METHOD FOR PRODUCING A WORK PIECE THROUGH GENERATIVE MANUFACTURING, AND CORRESPONDING WORK PIECE

Abstract

A method for producing a work piece includes the providing of a substrate having a predetermined surface structure and the generative manufacturing of a material for the work piece on the surface structure, such that the surface structure defines a base surface of the work piece to be manufactured, wherein the generative manufacturing is carried out by deposition welding and wherein the base surface is an at least partially interior surface of the work piece in respect of a contour of the work piece that is to be manufactured. The method furthermore includes the detaching of the substrate.

Claims

1.-10. (canceled)

11. A method for producing a workpiece for use in a hot gas path of a fluid-flow machine, comprising: providing a substrate having a predetermined surface structure, generative manufacturing of a material for the workpiece on the surface structure, so that the surface structure defines a base surface of the workpiece to be produced, wherein the generative manufacturing is carried out by deposition welding, wherein the base surface is an at least partially interior surface of the workpiece with respect to a contour of the workpiece that is to be manufactured, and wherein the provision is carried out in such a way that the surface structure for the definition of the base surface has at least one surface structure element with a dimension of less than 100 m, and detaching the substrate.

12. The method as claimed in claim 11, wherein the material is a nickel-based or cobalt-based superalloy or a starting material therefor.

13. The method as claimed in claim 11, wherein the workpiece is a high-temperature-resistant component.

14. The method as claimed in claim 11, wherein the provision is carried out in such a way that the substrate comprises a ceramic which forms the surface structure.

15. The method as claimed in claim 11, wherein the provision is carried out in such a way that the surface structure comprises a refractory metal as main constituent.

16. The method as claimed in claim 15, wherein the surface structure is produced by electron beam melting.

17. The method as claimed in claim 11, wherein the provision is carried out in such a way that the surface structure is produced by selective laser melting.

18. The method as claimed in claim 11, wherein the generative manufacturing is carried out by means of laser powder deposition welding, and wherein, during the generative manufacturing, a powder focus is established between the surface structure and a laser focus.

19. A workpiece for use in a hot gas path of a fluid-flow machine, which is produced in accordance with the method as claimed in claim 11, the workpiece comprising: a base surface which is an at least partially interior surface with respect to a contour of the workpiece, and wherein the surface structure for the definition of the base surface has at least one surface structure element with a dimension of less than 100 m.

20. The method as claimed in claim 17, wherein the provision is carried out in such a way that the surface structure is produced by selective laser melting with aluminum or copper as a main constituent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 shows, schematically, the sequence of a method for producing a workpiece.

[0042] FIG. 2 shows, schematically, a workpiece which has been produced by means of the method shown in FIG. 1.

[0043] FIG. 3 shows, schematically, the adjustment of part of a device for deposition welding according to the method described.

DETAILED DESCRIPTION OF INVENTION

[0044] FIG. 1 shows, schematically, the sequence of a method for producing a workpiece or component (cf. designation 100 in FIG. 2), for example a component for a fluid-flow machine such as a gas turbine. The workpiece 100 is advantageously a high-temperature-resistant workpiece used in conjunction with a hot air path of a gas turbine. The workpiece or component is advantageously composed of a nickel-based or cobalt-based superalloy or comprises a corresponding material.

[0045] The method comprises providing a substrate 1, which in FIG. 1 and FIG. 2 is illustrated in a side or sectional view. The substrate 1 comprises a predetermined surface structure 2. The predetermined surface structure 2 is advantageously a surface structure having surface structure elements 10, as indicated in FIGS. 1 and 2. The surface structure elements 10 each have a rectangular cross section. The surface structure elements 10 are advantageously microscopically small. In other words, the surface structure elements 10, advantageously each individual or at least one of the surface structure elements 10, has an external dimension in the micrometer range, advantageously less than 100 m, particularly advantageously less than 80 m or even smaller (cf. dimension a described further below). The surface structure 2 is advantageously predetermined or defined for the production of the workpiece. In other words, the topography of the surface structure is defined.

[0046] Although this is not illustrated explicitly in the figures, the surface structure elements or else only some of them can be different and/or have dimensions differing from one another.

[0047] The method also comprises the generative manufacturing of a material 5 for the workpiece on the surface structure 2, so that the surface structure 2 defines a base surface 3 of the workpiece to be produced. This is indicated in FIG. 1 by the fact that the surface structure 2 forms a negative and the base surface 3 or the surface structure of the latter (not explicitly identified) forms a corresponding positive. In other words, the surface structure 2 of the substrate 1 is formative for the base surface of the workpiece 100. The deposited material and/or the finished workpiece (cf. FIG. 2) accordingly have the base surface 3.

[0048] In FIG. 1, the workpiece has not yet been finally produced (cf. designation 100 in the figure). In the following, the material 5 can therefore be designated synonymously with the workpiece 100. The material can in particular be a starting material for the workpiece.

[0049] Furthermore, the method for producing the workpiece can comprise one or more heat treatments, for example for establishing specific phase precipitations. This can involve, in particular, expedient phase precipitations or settings of the y or y phases of the respective material of the superalloy to be produced.

[0050] The generative manufacturing is advantageously carried out by means of deposition welding, for example laser cladding (LMD), in particular laser powder deposition welding. The aforementioned methods or techniques of deposition welding are advantageously executed with CAD and/or robot assistance or can be controlled appropriately. A corresponding laser cladding device is indicated by the designation 6 in FIG. 1.

[0051] The material 5 for producing the workpiece 100 is advantageously fabricated or produced in accordance with the method described by laser powder deposition welding. Here, within the context of the method described for producing the workpiece, the latter is advantageously fabricated in accordance with the material properties that are expedient for the desired (3D) structure. Process parameters such as the laser power, the exposure time of the laser or further parameters can be set in accordance with the desired material phase. Furthermore, for example at points or edges of the workpiece to be produced that are difficult to access, a longer exposure time may be necessary than at other points. In addition, during scanning during the material construction, an apparatus head of the deposition welding device can be guided by or with the aid of a feedback loop.

[0052] FIG. 2 shows, inter alia, the finally produced workpiece or component 100 which has been or can be produced by means of the method described. The workpiece 100 is still connected in one piece to the substrate 1. Accordingly, the base surface 3 of the substrate constitutes an impression of the surface structure 2 or comprises the same. Advantageously, by means of the method described, by means of the pre-definition of the surface structure on the substrate, the base surface of the workpiece to be produced is defined, imaged or molded, in order to transfer the surface structure to the workpiece and thus to produce a particularly high-resolution and/or microscopically structured base surface of the workpiece.

[0053] The workpiece 100 in FIG. 2 has a contour 4 which encloses or envelops the workpiece 100, including the surface structure elements of the latter. The contour 4 is illustrated by the dashed line in FIG. 2 and, in conjunction with the material 5, also in FIG. 1. The base surface 3 is, with respect to the contour 4 of the workpiece 100 to be produced, an at least partly interior surface of the workpiece 100.

[0054] The surface structure elements 10 shown in FIGS. 1 and 2, or at least one of them, advantageously has/have a dimension a of less than 100 m. The dimension advantageously refers to a width (cf. horizontal direction in FIGS. 1 and 2) of the respective surface structure elements 10 and not to a corresponding depth or height. Accordingly, the width can designate a direction along the contour.

[0055] Therefore, the smaller the width or the dimension a of the surface structure elements 10 of the substrate 1, the smaller, finer or more intricately is the base surface 3 of the workpiece also structured.

[0056] Particularly advantageously, at least one of the aforementioned surface structure elements 10 or all of the same can have an external dimension a of less than 80 m or even less.

[0057] According to one embodiment of the present invention, the substrate 1 is a ceramic or a cast component or comprises, for example, a ceramic, at least on the surface structure 2. The substrate 1 can be produced or provided, for example, by precision casting with the aid of ceramic casting cores. Advantageously, the surface structure 2 is formed by a ceramic casting core. The casting core consists, for example, of aluminum oxide, for example Al.sub.2O.sub.3, or silicon dioxide (SiO.sub.2) or comprises one of these materials. In other words, the provision can be carried out appropriately in accordance with the method described.

[0058] Furthermore, the casting core advantageously has very fine powder granulation on the outside, in order expediently to be able to resolve a fine, for example microscopically small, surface structure. With increasing distance from the surface structure, the material of said substrate (of the casting core) can comprise a granulation or graduation becoming more and more porous or coarser, in order at the same time still to have an adequate (thermal) shock resistance. Such a graduated component advantageously has a particularly small and technologically desired surface roughness of only 50 m or less, for example 30 m. The aforementioned roughness can be an average roughness, a quadratic roughness or a median roughness.

[0059] According to one refinement, the substrate comprises a refractory metal, for example tantalum, zirconium, molybdenum or tungsten or another high melting-point, for example non-precious, metal of the fourth, fifth or the sixth secondary group of the periodic table, at least on or as the surface structure 2. According to this refinement, the surface structure is advantageously produced by electron beam melting.

[0060] According to a further refinement, the surface structure 2 is produced by selective laser melting. According to this refinement, the surface structure 2 of the substrate 1 advantageously has copper or aluminum as main constituent. Alternatively, the substrate 1 can consist of other materials or comprise said materials.

[0061] Although this is not explicitly illustrated in the figures, the method also comprises the detachment of the substrate 1 after the generative manufacturing. The substrate can be detached selectively in chemical ways for all the embodiments described. For example, irrespective of whether the substrate or the surface structure is metallic or ceramic, the workpiece can be detached chemically. For example, in the case of a substrate having an aluminum surface structure, the detachment can be carried out by means of concentrated nitric acid and at temperatures between 50 C. and 80 C.

[0062] FIG. 3 shows, schematically, the adjustment of part of a device for deposition welding according to one refinement of the method. This refinement relates in particular to the generative manufacturing by means of laser powder deposition welding. Accordingly, a laser cladding device 6 is indicated. In addition, according to this refinement, the surface structure 2 of the substrate 1, as described above, is advantageously formed from a ceramic or by means of selective laser melting from a metal, or comprising the latter.

[0063] It can be seen in particular in FIG. 3 that the laser cladding device 6 has a powder focus 7. The laser cladding device 6 also has a laser focus 8. The powder focus 7 is/has been established in the vertical direction, for example along a construction direction AR of the workpiece 100, between the substrate 1 and a laser focus 8. As a result, it is then advantageously possible to avoid the surface structure which, according to this refinement, is advantageously formed by a ceramic or a non high-melting-point metal, melting or burning as a result of the influence of the laser beam.

[0064] The invention is not restricted to the exemplary embodiments by the description using the same but in particular comprises any combination of features in the patent claims, even if this feature or this combination is not itself explicitly specified in the patent claims or exemplary embodiments.