] Such a system facilitates and improves the depowdering of green parts following their fabrication by successive layering of powder and binder spraying. The removable container allows for the easy removal of a powder block, in which at least one green part is immersed, from the manufacturing chamber and its transfer to a depowdering area. Furthermore, such a removable container can be easily implemented on an existing binder jetting additive manufacturing machine. In the depowdering area, opening the first holes in the first perforated wall facilitates the evacuation of powder through the bottom wall, while limiting the risk of deformation or even breakage of the at least one green part. The removable container allows for the transfer of any green parts, even smaller and / or lighter ones.Furthermore, the removable container is advantageously compatible with depowdering techniques such as immersion in a liquid bath, air blasting, or mechanical vibration. In addition, the removable container described in this disclosure helps limit a user's exposure to powder, for example, during the handling of the binder jetting additive manufacturing system.

[0011] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other.

[0012] A maximum dimension of the first orifices of the first perforated wall is preferably less than, preferably 50%, of a minimum dimension of said at least one part to be manufactured in the removable container.

[0013] The first openings of the first perforated wall may have a shape of circle, ellipse or polygon, for example a quadrangle.

[0014] The first openings of the first perforated wall may have a regular pattern or varied patterns.

[0015] The bottom wall may advantageously include a third wall that is removably attached to the first perforated wall and that comes against the first perforated wall so as to block the first openings of the first perforated wall when the third wall is attached to the first perforated wall. This feature makes it easy to unblock the first openings of the first perforated wall by detaching the third wall from the first perforated wall.

[0016] The third wall can, in particular, come against the first wall, which is perforated on the outside. The outside is understood to mean the opposite of the inside of the removable container.

[0017] The third wall may in particular have a plate shape.

[0018] The third wall can be substantially solid. By solid, it is understood that the third wall does not include any openings that could allow powder to pass through.

[0019] In particular, the first perforated wall can be interposed along the vertical axis between a volume receiving the powder and the third wall.

[0020] The third wall can be movable relative to the first perforated wall. For example, the third wall and the first perforated wall can be connected by sliding relative to each other, for example along an axis substantially perpendicular to the vertical axis. The third wall can be removed by sliding it against the first perforated wall along said axis.

[0021] The third wall and the first perforated wall can be fixed to each other by means of a screw, for example a quarter-turn screw.

[0022] Advantageously, the third wall may include initial protrusions designed to engage with the initial openings so as to close the initial openings of the first perforated wall. In other words, the initial protrusions of the third wall may fit into the initial openings of the first perforated wall. The third wall and the first perforated wall may together form a manufacturing support face oriented towards the interior of the removable container. The manufacturing support face is advantageously flat.

[0023] The bottom wall may include a build platform. A build platform is defined as a platform providing mechanical support for a block formed from powder and the parts. The build platform may also drive the bottom wall along the vertical axis during manufacturing.

[0024] The third wall may include the build platform. In particular, the build platform may form the third wall. The build platform may then be positioned against the first perforated wall so as to seal the first openings of the first perforated wall when the build platform is attached to the first perforated wall. Since additive manufacturing machines using binder jetting generally include a build platform, this feature allows such a build platform to be used, firstly, to provide mechanical support for the block formed from powder and parts and, secondly, to seal the first openings of the first perforated wall.

[0025] Alternatively, the third wall can be interposed between the first perforated wall and the manufacturing platform. The third wall can, in particular, rest on the manufacturing platform, and specifically be removably attached to the manufacturing platform.

[0026] The side wall may advantageously include a second perforated wall comprising second openings configured to be closed in the manufacturing configuration and unclosed in the depowdering configuration. This technical feature allows the depowdering operation to be carried out through the side wall of the removable container.

[0027] The second perforated wall can be perforated according to the same pattern or according to a different pattern than the first perforated wall.

[0028] A maximum dimension of the second orifices of the second perforated wall is preferably less than, preferably 50%, of a minimum dimension of said at least one part to be manufactured in the removable container.

[0029] The second openings of the second perforated wall may have a circular, elliptical or polygonal shape, for example a quadrangle.

[0030] The second openings of the second perforated wall may have a regular pattern or varied patterns.

[0031] The side wall may include a fourth wall removably fixed against the second perforated wall so as to close the second orifices in the manufacturing configuration and to unclose the second orifices in the depowdering configuration.

[0032] The fourth wall can be removably brought against the second wall, which is perforated from the outside.

[0033] The fourth wall may advantageously include second protrusions designed to engage in the second orifices so as to close the second orifices of the second perforated wall. In particular, the fourth wall and the second perforated wall may form a flat inner periphery, that is, oriented towards the interior of the removable container.

[0034] The second openings can be provided in a lower part of the second perforated wall along the vertical axis. The lower part of the second perforated wall can, in particular, extend from a lower end of the second perforated wall to a height of less than 75%, preferably 50%, of the height of the side wall.

[0035] The side wall may include means for retaining the bottom wall. The bottom wall can thus be held by the side wall during transfer of the removable container to the dusting area.

[0036] The side wall may include a shoulder at its lower end, against which the bottom wall is designed to rest. This feature helps maintain the vertical position of the bottom wall. In particular, the first perforated wall may rest against the shoulder. The first perforated wall can thus be held in place by the side wall during dust removal.

[0037] The system according to this disclosure may advantageously include means for hermetically sealing the top opening of the removable container. The hermetically sealing means may include a cover intended to be fitted against the upper periphery of the removable container. The cover may, for example, be attached to the removable container by means of a retaining collar.

[0038] The bottom wall can advantageously be driven along the vertical axis by a moving element removably mounted on the bottom wall. The moving element may, in particular, consist of a piston, for example, mounted on the bottom wall by means of a thread and a tapped hole. The piston may carry the tapped hole and the bottom wall the thread. Conversely, the piston may carry the thread and the bottom wall the tapped hole.

[0039] The removable container is advantageously fixed, in the manufacturing configuration, to the manufacturing enclosure and / or to a frame of the additive manufacturing system by a mechanical, magnetic, suction cup, or adhesion means of retention.

[0040] According to another aspect, an additive manufacturing process by binder jetting and depowdering is proposed for the system as previously described. The process comprises:

[0041] - insert the removable container into the manufacturing enclosure,

[0042] - to manufacture at least one green part by successively depositing layers of powder and binder projection into the removable container while sliding the bottom wall downwards along the vertical axis,

[0043] - remove the removable container from the manufacturing enclosure,

[0044] - unblock the first perforated wall.

[0045] The powder can thus flow through the first perforated wall.

[0046] Advantageously, unblocking the first perforated wall may include separating the third wall from the first perforated wall.

[0047] The process according to this disclosure may include an additional step of removing excess powder.

[0048] The manufacturing process is carried out using an additive manufacturing process by binder jetting. Green parts manufactured using this process are fragile due to the lack of powder fusion. In this context, the process described in this disclosure offers the considerable advantage of simplifying powder removal while limiting potential deformation and breakage of the green parts. Furthermore, the process described in this disclosure reduces powder removal time and therefore associated costs. Brief description of the drawings

[0049] Other features, details and advantages will become apparent from the detailed description below and from the analysis of the accompanying drawings, in which Fig. IA and IB are shown.

[0050] [Fig. IA] and [Fig. IB] schematically illustrate partial cross-sectional views of a conventional binder jetting additive manufacturing machine in two manufacturing configurations respectively. Fig. 2A, 2B and 2C

[0051] [Fig. 2A], [Fig. 2B] and [Fig. 2C] schematically illustrate partial cross-sectional views of a binder jetting additive manufacturing system according to an embodiment respectively in two manufacturing configurations and in a depowdering configuration. Fig. 3

[0052] [Fig.3] schematically illustrates an example of a first wall perforated according to a method of implementation. Fig. 4

[0053] [Fig.4] schematically illustrates another example of a first wall perforated according to a method of implementation. Fig. 5A, 5B and 5C

[0054] [Fig. 5A], [Fig. 5B] and [Fig. 5C] schematically illustrate partial cross-sectional views of a binder jetting additive manufacturing system according to another embodiment respectively in two manufacturing configurations and in a depowdering configuration. Description of the implementation methods

[0055] Reference is now made to Figures 2A, 2B, and 2C, which schematically represent partial cross-sectional views of a first example of an additive manufacturing system 1 according to this document, respectively at two time points in a manufacturing configuration (Figures 2A and 2B) and in a depowdering configuration ([Fig. 2C]), and to Figures 5A, 5B, and 5C, which schematically represent partial cross-sectional views of a second example of an additive manufacturing system 1 according to this document, respectively at two time points in the manufacturing configuration (Figures 5A and 5B) and in the depowdering configuration ([Fig. 5C]). System 1 is suitable for implementing a binder jetting additive manufacturing process. Preferably, such a system 1 can be used to produce parts in the aerospace industry.

[0056] The manufacturing configuration relates in particular to a phase of forming at least one part 6 in a volume of powder 7 and the depowdering configuration aims in particular to free said at least one part 6 from the powder 7.

[0057] The system comprises a manufacturing chamber 2 extending along a vertical axis Z and a removable container 10 suitable for insertion into the manufacturing chamber 2 in the manufacturing configuration and for removal from the manufacturing chamber 2 in the powdering configuration. The vertical axis Z corresponds in particular to the manufacturing direction.

[0058] The removable container 10 comprises a side wall 20 extending along the vertical axis Z and a bottom wall 30 that is able to move along the vertical axis Z inside the side wall 20. The side wall 20 may, in particular, come against an internal lateral surface of the manufacturing enclosure 2. The bottom wall 30 may advantageously be driven along the vertical axis Z by a moving element 3 removably mounted on the bottom wall 30. The moving element 3 may, in particular, consist of a piston, for example, mounted on the bottom wall 30 by means of a thread and a tapped hole. The piston may carry the tapped hole and the bottom wall the thread. Conversely, the piston may carry the thread and the bottom wall the tapped hole.

[0059] The removable container 10 can advantageously be fixed, in the manufacturing configuration, to the manufacturing enclosure 2 and / or to a frame of the additive manufacturing system 1 by a mechanical holding means, by suction cup, or by adhesion.

[0060] In the manufacturing configuration, the process includes successive steps of depositing a layer of powder 7 onto the bottom wall 30 in the manufacturing plane and translating the bottom wall 30 downwards along the vertical axis Z to allow the deposition of the next layer of powder. A binder jet is selectively sprayed onto the powder bed prior to the deposition of the next layer to form a section of the green part. It can be noted that the manufacturing plane is substantially perpendicular to the vertical axis Z. The preceding steps are repeated successively to form, layer by layer, the said at least one green part 6. Figures 2A and 2B represent, in particular, two successive moments in the manufacturing of parts in the first example of system 1. Similarly, Figures 5A and 5B represent, in particular, two successive moments in the manufacturing of green parts in the second example of system 1.Figures 2B and 5B correspond in particular to the end of the manufacturing of the green parts in manufacturing enclosure 2.

[0061] Furthermore, the bottom wall 30 comprises a first perforated wall 31 having first orifices 33 configured to be closed in the manufacturing configuration and unclosed in the depowdering configuration. "Closed" means that a powder flow cannot pass through the orifices, and "unclosed" means that a powder flow can pass freely through the orifices.

[0062] Thus, in the manufacturing configuration, the removable container 10 is advantageously housed in the manufacturing enclosure 2, and the first orifices 33 of the first perforated wall 31 are closed (Figures 2A and 2B, and 5A and 5B). In the In the depowdering configuration, as illustrated in Figures 2C and 5C, the removable container 10 can be moved out of the manufacturing enclosure 2, for example into a depowdering zone, and the first orifices 33 of the first perforated wall 31 can be unblocked to allow the powder to flow through the first orifices 33 (powder flow represented by dashed arrows in Figures 2C and 5C). The first perforated wall 31 acts as a sieve by retaining the parts 6 and allowing the powder 7 to flow out of the removable container 10 by gravity.

[0063] Such a system facilitates and improves the depowdering of parts following the production of said green parts by successive deposition of layers of powder and spraying of binder. Indeed, the removable container allows a block of powder, in which at least one green part is immersed, to be easily removed from the manufacturing chamber and moved to a depowdering zone. Furthermore, such a removable container can be easily implemented on an existing additive manufacturing machine. In the depowdering zone, the opening of the first holes in the first perforated wall facilitates the evacuation of powder through the bottom wall, while limiting the risk of deformation or even breakage of said at least one green part. The removable container also makes it possible to manufacture smaller and / or lighter parts.Furthermore, the removable container is advantageously compatible with depowdering techniques such as immersion in a liquid bath, air blasting, or mechanical vibration. In addition, the removable container described in this disclosure helps limit a user's exposure to powder, for example, during handling of the additive manufacturing system.

[0064] The bottom wall 30 may advantageously include a third wall that is removably attached to the first perforated wall 31 and that abuts the first perforated wall 31 so as to block the first openings 33 of the first perforated wall 31 when the third wall is attached to the first perforated wall 31. In particular, the third wall may abut the first perforated wall 31 from the outside. The outside is understood to mean the opposite side from the inside of the removable container. This feature makes it easy to unblock the first openings 33 of the first perforated wall 31 by detaching the third wall from the first perforated wall 31.

[0065] The third wall may in particular have a plate shape.

[0066] The third wall can be substantially solid. By solid, it is understood that the third wall does not include any openings that could allow powder to pass through.

[0067] In particular, the first perforated wall 31 can be intercalated along the vertical axis between a volume receiving the powder and the third wall.

[0068] The third wall can be movable relative to the first perforated wall 31. For example, the third wall and the first perforated wall 31 can be in a sliding connection relative to each other, for example along an axis substantially perpendicular to the vertical axis Z. The third wall can thus be removed by sliding it against the first perforated wall 31 along said axis.

[0069] The third wall and the first perforated wall 31 can be fixed to each other by means of screws, for example a quarter-turn screw.

[0070] Advantageously, the third wall may include first protrusions intended to engage in the first orifices so as to close the first orifices 33 of the first perforated wall 31. In other words, the first protrusions of the third wall may fit into the first orifices 33 of the first perforated wall 31. The first protrusions may in particular extend in projection along the vertical axis Z.

[0071] The third wall and the first perforated wall 31 can together form a manufacturing support face 35 oriented towards the inside of the removable container 10. The manufacturing support face 35 is advantageously flat.

[0072] Preferably, the bottom wall 30 may include a manufacturing platform 32. A manufacturing platform 32 is defined as a platform providing mechanical support for a block formed from powder and the parts. The manufacturing platform 32 may also drive the bottom wall 30 along the vertical axis during manufacturing.

[0073] The third wall may include the build platform 32. In particular, the build platform 32 may form the third wall. The build platform 32 may then come against the first perforated wall 31 so as to close the first openings 33 of the first perforated wall 31 when the build platform 32 is fixed to the first perforated wall 31. Since binder jetting additive manufacturing machines generally include a build platform, this feature allows such a build platform to be used, on the one hand, to provide mechanical support for the assembly formed from powder and green parts and, on the other hand, to close the first openings of the first perforated wall.

[0074] The manufacturing platform 32 may include the first protrusions 34 intended to engage in the first orifices so as to close the first orifices 33 of the first perforated wall 31.

[0075] Alternatively, the third wall can be interposed between the first perforated wall 31 and the fabrication platform 32 (not shown in the figures). The third wall can, in particular, rest on the fabrication platform, and specifically be removably attached to the fabrication platform. In this way, the third wall can advantageously fulfill the function of sealing the first openings of the first perforated wall, and the manufacturing platform can carry the function of mechanical support for the assembly formed from powder and said at least one green piece.

[0076] Figures 3 and 4 schematically illustrate the first perforated wall 31. A maximum dimension d of the first openings 33 of the first perforated wall 31 is preferably less than, preferably 50% of, a minimum dimension of said at least one part to be manufactured in the removable container 10. The first openings 33 of the first perforated wall 31 may, for example, be circular, elliptical, or polygonal, for example, a quadrangle. These shapes are not limiting. Furthermore, the first openings 33 of the first perforated wall 31 may have a regular pattern or varied patterns.

[0077] With reference to figures 2A, 2B and 2C, the side wall 20 can be formed in one piece.

[0078] With reference to Figures 5A, 5B and 5C, the side wall 20 may advantageously include a second perforated wall 21 comprising second openings 22 configured to be closed in the manufacturing configuration and unclosed in the depowdering configuration. This technical feature makes it possible to carry out the depowdering operation through the side wall 20 of the removable container 10, in addition to the bottom wall 30.

[0079] The side wall 20 can be formed of a plurality of second perforated walls when appropriate.

[0080] The second perforated wall 21 can be perforated according to the same pattern or according to a different pattern than the first perforated wall 31.

[0081] A maximum dimension of the second openings 22 of the second perforated wall 21 is preferably less than, preferably 50% of, a minimum dimension of said at least one part to be manufactured in the removable container 10. The second openings 22 of the second perforated wall 21 may be circular, elliptical, or polygonal in shape, for example, a quadrangle. Furthermore, the second openings 22 of the second perforated wall 21 may have a regular pattern or varied patterns.

[0082] The side wall 20 may include a fourth wall 23 removably fixed against the second perforated wall 21 so as to close the second orifices 22 in the manufacturing configuration and to unclose the second orifices 22 in the depowdering configuration.

[0083] The fourth wall 23 can be removably brought against the second perforated wall 21 from the outside. As a reminder, the outside is understood to mean the opposite of the inside of the removable container.

[0084] Furthermore, the fourth wall 23 may include second protrusions 24 designed to engage in the second orifices so as to close the second orifices 22 of the second perforated wall 21. In particular, the fourth wall 23 and the second perforated wall 21 can form an internal periphery, that is to say oriented towards the inside of the removable container, which is flat.

[0085] The fourth wall 23 can be movable relative to the first perforated wall 31. For example, the fourth wall 23 and the second perforated wall 21 can be connected to each other by sliding, for example along the vertical axis Z. The fourth wall 23 can thus be removed by sliding it against the second perforated wall 21 along the vertical axis Z.

[0086] The second openings 22 can be arranged in a lower part of the second perforated wall 21 along the vertical axis Z. The lower part of the second perforated wall 21 can in particular extend from a lower end of the second perforated wall 21 over a height of less than 75%, preferably 50%, of a height of the side wall.

[0087] The side wall 20 may include means for retaining the bottom wall 30 25. The bottom wall 30 can thus be held by the side wall during the transfer of the removable container to the dusting area.

[0088] The side wall 20 may include a shoulder at its lower end, against which the bottom wall 30 is designed to rest. This feature helps maintain the vertical position of the bottom wall 30. In particular, the first perforated wall 31 can rest against the shoulder. The first perforated wall can thus be held in place by the side wall during dust removal.

[0089] The system according to this disclosure may advantageously include means for hermetically sealing 40 of the top opening of the removable container 10.

[0090] For example, the airtight sealing means 40 may include a lid 41 intended to come against an upper periphery 26 of the removable container 10. The lid 41 may, for example, be fixed to the removable container 10 by means of a retaining collar 42.

[0091] Hermetic sealing means can be put in place, in particular, before the removable container is removed to the dust removal area. Thus, during the transfer of the removable container from the manufacturing enclosure to the dust removal area, the removable container is covered. This makes it possible to limit or even prevent the inhalation of loose powders by a user.

[0092] The hermetic sealing means can be maintained or removed during depowdering.

[0093] According to another aspect, an additive manufacturing process by binder jetting and depowdering is proposed for system 1 as previously described. The process comprises:

[0094] - insert the removable container 10 into the manufacturing enclosure 2,

[0095] - to manufacture at least one green part by successively depositing layers of powder and binder projection into the removable container 10 while translating the bottom wall 30 downwards along the vertical axis Z,

[0096] - remove the removable container 10 from the manufacturing enclosure 2,

[0097] - unblock the first perforated wall 31.

[0098] The powder can thus flow through the first perforated wall 31.

[0099] Advantageously, unblocking the first openwork wall 31 may include separating the third wall from the first openwork wall 31.

[0100] The process may include an additional step of removing excess powder after unblocking the first perforated wall 31.

[0101] The manufacturing process is carried out using an additive manufacturing process by binder jetting. Parts manufactured using this process are brittle due to the absence of fusion and are therefore susceptible to breakage. In this context, the process described in this disclosure offers the considerable advantage of simplifying powder removal while limiting potential deformation and breakage of the parts. Furthermore, the process described in this disclosure reduces powder removal time and therefore associated costs.

[0102] More specifically, the binder jetting additive manufacturing process consists successively of a step involving the deposition of a layer of powder onto the back wall, followed by a step involving the selective spraying of a liquid binder through a nozzle to solidify a section of the part in the build plane. The back wall is then translated downwards along the vertical Z-axis to allow the deposition of the next layer of powder. The preceding steps are repeated successively to form, layer by layer, at least one part, referred to as a "green part." The green parts are then subjected to a debinding treatment to remove most of the binder. The brown part obtained after debinding is heat-treated to ensure part cohesion and material densification, for example, using a sintering process.

Claims

Demands

1. Binder jetting additive manufacturing system (1) comprising a build chamber (2) extending along a vertical axis (Z) and a removable container (10) capable of being inserted into the build chamber (2) in a build configuration and removed from the build chamber (2) in a depowdering configuration, the removable container (10) comprising a side wall (20) extending along the vertical axis (Z) and a bottom wall (30) capable of moving along the vertical axis (Z) inside the side wall (20) and comprising a first perforated wall (31) having first orifices (33) configured to be closed in the build configuration and unclosed in the depowdering configuration, the system (1) wherein the bottom wall (30) comprises a third wall that is removably attached to the first perforated wall (31) and,which comes against the first perforated wall (31) so as to close the first orifices (33) of the first perforated wall (31) when the third wall (32) is fixed to the first perforated wall (31), the third wall comprising first protrusions (34) intended to engage in the first orifices so as to close the first orifices (33) of the first perforated wall (31), the third wall and the first perforated wall (31) together forming a manufacturing support face (35) oriented towards the interior of the removable container (10), the manufacturing support face (35) being flat.

2. System (1) according to claim 1, wherein the third wall comprises a manufacturing platform (32), the manufacturing platform forming the third wall.

3. System (1) according to any one of claims 1 to 2, wherein the side wall (20) comprises a second perforated wall (21) comprising second orifices (22) being configured to be closed in the manufacturing configuration and unclosed in the depowdering configuration.

4. System (1) according to claim 3, wherein the side wall (20) comprises a fourth wall (23) removably fixed against the second perforated wall (21) so as to close the second ports (22) in the manufacturing configuration and to release the second ports (22) in the depowdering configuration.

5. System (1) according to claim 4, wherein the fourth wall (23) comes removably against the second perforated wall (21) from the outside and includes second protrusions (24) intended to engage in the second orifices so as to close the second orifices (22) of the second perforated wall (21).

6. System (1) according to any one of claims 3 to 5, wherein the second orifices (22) are arranged in a lower part of the second perforated wall (21) along the vertical axis (Z).

7. System (1) according to any one of claims 1 to 6, wherein the side wall (20) may include means for retaining (25) the bottom wall (30).

8. System (1) according to any one of claims 1 to 7, wherein a maximum dimension (d) of the first orifices (33) is less than 50% of a minimum dimension of a part to be manufactured in the removable container (10).

9. System (1) according to any one of claims 1 to 8, comprising means for hermetically sealing (40) the upper opening of the removable container (10).

10. System (1) according to any one of claims 1 to 9, wherein the bottom wall (30) is driven along the vertical axis (Z) by a displacement member (3) removably mounted to the bottom wall (30).

11. Additive manufacturing method by binder jetting and depowdering for the system (1) according to any one of claims 1 to 10, the method comprising: - inserting the removable container (10) into the manufacturing chamber (2), - manufacturing at least one part by successively depositing layers of powder in the removable container (10) and selectively projecting binder while translating the bottom wall (30) downwards along the vertical axis (Z), - removing the removable container (10) from the manufacturing chamber (2), - unblocking the first perforated wall (31).

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