Apparatus for providing powder and method for an additive manufacturing apparatus

Abstract

The invention relates to an apparatus for providing powder (8) in a process chamber of a machine tool, which is designed to build up a workpiece layer by layer by means of applied material layers of the powder (8), the apparatus being designed to collect the powder (8) from a coater (7) after a first coating process and to provide the powder for a further coating process, the coater being designed to apply material layers of powder (8) to a print bed (9) on which the powder (8) is selectively solidified.

Description

[0001] DMG MORI ADDITIVE GmbH 1 August 8, 2025

[0002] Device for supplying powder and method for an additive manufacturing device

[0003] The present invention relates to a device for providing powder in a machine tool for the layer-by-layer additive construction of workpieces and a corresponding method.

[0004] Prior art has revealed primary forming processes for the additive manufacturing of three-dimensional workpieces, in the course of which a workpiece is built up layer by layer from a provided material.

[0005] For this purpose, a powdered material is usually applied as a material layer to a carrier located in a process chamber of a machine tool and then solidified into a workpiece layer by site-specific irradiation, for example by melting or sintering the individual material particles of the material layer.

[0006] Once a workpiece layer has solidified, a new layer of raw material is applied to the substrate or to the already formed workpiece layer, and the area is irradiated again at a specific location. In this way, the workpiece is successively built up layer by layer from a multitude of material layers applied to the substrate.

[0007] During the coating process, a slightly larger quantity of powder (material powder) is typically applied than is geometrically necessary for the desired layer thickness. The excess, unprocessed material is then conveyed, for example, into a discharge opening.

[0008] 220609 PC DMG MORI ADDITIVE GmbH 2 August 8, 2025

[0009] The state of the art demonstrates the removal of powder for subsequent processes using mechanical equipment such as a screw drive. However, such mechanisms negatively impact the manufacturing process, for example through vibration.

[0010] During the manufacturing process, undesirable effects occur that negatively impact the process conditions within the process chamber (main process) and ultimately affect the manufacturing quality. For example, exhaust gases generated during solidification or the stirring up of unsolidified material contaminate the process chamber, and the process chamber is progressively heated by the waste heat generated during irradiation. To maintain optimal process conditions, a process gas flow is typically directed through the process chamber to remove contaminants and waste heat. This process gas flow can be precisely directed through one or more defined inlets and / or outlets.Further openings and extensions in the process chamber, which are necessary for secondary processes, for example, can negatively affect the flow and atmosphere of the main process.

[0011] It is advantageous to minimize disruption to the main process, for example by keeping material flows low. Double coating is beneficial for increasing efficiency, whereby a second layer of powder is applied after an initial coating and, if necessary, exposure or selective hardening of the powder layer. This requires feeding more material into the machine tool's process chamber than is necessary for a single coating.

[0012] One object of the present invention is therefore to increase efficiency while minimizing the impact on the main process. In particular, it can be an object to efficiently provide material powder for a coating process in the process chamber of the machine tool.

[0013] 220609PC DMG MORI ADDITIVE GmbH 3 August 8, 2025

[0014] To solve these problems, the features of the independent claims are proposed. Advantageous further developments are found in the dependent claims. The respective dependent claims relate to preferred embodiments, which can be provided individually or in combination.

[0015] According to one aspect of the invention, a device for supplying powder to a process chamber of a machine tool is provided. The machine tool is designed for the layer-by-layer additive manufacturing of workpieces from layers of material made from powder (material powder). The machine tool is, in particular, a manufacturing system for selective laser melting (SLM).

[0016] Such a machine tool is described, for example, in German patent application number 10 2024 115 864.6, the disclosure of which is hereby fully incorporated by reference. In particular, the locking mechanism and the seals can also be combined with the present invention.

[0017] In the process chamber of the machine tool according to the invention, the powder discharge area, the print bed (located on the coating level), and the powder overflow area can preferably be arranged side by side. Preferably, the powder overflow area can be configured in a first position to receive powder and in a second position to supply powder to the recoater. The coating level or working level can be the level on which powder has been and / or is applied to be fully or partially solidified in a subsequent step. This level can also be the bottom of the process chamber. The powder discharge area for removing powder from the process chamber can separate the process chamber from the area of ​​ancillary processes by one or more active or passive sealing elements. Alternatively or additionally, conventional discharge mechanisms such as a screw conveyor are practical.

[0018] 220609PC DMG MORI ADDITIVE GmbH 4 August 8, 2025

[0019] Preferably, the powder overflow area can be an adjustable powder overflow with respect to the powder volume it can hold, which is arranged next to a powder application area in the process chamber of the machine tool.

[0020] The powder overflow area can be positioned (at least partially, preferably completely) below the coating or working plane next to the print bed, particularly on the side opposite the powder discharge area with respect to the print bed. The powder transport to the overflow area can be carried out by the recoater. By dosing the powder into the process chamber, an amount sufficient for the first coating of the print bed, as well as a small additional amount to compensate for tolerances, for example, can be maintained. The powder dosing into the process chamber can also be dimensioned to allow for a first and second coating of the print bed, and, if necessary, to maintain a small additional amount to compensate for tolerances.For a sealed process chamber, this results in increased efficiency with regard to the number of coating processes per feed or discharge of process material and improved separation of the process chamber from the powder conveying area.

[0021] For the second coating process, the coater can access the powder in the powder overflow area, remove the powder from the overflow area, and distribute it onto the print bed. The process chamber does not need to be opened separately, and the main process is less affected.

[0022] The device can be placed in a provisioning state in which the coater transfers stored powder, in particular onto the print bed for the application of another layer of material powder. The device can be placed in a separate collection state in which the coater cannot transfer stored powder. These states allow the coater to interact with the powder according to the process step described below. Therefore, a first position of the powder overflow area (or powder provisioning device) is advantageously a provisioning state in which the coater can transfer powder stored or collected in the powder overflow area for coating.

[0023] 220609PC DMG MORI ADDITIVE GmbH 5 8 August 2025 A second position of the powder overflow area (or powder supply device) is a collection state in which the coater cannot remove powder stored or collected in the powder overflow area. Thus, the second position of the powder overflow area is, for example, a position in which the powder overflow area can collect excess powder, which is moved, for example, by the coater when applying the coating.

[0024] The device can provide a volume below the coating level in the collection state. This can be achieved by completely or partially lowering geometric components. The device can be elongated in one spatial dimension or, in particular, predominantly linear. For example, a force can be applied to displace an elastic membrane, thus changing its shape. The force can be applied over a surface, at a point, or along a line. Possible mechanisms of action are shown in embodiments 1 to 3. For example, the spatial process can be initiated by a pressure difference between the upper and lower surfaces of an elastic membrane. This pressure difference can potentially drive a connecting rod, possibly via a pneumatic or hydraulic cylinder, which is coupled to an elastic membrane and / or a movable element.A spring element can also be incorporated into the pneumatic or hydraulic cylinder, allowing the powder dispensing mechanism to assume a home position, for example, in the collection or dispensing state. Other operating mechanisms are also conceivable, such as magnetic force, the use of one or more linear motors, or a spindle drive. The powder used (e.g., metal, plastic) can possess individual properties that can be taken into account through the targeted selection of the physical implementation.

[0025] Advantageously, the powder overflow (mechanism or elastic membrane) can be designed to be adjustable with respect to the powder volume it can hold, allowing excess powder to be collected during coating via a lifting motion. Furthermore, with the opposite lifting motion, the powder can be made available again for the coater, for example, for a subsequent coating process.

[0026] 220609PC DMG MORI ADDITIVE GmbH 6 August 8, 2025

[0027] Alternatively or additionally to the elastic membrane, a substantially non-stretchable film or a thin workpiece, for example made of synthetic fibers, metal, or plastic, can be bent by means of a process that bends the side walls, thereby creating a suitable depression in the previously essentially flat upper surface of the powder overflow area. This approach can be supported by prestressing in the coating material, a pressure gradient, or predominantly point or line weights integrated into or on the underside of the material. Preferably, the powder overflow area is designed to be flat or concave on one upper surface so that it can be traversed by the coater without damaging the coater and, in particular, the coater lip.

[0028] Advantageously, the powder supply device can be configured, upon appropriate control, to perform a change of state to switch between the first and second positions. The change of state of the powder overflow area can be achieved by mechanical adjustment and / or by generating a pressure differential. Preferably, the change of state includes at least a vertical movement of a surface, in particular a collection surface, of the powder overflow area. Particularly preferably, in the second position, the collection surface is flush with the process chamber floor or the working plane.

[0029] Furthermore, the machine tool can include one or more powder discharge areas through which powder is removed from the process chamber. The powder discharge area can be sealed off from the powder conveying area, thus impacting the main process and process gas flows less than with conventional discharge areas.

[0030] The surface of the powder overflow area can be essentially smooth, meaning without protruding objects such as edges, and with low surface roughness. Such a design allows for the most complete possible removal of the material powder stored in the overflow area by the coater. Gaps can be designed to minimize residues and the risk of potential contamination during powder changes. This reduces maintenance and setup times.

[0031] 220609PC DMG MORI ADDITIVE GmbH 7 August 8, 2025

[0032] For flexible use, the powder supply mechanism can be designed to be interchangeable. This can be achieved by replacing several subcomponents, such as the membrane. Alternatively, in the case of an integral design housed in a separate casing, the casing itself can be replaced; this casing is part of the machine tool used for layer-by-layer build-up. The latter solution allows for a comparatively simpler design and production process.

[0033] Furthermore, a powder feed can be provided into the powder overflow area. This ensures the coater is equipped with fresh powder material for a subsequent coating process. The risk of contaminated powder entering the additional coating process can be reduced. Preferably, the powder is dosed precisely for both coating directions before the first coating, so that any underdosing in the next cycle can be compensated for.

[0034] The device can also include a powder container, which may be located in the process chamber and is used for storing or transporting powder. If the container is positioned in a fixed location above the powder overflow area, the powder supply can be provided via a discharge mechanism. Material can be supplied to the powder container, for example, via a chute through a powder inlet, which provides the material powder for the first coating process. Additionally or alternatively, at least one further powder supply can be provided, which supplies material powder to the powder container.

[0035] The powder container can be in contact with the coater. Advantageously, the powder container can be permanently attached to the coater and move with it. Loading the powder container with material powder can occur simultaneously with supplying powder to the coater for the first coating process, either via the same powder feeder or via at least one additional powder feeder. Alternatively, or in addition, the supply of material powder to the powder container and the coater for the first coating process can be staggered using the same powder feeder. This can be done in

[0036] 220609PC DMG MORI ADDITIVE GmbH 8 August 8, 2025

[0037] This can be combined with the spatial relocation of the coater and / or the complete or partial unloading of the material powder from the powder container and reloading of the powder container. The loading can also be directed by sliding the powder in front of the coater for the first coating and / or into the powder container.

[0038] A method for supplying powder to a process chamber of a machine tool configured for the layer-by-layer construction of a workpiece using applied layers of powder is proposed. This method comprises a coater configured for applying material layers and a build-up bed on which layers of powder are applied. The method includes a powder supply device comprising a powder overflow area adjacent to the build-up bed, through which powder is supplied to the coater. Furthermore, a method is proposed in which the coater transfers powder from and / or into the powder overflow area.

[0039] One proposed method describes the movement of the coater, which performs a first movement from the side of the powder overflow area facing the printing bed towards the powder overflow area.

[0040] Furthermore, a method is proposed which can determine the positioning of the recoater at the time of the exposure process, in which one or more material layers in the print bed are selectively solidified by local energy input, so that the positioning can be fixed next to or above the powder overflow area.

[0041] This method is advantageous due to the shielding function that the recoater provides to protect the powder overflow area. Potential contamination of the stored powder by material misdirected from the print bed by sparks is prevented. Furthermore, the established flow across the print bed is positively influenced.

[0042] 220609PC DMG MORI ADDITIVE GmbH 9 August 8, 2025

[0043] Another method describes the movement of the recoater, which can perform a further movement from the side of the powder overflow area facing away from the print bed towards the powder overflow area. The described movements can be interrupted and / or performed at variable speeds.

[0044] One method additionally includes a powder container designed for storing and transporting powder. This powder container can also be configured to unload powder at a specific location. Unloading can occur on the side of the powder overflow area facing the print bed, on the opposite side, or into the powder overflow area itself.

[0045] Furthermore, a computer-implemented method is proposed which, when applied to the described machine tool and a controllable computing unit, causes the device to perform at least one or more of the aforementioned process steps.

[0046] Advantageous embodiments and further details of the present invention are described below with reference to various exemplary embodiments and schematic figures. The connection is explained in more detail in the schematic drawings.

[0047] 220609PC DMG MORI ADDITIVE GmbH 10 August 8, 2025

[0048] Brief description of the characters

[0049] Figures 1a to 1c: show exemplary embodiments in the provision and collection states;

[0050] Figures 2a to 2c: show process steps for collecting, inserting and providing powder;

[0051] Figures 3a to 3d: show process steps of the coating process;

[0052] Figures 4a to 4d: show process steps of the coating process of a first modification;

[0053] Figures 5a to 5d: show process steps of the coating process of a second modification;

[0054] Detailed description of preferred embodiments

[0055] Exemplary embodiments of the present invention are described in detail below with reference to exemplary figures. The features of the exemplary embodiments can be combined in whole or in part, and the present invention is not limited to the described exemplary embodiments.

[0056] Figures 1a to 1c show schematic cross-sectional views of the powder dispensing device 1A; 1B; 1C. The upper figures show the device in the dispensing state. The lower figures show the device in the collection state.

[0057] Figure 1a shows the cross-section through the powder supply device 1A in a first embodiment. The powder supply device 1A is part of the machine tool and is typically located in the process chamber. Further

[0058] 220609PC DMG MORI ADDITIVE GmbH 11 August 8, 2025

[0059] The surroundings are described starting from Figure 3a. The upper half of each figure shows the device in its ready-to-use state. In this embodiment, the membrane 2A is elastic, for example made of silicone or rubber. The surface facing the process chamber, in particular, can be coated to modify its properties. Advantageous designs are, for example, low roughness, smooth, and / or antistatic, so that the material powder adheres to the surface only to a reduced extent. The membrane 2A separates the volume above the coating layer from the cavity 13 below. In this application example, the cavity 13 is also sealed from below. A pressure differential can be created between the pressure port 3A and the volume above the membrane 2A.

[0060] In this application example, a pressure differential through pressure port 3A, with a lower pressure inside cavity 13 compared to above membrane 2A, puts the powder supply device 1A into the collection state. Viewed from the top, the membrane 2A is formed into a predominantly concave shape. The cavity 13 shrinks, and the released volume becomes available to the space above. The resulting depression is designed to collect excess material, particularly powder conveyed from the coating unit. In the first embodiment, the depression provides the powder overflow area. The membrane 2A can also be configured such that the collection state is maintained when the pressure is balanced between both sides of the membrane 2A. To bring about this state, a pressure must be applied to pressure port 3A, which is higher in cavity 13 relative to the top of the membrane.

[0061] Membrane 2A is essentially elongated in one spatial dimension. It can be attached to the base block 12A by positive locking and / or frictional locking, for example, by gluing and / or screwing and / or plugging. The latter option allows for easy replacement and facilitates maintenance, or reduces setup time during powder changes. The base block 12A can be integrated into the machine tool or, for example, as a separate, replaceable part. In this illustration, no physical separation such as a joint or screw connection to the machine tool is visualized.

[0062] 220609PC DMG MORI ADDITIVE GmbH 12 August 8, 2025

[0063] Figure 1b shows a modification of the first application example. The fundamental properties of the membrane 2B with respect to surface area or elasticity are comparable to those of the first embodiment in Figure 1a. The shaft 14, through which the connecting rod 5A runs, is integrated into the base block 12B. The distinguishing feature lies in the force applied to change the state between the supply and collection states. The connecting rod 5A is in contact with the membrane 2B on one side and with a pneumatic cylinder 4A on the other. The pneumatic cylinder 4A is designed such that movement of the piston is caused by a change in internal pressure due to fluid supply or discharge at the pressure port 3B. The connecting rod 5A transfers the force to the membrane 2B, which acts as described above and provides the powder overflow area.

[0064] Figure 1c shows another application example of the powder lifting mechanism 1C. A movable element 6, for example a piston, is incorporated into the base block 12C. The movable element 6 can be made of the same material as the base block 12C. The surface can be smooth with respect to its roughness, which has an advantageous effect on powder discharge. The surface is preferably straight or predominantly flat. Other contour variants of the movable element 6 can be convex or concave, preferably concave. Sealing elements can be provided on the surfaces adjacent to the base block 12C, so that, firstly, the process chamber is sealed, and secondly, material powder or other residues remain in the designated volume.The movable element 6 can be made in one piece or in multiple pieces and can, for example, be provided with a mechanism by which the end positions are defined, such as a stop or several stops on the base body 12C.

[0065] The movable element 6 is in contact with the connecting rod 5B. The connecting rod 5B is also in contact with the pneumatic cylinder 4B. The pneumatic cylinder 4B from the third application example differs from the pneumatic cylinder 4A from the second application example by the provision of the spring 15. This spring, also in combination with the mechanism for defining the end positions of the movable element 6, allows the change of state from the provision to the receiving state and / or in reverse order from a pressure differential.

[0066] 220609PC DMG MORI ADDITIVE GmbH 13 8 August 2025 between the chamber to the outside or the chambers in hydraulic cylinder 4B. Depending on the coordination of the described elements, either the collection state or the provision state can be set as a state without external pressure supply.

[0067] Figures 2a to 2c describe the process steps for collecting, inserting, and providing powder using the first embodiment. To reduce complexity, technical features from the above description that are necessary for implementation are omitted below, thus eliminating the need to explain the process.

[0068] Figure 2a shows a cross-section through the powder supply device 1A in its collection state. The membrane 2A is curved and provides a volume below the working plane. This volume is empty, meaning it contains no residue or material powder. To the right of the figure (not shown) are, among other things, the powder feed and discharge, as well as the print bed. The coater 7 has completed the first coating process and is transporting the powder 8 to the left, pushing it across the surface of the base body 12A. The powder 8 is a dose for a further coating, as well as some additive for tolerance compensation.

[0069] Figure 2b shows the powder 8 located in the powder overflow area, which is formed by a recess in the membrane 2A. The powder supply device 1A is in the collection state. The powder was moved into the powder overflow area by the movement of the coater 7. At the time of the illustration, the coater 7 is stationary above the membrane 2A. This position can be chosen to shield the stored powder 8 from the effects of the exposure process on the print bed. Alternatively, the coater 7 could continue moving or, for example, assume a position to the right of the powder overflow area.

[0070] Figure 2c shows in a further step the coater 7 to the left of the

[0071] Powder overflow area and positioned above the base block 12A.

[0072] 220609PC DMG MORI ADDITIVE GmbH 14 August 8, 2025

[0073] Powder supply device 1A has lifted the powder 8 and is in the supply state. The powder 8 can be moved by the coater 7. When the coater 7 moves to the right, the powder 8 that is in the powder overflow area is removed and can be used, for example, for a second coating on the print bed.

[0074] In other words, in this embodiment, sufficient powder for pre- and back-coating can first be metered in front of the coating lip of the coater 7, as shown in Figure 2a. During coating, the mechanism creates a volume that can accommodate the powder not required for the coating process. Before back-coating, the mechanism conveys the powder to the level of the process chamber floor. The coater can then use the powder for back-coating and convey the excess powder into an overflow at the end of the process chamber.

[0075] Figures 3a to 3d show process steps of the coating process, considering the first embodiment. The explanations are subsequently reduced by omitting previously described features that are irrelevant for understanding.

[0076] Figure 3a shows the cross-section through the lower part of the process chamber. On the left, the powder supply device 1A with the membrane 2A in its collection state is shown. The print bed 9, onto which powder 8 is applied and selectively solidified by energy input, is located in the center of the figure. The powder discharge area 10, through which powder 8 can be removed from the process chamber and fed into processing operations, is positioned on the right. Powder 8 has been introduced into the process chamber onto an area above the coating plane to the left of the coater 7 and is available for the coating process.

[0077] As the recoater 7 moves to the left, the powder 8 is distributed on the build plate 9. Depending on the desired layer thickness, the surface of the build plate lies below the area onto which the powder 8 is deposited in the process chamber.

[0078] 220609PC DMG MORI ADDITIVE GmbH 15 8 August 2025. The height adjustment of the print bed 9 can, for example, be carried out via an interchangeable cylinder.

[0079] After passing over the print bed 9, the coater 7 passes over the base block 12A. Powder 8, which was not used for the first coating process, falls into the trough provided by the lowering of the membrane 2A.

[0080] Figure 3b shows the coater 7, which has passed over the print bed 9 and the membrane 2A after the coating process. Part of the powder 8 has been distributed on the print bed 9. Another part of the powder 8 lies in the powder overflow area of ​​the powder supply device 1A. After this step, exposure or selective solidification of the applied powder 8 can take place.

[0081] In Figure 3c, the powder supply unit 1A is in its ready state. The print bed has been lowered to provide a volume for a second coating of material powder. The powder 8 previously stored in the powder overflow area is now within the reach of the coater 7. The coater 7 moves to the right across the base block 12A in the figure, in the opposite direction to its previous movement. During this movement, the coater 7 removes the stored powder 8 from the powder overflow area. In its subsequent movement, the coater 7 applies and distributes the powder 8 onto the print bed 9 to form a second powder layer. Excess powder 8 is removed via the powder discharge area 10.

[0082] Figure 3d shows the following state. The powder overflow area at membrane 2A has been cleared of powder 8. Small residual powder material may remain, for example, at joints, transitions, or on the surface, due to tolerances. The print bed 9 has been filled with powder 8 to the previously determined surface height. The excess powder 8 has been gravimetrically transferred to the powder removal area 10 and can leave the process chamber, for example, for powder processing.

[0083] 220609PC DMG MORI ADDITIVE GmbH 16 August 8, 2025

[0084] In other words, in this design, powder for pre-coating can be conveyed to the coater and for recoating to a volume at the coater. During coating, the mechanism creates a volume that can hold the powder not required for the coating process. Before recoating, the mechanism conveys the powder to the level of the process chamber floor, and the powder from the additional volume at the coater is deposited. The coater can then use this powder for recoating and convey the excess powder to an overflow at the end of the process chamber.

[0085] Figures 4a to 4d show the process steps of a first modification of the first embodiment. In addition to the first embodiment, the coater 7 is provided with a powder container 11A on the side opposite the first direction of movement of the coater 7. The powder container 11A is provided for storing and transporting powder 8. Furthermore, the powder container 11A is provided with a discharge mechanism that allows powder 8 to be released by tilting it.

[0086] Figure 4a shows the situation analogous to Figure 3a. The difference is that the powder container 11A is loaded with powder 8. This can be supplied via the same powder feed as the supply of powder 8 to the recoater 7 for applying the first powder layer to the print bed 9. Alternatively, a separate powder feed can be used.

[0087] Figure 4b shows that the recoater has transferred excess powder 8, supplied by the membrane 2A, into the powder overflow area. The discharge mechanism of the powder container 11A was triggered, and additional powder 8 was discharged onto the top of the base block 12A in the area between the print bed 9 and the membrane 2A.

[0088] As shown in Figure 4c, the powder supply device 1A was moved into the ready state. The stored powder 8 was lifted and can be removed by the coater 7. During the movement of the coater 7, the

[0089] 220609PC DMG MORI ADDITIVE GmbH 17 8 August 2025 stored powder 8 together with the powder 8 previously provided by powder container 11A transported to the right and used for a further coating on the print bed 9.

[0090] Figure 4d shows the coater 7, which, together with the powder container 11A, has moved to the right over the edge of the powder discharge area 10. The powder container 11A is ready to receive powder 8, which can be used in a new coating process. The excess powder 8 from the last coating process is located in the powder discharge area 10, where it can be removed from the process chamber.

[0091] Figures 5a to 5d show the process steps of a second modification of the first embodiment. In contrast to the first modification, the coater 7 is provided with a powder container 11B on the side facing the first direction of movement of the coater 7. The discharge mechanism of the powder container 11B is implemented by opening a flap on the underside of the container.

[0092] In Figure 5a, the coater 7 with the powder container 11B is positioned on the right. Powder 8 is provided in front of the coater 7 and in the powder container 11B. The coater 7 moves to the left together with the powder container 11B towards the print bed 9. The powder supply device 1A is in the collection state.

[0093] Figure 5b shows the coater 7 after the first coating process of the print bed 9 with powder 8. The discharge mechanism of the powder container 11B has been triggered and the powder 8 has been transferred to the powder transfer area. Excess powder 8 from the first coating process is also transferred to the powder transfer area. The coater 7 passes completely over the powder supply device 1A.

[0094] Figure 5c shows the powder supply device 1A in the ready state; the powder 8 has been raised. The print bed 9 has been lowered to receive it.

[0095] 220609PC DMG MORI ADDITIVE GmbH 18 8 August 2025 of another layer of powder 8. The coater 7 moves to the right over the powder supply device 1A and transports powder 8 from the powder transfer area.

[0096] Figure 5d shows the print bed 9 after a second coating with powder 8. The coater 7 with the powder container 11B is moving to the right. The excess powder 8 has been transported to the powder discharge area 10. The discharge mechanism on the powder container 11B has been deactivated, allowing the intake of powder 8.

[0097] In summary, it is proposed that the coater performs the first coating, pushing the powder into a recess of the mechanism (lowered membrane), thus passing over this recess. During the reverse coating, the mechanism (e.g., membrane) is returned to a home position, allowing the coater to use the previously deposited powder for the reverse coating or to carry it along during the reverse coating process and discharge it into the rear overflow. The home position can be adjustable to accommodate manufacturing tolerances and tolerances encountered during operation. During the reverse coating, the powder is pushed into a powder discharge area, such as a drop chute, at the end of the process chamber. This allows for the efficient reuse of excess powder and eliminates the need for a front (conventional) overflow.

[0098] The features, components, and specific details provided can be exchanged and / or combined to create further embodiments, depending on the required purpose. Any modifications that are within the knowledge of a person skilled in the art are implicitly disclosed in this description.

[0099] 220609PC DMG MORI ADDITIVE GmbH 19 August 8, 2025

[0100] Reference symbol:

[0101] 1A; 1B; 1C Powder dispensing device

[0102] 2A; 2B membrane 3A; 3B; 3C pressure port

[0103] 4A; 4B Pneumatic cylinders

[0104] 5A; 5B Connecting rod

[0105] 6 movable element

[0106] 7 Coaters 8 Powders

[0107] 9 print bed

[0108] 10 Powder removal area

[0109] 11 A; 11 B Powder container

[0110] 12A; 12B; 12C Base block 13 Cavity

[0111] 14 Shaft

[0112] 15 springs

[0113] 220609PC

Claims

1. DMG MORI ADDITIVE GmbH 20 August 8, 2025 Claims 1. Powder supply device (1A; 1B; 1C) for supplying powder (1A; 1B; 1C) during the production of a workpiece using a machine tool configured for the layer-by-layer construction of the workpiece by means of applied layers of material made of powder (8); the powder supply device (1A; 1B; 1C) comprising: a coater (7) configured for applying layers of material made of powder (8) to a work surface, and a powder overflow area for receiving and supplying powder (8), wherein the powder overflow area is arranged on the work surface, in particular at least partially below the work surface, and wherein the powder overflow area is configured in a first position to receive powder (8) and in a second position to supply powder (8) to the coater (7).

2. Powder supply device (1A; 1B; 1C) according to claim 1, wherein the first position of the powder overflow area is a supply state in which the coater (7) can remove powder (8) received in the powder overflow area and the second position of the powder overflow area is a collection state in which the coater (7) cannot remove powder (8) received in the powder overflow area.

3. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the powder supply device (1A; 1B; 1C), in the collection state of the powder overflow area, releases a volume below the working plane for receiving powder. 220609PC DMG MORI ADDITIVE GmbH 21 August 8, 2025 4. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the powder supply device (1A; 1B; 1C) is configured, upon appropriate control, to perform a change of state in order to switch between the first and second positions, and wherein the change of state of the powder overflow area is achieved by a mechanical adjustment and / or by generating a pressure differential.

5. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, further comprising an additional powder discharge area through which powder (8) is discharged from a process chamber.

6. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the powder overflow area is designed to be flat or concave on a top surface so that it can be driven over by the coater (7).

7. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the powder overflow area is an adjustable powder overflow with respect to the powder volume to be received, which is arranged next to a powder application area in the process chamber, and is preferably designed to be interchangeable.

8. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the powder overflow area comprises at least one elastic membrane (2A; 2B). 220609PC DMG MORI ADDITIVE GmbH 22 August 8, 2025 9. Powder supply device (1A; 1B; 1C) according to at least one of the preceding claims, wherein the elastic membrane (2A; 2B) is configured to receive overdosed powder (8) during coating by means of a lifting movement.

10. Powder dispensing device (1A; 1B; 1C) according to at least one of the preceding claims, wherein an additional powder container (11A; 11B) is provided for receiving powder (8), and wherein a discharge mechanism is provided for discharging powder (8) from the additional powder container (11A; 11B).

11. Powder supply device (1 A; 1 B; 1 C) according to at least one of the preceding claims, wherein the additional powder container (11 A; 11 B) is in contact with the coater (7) and is in particular attached to the coater (7).

12. Method for supplying powder in a process chamber of a machine tool configured for the layer-by-layer construction of a workpiece by means of applied layers of material made of powder (8), comprising: a coater (7) configured for applying layers of material made of powder (8) and a print bed (9) on which layers of material made of powder (8) are applied, and a powder supply device (1A; 1B; 1C), wherein a powder overflow area of ​​the powder supply device (1A; 1B; 1C) is brought into a first position to receive powder (8) and into a second position to supply powder (8) to the coater (7).

13. Method according to claim 12, wherein, in the first state of the powder overflow area, the coater (7) introduces powder (8) into the powder overflow area and wherein, in the second state of the powder overflow area, the coater (7) removes powder (8) from the powder overflow area. 220609PC DMG MORI ADDITIVE GmbH 23 August 8, 2025 14. Method according to at least one of claims 12 or 13, comprising the additional step: Exposure of one or more powder layers in the print bed (9) by local energy input, wherein the coater (7) occupies a position on the side of the powder overflow area facing the print bed (9) or substantially above the powder overflow area or on the side of the powder overflow area facing away from the print bed (9) before and / or during the exposure process.

15. Method according to at least one of claims 12 to 14, wherein the powder overflow area comprises a membrane which receives overdosed powder (8) during coating via a lifting movement.

16. Computer-implemented method which, when applied to a computing unit controllable to the powder supply device (1A; 1B; 1C) according to claim 1, causes the powder supply device (1A; 1B; 1C) according to claim 1 to perform at least the method steps according to claim 12. 220609PC

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