WORKPIECE CLEANING DEVICE, CLEANING METHOD AND MANUFACTURING METHOD

Description

FIELD OF THE INVENTION

[0001] The invention relates to a cleaning device according to claim 1. The device is for cleaning a workpiece manufactured by additive manufacturing from a granular and / or powdery production material and / or for removing excess granular and / or powdery production material after additive workpiece manufacturing. In this respect, the device can be designed as a depowdering device. The production material can be a plastic or metal powder or granulate. The cleaning device can be integrated into a workpiece manufacturing system (3D printer) or can be integrated therein, or can be part of a 3D workpiece production line formed from multiple components. The device comprises a housing, in particular a fluid-tight housing, in which a workpiece holder is arranged, on or at which the manufactured (printed) workpiece can be arranged.The workpiece holder can be formed, for example, as a construction frame or (fluid-tight) construction chamber for the workpiece. At least one conveying device for conveying production material, in particular excess, from the housing interior is arranged in or on the housing. At least one movable nozzle is arranged on at least one movable nozzle arm in the housing interior. The workpiece and the housing interior can be exposed to at least one cleaning fluid flow during a cleaning cycle, in which the workpiece and / or the housing interior are cleaned of production material, in particular excess.

[0002] The invention also relates to a cleaning method according to claim 17 and a workpiece manufacturing method according to claim 18. TECHNOLOGICAL BACKGROUND

[0003] Additive manufacturing processes are becoming increasingly relevant, particularly in industrial production. The production raw material or material is usually granular or powdery, and a three-dimensional workpiece is manufactured from the granular or powdery material in a manufacturing process. After production, either post-processing or further treatment or reuse of the workpiece is planned. Beforehand, the workpiece must be cleaned of powder residues. This can be done in an air or gas stream. Potential contamination of the air / gas cleaning environment and the quality of the cleaning process are problematic: not all surface elements of the workpiece are always exposed to the air / gas stream, and residues of the production material remain on the workpiece after cleaning. It has therefore proven effective to depowder the workpiece in a sealed container.However, this is time-consuming and costly.

[0004] The document DE-A1-102018118067 discloses a device for cleaning a workpiece manufactured from a granular and / or powdery production material by means of additive manufacturing and / or for removing excess granular and / or powdery production material after additive workpiece manufacturing, wherein the device comprises a housing in which a workpiece holding ring is arranged, at least one conveying device for conveying excess production material from the interior of the housing is arranged in or on the housing, and at least one movable nozzle is arranged on at least one movable nozzle arm in the interior of the housing, wherein at least one nozzle rotation is provided, in which the nozzle is rotatable about at least one nozzle rotation axis relative to the nozzle arm, and at least one arm rotation is provided, in which the nozzle arm is rotatable about an arm rotation axis relative to the workpiece holder. PRESENTATION OF THE INVENTION

[0005] Against this background, the object of the invention is to specify measures by which an additively manufactured workpiece can be cleaned of production material residues efficiently and in a cost- and time-saving manner. This object is achieved by a cleaning device according to claim 1. Further embodiments of the invention arise from the auxiliary and dependent claims. In the cleaning device according to claim 1, at least one nozzle rotation is provided, in which the nozzle is rotatable about at least one nozzle rotation axis relative to the nozzle arm. Furthermore, at least one arm movement and / or at least arm rotation is provided, in which the nozzle arm is movable and / or rotatable at least along an arm path and / or about at least one arm rotation axis relative to the workpiece holder. The orientations of the nozzle rotation axis and the arm rotation axis can differ.For example, the nozzle rotation axis can be perpendicular or almost perpendicular to the nozzle arm rotation axis. The rotation speeds of the nozzle rotation and the speed of the arm movement and / or the arm rotation are designed such that during a cleaning cycle the cleaning fluid flow assumes all or almost all flow directions within the interior of the housing, so that the entire or almost entire surface of the workpiece and the interior of the housing can be exposed to the cleaning flow from all or almost all directions. A cleaning cycle is roughly the period in which the workpiece is sufficiently cleaned, i.e. depowdered. By also directing the cleaning fluid flow directly onto the interior of the housing, backdusting, i.e. contamination of the workpiece by powder residues inside the housing, is avoided.These powder residues can be deposited there by the cleaning process itself or by a previous cleaning process. The device described particularly prevents the residues from the cleaning of a first workpiece from contaminating a second workpiece that is subsequently to be cleaned. As the nozzle and the arm on which the nozzle is arranged rotate, the vector space of all cleaning fluid flow vectors during a cleaning cycle encompasses the full solid angle (4 π) or almost the full solid angle (≈ 4 π, where a solid angle is a - mathematically describable - portion of the entire three-dimensional space). It can be expedient to provide a device for introducing the workpiece into the cleaning device in order to avoid contamination of the environment of the cleaning device.

[0006] The arm movement and / or the arm rotation preferably causes the rotating nozzle to move along a round, circular, oval, rectangular or nearly rectangular or freely formed path around the workpiece holder and between the workpiece holder and the housing wall. For example, the path can be rectangular with rounded corners. In particular, with a rectangular frame, the nozzle arm essentially follows the shape of the frame. For this purpose, appropriate toothing can be provided, which is arranged along the arm path. Depending on the design of the device, the frame and thus the arm path can be of variable length. The nozzle arm of the device therefore moves the rotating nozzle around the workpiece or around the workpiece holder along a path. As the nozzle arm and nozzle themselves rotate, all or nearly all surface elements of the workpiece are exposed to the fluid flow.This ensures that all or almost all of the production material or powder residues on the workpiece and the housing wall are captured by the fluid flow and at least removed from the workpiece. After just one cleaning cycle, the workpiece is depowdered and can be forwarded for further processing or recycling.

[0007] By rotating the nozzle and nozzle arm in the manner described, not only is the workpiece cleaned of production material residues or contaminants, but also the cleaning device itself, i.e., the interior of the device's housing. This aspect of cleaning is of considerable importance for the cleaning result in that it prevents recontamination of the workpiece during a cleaning cycle, which is due to production material residues on the interior of the housing contaminating the workpiece located therein during cleaning. Furthermore, "cross-contamination" can be avoided, i.e., contamination of production material contaminants of a first workpiece, created during a first cleaning cycle and capable of contaminating a second workpiece that is in a subsequent, second cleaning cycle.

[0008] Preferably, nozzle rotation and arm movement and / or arm rotation can be coupled. During one revolution of the arm rotation, an adjustable constant or an adjustable variable or a non-adjustable variable or any number of revolutions of the nozzle rotation takes place. For example, the nozzle can make x nozzle revolutions during one arm revolution, where x can be a natural number, in particular greater than 1 ( x ∈ ℕ ) or a rational number, especially greater than 1, ( x ∈ ℚ ). If x is a non-integer, the position of the nozzle changes after each full arm revolution, so that the cleaning fluid flow leaving the nozzle has a different direction after each arm revolution, so that each or almost each surface element of the workpiece and the housing interior is exposed to the air. Alternatively, an adjustable constant, an adjustable variable, a non-adjustable variable, or any number of revolutions of the arm rotation can occur during one revolution of the nozzle rotation. For example, y arm revolutions can be provided for one nozzle revolution ( y ∈ ℕ or y ∈ ℚ ).

[0009] Preferably, the position of the nozzle on the nozzle arm after one rotation of the nozzle arm has a small (angular) offset compared to its position before the nozzle arm rotation, whereby a large angular range of the flow directions of the cleaning fluid flow is covered over several rotations.

[0010] Due to the rotation configuration described herein, the workpiece is subjected to air flow from a multitude of directions, in particular all directions, and thus cleaned efficiently and thoroughly in a particularly short time. The coupling between nozzle rotation and arm rotation can also be chaotic, i.e., disordered or non-deterministic, so that the nozzle "whirls" around the nozzle rotation axis, while the nozzle arm rotates around the arm rotation axis at a comparatively constant or, in particular, variably determinable, rotational speed. During the rotation of the nozzle and / or arm, at least one reversal of direction in one or both directions of rotation (nozzle / arm) can be provided during a cleaning cycle.

[0011] It can be provided that the coupling of the nozzle rotation and arm movement and / or arm rotations takes place mechanically and / or electronically, in particular by means of a control device. At least one gear can be arranged on or in the nozzle arm, which gears the movement of the nozzle arm up or down into a movement of the nozzle. The nozzle arm can be driven by a preferably controllable (arm) motor. The nozzle rotation can be driven by means of a gear by the motor of the nozzle arm or by a separate (nozzle) motor. The rotation of the nozzle can also be achieved by (fluid-mechanical) forces generated by the flow of the cleaning fluid.

[0012] The nozzle can be designed as a double or multiple nozzle. For example, a double nozzle can be provided at the end of the nozzle arm, generating a first fluid flow on one side of the arm and a second flow on the opposite side. The flow directions can be different, in particular, variable. Double or multiple nozzles create even more fluid flow directions, which optimizes and, in particular, accelerates the depowder removal process.

[0013] The angle(s) at which the cleaning fluid flow leaves the nozzle can be set or adjusted in or on or by means of the nozzle, in particular by changing the angle between the rotatable nozzle and the rotatable and / or movable nozzle arm.

[0014] According to the invention, the workpiece holder is movable within the housing, in particular displaceable and / or pivotable and / or rotatable. Furthermore, a workpiece actuator can be provided, with which the workpiece can be moved in or on the workpiece holder during a cleaning cycle, in particular incrementally. The workpiece is thus exposed to the cleaning fluid at least once at every position (for example, at every height with vertical displacement of the workpiece) and at every (spatial) angle. This increases cleaning efficiency and reduces the time required for the cleaning cycle. Thus, more workpieces can be cleaned per unit of time. A linear displacement of the nozzle arm can also be provided.

[0015] The cleaning fluid is preferably a gas or gas mixture, in particular comprising an inert gas. The gas pressure can be variable, meaning the flow rate of the cleaning fluid can be adapted to the workpiece size or geometry. A solid or liquid cleaning fluid, such as a liquid or a particle jet, can also be provided.

[0016] It is expedient if the conveying device for removing the production material residues is designed as a vacuum conveyor. Since the cleaning fluid can create excess pressure in the fluid-tight housing interior, pressure equalization is achieved by vacuum conveying.

[0017] The conveying device can be fluidically connected to a conveying connection arranged such that the granular and / or powdery production material to be removed, in particular excess, flows towards the conveying connection by gravity. To prevent fluid buildup or blockage of the connection or the channels or lines arranged thereon, a fluid flow monitoring device can be provided, which is arranged in particular in the region of the conveying connection.

[0018] In particular, to support the gravity-assisted removal of (excess) production material, the position of the cleaning device can be changed, in particular, displaced, rotated, and / or pivoted. This allows the (excess) production material to fall downwards and connect to the (vacuum) conveying device.

[0019] To ensure the device can be integrated into a manufacturing process as easily as possible, it is advisable for the cleaning device to be mounted on the workpiece holder, forming a fluid-tight volume. Therefore, there is no need to change the workpiece holder; rather, the workpiece holder is designed to be used in other process stages (manufacturing, post-processing, etc.).

[0020] To improve the cleaning effect, a vibration device can be provided in or on the device, with which the device and / or the workpiece holder and / or the workpiece can be subjected to at least one vibration. The vibration can be amplitude and / or frequency modulated. Frequency modulation can be provided, which includes at least one natural or resonant frequency of the component.

[0021] Efficient, cost- and time-saving cleaning of an additively manufactured workpiece of production material residues is further achieved with a cleaning method according to claim 17. The method provides that the workpiece is arranged in a cleaning device, in particular in a cleaning device described herein. During a cleaning cycle, in which the workpiece and / or the housing interior are cleaned of, in particular, excess, production material, the workpiece is subjected to a cleaning fluid flowing from at least one movable nozzle arranged on at least one movable nozzle arm. The workpiece and the housing interior of the device are subjected to at least one cleaning fluid flow during a cleaning cycle.At least one nozzle rotation is provided, in which the at least one nozzle rotates about at least one nozzle rotation axis relative to the nozzle arm, as well as at least one arm movement and / or arm rotation, in which the nozzle arm moves along at least one arm path relative to the workpiece holder and / or rotates about at least one arm rotation axis relative to the workpiece holder. According to the invention, the orientations of the nozzle rotation axis and the arm rotation axis differ. The rotational speeds of the nozzle rotation and the speed of the arm movement and / or the arm rotation are formed such that during a cleaning cycle the cleaning fluid flow assumes all or almost all flow directions within the housing interior, so that the entire or almost entire surface of the workpiece and the housing interior is exposed to the cleaning flow.

[0022] An efficient and cost- and time-saving cleaning of an additively manufactured workpiece from production material residues is further achieved with an additive manufacturing method according to claim 18. In the method, a workpiece is manufactured from a granular and / or powdery production material and is subsequently cleaned according to a cleaning method described herein.

[0023] The aforementioned components to be used according to the invention as well as those claimed and described in the exemplary embodiments are not subject to any special exceptional conditions in terms of their size, shape, material selection and technical conception, so that the selection criteria known in the field of application can be applied without restriction.

[0024] Further details, features, and advantages of the subject matter of the invention emerge from the dependent claims, as well as from the following description and the accompanying drawing, which illustrates, by way of example, an embodiment of a depowdering device. Individual features of the claims or embodiments can also be combined with other features of other claims and embodiments. BRIEF DESCRIPTION OF THE CHARACTERS

[0025] In the drawing show Fig. 1 a cleaning device in a schematic side view, Fig. 2A / Ben cleaning device with build chamber and workpiece in various side schematic views, Fig. 3 a build chamber with workpiece in a side schematic view and Fig. 4 a cleaning device in a schematic sectional view (top view). DETAILED DESCRIPTION OF EMBODIMENTS

[0026] Fig. 1 shows a side schematic view of a cleaning device 1 or a depowdering module for depowdering an additively manufactured workpiece (2). In the housing 3 of the device 1, a nozzle arm 4 is arranged, which is rotatable about the nozzle arm rotation axis 6 via a nozzle arm drive 5. At the end of the nozzle arm 4, a bend 7 is provided, on which a rotatable nozzle 8 is arranged. From the nozzle 8, a cleaning fluid, such as a gas or gas mixture, flows into the housing interior 9. The fluid flow removes production material residues from a workpiece (2), which is inserted into the device 1 according to Fig. 1 can be used. The production material residues are suctioned out of the housing interior 9. For this purpose, a conveying connection 10 is provided, to which a vacuum conveying system can be fluidly arranged. Furthermore, the housing interior 9 is fluid-tight so that no production material residues can enter the environment 11 of the depowdering device 1.

[0027] The housing 3 can have a cylindrical geometry, ie the housing cross-section can be round, which can be seen from the view according to Fig. 4 becomes clear. On an end face 12 of the housing 3, an opening 13 or connection option for a lock or for a construction chamber (14) can be provided, through which the workpiece to be cleaned can be brought into the housing interior 9.

[0028] The Figuren 2A and 2B show a depowdering module 1 on which a workpiece holder 14 is arranged, in which a workpiece 2 to be cleaned is arranged.

[0029] The workpiece holder 14 is in Fig. 3 The workpiece 2 was previously manufactured from a production material using additive manufacturing. Due to the manufacturing process, production material residues adhere to the workpiece 2. These production material residues are removed by cleaning the workpiece 2 in the cleaning device 1. The workpiece holder 14 forms a build chamber, which is connected to the housing 3 of the cleaning device 1 in such a way that the volume of the build chamber 14 and the housing interior 9 are fluid-tightly connected. In principle, the cleaning device 1 can be slipped or placed over the build chamber 14.

[0030] The workpiece 2 is displaceable within the workpiece holder 14 linearly along the direction of the rotation axis 6, which allows a summary of the Figuren 2A and 2B It is intended that the holder 14 (building plate) is moved back and forth during the powder removal process. Fig. 2A the workpiece 2 is partly located in the housing interior 9, according to Fig. 2B the workpiece 2 to be cleaned is arranged completely inside the housing 9.

[0031] The workpiece 2 is cleaned by guiding the nozzle arm 4 with the rotating nozzle 8, from which the cleaning fluid flows, around the workpiece 2 by rotating it around the nozzle arm rotation axis 6. During these rotations (arm 4 and nozzle 8), the workpiece 2 is moved linearly, for example by an actuator that causes the workpiece 2 to be moved incrementally. In this way, each surface element of the workpiece 2 to be cleaned is subjected to a fluid flow during a cleaning cycle. During a cleaning cycle, the nozzle arm 4 makes several revolutions around the workpiece 2, and the nozzle 8 makes several or a multitude of revolutions around the nozzle rotation axis for each nozzle arm rotation. The nozzle rotation axis is almost perpendicular to the nozzle arm rotation axis 6. The angle at which the fluid leaves the nozzle 8 can be changed by pivoting or adjusting the nozzle 8.Where the workpiece 2 is subjected to air flow, excess production material adhering to the workpiece 2 is removed and enters the interior of the housing 9 of the cleaning device 1. From there, it is removed from the interior of the housing 9 by a vacuum conveying system.

[0032] To ensure efficient suction of excess production material that must be removed, the vacuum conveyor connection 10 is located in a recess 15 of the housing 3. Gravity causes the remaining production material to fall toward the vacuum conveyor connection 10. This is facilitated by the funnel shape of the housing's front end.

[0033] By providing at least two axes of rotation during the movement of the nozzle 8, the cleaning fluid is not only directed onto the workpiece 2 but also onto the housing wall 16 of the housing interior 9. Thus, the housing interior 9 is also cleaned of production material residues. This prevents, on the one hand, dust from accumulating on the workpiece 2 and, on the other hand, cross-contamination when cleaning a first workpiece 2 made of a first production material and subsequently cleaning a second workpiece 2 made of a second production material that differs from the first. LIST OF REFERENCE SYMBOLS

[0034] 1Cleaning device / Depowdering module 2Workpiece 3Housing 4Nozzle arm 5Nozzle arm drive 6Nozzle arm rotation axis 7Angled section 8Nozzle 9Housing interior 10Feed connection 11Surroundings 12Front side 13Opening 14Workpiece holder / Build chamber 15Depression 16Housing wall

Claims

1. A device (1) suitable for cleaning a workpiece manufactured by means of additive manufacturing from a granular and / or powdery manufacturing material (2) and / or suitable for removing excess granular and / or powdery manufacturing material after manufacturing the additive workpiece, wherein the device (1) comprises a housing (3) in which a workpiece holder (14) is arranged, at or on which the manufactured workpiece (2) can be arranged, at least one conveyor device is arranged in or on the housing (3) for removing excess manufacturing material from the inside of the housing (9), and at least one moveable nozzle (8) is arranged on at least one moveable nozzle arm (4) in the inside of the housing (9) so that at least one cleaning fluid flow can be applied to the workpiece (2) and the inside of the housing (9) during a cleaning cycle in which the workpiece (2) and / or the inside of the housing (9) are cleaned of excess manufacturing material, wherein, an angle (7) is provided at the end of the nozzle arm (4), on which the moveable nozzle (8) is arranged, at least one nozzle rotation is provided in which the nozzle (8) can be rotated about at least one nozzle rotational axis relative to the nozzle arm (4), and at least one arm rotation is provided, in which the nozzle arm (4) can be rotated around an arm rotational axis (6) relative to the workpiece holder (14), wherein the rotation speed of the nozzle rotation and the speed of the arm movement are designed in such a way that, during a cleaning cycle, the cleaning fluid flow assumes all or almost all flow directions within the housing (9) so that the entire or almost the entire surface of the workpiece (2) and the housing (9) can be directly affected by the cleaning flow from all or almost all directions, wherein the orientations of the nozzle rotational axis and the arm rotational axis (6) differ, wherein the nozzle (8) undergoes a multitude of revolutions per nozzle arm revolution, and wherein the workpiece holder (14) inside the housing (9) can be moved, or swivelled, or rotated, or moved and swivelled, or moved and rotated, or swivelled and rotated, or moved and swivelled and rotated, or could be moved and swivelled and rotated.

2. The cleaning device (1) according to Claim 1, characterized in that the arm movement causes the rotating nozzle (8) to move along a round, circular, oval, rectangular or almost rectangular or free-formed path around the workpiece holder (14) and between the workpiece holder (14) and the housing wall (16).

3. The cleaning device (1) according to any one of the Claims 1 or 2, characterized in that nozzle rotation and arm movement are coupled so that during one revolution of the arm movement there is an adjustable constant, or an adjustable variable or a non-adjustable variable or any number of revolutions of the nozzle rotation, or so that, during one revolution of the nozzle rotation, there is an adjustable constant or an adjustable, changeable or a non-adjustable variable or any number of revolutions of the arm movement.

4. The cleaning device (1) according to Claim 3, characterized in that the coupling of the nozzle rotation and the arm movement is mechanical.

5. The cleaning device (1) according to any one of the Claims 1 to 4, characterized in that the coupling of the nozzle rotation and the arm movement is carried out electronically by means of a control device.

6. The cleaning device (1) according to any one of the Claims 1 to 5, characterized in that at least one gearbox is arranged on or in the nozzle arm (4) which reduces or transmits the movement of the nozzle arm (4) into a movement of the nozzle (8).

7. The cleaning device (1) according to any one of the Claims 1 to 6, characterized in that the nozzle (8) is designed as a rotating double or multiple nozzle.

8. The cleaning device (1) according to any one of the Claims 1 to 7, characterized in that the angle(s) at which the cleaning fluid flow leaves the nozzle (8) is adjustable in or on or by means of the nozzle (8), or that the angle(s) at which the cleaning fluid flow leaves the nozzle (8) is adjustable in or on or by means of the nozzle (8) by changing the angle between the rotatable nozzle (8) and the moveable nozzle arm (4).

9. The cleaning device (1) according to any one of the Claims 1 to 8, characterized by a workpiece actuator via which the workpiece (2) can be moved incrementally in or on the workpiece holder (14) during a cleaning cycle.

10. The cleaning device (1) according to any one of the Claims 1 to 9, characterized in that the conveyor is designed as a vacuum conveyor.

11. The cleaning device (1) according to any one of the Claims 1 to 10, characterized in that the conveyor is fluidically connected to a conveyor port (10) which is arranged in such a way that the excess granular and / or powdery manufacturing material to be removed flows in the direction of the conveyor port (10) due to gravity.

12. The cleaning device (1) according to any one of the Claims 1 to 11, characterized in that a fluid flow monitoring device is located in the area of the conveyor connection (10).

13. The cleaning device (1) according to any one of the Claims 1 to 12, characterized in that the position of device (1) can be changed.

14. The cleaning device (1) according to Claim 13, characterized in that the position of the device can be moved, or rotated, or swivelled, or displaced and twisted, or displaced and pivoted, or twisted and pivoted, or displaced and twisted and pivoted.

15. The cleaning device (1) according to any one of the Claims 1 to 14, characterized in that the device (1) can be placed on the workpiece holder (14) to form a fluid-tight volume.

16. The cleaning device (1) according to any one of the Claims 1 to 15, characterized in that a vibration device is provided in or on the device (1) by means of which at least one vibration can be applied to the device (1), the workpiece holder (14), and / or the workpiece (2).

17. A method for cleaning a workpiece made of a granular and / or powdery manufacturing material by means of additive manufacturing (2), and / or for the removal of excess granular and / or powdery manufacturing material after additive workpiece production, wherein the workpiece is arranged in a cleaning device, in particular, in a cleaning device (1) according to one of the Claims 1 to 16, and wherein during a cleaning cycle, in which the workpiece and / or the inside of the housing (9) are cleaned of excess manufacturing material, a cleaning fluid flowing from at least one moveable nozzle (8), which is located on at least one moveable nozzle arm (4), flows onto the workpiece so that at least one flow of cleaning fluid is applied to the workpiece and the inside of the housing of the device during a cleaning cycle, wherein at least one nozzle rotation is provided in which the nozzle rotates around at least one nozzle rotational axis relative to the nozzle arm, at least one arm rotation is provided, in which the nozzle arm rotates about at least one arm rotational axis relative to a workpiece holder (14) and the rotation speeds of nozzle rotation and speed of arm movement are designed in such a way that during a cleaning cycle the cleaning fluid flow assumes all or almost all flow directions within the inside of the housing so that the cleaning flow directly applies the cleaning flow to the entire or almost all surface of the workpiece and the inside of the housing, wherein the orientations of the nozzle rotational axis and the arm rotational axis differ, wherein the nozzle undergoes a multitude of revolutions per nozzle arm revolution, and wherein the workpiece holder inside the housing can be moved, or swivelled, or rotated, or moved and swivelled, or moved and rotated, or swivelled and rotated, or moved and swivelled and rotated.

18. An additive manufacturing method for producing a workpiece from a granular and / or powdery manufacturing material, characterized by a cleaning method according to Claim 17.