IRRADIATION STRATEGY FOR A COOLABLE, ADDITIVELY MANUFACTURED STRUCTURE

Abstract

A method for providing manufacturing instructions for the powder-bed-based additive manufacturing of a component includes providing first irradiation vectors for a layer to be additively manufactured, which first irradiation vectors, upon appropriate irradiation by an energy beam, in particular a laser beam or electron beam, cause a porous structure of the layer, as well as providing the first irradiation vectors for a layer which is to be additively manufactured and which follows the layer, in such a way that paths of a porous structure of the layer and of the following layer at least partially overlap in order to allow for a flow through the manufactured component along a build-up direction.

Claims

1.-14. (canceled)

15. A method for providing manufacturing instructions for powder-bed-based additive manufacturing of a structural part, comprising: providing first irradiation vectors (V1) for a layer (n) to be additively manufactured, which upon corresponding irradiation by an energy beam bring about a porous structure of the layer, and providing the first irradiation vectors (V1) for a layer (n+1) that follows the layer (n) and is to be additively manufactured in such a way that paths of a porous structure of the layer (n) and of the following layer (n+1) at least in part overlap in order to allow flow through the manufactured structural part along a build-up direction (Z) of the structural part (10), wherein the first irradiation vectors (V1) of the following layer (n+1) are twisted (φ) relative to the first irradiation vectors (V1) of the layer (n), wherein the first irradiation vectors (V1) of the layer (n) and of the following layer (n+1) overlap in a layer plane by an amount that is smaller than a lateral extent of the paths, and wherein second irradiation vectors (V2) are provided for irradiation of the layer (n) to be additively manufactured and/or in the following layer (n+1) to be additively manufactured, which bring about a dense structure of the corresponding layer.

16. The method as claimed in claim 15, wherein the first irradiation vectors (V1) of the following layer (n+1) are offset (d) relative to the first irradiation vectors (V1) of the layer (n).

17. The method as claimed in claim 15, wherein an irradiance (P) of the first irradiation vectors (V1) is reduced and/or an irradiation speed (v) thereof is increased relative to standard parameters for forming a solid material structure.

18. The method as claimed in claim 15, wherein the first irradiation vectors (V1) represent a plurality of parallel irradiation vectors of each layer for the structural part.

19. The method as claimed in claim 15, wherein the first irradiation vectors (V1) represent a plurality of radially or radially symmetrically running irradiation vectors of each layer for the structural part, and wherein the first irradiation vectors (V1) of the following layer are twisted (φ) relative to the first irradiation vectors of the layer.

20. The method as claimed in claim 19, wherein further irradiation vectors (V3) are provided which represent a plurality of concentric irradiation vectors of each layer for the structural part, and wherein the further irradiation vectors (V3) bring about an at least in part porous structure of each layer.

21. The method as claimed in claim 20, wherein the further irradiation vectors (V3) for the layer (n) and for the following layer (n+1) are provided, and wherein the further irradiation vectors (V3) of the following layer are offset radially relative to the further irradiation vectors (V3) of the layer.

22. The method as claimed in claim 15, wherein the method is a Computer-Aided-Manufacturing (CAM) method.

23. A method of additively manufacturing the structural part by selective laser melting or electron beam melting, comprising: implementing the manufacturing instructions as claimed in claim 15.

24. The method as claimed in claim 23, wherein the manufacturing instructions for the layer to be additively manufactured are defined in a first structural part region of the structural part, and wherein further manufacturing instructions which are different from the manufacturing instructions are defined in a second structural part region which is different from the first structural part region.

25. A structural part manufactured according to the method as claimed in claim 23, wherein the structural part is a component of a hot gas path of a turbomachine that is to be cooled, a turbine blade, a heat shield component of a combustion chamber, and/or a resonator structural part.

26. A non-transitory computer readable medium comprising a computer program product stored thereon, comprising: manufacturing instructions for powder-bed-based additive manufacturing of a structural part, wherein the manufacturing instructions implement the method as claimed in claim 1 when executed by a computer.

27. The non-transitory computer readable medium of claim 26, which, when executed by a computer, control and/or program a build processor and/or an irradiation apparatus of an additive manufacturing system, to cause the computer to carry out the manufacture of a structural part, wherein the structural part is a component of a hot gas path of a turbomachine that is to be cooled, a turbine blade, a heat shield component of a combustion chamber, and/or a resonator structural part.

28. The method as claimed in claim 15, wherein the energy beam comprises a laser or electron beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 uses a schematic illustration to indicate a powder-bed-based additive manufacturing method.

[0052] FIG. 2 indicates a schematic perspective view of courses of a cooling fluid flow in a structural part and also individual layers thereof that are to be solidified.

[0053] FIG. 3 shows a schematic plan view of irradiation vectors for a layer to be additively manufactured.

[0054] FIG. 4 shows a schematic plan view of irradiation vectors for a following layer to be additively manufactured.

[0055] FIG. 5 indicates on the left—similarly to FIG. 2—a schematic lateral or sectional view (XZ-plane) of flow courses in a structural part. In the right part of the illustration, a layer profile and an offset of the irradiation paths are indicated.

[0056] Analogously to FIG. 5, FIG. 6 indicates a schematic lateral or sectional view (YZ-plane) of flow courses in a structural part.

[0057] FIG. 7 shows a schematic plan view of irradiation vectors running radially.

[0058] FIG. 8 shows a schematic plan view of irradiation vectors running radially and concentrically.

[0059] Similarly to FIG. 8, FIG. 9 shows a schematic plan view of irradiation vectors for a layer to be additively manufactured.

[0060] FIG. 10 shows a schematic plan view of irradiation vectors for a layer to be additively manufactured following the aforementioned layer.

[0061] FIG. 11 shows a schematic perspective view of a rotationally symmetric structural part portion with flow paths running in part longitudinally and circumferentially.

[0062] Similarly to FIGS. 9 and 10, FIGS. 12 and 13 indicate a radial offset of concentrically running irradiation courses of layers to be additively manufactured that follow one after the other.

[0063] Analogously to FIG. 11, FIG. 14 shows a corresponding perspective view of a structural part portion according to FIGS. 12 and 13.

[0064] FIG. 15 indicates a radial section of the structural part according to the embodiment shown in FIGS. 12 to 14.

DETAILED DESCRIPTION OF INVENTION

[0065] In the exemplary embodiments and figures, elements that are identical or have the same effect can each be provided with the same reference signs. The elements shown and their proportions to one another are fundamentally not to be regarded as true to scale; rather, individual elements can be shown exaggeratedly thick or with large dimensions for better presentability and/or for better understanding.

[0066] FIG. 1 indicates steps of an additive manufacturing process of a structural part 10 with reference to a manufacturing system 100 shown in simplified form.

[0067] The manufacturing system 100 is preferably designed as an LPBF system and for the additive buildup of structural parts or components from a powder bed, in particular for selective laser melting. The system 100 can in particular also relate to a system for selective laser sintering or electron beam melting. Accordingly, the system has a build platform 1. A structural part 10 to be additively manufactured is created layer by layer from a powder bed on the build platform 1. The powder bed is formed by a powder P, which can be distributed layer by layer on the build platform 1 by a coating device 3.

[0068] After each layer L of powder P has been applied with a layer thickness, regions of the layer L are selectively melted with an energy beam 5, for example a laser or electron beam, from an irradiation device 2 and then solidified according to the specified geometry of the structural part 10.

[0069] The system 100 preferably has an irradiation apparatus 2 for irradiating the powder layers L with an energy beam 5.

[0070] After each layer L, the build platform 1 is preferably lowered by an amount corresponding to the layer thickness L (cf. the downwardly pointing arrow in FIG. 1). The thickness L is usually only between 20 and 40 μm, so that the entire process easily requires a number of thousands to several tens of thousands of layers.

[0071] The geometry of the structural part 10 is usually defined by a CAD file (“computer-aided design”). After such a file has been read into the manufacturing system 100, the process then first requires the definition of a suitable irradiation strategy, for example by means of CAM (“computer-aided manufacturing”), as a result of which the structural part geometry is also divided into the individual layers. This can be carried out or implemented by a corresponding build processor 4 using a computer program.

[0072] The structural part 10 is preferably a coolable component of the hot gas path of a turbomachine that it to be cooled during operation, such as a turbine blade, heat shield component of a combustion chamber, and/or a resonator component, for example a Helmholtz resonator.

[0073] Alternatively, the structural part 10 may be a ring segment, a burner part or a burner tip, a frame, a shield, a heat shield, a nozzle, a seal, a filter, an orifice or lance, a stamp or an agitator, or a corresponding transition, insert, or a corresponding retrofit part.

[0074] In order to implement or process manufacturing instructions for the buildup of the structural part (see further below), for example based on a specified CAD geometry of the structural part, the aforementioned build processor 4 or a corresponding circuit is provided which can be programmed, for example, with corresponding CAM information or manufacturing instructions and/or can correspondingly cause the irradiation apparatus 2 to build up the structural part layer by layer in accordance with the manufacturing instructions described further below. The build processor circuit 4 preferably acts as an interface between the software that prepares the actual build process and the corresponding hardware of the manufacturing system 100. For this purpose, the build processor can be set up, for example, to execute a computer program (cf. computer program product CPP) with corresponding manufacturing instructions.

[0075] Methods for providing manufacturing instructions for the powder-bed-based additive manufacturing of the structural part 10 comprise, according to the invention, providing first irradiation vectors V1 for a layer n to be additively manufactured (see figures further below), which, when correspondingly irradiated by the energy beam 5, bring about a porous structure of the layer n. The method furthermore comprises providing the first irradiation vectors V1 for a layer n+1 to be additively manufactured following layer n in such a way that paths 11 of a porous structure 12 of the layer n and of the following layer n+1 at least partially overlap in a layer plane in order to allow flow through the manufactured structural part along and/or obliquely to its build-up direction Z.

[0076] FIG. 2 indicates a perspective view of a structural part or a structural part portion which can be built up additively layer by layer. The dashed lines distinguish individual structural part layers. The arrows running diagonally or obliquely denoted by the reference sign F are intended to indicate a corresponding direction of flow, according to which a cooling fluid can expediently flow through the structural part portion for cooling during intended operation.

[0077] According to the illustration, the direction of flow F runs at least partially in the XZ-plane and is slightly inclined relative to the build-up direction Z. In order to ensure such through-flow capacity or permeability of the structural part, a scanning or irradiation strategy according to the invention must already be defined in advance.

[0078] In particular, such a functionality with a porosity or permeability running diagonally or obliquely to the build-up direction Z can no longer be achieved by way of irradiation parameters that are of the same type layer by layer or are arranged in the same way layer by layer, but rather an offset of irradiation vectors with correspondingly selected or varied irradiation parameters is preferably required.

[0079] To achieve a porous structure in the described cooling passages or channels, for example, an irradiance P of the first irradiation vectors V1 can be reduced and/or an irradiation speed v thereof can be increased relative to standard parameters for forming a solid material structure. This is indicated in FIG. 3 and the following figures.

[0080] FIG. 3 shows the first irradiation vectors V1 (vertical), which bring about the functional porosity. These are arranged in a grid-like manner only as an example. According to the illustration in FIG. 3, the first irradiation vectors V1 comprise a plurality of parallel irradiation vectors of a given layer n for the structural part 10. The layer n can mean any layer in the layer construction of the structural part.

[0081] In addition, second irradiation vectors V2 can be provided for irradiating the layer n to be additively manufactured and/or in the following layer n+1 to be additively manufactured (cf. FIG. 4 further below), which bring about a dense structure of the corresponding layer, in particular a solid material. This is indicated in FIG. 3 by the background. Such a dense structure is usually expedient for reasons of stability or for the dimensional stability of the structural part 10.

[0082] Moreover, further, third irradiation vectors V3 can be provided (horizontally) in the manner of a grid. These vectors V3 can likewise bring about a porous structure in the structural part portion, for example a different type of porous structure with a differently dimensioned porosity, of the corresponding layer.

[0083] Irradiation according to the first irradiation vectors V1 and the further irradiation vectors V3 can, for example, each involve a porosity of between 5% and 40%, preferably of about 20%.

[0084] FIG. 4 schematically shows—analogously to FIG. 3—a plan view of a structural part layer n+1 following that shown in FIG. 3, or a corresponding raw powder layer. The arrangement of the first irradiation vectors V1 shows a linear offset of these irradiation vectors relative to layer n (cf. FIG. 5).

[0085] This offset allows the permeability profiles shown in FIG. 5 to form obliquely to the build-up direction (cf. also FIG. 2). In the left-hand part of the illustration, FIG. 5 shows a lateral view of the structural part portion in the XZ-plane with paths 11 running diagonally in the structure of the structural part, which are intended to indicate a cooling or flow path.

[0086] In the right-hand part of the illustration in FIG. 5, the situation is shown enlarged for three successive layers n, n+1 and n+2. It can be seen that the structure paths 11 solidified by the first irradiation vectors V1 in the course of the additive manufacturing process are offset layer by layer by the amount d in order to produce the diagonal or oblique profile.

[0087] In other words, the scanning strategy introduced is based on a shift of the irradiation vectors in a preferred direction in order to promote the formation of the cavities or flow paths to be flowed through. If, for example, a flow is to occur, as in the example shown, at an angle of more or less than 90° relative to the XY- or layer plane, i.e. at least partially along the Z-direction, a vector V1 in the layer n+1 is translationally shifted by the amount d along the positive X- or Y-direction. The amount d determines here the desired angle that the course of the flow paths should form with respect to the build-up direction Z.

[0088] As an alternative to this arrangement, an offset can also be dispensed with completely in order to achieve an exactly vertical course of the paths 11 (not explicitly marked).

[0089] Analogously to FIG. 5, FIG. 6 indicates a situation in the other lateral direction, the Y-direction, relative to the build-up direction Z.

[0090] On the left is again shown a lateral view of the structural part portion in the YZ-plane with diagonally running paths 11 in the structure of the structural part, which are intended to indicate a through-flow.

[0091] In the right-hand part of the illustration in FIG. 6, the situation in the layer cross section is again indicated. Without restricting generality, an offset d similar to that shown in FIG. 5 is indicated here, so that overall a uniform diagonally oblique course of the paths 11 results for the structural part 10.

[0092] FIG. 7 shows a plan view of a circular manufacturing area or a round layer region. A radial direction is marked starting from a central region with an arrow and the reference sign R. First irradiation vectors V1 of a corresponding irradiation pattern are arranged or provided along R—in the present case arranged radially symmetrically only by way of example—in order to form a porous layer structure. After manufacturing, this advantageously again allows a radial through-flow of a fluid F and a correspondingly achievable cooling in the structural part.

[0093] The aforementioned first irradiation vectors V1 run uniformly at a distance of a polar angle. Contrary to what is shown, this angular distance can of course also vary between individual vectors V1.

[0094] Furthermore, second irradiation vectors—for forming a dense material structure of the layer—are designated. These vectors V2 signify the remaining layer structure and—for the sake of clarity—are shown without individual irradiation paths.

[0095] In particular in the case of rotationally symmetric structural parts or structures, scan vectors according to FIG. 7 can be provided.

[0096] In addition to this, a plurality of further, concentrically arranged irradiation vectors V3 are indicated in FIG. 8, which likewise bring about an at least in part porous structure of one of the layers. This is so that, for example, a cooling effect can also be brought about in the circumferential direction if the structural part is intended to be flowed through and cooled accordingly during operation.

[0097] In FIG. 8, the stated irradiation vectors V1 running radially are supplemented by concentric tracks or profiles V3, which run at a radial distance from one another and can form both a closed and an interrupted profile. This applies equally to the other irradiation vectors described. The permeability for a cooling fluid F can be achieved, for example, by omitting layers and reducing their introduced energy. For example, open sites, which allow a corresponding permeability, can also be provided in a targeted manner.

[0098] For other applications, an impermeable “wall” can in contrast be provided—for example in sectors—if the structural part 10 or the corresponding structural part region is to be cooled only in the Z-direction, for example.

[0099] If the vectors are now adapted or shifted from layer to layer, similarly to the embodiments described above, a three-dimensional through-flow can likewise be made possible. This is indicated in the following figures.

[0100] FIG. 9 shows, for a given layer n, an irradiation pattern already described with reference to FIG. 8, comprising the first, second and further, third irradiation vectors V1, V2 and V3.

[0101] FIG. 10 shows the situation again for a—preferably immediately—following layer n+1. It can be seen that the first irradiation vectors V1 of the following layer n+1 have been twisted clockwise by a small angle Ay relative to the first irradiation vectors V1 of the layer n. With this configuration of the present invention, the through-flow capacity and cooling effect can likewise be tailored in an advantageous manner and decisively improved locally.

[0102] FIG. 11 shows a perspective schematic view of a cylindrical or approximately rotationally symmetric structural part structure which can be manufactured according to an irradiation pattern according to FIGS. 9 and 10. In this case, the first irradiation vectors V1 were in each case twisted or rotationally offset, layer by layer, so that the paths 11 of the structural part 10 that are shown and run obliquely relative to the build-up direction Z can be manufactured. According to the illustration in FIG. 11, a counterclockwise twist is shown.

[0103] FIGS. 12 to 14 moreover indicate that, in addition to twisting the flow-active paths (cf. V1) in the structural part 10, a whirlpool effect (cf. irradiation vectors V3) or eddy-like through-flow and cooling can also be achieved. For this purpose, the concentric tracks can be provided layer by layer, for example, with a radial offset (cf. Ar), and thus a correspondingly improved through-flow and cooling can be specified over the entire structural part. This is shown in particular in FIG. 13 for the layer n+1.

[0104] The radial offset can also be provided without a polar offset, and vice versa.

[0105] FIG. 14 shows a perspective schematic view of the structural part 10 with both a radial and a polar offset of the porosity-creating irradiation vectors V1 and V3.

[0106] Such a scanning or irradiation strategy could, for example, be used to supply a lubricant to a structural part region or to a bearing in the Z-direction, and then can evenly transfer to a shaft both circumferentially and over the length and radius of the bearing.

[0107] A radial or longitudinal section of the structure from FIG. 14 is shown in FIG. 15, where in particular the concentric and longitudinal flow paths are oriented slightly obliquely to the Z-direction due to the radial offset layer by layer (cf. FIGS. 12 and 13).

[0108] The irradiation strategies introduced advantageously allow a tailoring of cooling or heat dissipation properties of thermally highly loaded structural parts in general. Of course, the thermal properties could likewise be adapted and improved only with respect to local or individual regions of the component with the solutions introduced.