MANUFACTURING SYSTEM FOR ADDITIVE MANUFACTURING OF A WORKPIECE

Abstract

The present disclosure relates to a manufacturing system for additive manufacturing of a workpiece and an additive manufacturing method. The manufacturing system for additive manufacturing of a workpiece includes a building panel, a lifting device for the building panel, a blade device, an optical device, and a control unit. The blade device comprises at least one coater element for applying or removing a powder material to the building panel. The optical device comprises an optical element for reception of image data from the building panel and/or from the powder layer. The lifting device is configured to raise and/or lower the building panel. The control unit is configured to control the lifting device based on the image data.

Claims

1. A manufacturing system for additive manufacturing of a workpiece, comprising a building panel, a lifting device for the building panel, a blade device, an optical device, and a control unit, wherein the blade device comprises at least one coater element for applying or removing a powder material to or from the building panel, wherein the optical device comprises an optical element for reception of image data from the building panel and/or from the powder layer, wherein the lifting device is configured to raise and/or lower the building panel, and wherein the control unit is adapted to control the lifting device based on the image data.

2. The additive manufacturing system according to claim 1, wherein the blade device comprises a blade turret having a cylindrical base body, the peripheral surface of which has at least one reception into which the coater element is inserted.

3. The additive manufacturing system according to claim 2, wherein the blade turret has at least one further reception into which a further coater element to be inserted.

4. The additive manufacturing system according to claim 2, wherein the blade turret has at least one further reception, into which a cleaning element for removing powder residues to be inserted.

5. The additive manufacturing system according to claim 2, wherein the blade turret having at least one further receptacle into which an illumination element for illuminating the powder layer to be inserted for reception of the image data.

6. The additive manufacturing system according to claim 1, wherein the optical element is designed an off-axis camera with a filter device for capturing image data only with wavelengths between 820 and 870 nm.

7. The additive manufacturing system according to claim 1, wherein the blade device comprises a support body and the support body and/or the blade turret comprises an interchangeable mechanism element for releasably attaching the blade turret to the support body.

8. The additive manufacturing system according to claim 7, wherein the carrier body and/or the blade turret comprises a fastening element for releasably fastening a container lid of a building container and/or a powder container.

9. The additive manufacturing system according to claim 8, wherein the carrier body and/or the blade turret comprises a height adjustment element for height mobility of the held container lid.

10. The additive manufacturing system according to claim 1, further comprising a distance sensor for detecting a distance between the building panel and the coater element.

11. The additive manufacturing system according to claim 1, further comprising a contact sensor for detecting a contact between the building panel and the coater element.

12. The additive manufacturing system according to claim 1, wherein the optical device further comprises at least one on-axis sensor disposed in a beam path for irradiating the powder layer to detect process emissions from a molten bath region when irradiating the powder layer.

13. An additive manufacturing process, comprising: S1 applying or removing a powder material to or from a building panel using a blade device having at least one coater element, S2 recording image data from the building panel and/or from the powder layer by means of an optical device having an optical element, and S3 lifting and/or lowering the building panel by means of a lifting device, wherein the lifting device is controlled by a control unit based on the image data.

14. The additive manufacturing method according to claim 13, wherein the steps S1 (removing), S2 (recording image data) and S3 (lifting) are repeated until the evaluation shows that the building panel is substantially free of powder, and in this case, setting the position of the coating element relative to the building panel as a reference position for this coating element.

15. The additive manufacturing method according to claim 13, wherein recording of image data is limited to wavelengths between 820 and 870 nm, and visible light and/or laser radiation is masked out.

16. The additive manufacturing method according to claim 13, further comprising illuminating the powder layer with wavelengths between 820 and 870 nm, when recording image data in step S2.

17. The additive manufacturing method according to claim 13, further comprising releasably connecting the blade device to a container lid of a building container and/or a powder container and transporting the container lid to a storage location by means of the blade device.

18. The additive manufacturing system according to claim 6, wherein the wavelengths are between 830 to 860 nm.

19. The additive manufacturing method according to claim 15, wherein the wavelengths are between 830 to 860 nm.

20. The additive manufacturing method according to claim 16, wherein the wavelengths are between 830 to 860 nm.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0071] FIG. 1 shows a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0072] FIG. 2 shows a blade device of a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0073] FIG. 3 shows a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0074] FIG. 4 shows a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0075] FIG. 5 shows a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0076] FIG. 6 shows a manufacturing system for additive manufacturing of a workpiece according to an embodiment.

[0077] FIG. 7 shows a flow diagram of an additive manufacturing process.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0078] FIG. 1 shows a manufacturing system 100 for additive manufacturing of a workpiece. The manufacturing system 100 comprises a building chamber 10 to which a building container 30 and a powder container 40 can be coupled (see also FIG. 3). The powder container 40 is configured to store powder material 41 and the building container 30 is configured to perform additive manufacturing of a workpiece on a building panel 31 located in the building container 30.

[0079] The build chamber 10 includes an opening sealed, for example, by an optically transparent material. Through this opening, the laser beam can be provided to expose a fresh powder layer applied to the building panel 31.

[0080] A blade device 20 is located in the building container 10 to layer the fresh powder material 41 from the powder container 40 onto the building panel 31 of the building container 30, and to discharge the excess residual powder material from the building panel 31 into a powder overflow container 35 (see also FIG. 2).

[0081] The manufacturing system 100 further comprises an optical device 50 comprising an off-axis optical element 51 and at least one on-axis sensor 52. The off-axis optical element 51 may comprise, for example, an off-axis camera. The off-axis optical element 51 is configured for reception of image data from the building panel and/or from the powder layer. The off-axis camera 51 includes a filter device configured to capture image data only at wavelengths between 820 and 870 nm, preferably 830 to 860 nm. The on-axis sensor 52 may comprise, for example, a ratio pyrometer. The on-axis sensor 52 is arranged in a beam path for irradiating the powder layer in order to detect process emissions from a melt pool region during irradiation of the powder layer.

[0082] FIG. 2 shows the blade device 20 of the additive manufacturing system 100. The blade device 20 comprises a blade turret 60 having a cylindrical base body 67, the peripheral surface of which has at least one reception 61 into which a coater element 62 is inserted. The coater element 62 is configured for applying or removing powder material 41 to or from the building panel 31 of the building container 30. Preferably, the blade turret 60 has a plurality of receptacles 61 into which additional coater elements 62 are inserted. The coater element 62 may be a rubber lip or a blade made of metal and/or ceramic.

[0083] A cleaning element 63 is positioned in one of the plurality of receptions 61 of the blade device 60, which is configured to remove powder residues according to the additive manufacturing of the workpiece. The cleaning element 63 may be, for example, a silicone impregnated brush and/or a carbon brush.

[0084] As shown in FIG. 3, the cleaning element 63 can clean an interface 12 between a bottom 11 of the build chamber 10 and the powder container 40, the powder overflow container 35, and/or the building container 30. According to the completion of additive manufacturing, the blade turret 60 can rotate and switch to the cleaning element 63 so that it faces the bottom 11 of the build chamber 10. The cleaning element 63 can thus remove the powder residue and/or weld spatter from the floor 11 of the build chamber 10 and/or the interface 12 between the floor 11 and the containers 30, 40, 35. In this way, it can be ensured that no powder residue can be carried away during the removal of the containers.

[0085] Further, an illumination element 64 is positioned in one of the plurality of receptacles 61 of the blade device 60 and is configured to illuminate the powder layer for reception of the image data. The illumination element 64 comprises at least one illuminant, such as LED, halogen, laser, neon and/or xenon lamp, preferably NIR (Near Infrared)—LED.

[0086] The coater element 62, the cleaning element 63 and/or the illumination element 64 extend at least partially in the longitudinal direction of the cylindrical body 67 of the blade turret 60.

[0087] The blade device 20 further comprises a support body 24 to which the blade turret 60 is releasably attached by means of an interchangeable mechanism element 66. The interchangeable mechanism element 66 can provide for easy and quick removal of the blade turret 60 from the blade device 20. The interchangeable mechanism element 66 may have a positive connection, a friction connection, an (electro)magnetic connection, and/or a clamping connection.

[0088] The blade device 20 further comprises at least one distance sensor 21 for detecting a distance between the building panel 31and the coater element 62. The distance sensor 21 is arranged on a bottom side 26 of the blade device 20 so as to face the bottom 11 of the building chamber 10. Preferably, the blade device 20 includes a plurality of distance sensors 21 to enable precise measurement of the distance between the building panel 31 and the coater element 62.

[0089] The distance sensor 21 may further be configured to measure the distance between the coater element 62 and a base plate 43 of the powder container 40 to determine the amount of powder material 41 currently present in the powder container 40. The distance sensor 21 may be, for example, an inductive sensor, an ultrasonic sensor, or a radar sensor that provides a non-contact distance measurement.

[0090] The blade device 20 further comprises a contact sensor 25 for detecting a contact between the building panel 31 and the coater element 62. The contact sensor 25 is arranged on the bottom side 26 of the blade device 20 so as to face the building panel 31 of the building container 30.

[0091] As shown in FIG. 4, the building container 30 is coupled to a lifting device 32 configured to raise and/or lower the building panel 31 within the building container 30. The base plate 43 of the powder hopper 40 may also be coupled to a separate lifting device (not shown) to deliver the fresh powder material 41 to the bottom 11 of the build chamber.

[0092] Prior to the start of additive manufacturing, the building panel 31 can be raised to the floor 11 of the build chamber 10 by means of the lifting device 32. During this process, the contact sensor 25 may detect contact with the building panel 31 at a plurality of locations. To facilitate this detection, the blade device 20 may include two or more contact sensors 25 that may be spaced apart from each other on the bottom 26 of the blade device 20. In this way, a position of the building panel 31, in particular height and inclination relative to a horizontal plane can be precisely detected and corrected according to the measurement results.

[0093] The blade device 20 further comprises a fastening element 22 for releasably fastening a container lid 33, 42 of the building container 30 and/or the powder container 40 and a height adjustment element 23 for height mobility of the held container lid 33, 42. In order to maintain an inert atmosphere within the building container 30 and powder container 40, the containers 30, 40 are to be handled outside the additive manufacturing system 100 exclusively with the container lids 33, 42 in place.

[0094] As shown in FIG. 5, according to an insertion of the building container 30 and powder container 40 into the building chamber 10 and an inerting of the building chamber 10, the blade device 20 moves over a container lid 33, 42 of these containers 30, 40. At the same time, the carrier body 24 of the blade device 20 can positively grip the container lid 33, 42 by means of the fastening element 22, which is designed like a T-shaped groove, via a connecting element 34 located thereon, which is designed like a T-shaped projection. Preferably, the blade device 20 comprises at least two fastening elements 22 and the container lid 33, 42 comprises at least two connecting elements 34, 43 in order to be able to lift the lid 33, 42 from respective containers 30, 40 uniformly in the vertical direction.

[0095] The height adjustment element 23 can raise the container lid 33, 42, which has been removed from either the powder container 40 or the building container 30, in the vertical direction to ensure contactless transport of the lid 33, 42 with the building field. To prevent the container lid 33, 42 from becoming detached from the blade device 20 during transport, its movement is restricted by a cam 65 arranged in the blade turret 60. The cam 65 may be arranged in an opposite direction relative to the direction of insertion of the lid 33, 42 to the blade device 20. In this manner, the container lid 33, 42 cannot slide out of the fastening element 22 of the blade device 20 during reception, but instead is held in place by the cam 65.

[0096] The build container lid 33 and powder container lid 42 removed from the blade device 20 are transported to a storage location (not shown), which is inside the build chamber 10, but outside the build area.

[0097] FIG. 6 shows powder application monitoring during additive manufacturing. As the powder material 41 is applied, line-like structures may be formed in the direction of travel of the blade device 20. Visibility of such a powder application defect may increase most when illuminated by side lighting to create a shadow. The powder application defect and/or the coating defect can be detected indirectly via a characteristic shadow using the optical element 51, preferably the off-axis camera.

[0098] The control unit (not shown) can detect an application quality of the powder material 41 using the optical device 50, and detect an error on the currently used coating element 62 if the application quality of the powder material 41 deviates from the predetermined requirement. In the event of the defect, the blade turret 60 can rotate according to the severity of the damage to the current coater element 62 and switch to a next coater element 62, particularly one that is free of defects.

[0099] FIG. 7 shows a flowchart of an additive manufacturing process.

[0100] In step S0, the building container 30 and the powder container 40 are inserted into the build chamber 10 of the manufacturing system 100, and the build chamber 10 is then inerted to minimize the oxygen content in the build chamber 10.

[0101] In step S010, the lid 33 of the building container 30 is removably connected to the fastening element 22 of the blade device 20. The lid 33 is raised by the height adjustment member 23 and transported to the lid storage location by a horizontal movement of the blade device 20.

[0102] In step S020, a position of the building panel 31 is aligned. For this purpose, the building panel 31 is lifted S021 to the bottom 11 of the building chamber 10 by means of the lifting device 32. In this process, the contact sensor 25 can detect contact with the building panel 31 at a plurality of locations S022. In this way, a position of the building panel 31, in particular height and inclination relative to a horizontal plane is precisely detected and corrected according to the measurement results S023.

[0103] The building panel 31 is then lowered slightly more than 3 mm below the calculated building panel position (level 0) on contact S024. Thus, the building panel 31 can be minimally below level 0. The level 0 can, for example, be the position of a floor 11 of the building chamber 10, to which a powder container 40, a building container 30 and/or a powder overflow container can be coupled. In this way, it can be ensured that the blade device 20 does not come into contact or collide with the building panel 31 during operation, as the coater element can be located approximately 0.05 mm above level 0. According to the alignment of the building panel 31, the optical element 51 creates a reference image of the building panel S025 still untouched by the powder material 41.

[0104] In the following step S1, the powder material 41 is applied to the building panel 31 by means of the coating element 62 of the blade device 20. According to the application of the powder layer, the building panel 31 is lifted S2 by an amount of 10-100 μm. The blade device 20 subsequently removes a portion of the lifted powder layer.

[0105] In step S3, image data of the powder layer on the building panel 31 is acquired by means of the optical device 50, preferably the off-axis camera 51. In step S31, an image-processing algorithm checks, on the basis of the reference image, whether the building panel 31 is still completely covered with powder or whether building panel areas already untouched by the powder show through.

[0106] If S4 the algorithm confirms the building panel 31 is still completely covered with powder material 41, steps S1 to S3 can be repeated with the removal of a 10-100 μm thick layer of powder. These steps can be repeated until the optical element 51, i.e. off-axis camera and associated algorithm detects minimal residue of powder material 41 on the building panel 31. Ideally, the position of the building panel 31 can be set as the start position of additive manufacturing when only a few areas of the building panel 31 are still covered with the powder material 41.

[0107] The control unit of the manufacturing system 100 stores S5 the exact horizontal position of the building panel 31 in conjunction with the coater element 62 to be used. For the remaining coater elements 62 in the blade turret 60, the steps described above can be repeated to determine an optimal position of the building panel 31 for each coater element 62.

[0108] Supplementally, it should be noted that “comprising” and “comprising” do not exclude other elements or steps. Further, it should be noted that features or steps that have been described with reference to any of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be regarded as a limitation.