Method for the modular additive manufacturing of a component and a component

0001The present invention relates to a method for the additive, in particular modular, production of a component or workpiece as well as a component produced or producible with the method.

0002The component is preferably intended for use in a turbomachine, preferably a gas turbine. The component is particularly preferably a turbine blade and / or a blade of a turbine blade.

0003Generative or additive manufacturing processes are, for example, laser deposition welding (LMD) or selective laser melting (SLM).

0004A build-up welding process is known from, for example <patcit id="pcit0001" dnum="EP2756909A1"><text>EP 2 756 909 A1</text></patcit>.

0005A method for selective laser melting, however, is for example from the <patcit id="pcit0002" dnum="EP1355760B1"><text>EP 1 355 760 B1</text></patcit> known.

0006To produce a component from a powder bed, for example by means of SLM, the powder bed is exposed, for example, with a laser beam according to a predetermined exposure geometry, with corresponding data preferably being taken from a 3D CAD file.

0007Additive manufacturing processes in the area of ​​AM ("additive manufacturing") have proven to be particularly advantageous for complex or complicated or filigree designed components, for example lightweight structures. In particular, additive manufacturing is advantageously characterized by a particularly short chain of process steps, since a manufacturing or manufacturing step of the component can under certain circumstances take place directly on the basis of a CAD file.

0008Furthermore, additive manufacturing is particularly advantageous for the development or manufacture of prototypes, which, for cost reasons, cannot be manufactured or cannot be manufactured efficiently using conventional, subtractive, machining or casting processes, for example.

0009A problem that often occurs with additive manufacturing, however, is that, especially in powder bed-based processes such as selective laser melting, the design of the component cannot be easily reproduced or implemented in terms of production technology from the corresponding CAD file. These restrictions can affect both the geometry and the material of the component; For example, circular and / or horizontal internal cavities or channels in the SLM process require support structures which have to be built up, but are not present in the originally intended design and are also not desired. Another problem relates to the formation of particularly fine surface structures or labyrinth-like features or structures which have to be reworked in the manufactured component or design to be manufactured and / or freed from excess powder. However, this can be complicated or impossible, particularly due to the size of the cavities.

0010Even if, for example, in the SLM production of parts or components, the component orientation, for example relative to the direction of construction, takes place in such a way that the mentioned production-related disadvantages or artifacts, for example through support structures, are minimized, they can never be completely avoided.

0011Further procedures are in the <patcit id="pcit0003" dnum="US20140044982A1"><text>US 2014/0044982 A1</text></patcit> and in the <patcit id="pcit0004" dnum="US20160090845A1"><text>US 2016/0090845 A1</text></patcit> disclosed. In particular disclosed<patcit id="pcit0005" dnum="US20160090845A1"><text>US 2016/0090845 A1</text></patcit> a method whereby partial sections are fixed to form a composite in order to produce a component.

0012It is therefore an object of the present invention to provide means with which the problems mentioned can be solved. In particular, an improved method and / or an improved component is presented, which can advantageously include particularly finely resolved internal structures and yet can be manufactured in a particularly time-efficient and / or resource-efficient manner.

0013This object is achieved by the subject matter of the independent patent claims. Advantageous refinements are the subject matter of the dependent claims.

0014One aspect of the present invention relates to a method for the additive production of a component, preferably a turbine blade or a blade of the turbine blade, comprising the additive construction of a plurality of partial sections for the component using a powder-bed-based method. The powder bed-based method can be, for example, selective laser melting (SLM), selective laser sintering (SLS) or electron beam melting (EBM).

0015The additive construction or manufacture can be modular.

0016The sections described can be built up in series or in parallel using the powder bed-based method.

0017The method further comprises arranging, for example connecting, joining or joining together, the subsections to form a composite, in particular to form a detachable composite or connection by detachably fixing or juxtaposing the subsections. In this step, the subsections are preferably not (yet) connected to one another in a materially bonded manner.

0018The method further comprises the additive finishing of the component, material being deposited along a circumferential direction, at least partially around the composite of the subsections, using a cladding process, preferably laser cladding (LMD), in such a way that the subsections are connected to one another in a materially or materially bonded manner will.

0019As a result of the material connection, the component can advantageously obtain its final dimensional stability. The material that is deposited by means of the build-up welding process can form a stabilizing framework.

0020In the present case, the term “finishing” preferably relates to the additive structure, mechanical post-processing of the surface of the component for the finished production preferably not yet being included. Alternatively or additionally, “finishing” can mean that - for its stabilization - at least one outline or a contour of the component or for the component is defined.

0021The deposition welding method can be a laser powder deposition welding method.

0022The above-mentioned restrictions, which are usually associated with the powder-bed-based production of components or parts, for example for turbine blades, can advantageously be circumvented in a simple manner using the method described. This applies in particular to components with a particularly complicated or intricately structured or to be structured internal geometry, such as for example turbine blades with a support and / or cooling channel structure which is intended to support the lightweight construction or its cooling during operation. As is usual in additive manufacturing, the entire component can thus be divided into individual sub-areas or sub-sections in a CAD data model, for example. Each of these subsections can then be built up, for example either in parallel or in series, by means of selective laser melting or another powder bed-based method, such as electron beam melting.

0023The mentioned subdivision is expediently carried out in such a way that as few undercuts or cavities as possible occur in the individual modules or subsections, so that support structures for the powder-bed-based method can advantageously be essentially dispensed with.

0024This also avoids the problem that filigree cavities or internal structures - such as in the monolithic additive production of a complete turbine blade from the powder bed - inner surfaces can no longer be mechanically or otherwise reworked, and that, for example in the case of labyrinth-like geometries, excess powder only very much difficult or impossible to remove from the interior. Instead, those areas of the individual subsections can advantageously first be reworked without problems, since they are initially freely accessible, that is to say before the additive finishing. Second, you can also be completely and easily freed from powder (see above).

0025The aforementioned free accessibility of the inner surfaces and the individual sections enables mechanical finishing and / or surface treatment on virtually any surface of the component, which in turn - for example in the case of cooling ducts inside the turbine blade - can mean significantly higher cooling efficiency for the component . As a result, higher operating temperatures of the turbine are also possible, as a result of which the efficiency of the energy conversion in turbo machines can be improved significantly.

0026Even if support structures are still provided for the powder-bed-based construction of the individual subsections, these can also be removed later, ie before the component is completed, through the free accessibility (see below).

0027As a further advantage of the method described, material can be deposited at least partially along the circumferential direction by means of build-up welding, ie particularly quickly or in a time-efficient manner, which means that cost advantages can be exploited compared to manufacturing the component exclusively by means of powder-bed-based methods.

0028In particular, geometries or designs can be produced with the present method, which are complex and / or in particular very expensive by means of casting technology, for example complicated nested cavities, for example with a large number of internal walls or a multiple wall (English: "multi-walls"), which would require the use of multiple casting cores for the component.

0029Said deposition of material can for example take place at least partially around the circumference of the composite. It may be necessary to take into account the additional material deposited by build-up welding for the final dimensions of the component, for example by calculating the layer or edge thickness of the (welding) material from the outset, or by, for example, already in the geometrical design of the Subsections, recesses are provided.

0030The described combination of additive powder-bed-based manufacturing processes, in particular for the individual subsections of the component, together with additive build-up welding processes, in particular laser powder build-up welding for finishing the component, also advantageously utilizes the compatibility of the types of process mentioned. In particular, the same materials or materials can be processed for the component both for the partial construction and for the completion with the described method, which is advantageous or even necessary in particular for high-performance components or materials.

0031In one embodiment, the composite of the subsections is completely covered with the material. This configuration is particularly advantageous for the stability of the component, since a complete shape-stabilizing framework can be provided by means of the build-up welding technique.

0032According to the invention, all sub-sections or at least a plurality of the sub-sections are mutually fixed after they are arranged to form the composite or during the arrangement to form the composite. The said fixing is expediently carried out in any case before the additive finishing. The fixation is particularly advantageous in order to maintain a certain manufacturing accuracy for the entire component. For example, the fixing may be necessary in order to prevent a distortion or mutual loosening of the subsections arranged to form the composite during the completion.

0033According to the invention, said fixing takes place in a form-fitting manner.

0034The term “mutually” can refer to all or only to a plurality of the subsections in the present case, to the effect that only two or more of the subsections are fixed to one another.

0035According to the invention, all sub-sections or at least a plurality of the sub-sections are provided with complementary connecting means or built up with complementary connecting means during the additive construction, such that the corresponding sub-sections can then be connected to one another in a form-fitting manner.

0036In one embodiment, the complementary connecting means are designed to interact via a tongue and groove connection of the corresponding subsections. This configuration particularly expediently enables a form-fitting fixation or connection, for example along at least one movement axis of two subsections relative to one another.

0037In one embodiment, at least one of the subsections forms an inner wall, inner wall or inner surface of the component. This embodiment is particularly expedient because - by means of the powder-bed-based methods described - inner surfaces with almost any complex geometry can be easily constructed.

0038When the component is referred to here, in particular the component to be produced and / or the component that has already been produced or completed can be meant.

0039In one embodiment, all or a plurality of subsections form a multiple wall of the component. In particular, a multiple wall can comprise an outer wall and a plurality of inner walls or walls. This example advantageously enables the component to be configured with a complicated but particularly effective cooling channel structure.

0040According to the invention, all or a plurality of subsections are constructed in such a way that they define a cavity of the component or for the component to be produced, in particular comprising at least one cooling channel. Alternatively, the component can be provided with the cavity in such a way, preferably during the additive construction, that the cavity comprises a plurality of cooling channels or any complex cooling structure.

0041In one embodiment, all or a plurality of the subsections are constructed in such a way that they comprise or form a support structure of the component.

0042In one embodiment, at least one of the subsections is reworked, for example mechanically, after the additive construction. Said post-processing can be applied to a surface that will later be on the inside of the component, whereby the above-mentioned inventive advantages can be exploited.

0043In one embodiment, all partial sections are preferably arranged on a prefabricated workpiece. The finished component then preferably also comprises said prefabricated workpiece.

0044In one embodiment, the component is a turbine blade, comprising a blade root section and an airfoil section, in particular a rotor blade for a gas turbine.

0045In one embodiment, the component is an airfoil or an airfoil section for a turbine blade, in particular a rotor blade for a gas turbine.

0046Another aspect of the present invention relates to a component that can be manufactured or manufactured using the method described, further comprising a cavity, in particular with at least one cooling channel and / or a support structure. Depending on the material deposited by means of laser deposition welding, the component comprises, for example, welding traces. Externally, for example, recognizable weld beads, e.g. after the completed structure, can be subsequently processed or removed using the procedure described.

0047Refinements, features and / or advantages, which in the present case relate to the method, can also relate to the component or vice versa.

0048Further details of the invention are described below with reference to the figures.<dl id="dl0001"><dt>Figure 1</dt><dd>shows a schematic perspective view of partial sections which are produced according to the invention.</dd><dt>Figure 2</dt><dd>FIG. 4 shows a schematic perspective view of the sections from FIG <figref idref="f0001">Figure 1</figref>which are or will be arranged according to the method according to the invention, for example to form a composite.</dd><dt>Figure 3</dt><dd>shows a schematic plan view of at least part of a component which is produced according to the invention.</dd><dt>Figure 4</dt><dd>shows a schematic side view of a component which is produced according to the invention.</dd><dt>Figure 5</dt><dd>shows a schematic perspective view of a component produced according to the invention.</dd><dt>Figure 6</dt><dd>shows a schematic plan view or sketch of partial sections which are or will be produced according to an alternative embodiment according to the invention.</dd></dl>

0049In the exemplary embodiments and figures, identical or identically acting components can each be provided with the same reference symbols. The elements shown and their size relationships 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 illustration and / or for better understanding.

0050An additive manufacturing method according to the invention for a component and a corresponding component are described here with the aid of the figures.

0051<figref idref="f0001">Figure 1</figref> shows a schematic perspective view of two subsections 1 for a component 10 to be produced additively (cf. <figref idref="f0002 f0003">Figures 3 to 5</figref>). The component is preferably intended for use in a turbomachine, preferably a gas turbine. The component is particularly preferably a turbine blade and / or an airfoil, or an airfoil section of a turbine blade. The blade can be a guide blade or a moving blade.

0052In particular, a subsection 1A and a subsection 1B are shown as subsections 1 for the component 10. The subsections 1A, 1B can be modules for said component. The subsections 1A, 1B were built using a powder-bed-based additive manufacturing process. This can be done either in parallel or in series. For example, the powder-bed-based process is selective laser melting (SLM) or electron beam melting (EBM). These methods are particularly useful for manufacturing turbine components from high performance materials such as precipitation hardened or precipitation hardenable superalloys.

0053The subsections 1A, 1B each comprise connecting means 3. The subsection 1A comprises as connecting means 3, for example, a plurality of grooves 13. As connecting means 3, subsection 1B comprises, for example, a plurality of tongues or lugs 12 which are complementary to or corresponding to the grooves described , in such a way that the subsections 1A, 1B, in particular before their final cohesive connection, form a composite 2 (cf. <figref idref="f0001">Figure 2</figref>) can be arranged and / or pre-fixed. The lugs 12 can, in particular, at least partially engage in the preferably correspondingly arranged grooves 13.

0054By means of the connecting means 3 described, the subsections 1A, 1B are fixed relative to one another at least along one, but preferably two, linearly independent movement axes or directions of the subsections 1A, 1B such that a corresponding movement is prevented.

0055The tongue and groove connection described (compare lugs 12 and grooves 13) can be used to produce a form fit.

0056The described mechanical connecting means for fixing the subsections 1A, 1B relative to one another are, according to the invention, preferably built up during the additive manufacturing or, during this, provided with the corresponding base bodies of the subsections.

0057The side surfaces of the partial sections shown, which have the connecting means 3, are preferably inner surfaces in the later component and can have a predetermined, complex structure.

0058Immediately after the additive construction of the subsections 1A, 1B, the subsections can be post-treated according to the invention, for example mechanically or in some other way, preferably in such a way that the named inner surfaces are adapted to their later use. In the case of cooling channel structures, reworking can be carried out, for example, in such a way that the component can later be cooled from the inside as efficiently as possible during operation.

0059Furthermore, in the <figref idref="f0001">Figures 1 and 2</figref> For the sake of simplicity, no support structures are shown, which are often used or built up in powder-bed-based additive manufacturing for "supporting" cavities or undercuts. The described modular or partial structure of the subsections can advantageously make a (significant) use of support structures superfluous.

0060In <figref idref="f0001">Figure 1</figref> the described subsections 1A, 1B are shown, for example, lying down. According to this orientation, the sub-sections can also be built up on a construction platform, ie lying down, in the powder-bed-based method described, which in particular corresponds to the advantage of time- and powder-efficient production. In the case of a horizontal structure, where, for example, a longitudinal axis or the main extent of the component is arranged perpendicular to the direction of construction, required support structures (see above) can be arranged or provided on the outside of the respective subsection so that they can then be removed easily and without problems.

0061As an alternative to this, the subsections 1A, 1B can, for example, be built up or produced standing out of the powder bed. In the case of the upright construction, in which, for example, a longitudinal axis of the corresponding subsection is aligned along or parallel to a construction direction of the powder bed-based method, support structures can preferably be completely or almost completely dispensed with.

0062<figref idref="f0001">Figure 2</figref> indicates in particular the composite 2 or the process (compare arrows) of arranging the subsections to form the composite 2. The composite 2 comprises the in<figref idref="f0001">Figure 1</figref> described subsections 1A, 1B.

0063The composite 2 is also shown as part of a component 10 in FIG. 3, but the connecting means 3 of the subsections at least partially interlock or interact in a complementary manner.

0064<figref idref="f0002">Figure 3</figref> shows a schematic plan view of part of a component 10. The component is, for example, a component for a turbomachine, for example a turbine blade.

0065Component 10 preferably designates a turbine blade for a gas turbine with a subtle and / or complicated internal structure, for example a support structure or, preferably, a cooling channel structure. Although this structure in the present<figref idref="f0001 f0002">Figures 1 to 4</figref> is not explicitly shown, the subsections can comprise a correspondingly arbitrarily designed geometry which, for example, has a cavity (see reference symbol 14 in FIGS <figref idref="f0002">Figures 3</figref> and <figref idref="f0003">5</figref>) Are defined.

0066In <figref idref="f0002">Figure 3</figref> it can be seen that the connecting means 3 (in particular the lugs 12) are arranged in the finished component in the cavity 14 of the same or extend through this and can therefore have a supporting effect (support structure), for example. These features are expediently already taken into account in the original conception or design of the subsections, for example using CAD (English: "computer-aided design").

0067In the <figref idref="f0002">Figure 3</figref> the component 10 is also shown as a turbine blade, the (preliminary) composite or the arrangement of the subsections 1A, 1B forming a cross-sectional area of ​​the turbine blade in the vicinity of the trailing edge. At the same time, the spaces between the connecting means 3 can function as cooling channels.

0068After the sub-sections 1 have been arranged, the additive manufacturing process of the component 10 includes additive finishing, with at least one material 4 along a circumferential direction UR (compare the double arrow) around the composite 2 of the sub-sections, using a deposition welding process, for example a laser powder deposition welding process is partially deposited on the circumferential side, such that the subsections are connected to one another in a materially or materially bonded manner. This is already shown in advance by the material 4 in the illustration in FIG. In other words, the material 4 forms a stabilizing framework of or for the component 10. An example is shown in FIG<figref idref="f0002">Figure 3</figref> In particular, it is shown that the subsections 1A, 1B are or will be completely coated with the material 4. Alternatively, however, only part of the circumference of the composite 2 can be coated with the material 4 (cf.<figref idref="f0003">Figure 5</figref>).

0069Said circumferential direction UR preferably describes one or more directions perpendicular to a longitudinal axis LA of the component 10 or a blade of the same.

0070The circumferential direction UR preferably further describes one or more directions according to or along which the described composite is at least partially encased with the material 4.

0071In order to mechanically stabilize the described composite 2 or the subsections 1A, 1B - in addition to the described bond with the material 4 -, the material 4 is preferably deposited by means of surfacing in such a way that projections 15 are built up for the finished component, which the Fix or hold composite 2 relative to material 4.

0072In <figref idref="f0002">Figure 4</figref> is the component 10 described (cf. <figref idref="f0002">Figure 3</figref>) indicated in a side view during its additive manufacture, the composite 2 described being preferably completely encased with the material 4 along a longitudinal axis LA of the component. A deposition welding tool 5, preferably a tool for laser powder deposition welding, with which the paths for the material 4 are applied additively, is shown as an example.

0073A direction of construction for the material 4 preferably corresponds to the described longitudinal axis LA or a direction parallel to this.

0074The composite described further above can in particular represent an airfoil section (SBA) of the turbine blade or extend over the latter. A corresponding blade root section (SFA) is shown below the composite 2. This can also belong to the component 10. Alternatively, the component 10 can only designate the airfoil section SBA.

0075The blade root section SFA can, for example, be an, in particular, prefabricated workpiece.

0076<figref idref="f0003">Figure 5</figref> shows a perspective schematic view of the component 10 according to the invention in an alternative embodiment. According to this embodiment, the component 10 has a complex internal geometry. According to this embodiment, the component is also a turbine blade that can be cooled from the inside, preferably a rotor blade for a gas turbine. In particular, the component 10 includes a multiple wall to define corresponding cooling channels.

0077In particular, the component 10 comprises an outer wall or outer wall 11, which is composed of a plurality of sub-sections 1 (compare dashed lines which indicate the boundaries of the individual sub-sections 1). The subsections of the outer wall 11 are preferably arranged on the circumference or along the circumferential direction UR (next to one another).

0078The component 10 furthermore comprises an inner wall or inner wall 9. Just like the outer wall 11, the inner wall is composed of individual subsections 1.

0079In the outer wall 11 and the inner wall 9, for example, a multiple wall or multiple wall of or for the component 10 can be represented.

0080The inner wall 9 and / or the outer wall 11 furthermore defines a cavity 14.

0081The component further comprises a support structure 8. The support structure 8 connects the outer wall 11 to the inner wall 9 at several points, preferably in such a way that a particularly expedient mechanical stabilization or support of the structure of the component is effected. Although this is not explicitly shown, the inner wall 9 can also comprise a corresponding support structure 8 or corresponding support structure elements for supporting opposing wall areas of the inner wall 9.

0082As described above, the subsections 1 are at least partially connected to one another and / or mutually fixed by means of mechanical, complementary connecting means to form a composite.

0083It can be sufficient here that not all, but preferably only a plurality of or some of the subsections 1 are fixed together or mutually. In particular, the pre-fixing or connection of individual pairs of sub-sections in the overall assembly, for example all sub-sections, can bring about sufficient stabilization of the entire assembly 2, so that the component 10 can be completely manufactured or assembled in the next process step, as described.

0084Said deposition from the material 4 takes place at least partially on the circumferential side around the composite 2. It is normally necessary to take the deposited material 4 into account for the final dimensions of the component, for example by calculating the (circumferential) space of the casing or the contour of the material 4 from the outset.

0085In particular, the representation of the <figref idref="f0003">Figure 5</figref> represent the composite 2 of all subsections 1. This composite 2 can be completely or only partially sheathed with the material 4.

0086According to the invention, it is also provided and expedient to deposit the material 4, for example, only at the points overlapping the "joints" of the subregions 1 of the composite 2. This is indicated by way of example by means of the dashed rectangles at connection points of four partial areas. In order to take into account the material only at the joints for the geometry of the entire component 10, the subregions can, for example, be provided with corresponding recesses (not only explicitly marked) at the points where material 4 is to be deposited. In particular, the subregions 1 can be provided with the recesses accordingly during the additive manufacturing via a CAD file. Due to the recesses, the component 10 can be provided with a flat surface, for example, despite the partial deposition of (welding) material 4.

0087As an alternative to the present representations, the described method and / or the described component can relate to a guide vane for a turbo machine. Accordingly, similar to that in FIG<figref idref="f0002">Figure 4</figref> Shovel root section SFA shown, for the component 10, a cover section or shroud (not explicitly identified) can be produced or built up additively.

0088<figref idref="f0003">Figure 6</figref> shows a schematic plan view of subsections 1, according to an alternative embodiment of the method and / or the component of the present invention. According to this embodiment, the component 10 is also preferably a turbine blade, although only partial aspects of the manufacture or the structure are described.

0089In particular, a subsection 1C is shown in simplified form in the left part. A flat convex or outer surface of the subsection 1C can, for example, simulate a pressure side of the turbine blade, although the (casing) material 4 (not shown) can define the final circumference. A concave or internal surface or wall, for example, in contrast to the representations of the<figref idref="f0001">Figures 1 and 2</figref> a predefined structure, for example a cooling structure, which defines cooling channels (not explicitly identified) in the finished component 10. This structure (not further identified here) is indicated by small, angular elements which form the inner wall 9 or the inner surface. Support structure elements 8 are also shown which have connecting means 3 at one end (cf. above).

0090In the right part of the <figref idref="f0003">Figure 6</figref> a subsection 1D is also shown in simplified form.

0091The subsection 1D is preferably built up additively from the powder bed in such a way that it interacts or fits in a complementary manner with the subsection 1C (or vice versa) for use in the finished component, for example to form an inner cooling channel.

0092The subsection 1D expediently has connecting means or elements (also identified with the reference number 3) which are complementary to the connecting means 3 of the subsection 1C. Furthermore, the sub-section 1D has in particular a structured inner surface or inner wall 9, similar to the corresponding inner surface of the sub-section 1C. The marked arrow indicates, for example, analogously to<figref idref="f0001">Figure 2</figref> also arranging the subregions 1C, 1D to form a composite 2.

0093Based on <figref idref="f0003">Figure 6</figref> In particular, the advantage of the method described becomes clear, whereby the advantages of additive manufacturing can be exploited and, in particular, its disadvantages can be largely avoided. The advantages mentioned relate, among other things, to the possibility of building customized, complex-shaped structures directly from a 3D CAD file. For example, geometries by means of additive manufacturing are possible which cannot be manufactured using conventional manufacturing processes or can only be manufactured with excessive effort.

0094The description based on the exemplary embodiments is not restricted to the invention.