METHOD FOR ADDITIVE MANUFACTURING WITH SELECTIVE REMOVAL OF BASE MATERIAL

Abstract

A method for the additive manufacturing of a component, includes the selective removal, in particular suctioning, of a base material for the component during the additive buildup, wherein the base material is removed from a predetermined region of a production surface during a movement of a coating device for the additive manufacturing.

Claims

1.-14. (canceled)

15. A method for additive manufacturing of a component, comprising: selectively removing a base material for the component during additive build up, wherein the base material is removed from a predetermined region of a production surface during a movement of a coating device for the additive manufacturing, and introducing at least one pre-manufactured component element, after the selectively removing, into an additive buildup in such a way that the component element delimits a cavity, defined by removed base material, directly in a buildup direction.

16. The method as claimed in claim 15, wherein the selectively removing is carried out during a coating process of the method.

17. The method as claimed in claim 15, wherein the selectively removing is carried out during a rearward movement of a coating device for the additive manufacturing and/or after an exposure process.

18. The method as claimed in claim 15, wherein sidewalls of the component, which adjoin the predetermined region, are mechanically afterworked after the selectively removing.

19. The method as claimed in claim 18, wherein the component element for the additive buildup of a subsequent component layer forms at least partially a production surface which, after introduction of the component element, is coated with a new base material layer.

20. The method as claimed in claim 15, wherein software automatically calculates a quantity of the base material required for a subsequent coating process, based on a volume of the removed base material.

21. The method as claimed in claim 15, further comprising: laterally coating of the production surface with the base material by a coating device, wherein, depending on a volume to be covered of the region of the production surface brushed over by the coating device, the coating speed is adjusted for an optimum coating result.

22. The method as claimed in claim 21, wherein for large layer thicknesses or for large volumes to be covered with base material the coating speed is selected to be lower than for proportionally smaller layer thicknesses or smaller volumes to be covered with base material.

23. A device for the additive manufacturing of a component, wherein the device is designed for selectively removing a base material from the predetermined region by suction during the additive manufacturing according to the method as claimed in claim 15, comprising: a suction head which is connected to a coating device for the additive manufacturing and is moveable relative to the production surface.

24. The device as claimed in claim 23, wherein the suction head is moveable both laterally along the production surface and perpendicularly to the production surface so that powder beneath the production surface is also removeable.

25. The device as claimed in claim 23, wherein a suction power of the device is sufficient to move component elements up to a predetermined thickness over the production surface by a negative pressure during the additive manufacturing.

26. The device as claimed in claim 23, further comprising: a protective gas suction device which is designed for removing the removed base material via from a production space for the additive manufacturing.

27. A plant for additive manufacturing, comprising: the coating device, and the device for the additive manufacturing of a component as claimed in claim 23.

28. The method as claimed in claim 15, wherein the selectively removing of the base material comprises suction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Further details of the invention are described below with reference to the figures.

[0052] FIG. 1 shows a schematic sectional or side view of a plant, comprising a device according to the invention.

[0053] FIG. 2, corresponding to the view of FIG. 1, shows an alternative view of the device according to the invention.

[0054] FIGS. 3 to 6 indicate in each case, in a view similar to FIGS. 1 and 2, method steps according to the invention.

[0055] FIGS. 7 and 8 indicate in each case, in a view similar to FIGS. 1 and 2, embodiments of the method according to the invention.

[0056] FIG. 9 shows a schematic flow diagram of the method according to the invention.

DETAILED DESCRIPTION OF INVENTION

[0057] In the exemplary embodiments and figures, the same elements or elements functioning in the same way can be provided in each case with the same designations. The depicted elements and their proportional relationships to each other are not basically to be seen as being to scale, rather individual elements can be shown as being excessively thick or with large dimensions for better presentability and/or for better understanding.

[0058] FIG. 1 shows a plant 100 for the additive manufacturing of a component 3. The plant 100 comprises a device 10 for the additive manufacturing of the component 3.

[0059] In the case of the additive manufacturing process for the component 3, described in the present case with reference to the plant 100 and to the device 10, it is advantageously a powder bed-based manufacturing process, advantageously a selective laser melting process, or alternatively to this, an electron beam melting process or selective laser sintering process.

[0060] Shown in the bottom region of FIG. 1 is a powder bed with a powdered base material 1 for the component 3 (compare FIG. 3). The base material 1 forms a powder bed with a production surface HOB. Shown above the production surface HOB is the device 10. The device 10 is a device for the selective removal, especially sucking out, of powder from regions of the production surface HOB in order to simplify or to improve an additive manufacturing process for the component 3.

[0061] The component 3 is advantageously a high temperature-resistant component, advantageously for use in the hot gas path of a gas turbine. Consequently, the component 3 is advantageously produced from a nickel-based alloy or superalloy. Consequently, the base material is advantageously a powder of a corresponding alloy.

[0062] The device 10 comprises a suction head 12. The suction head 12 advantageously has a comparatively small diameter for sucking out the base material or powder in order to provide a corresponding suction power (for the powder removal) for an expedient spatial dissipation. The suction head 12 is also advantageously movable relative to the production surface HOB, i.e. in the X, Y and Z-directions (compare the coordinate systems at bottom left in the powder bed). The Z-direction advantageously describes a buildup direction for the component (compare FIG. 3).

[0063] The device 10 furthermore comprises a collecting bin 11 in which the removed or sucked out powder can be collected and held for example during the movement of the device 10. The base material or powder 1, differing from that identified in the figure, can be directed by means of a corresponding pipe or hose into the collecting bin 11 and be separated out therein for example by means of a cyclone.

[0064] The device 10 advantageously also has a coating tool or a coating device 20. The device 10 can especially be connected to the coating device 20 or be provided in one piece with this. The coating device 20 can for example comprise or constitute a slide, a doctor knife, a blade and/or a brush.

[0065] Alternatively or additionally, the device 10 could be connected to the coating device 20 in such a way that the device 10 is still movable, for example in the X- and/or Y-direction relative to the coating device. Consequently, the device 10similar to a carriagecould be able to run over a rail for example in the X- and/or Y-direction.

[0066] FIG. 1 furthermore shows an irradiating device, advantageously a device for exposing the powder bed to a laser beam or electron beam according to a geometry which is predetermined for the component 3. The geometry advantageously already exists in the form of CAM/CAD data or other construction data before the manufacturing process. By the same token, the component is already divided into the individual component layers (slicing) in the construction data beforehand.

[0067] By means of the vertical dashed line in FIG. 1, it is indicated purely schematically that the powder bed can comprise a spillover at the edge into which surplus powder which is moved by the coating device 20 can be emptied.

[0068] FIG. 1 advantageously shows a sectional view sectioned along the XZ-plane (compare coordinate system at bottom left).

[0069] FIG. 2 shows an alternative view of the device 10. In contrast to FIG. 1, the device from FIG. 2 shows a connection, connected to a protective gas suction device 30, via which the powder 1 can be removed for example from a manufacturing or installation space (not further identified). This advantageously takes place during a movement of the coating device 20. The referenced connection (not explicitly identified in the figure) can have an angle piece, especially of any practical shape, which is advantageous for producing a fluidic communication between the suction head 12 and the protective gas suction device 30.

[0070] In the embodiment of the device 10 according to FIG. 2, the collecting bin 11 shown in FIG. 1 can be dispensed with.

[0071] FIG. 2 shows a sectional or side view sectioned along the YZ-plane (compare coordinate system at bottom left).

[0072] FIG. 3 shows a situation of the plant 100 in which a component 3 has already been partially additively built up, that is to say built up in layers by alternative coating of the production surface HOB and by irradiating the corresponding powder layer, e.g. by means of a laser beam. The component 3, as is customary in additive production, has been built up on a lowerable build platform 6.

[0073] It is also shown that during a movement of the device 10 along a coating direction BR (compare arrow directed to the left) base material is removed from the production surface HOB above the component 3 by means of suction. This can also be carried out in a number of steps or movements of the device 10.

[0074] FIG. 4 shows a method step of the method according to the invention, in which subsequent to the situation shown in FIG. 3, but advantageously after a complete cavity 8 or sucked out region AB has been freed of base material 1 (compare FIG. 4), a component element 5 is advantageously moved from a location behind the described spillover into a region above the component 3 and advantageously above the referenced cavity 8. The component element is in particular moved along a rearward direction RR which is opposite to the coating direction BR.

[0075] During the sucking out, for example during the rearward movement RR of the coating device 20, the build platform 6 can also be lowered. In this way, the coating device 20, e.g. its blade, does not touch the last produced component layer.

[0076] Since, moreover, depending on the suction power of the device 10, powder can only be sucked out from a specified depth of the powder bed, the suction head 12 or a corresponding nozzle thereof can be movable along the Z-direction and can also suck out powder 1 below the production surface HOB accordingly.

[0077] The component element 5 can consist of the same or a similar material as the rest of the component 3. The component element 5 can for example be pre-manufactured by means of the same method.

[0078] Shown in FIG. 5 is a situation in which the component element 5 has already been moved by the device 10 onto the component 3 by means of a negative pressure applied by the suction head 12 in such a way that the cavity 8 is completely covered.

[0079] For this purpose, a thickness of the component element 5 should not be selected to be excessively thick in order to also keep the weight of the component element within reasonable limits and to be able to reliably suck it on and moved it by means of the suction head 12.

[0080] The thickness D of the component element 5 can for example correspond to a multiple of a component layer thickness or to a corresponding thickness of a layer of the base material. Normal base material layer thicknesses lie within the range of between 20 and 50 m. The thickness D can for example be a few millimeters.

[0081] Reference should be made to the fact that the sucking on of the component element 5 and the removal of the base material 1 from the production surface HOB offers an associated advantage (synergy) for the described method since only in this way can closed cavities in additively produced components be freed of powder and therefore be expediently manufactured without excessively complicated plant engineering.

[0082] Correspondingly, the cavity 8, which in addition to the component element 5 is also defined by the hitherto built up structure of the component 3, can be completely closed (compare FIG. 6).

[0083] During the further additive manufacturing, a production surface, formed by the component element 5, is now advantageously coated with new base material (a coating with new base material is not explicitly identified in FIGS. 3 to 6), as a result of which more stability can be imparted to the structure of the component with the increase in built up layers, and therefore a bridge also extends over the cavity 8 without the risk of breaking.

[0084] FIG. 7 shows a situation in which a production surface, especially regions in places of the component 3 solidified last, has been freed of base material 1 by the device (not explicitly identified in FIG. 7), as described above. These regions are identified by AB (sucked out region). It can in particular be expedient to free edge regions of the component 3 of powder during the additive manufacturing in order to machine the edge regions mechanically or using the laser without the adjacent powder influencing the process.

[0085] FIG. 8 schematically indicates that within the scope of the present invention, for example depending on flow behavior of the powder in specified regions of the production surface, the coating speed, in contrast to other V1-regions, can be altered in order to ensure a cleaner or more reliable filling up, deposition or coating.

[0086] In other words, the described method can comprise the lateral coating of the production surface HOB with base material 1 by means of the coating device 20, whereindepending on the volume to be covered of the lateral region of the production surface HOB brushed over by the coating devicethe coating speed (cf. V1, V2) is adjusted for an optimum coating result.

[0087] For example, for large coating thicknesses or for large volumes to be covered with base material 1 the coating speed V2 can be selected to be lower than for proportionally smaller layer thicknesses or smaller volumes to be covered with base material 1 in order to achieve a better coating result.

[0088] The coating speed can also be adjusted or reduced automatically or semi-automatically via software (compare method steps B in FIG. 9). In particular, starting from a specified sucked out volume multiple coatings can be, or should be, applied as standard. A so-called boost factor in the software can for example automatically adjust the quantity of powder which is made available in a coating step.

[0089] After deposition of a new layer in a region previously freed of powder, a check can advantageously be carried out as to whether a uniform powder bed exists again. This can be carried out visually or by other suitable means. In the event of a negative result, the coating process can be repeated (before scanning or exposure).

[0090] FIG. 9 shows schematically and possibly incompletely method steps according to the invention based on a flow diagram.

[0091] The flow diagram comprises a method step a) which relates to a coating step, for example of the above-described production surface HOB. This step can be a conventional technique or a technique which is common in the prior art for coating a component surface.

[0092] The method step b) describes an exposure to, irradiation by, or subjection to, an energy beam, for example a laser beam, in order to correspondingly additively build up the component according to its predetermined geometry (see above).

[0093] In a subsequent method step (not explicitly identified in FIG. 9), a data processing device of the plant 100 and/or of the device 10, for example via a corresponding program or software, can automatically calculate the quantity of base material 1 required for a subsequent coating process, based on the volume of the previously removed base material 1. The sucked out volume in this case increases the quantity of powder which has to be deposited in the following step, unless the volume has been closed off in an intermediate step by the insertion of a component element, as described above. This aspect can be automatically adjusted by the described software for example by a travel distance, along which a piston of a powder feed device is moved upward for example along the Z-direction, being increased each time via a corresponding parameter in the software. In the case of other deposition mechanisms the deposited quantity of powder can also be correspondingly adjusted.

[0094] The method step c) advantageously relates to the selective removal of the base material for predetermined regions of the production surface, especially for freeing regions of the component which are not intended to hold powder, as described above, by suction.

[0095] As possible subsequent method steps, the steps d1), d2) and d3) are shown cumulatively or alternatively in FIG. 9.

[0096] Step d1) indicates a further exposure step (laser scanning) for solidifying the base material (cf. step b) above). After the selective removal of the powder, further powder-freed or deeper lying regions can therefore be exposed and/or remelted within the scope of the present invention.

[0097] Step d2) indicates a possible mechanical afterworking of side surfaces of the component which are freed of powder, as described above, in order to improve corresponding surface properties.

[0098] Step d3) relates to the introduction of a component element, as described above, especially for covering a cavity, so that in this region the construction of costly support structures can be advantageously dispensed with.

[0099] The method steps shown in the flow diagram of FIG. 9 can advantageously be iteratively implemented within the scope of an additive manufacturing process.

[0100] By the description based on the exemplary embodiments, the invention is not limited to these but covers each new feature and each combination of features. This especially contains each combination of features in the patent claims, even if this feature or this combination itself is not explicitly disclosed in the patent claims or exemplary embodiments.