Method for producing at least one workpiece, holding device and system comprising a holding device and a device for friction stir welding

Abstract

The invention relates to a method for producing at least one workpiece (6) consisting of at least two workpiece parts (2, 4), comprising the following steps: providing (108) the at least two workpiece parts (2, 4); providing (110) at least one holding device (24) for clamping the at least two workpiece parts (2, 4); clamping (112) the at least two workpiece parts (2, 4) in the at least one holding device (24); and friction stir welding (114) the at least two workpiece parts (2, 4) to form the at least one workpiece (6). The invention also relates to a holding device for clamping at least two workpiece parts (2, 4) for friction stir welding the at least two workpiece parts (2, 4) to form at least one workpiece (6). The invention further relates to a system for friction stir welding of at least two workpiece parts to form at least one workpiece, comprising: at least one holding device (24) according to one of claims 8 to 13 and at least one device for friction stir welding (10).

Description

[0001]

[0002] July 17, 2025

[0003] Method for producing at least one workpiece, holding device and system comprising holding device and device for friction stir welding

[0004] The invention relates to a method for producing at least one workpiece consisting of at least two workpiece parts, comprising the following steps: providing the at least two workpiece parts; providing at least one holding device for clamping the at least two workpiece parts; clamping the at least two workpiece parts in the at least one holding device; and joining, in particular by friction stir welding, the at least two workpiece parts to form the at least one workpiece. The invention also relates to a holding device for clamping at least two workpiece parts for friction stir welding of the at least two workpiece parts to form at least one workpiece, wherein the holding device is in particular a holding device as described in the aforementioned method.Furthermore, the invention relates to a system for joining, in particular for friction stir welding, at least two workpiece parts to form at least one workpiece, comprising at least one of the aforementioned holding devices and at least one device for friction stir welding.

[0005] Methods for joining workpiece parts to form at least one workpiece are known from the prior art. One of these methods is so-called friction stir welding.

[0006] In friction stir welding, for example, a rotating tool is moved along several workpiece parts, making contact with the parts to be joined. The rotation of the tool against the workpiece parts leads to a temperature increase and plastic deformation of the material. This creates a weld seam, joining the two workpiece parts into a single workpiece.

[0007] To secure the workpiece parts to be joined against twisting, shifting, tilting and / or tipping in as many spatial directions as possible, so-called holding devices are used to clamp the workpiece parts to be joined.

[0008] Due to the friction and heat-based operating principle of friction stir welding, as well as the loads involved, such holding devices for friction stir welding are subject to high demands. For example, the holding devices must effectively absorb the forces and moments generated during the friction stir welding process and / or essentially ensure the dimensional accuracy of the workpiece parts to be joined by positioning them as precisely as possible (relative to each other).

[0009] If the preceding requirements are insufficiently considered, undesirable rework, limitations regarding dimensional accuracy requirements, and even component rejection due to damage may occur.

[0010] Therefore, the production of holding fixtures for friction stir welding is carried out individually for each component type to be joined and is often associated with high material costs and manufacturing effort. In particular, the increasing complexity of the workpiece parts to be joined necessitates a correspondingly complex holding fixture, meaning that the cost of the holding fixture regularly represents a large proportion of the total cost of the friction stir welding system.

[0011] Furthermore, existing holding devices are primarily made of steel, being solidly manufactured and not individually adapted to the respective requirements during the process.

[0012] HF / HF 240377WO

[0013] July 17, 2025, the thermal and mechanical loads generated by friction stir welding are adapted to these requirements. This can necessitate costly rework and, furthermore, lead to an over-dimensioning of the holding device, resulting in increased manufacturing and material costs. Such a robust design also leads to a greater space requirement.

[0014] Based on this, the task was therefore set to specify a method for producing at least one workpiece consisting of at least two workpiece parts, a holding device for clamping at least two workpiece parts for friction stir welding of the at least two workpiece parts to form at least one workpiece, and a system for friction stir welding of at least two workpiece parts to form at least one workpiece, which enable reliable joining, in particular reliable joining within a given specification, of the at least two workpiece parts to form at least one workpiece in a cost-efficient manner.

[0015] According to a first aspect, the aforementioned problem is solved by the method further comprising: manufacturing the at least one holding device by means of 3D printing and / or by means of casting or a casting process; wherein the at least one holding device corresponds at least partially to the outer contours of the at least two workpiece parts. In particular, the at least one holding device, preferably at least a portion of the surface facing the workpiece parts to be joined, is adapted such that the respective surface areas can reliably absorb the loads generated during friction stir welding and, for example, conform positively to the outer contours of the at least two workpiece parts. For example, those areas that are required to have increased mechanical strength, since they essentially support the at least two workpiece parts, can be made of a material with high stiffness.Areas with reduced stiffness are also possible.

[0016] HF / HF 240377WO

[0017] 17 July 2025 is planned, which will improve the dimensional accuracy of at least one joined workpiece.

[0018] By manufacturing at least one holding device using 3D printing and / or casting, a holding device can be provided in a production-technically advantageous manner, which corresponds at least partially to the outer contours of the workpiece parts to be joined and thus enables advantageous clamping of the workpiece parts to be joined.

[0019] For example, the at least two workpiece parts can be arranged or clamped in a receptacle of a base body of a holding device, whereby they can additionally be arranged or clamped in the at least one receptacle of the holding device by means of clamping elements, in particular clamping clamps.

[0020] Preferably, the at least one holding device corresponds, particularly in those areas or regions, to the outer contours of the at least two workpiece parts (to be joined), which rest essentially directly on the at least one holding device during friction stir welding. Preferably, the at least two workpiece parts (to be joined) rest on the at least one receptacle of the at least one holding device. In this respect, it is preferred that at least one receptacle corresponds to the outer contours of the at least two workpiece parts (to be joined).

[0021] Preferably, at least the side of the holding device facing the at least two workpiece parts corresponds, preferably substantially completely, to the outer contours of the at least two workpieces, in particular to the outer contours of the side of the at least two workpieces facing the holding device.

[0022] HF / HF 240377WO

[0023] July 17, 2025 The method preferably relates in particular to the manufacture of at least one component as a workpiece which is used as part of a vehicle battery pack. For example, the workpiece is a battery tray, a battery carrier or a housing for a component of a battery pack.

[0024] According to a preferred embodiment, the method further comprises: capturing at least a portion of the outer contours of the at least two workpiece parts; modeling at least one at least partial negative of the at least two workpiece parts based on the at least partially captured outer contours of the at least two workpiece parts; and manufacturing the at least one holding device based on the at least one at least partial negative. This advantageously allows a holding device to be manufactured using 3D printing and / or a casting process, which at least partially corresponds to the outer contours of the at least two workpiece parts to be joined.

[0025] For example, at least part of the outer contours of the at least two workpiece parts can be detected by means of at least one sensor device, in particular, for example, by means of at least one camera.

[0026] For example, at least one negative of the at least two workpiece parts is then modeled based on the captured outer contours.

[0027] For example, a CAD model of a negative of the at least two workpiece parts to be joined is created or modeled, particularly automatically. Subsequently, the CAD model of the negative can be used, for example, to manufacture the at least one holding device, in particular the at least one receptacle of the at least one holding device, by means of 3D printing or a casting process.

[0028] Within the framework of the modeling, the thermal material properties can be taken into account under the expected or actual loads during friction stir welding.

[0029] HF / HF 240377WO

[0030] July 17, 2025 This is advantageous because the strength of the material or materials from which the at least one holding device is made typically decreases when heated. Therefore, taking into account the yield strength of the materials used, the at least one holding device can be designed according to a thermal load profile.

[0031] Another preferred embodiment is characterized in that, after modeling at least a partial negative of the at least two workpiece parts, an evaluation step of the modeling is performed. For example, such an evaluation step can be a plausibility check. This can reduce modeling errors.

[0032] According to a preferred embodiment, the method further comprises: creating at least one load profile, in particular by means of an FEM analysis, of the loads expected during friction stir welding on the at least one holding device based on the at least one at least partially modeled negative; and / or manufacturing the at least one holding device taking the at least one load profile into account. This allows the holding device to be designed in such a way that it reliably absorbs the resulting loads. Preferably, the at least one holding device is manufactured in such a way that, in addition to the at least one load profile, a safety factor is also taken into account.

[0033] Finite element method (FEM) analysis, for example, is a computerized method for modeling and solving technical problems related to complex systems such as three-dimensional, nonlinear structures. FEM analysis derives its name from the way in which the geometry of the object under consideration is specified. For this purpose, the FEM software is provided with a grid-based model that describes the geometric features and the associated material properties, particularly at each point in the model. In a

[0034] HF / HF 240377WO

[0035] In such a model, the geometry of the system to be analyzed is represented by various quantities called elements. The vertices of the elements are called nodes. The model typically consists of a finite number of elements, to which material properties are assigned. The model thus represents, for example, a physical space occupied by the object to be analyzed, along with its immediate surroundings. Once the model is defined, a simulation of the physical behavior, e.g., during the friction stir welding process, can be performed using FEM analysis.

[0036] For example, the negative of at least two workpiece parts is modeled within the framework of such a FEM analysis, and the physical behavior of the negative during the friction stir welding process is then simulated. This allows the respective mechanical requirements for the negative during the welding process to be identified, and the holding fixture to be manufactured using 3D printing and / or casting in such a way that it meets the mechanical requirements identified by the FEM analysis. For example, in areas requiring higher strength, a material with higher mechanical strength can be used. Alternatively, areas requiring higher strength can be designed with greater solidity to provide the necessary mechanical strength.To achieve high dimensional accuracy, areas with reduced stiffness can also be incorporated. For example, joining by friction stir welding can lead to component distortion due to thermomechanical stresses. By incorporating areas of reduced stiffness, clamped workpieces can be advantageously held in such a way as to counteract any resulting component distortion.

[0037] In particular, materials that exhibit elastic material behavior can be used for such areas.

[0038] HF / HF 240377WO

[0039] July 17, 2025 Based on the results of such an FEM analysis and taking into account the geometry, in particular the outer contours, of the at least two workpiece parts, the at least one holding device can then be advantageously manufactured.

[0040] As a result of mechanical and / or thermal modeling, it is preferred that a biometric design be chosen for at least one holding device. This can enable savings in space and material.

[0041] According to a further embodiment, the method also comprises: manufacturing at least a first region of the at least one holding device and at least a second region of the at least one holding device; wherein the at least first region of the at least one holding device has increased stiffness compared to the at least second region of the at least one holding device and / or wherein the at least first region of the at least one holding device has increased thermal conductivity compared to the at least second region of the at least one holding device. This makes it possible to tailor the holding device to the specific requirements that arise during friction stir welding.

[0042] For example, areas of the at least one holding device can be provided that exhibit increased stiffness and are primarily intended to support or hold the at least two workpiece parts. These are preferably designed such that they correspond to the outer contours of the at least two workpiece parts that contact them.

[0043] For example, additional areas of the at least one holding device can be provided that have reduced stiffness and can therefore optimize the dimensional accuracy of the at least one holding device.

[0044] HF / HF 240377WO

[0045] July 17, 2025 For example, additional areas of the at least one holding device can be provided which have a specific elastic material behavior, so that the holding device can hold the at least two workpiece parts and thus counteract component distortion as a result of thermomechanical loads.

[0046] For example, areas of the at least one holding device can also be provided that exhibit specific thermal properties, such as cooling properties and / or cooling structures, thereby improving the thermal load on the at least two workpiece parts and / or the at least one holding device. In particular, this eliminates the need for additional cooling elements / structures, thus saving costs. Preferably, the cooling structures are also incorporated directly during 3D printing and / or casting.

[0047] Preferably, the at least one holding device can include heat exchange structures, which can form part of a thermal management system. For example, the thermal management system, comprising the heat exchange structures, can be configured to both cool and heat. Cooling can be used, for example, to selectively dissipate heat. Heating can be used to establish a steady-state temperature level, thus preventing the device from overheating.

[0048] For example, heat exchange structures can be formed by cooling or heating elements, such as cooling channels, heating elements, and / or Peltier elements. In particular, the aforementioned heat exchange structures, in conjunction with thermal management, can ensure dimensional compensation for at least one holding device. For instance, materials, and consequently the holding device itself, expand when heated, so this can be compensated for by means of such a system.

[0049] HF / HF 240377WO

[0050] July 17, 2025 Thermal management can be counteracted, thereby improving the dimensional accuracy of at least two workpiece parts to be joined.

[0051] Preferably, the thermal management system comprises appropriate sensors for temperature measurement and a control device that essentially automatically controls the heat exchange structures according to the measured values ​​provided by the sensors, thereby essentially automatically cooling and / or heating the at least one holding device.

[0052] Another preferred embodiment is characterized in that the at least one first region of the at least one holding device is made of a different material than the at least one second region of the at least one holding device. In particular, the other aforementioned regions are also each made of different materials.

[0053] Using 3D printing and / or casting, at least one holding device made of different materials can be provided in a manufacturing-efficient manner, which is advantageously adapted to the workpiece parts to be joined and the friction stir welding process.

[0054] According to a further embodiment, the method further comprises: introducing heat exchange structures, in particular cooling structures, into which at least one holding device is incorporated during and / or after the manufacture of the at least one holding device; wherein the heat exchange structures, in particular cooling structures, are preferably made of a metal, in particular steel, copper, and / or aluminum; and / or wherein the heat exchange structures, in particular cooling structures, are preferably incorporated into a plastic matrix of the at least one holding device. For example, cooling structures can be cooling channels. For example, the heat exchange structures, in particular cooling structures, can also be provided by a specific material which, during the

[0055] HF / HF 240377WO

[0056] July 17, 2025. The material should efficiently dissipate the heat generated during the welding process and therefore exhibit good thermal conductivity. This could be, for example, a metal such as steel, copper, and / or aluminum. Alternatively, a ceramic material could be used in an area where low thermal conductivity is desired.

[0057] For example, heat exchange structures, particularly cooling structures, can be arranged in a polymer matrix in the manner of a fiber-reinforced polymer composite. Metallic reinforcing fibers, such as steel fibers, can be incorporated. The polymer matrix can surround the fibers and bind them to the matrix through adhesive interactions. The reinforcing fibers can also include basalt fibers, boron fibers, glass fibers, ceramic fibers, silica fibers, carbon fibers, quartz fibers, aramid fibers, PBO fibers, polyester fibers, nylon fibers, polyethylene fibers, and / or polymethyl methacrylate fibers.

[0058] According to a further embodiment, the at least one holding device is manufactured by means of 3D printing, in particular by means of 3D printing with thermoplastics, by means of a casting compound, in particular by means of a casting compound made of temperature-resistant materials, such as concrete and / or epoxy resin, and / or by casting the structures. This has proven particularly advantageous for smaller dimensions of the at least one holding device. For example, the dimensions of a holding device manufactured in this way are preferably in the range of less than 500 mm x 500 mm.

[0059] According to a further embodiment, the at least one holding device is manufactured using wire arc additive manufacturing and / or potting compound. Preferably, the at least one holding device can also be produced by 3D printing in a stack configuration. This allows the at least one holding device to be provided in a manufacturing-efficient manner. These manufacturing options have proven particularly advantageous.

[0060] HF / HF 240377WO

[0061] On July 17, 2025, it was found that larger dimensions of at least one holding device are advantageous. For example, the dimensions of such a holding device are preferably in a range larger than 500 mm x 500 mm.

[0062] For example, in wire arc additive manufacturing, a wire, such as one made of aluminum, is melted by an electric arc. A robot, controlled by software, lays many wires or welds on top of each other until the entire component, especially the holding fixture, is complete. This allows for the production of structures that are both highly rigid and lightweight. Wire arc additive manufacturing can also be used to produce near-net-shape structures.

[0063] The use of potting compound allows for the advantageous creation of complex contours. The same applies analogously to casting processes. For example, die casting processes can be used to manufacture at least one holding device.

[0064] In a further preferred embodiment, the at least one holding device is provided by at least one 3D-printed sand core. This sand core can, for example, be a type of sand core typically used in casting processes. This enables, in particular, a holding device that can withstand high thermal loads and in which complex contours and heat exchange structures, especially cooling structures, can be realized.

[0065] According to a second aspect, the aforementioned problem is solved by a holding device for clamping at least two workpiece parts for friction stir welding of the at least two workpiece parts to form at least one workpiece, wherein the holding device is in particular a holding device as described above; wherein the holding device is in particular by means of

[0066] HF / HF 240377WO

[0067] July 17, 2025, manufactured by 3D printing and / or casting, wherein the at least one holding device has at least one base body, wherein the at least one base body has at least one receptacle, and wherein the at least one receptacle corresponds at least partially to the outer contours of the at least two workpiece parts.

[0068] Regarding the advantages of the holding device, reference is essentially made to the explanations concerning the first aspect. For example, the holding device has a base body into which the at least two workpiece parts can be inserted. For this purpose, the base body has, for example, at least one receptacle, and in particular several receptacles, wherein the receptacles preferably correspond at least partially to the outer contours of the at least two workpiece parts. For example, the at least one receptacle can form stop or fixed points that secure the workpiece parts to be joined against rotation, displacement, and / or tilting in essentially all spatial directions. Preferably, clamping elements and / or clamps are also used for this purpose.

[0069] For example, post-processing can be carried out after 3D printing and / or casting.

[0070] A further embodiment is characterized in that the at least one receptacle of the holding device has at least a first region and at least a second region, wherein the at least one first region has increased stiffness compared to the at least one second region; and / or wherein the at least one first region has increased thermal conductivity compared to the at least one second region. This allows a holding device to be provided that is adapted to the respective requirements arising during the friction stir welding process.

[0071] HF / HF 240377WO

[0072] July 17, 2025. A further embodiment is characterized in that regions of the holding device, in particular the at least one first area and the at least one second area, comprise different materials. This advantageously allows for different properties of the holding device.

[0073] A further embodiment is characterized in that a first region of the holding device, in particular the first area, comprises a metallic material, especially steel, a steel alloy, aluminum, an aluminum alloy, copper, and / or a copper alloy; wherein a second region of the holding device, in particular the second area, comprises a ceramic. For example, this can counteract local heat sinks or hotspots, since the materials have different thermal conductivities. For example, metallic materials, especially copper, have a high thermal conductivity, whereas ceramics have a rather low thermal conductivity.

[0074] A further embodiment is characterized in that the holding device, in particular the at least one receptacle of the holding device, further comprises at least one recess; wherein at least one detection means, in particular at least one eddy current sensor, is incorporated into the at least one recess; wherein the at least one detection means is configured to detect a characteristic parameter indicative of the quality of a weld produced by friction welding. This enables in-situ testing of the joint produced between the at least two workpiece parts. For example, the materials of the at least one recess or of the region surrounding the at least one recess are selected such that they reliably enable this type of quality testing.For example, at least one eddy current sensor can be used as a detection device, whereby such a sensor can check the quality at a weld root. At least in this case.

[0075] HF / HF 240377WO

[0076] July 17, 2025, a key figure, however, it can also be other key figures that are indicative of the quality of the produced weld.

[0077] Another preferred embodiment is characterized in that the holding device further comprises clamping elements, in particular clamping clamps; wherein the clamping elements are preferably designed to hold the at least two workpiece parts in the at least one holding device during friction stir welding; and wherein the clamping elements preferably correspond at least partially to the outer contours of the at least two workpiece parts. This enables reliable clamping of the at least two workpiece parts during friction stir welding. In particular, the at least two workpiece parts are secured against rotation, displacement, and tilting / tilting in essentially all spatial directions.

[0078] According to a third aspect, the aforementioned task is solved by a system for friction stir welding of at least two workpiece parts into at least one workpiece, comprising: at least one of the aforementioned holding devices and at least one device for friction stir welding. Regarding the advantages of the system, reference is made to the description of the first and second aspects.

[0079] Further advantageous exemplary embodiments of the invention can be found in the following detailed description of some exemplary embodiments of the present invention, particularly in conjunction with the figures. However, the figures accompanying the application are intended only for illustrative purposes and not to determine the scope of protection of the invention. The accompanying drawings are not necessarily to scale and are intended only to reflect the general concept of the invention by way of example. In particular, features included in the figures should by no means be considered a necessary component of the present invention. The sequence of the individual steps in the illustrated process summaries does not necessarily represent the actual (temporal) sequence of the steps.

[0080] HF / HF 240377WO

[0081] July 17, 2025 is merely an example. Nevertheless, the steps can occur / be carried out in the exact sequence shown in the process overviews. Furthermore, they can be carried out in response to one another, but this is not mandatory.

[0082] They show:

[0083] Fig. 1 shows an embodiment of a method for producing at least one workpiece consisting of at least two workpiece parts;

[0084] Fig. 2a shows a schematic top view of a workpiece made from at least two workpiece parts; and

[0085] Fig. 2b is a schematic sectional view along section 11b shown in Fig. 2a.

[0086] Fig. 1 shows an embodiment of a method for producing at least one workpiece 6 consisting of at least two workpiece parts 2, 4.

[0087] First, for example, the outer contours of at least two workpiece parts 2 and 4 can be captured in process step 102. Subsequently, at least one negative can be modeled based on the captured outer contours of at least two workpiece parts 2 and 4 in process step 104. Based on such a model of at least one negative, at least one holding device 24 can then be manufactured in process step 106 using 3D printing and / or casting.

[0088] HF / HF 240377WO

[0089] July 17, 2025 Once at least one holding device 24 has been manufactured, the at least two workpiece parts 2, 4 to be joined can be provided in process step 108, and the at least one holding device 24 can be provided in process step 110. Subsequently, the at least two workpiece parts 2, 4 can be clamped in process step 112 and friction stir welded to form at least one workpiece 6 in process step 114.

[0090] Figures 2a and 2b show an example of a workpiece 6 produced using the method described above. The workpiece 6 shown, or the two workpiece parts 2 and 4 to be joined, is, for example, a battery carrier or a housing for power electronics, which is used particularly in the field of electromobility, e.g., in electric vehicles and / or hybrid vehicles.

[0091] The two workpiece parts 2 and 4 to be joined are connected, in particular, by means of at least one weld seam 8. This weld seam 8 is produced, for example, by means of a friction stir welding tool 10, wherein the friction stir welding tool 10 comprises a base body 12 with a shoulder and a welding pin 14. By rotating the friction stir welding tool 10, the workpiece parts 2 and 4 to be joined can be plasticized and joined to form the workpiece 6.

[0092] The finished workpiece 6 or the two workpiece parts 2 and 4 to be joined have a complex shape, which, for example, has a plurality of essentially cylindrical and hollow projections 16, a plurality of essentially rectangular recesses 18 and circumferential depressions 20 and 22.

[0093] It can be seen that the two workpiece parts 2 and 4 to be joined are clamped in a holding device 24. The holding device 24 has a

[0094] HF / HF 240377WO

[0095] July 17, 2025 Surface that essentially corresponds to the outer contours of the two workpiece parts 2 and 4 to be joined. The outer contours of the two workpiece parts to be joined can be, for example, the projections 16, the recesses 18, and the circumferential depressions 20 and 22.

[0096] For example, the holding device 24 has projections 26 on the surface corresponding to the projections 16, which essentially fill the interior of the projections 16. For example, the projections 26 of the holding device could be cooling structures. The holding device 24 could also have projecting parts 28 that protrude from the recesses 18.

[0097] Furthermore, the holding device 24 can also have circumferential recesses 30 and 32 in the area of ​​the circumferential recesses 20 and 22. For example, circumferential recess 32 can be a first area of ​​the at least one holding device 24 and / or a first region of the at least one holding device 24. For example, circumferential recess 30 can be a second area of ​​the at least one holding device 24 and / or a second region of the at least one holding device 24. For example, recess 32 has a higher stiffness and / or a different material than recess 30. For example, the material of recess 32 has a higher thermal conductivity than the material of recess 30. For example, the holding device 24 is composed of a base body 33 and a plurality of receptacles formed in the base body 33.The recesses are formed, for example, by the projections 26, the protruding parts 28 and the circumferential depressions 30 and 32.

[0098] In the area of ​​the weld seam 8, a protruding step 34 of the two workpiece parts 2 and 4 can also be arranged, wherein the holding device 24 has a projection 36 corresponding to the contour of the step 34.

[0099] HF / HF 240377WO

[0100] July 17, 2025 By means of such a design of the holding device 24, the workpiece parts to be joined can be securely fixed in the holding device 24. To improve the fixation, clamping elements 38 can also be provided, which fix the two workpiece parts 2 and 4 during friction stir welding.

[0101] The exemplary embodiments of the present invention described in this specification are to be understood as being disclosed in all combinations with one another. In particular, the description of a feature included in an embodiment—unless explicitly stated otherwise—is not to be understood as meaning that the feature is indispensable or essential for the function of the embodiment. The sequence of the process steps described in this specification is not mandatory; alternative sequences of process steps are conceivable.All disclosures in this specification are to be understood with regard to all categories of device, method, and computer program, such that, for example, the description of a method step also discloses a corresponding device that includes means for carrying out and / or controlling the method step, and a corresponding device that is configured to control and / or carry out the method step.

[0102] Terms used in the patent claims, such as "comprise," "have," "include," "contain," and the like, do not exclude further elements or steps. The phrase "at least partially" covers both "partially" and "completely." The phrase "and / or" should be understood to mean that both the alternative and the combination are disclosed; thus, "A and / or B" means "(A) or (B) or (and BJ)." A plurality of units, persons, or the like, in the context of this specification, means several units, persons, or the like. The use of the indefinite article does not preclude a plurality. A single device can perform the functions of several units or devices mentioned in the patent claims. In the patent claims

[0103] HF / HF 240377WO

[0104] The reference marks specified for July 17, 2025, are not to be regarded as restrictions on the resources and steps to be used.

[0105] HF / HF 240377WO

[0106] July 17, 2025 Reference List

[0107] 2 workpiece parts

[0108] 4 workpiece part

[0109] 6 workpieces

[0110] 8 weld seam

[0111] 10 friction stir welding tools

[0112] 12 Basic body of the friction stir welding tool

[0113] 14 Welding pin of the friction stir welding tool

[0114] 18 Recess of the workpiece part

[0115] 20 circumferential recesses of the workpiece part

[0116] 22 circumferential recesses of the workpiece part

[0117] 24 Holding device

[0118] 26 Projection of the holding device

[0119] 28 protruding parts of the holding device

[0120] 30 circumferential recess of the holding device

[0121] 32 circumferential recess of the holding device

[0122] 33 Base body of the holding device

[0123] 34th stage of the workpiece parts

[0124] 36 Projection of the holding device

[0125] 38 clamping element

[0126] 102 Capture

[0127] 104 Modeling

[0128] 106 Manufacturing

[0129] 108 available

[0130] 110 Provide

[0131] 112 Clamping

[0132] 114 Friction stir welding

[0133] HF / HF 240377WO

[0134] July 17, 2025

Claims

July 17, 2025 Patent claims 1. Method for producing at least one workpiece (6) consisting of at least two workpiece parts (2, 4) comprising the following steps: providing (108) the at least two workpiece parts (2, 4); Providing (110) at least one holding device (24) for clamping the at least two workpiece parts (2, 4); Clamping (112) the at least two workpiece parts (2, 4) in the at least one holding device (24); and Friction stir welding (114) of the at least two workpiece parts (2, 4) to form the at least one workpiece (6); characterized in that the method further comprises: Manufacturing (106) the at least one holding device (24) by means of 3D printing and / or casting; wherein the at least one holding device (24) corresponds at least partially to the outer contours (16, 18, 20, 22) of the at least two workpiece parts (2, 4).

2. The method of claim 1, wherein the method further comprises: Capturing (102) at least one part of the outer contours (16, 18, 20, 22) of the at least two workpiece parts (2, 4); Modeling (104) of at least a partial negative of the at least two workpiece parts (2, 4) based on the at least partially captured outer contours (16, 18, 20, 22) of the at least two workpiece parts (2, 4); Manufacturing the at least one holding device (24) based on the at least one at least partial negative.

3. The method of claim 2, wherein the method further comprises: Creating at least one load profile, in particular by means of an FEM analysis, of the loads expected during friction stir welding (114) on the at least one holding device (24) based on the at least one at least partially modeled negative; and Manufacturing the at least one holding device (24) taking into account the at least one load profile.

4. A method according to any one of claims 1 to 3, wherein the method further comprises: Producing at least one first region (32) of the at least one holding device (24) and at least one second region (30) of the at least one holding device (24); wherein the at least one first region (30) of the at least one holding device (24) has increased stiffness compared to the at least second region (30) of the at least one holding device (24) and / or wherein the at least one first region (32) of the at least one holding device (24) has increased thermal conductivity compared to the at least one second region (30) of the at least one holding device (24).

5. Method according to claim 4, wherein the at least one first region (32) of the at least one holding device (24) is made of a different material than the at least one second region (30) of the at least one holding device (24). HF / HF 240377WO July 17, 2025 6. A method according to any one of claims 1 to 5, wherein the method further comprises: Introducing heat exchange structures, in particular cooling structures (26), into the at least one holding device (24) during and / or after the manufacture of the at least one holding device (24); wherein the heat exchange structures, in particular cooling structures (26), are preferably made of a metal, in particular of steel, copper and / or aluminium; and / or wherein the heat exchange structures, in particular cooling structures (26), are preferably introduced into a plastic matrix of the at least one holding device (24).

7. Method according to any one of claims 1 to 6, wherein the at least one holding device (24) is manufactured by means of wire arc additive manufacturing and / or using potting compound.

8. Holding device for clamping at least two workpiece parts (2, 4) for friction stir welding of the at least two workpiece parts (2, 4) to form at least one workpiece (6), wherein the holding device (24) is in particular a holding device (24) manufactured according to claims 1 to 7; wherein the holding device (24) is in particular manufactured by means of 3D printing and / or by means of casting, wherein the at least one holding device (24) has at least one base body (33), wherein the at least one base body (33) has at least one receptacle (26, 28, 30, 32, 36), and wherein the at least one receptacle (26, 28, 30, 32, 36) corresponds at least partially to the outer contours of the at least two workpiece parts (2, 4). HF / HF 240377WO July 17, 2025 9. Holding device according to claim 8, wherein the at least one receptacle (26, 28, 30, 32, 36) of the holding device (24) has at least one first region (32) and at least one second region (30), wherein the at least one first region (32) has increased stiffness compared to the at least one second region (30); and / or wherein the at least one first region (32) has increased thermal conductivity compared to the at least one second region (30).

10. Holding device according to claim 8 or 9, wherein regions of the holding device (24), in particular the at least one first region (32) and the at least one second region (30), comprise different materials.

11. Holding device according to claim 10, wherein a first region of the holding device (24), in particular the first region (32), comprises copper and / or a copper alloy; wherein a second region of the holding device (24), in particular the second region (30), comprises ceramic.

12. Holding device according to one of claims 8 to 11, wherein the holding device (24), in particular the at least one receptacle (26, 28, 30, 32, 36) of the holding device (24), further comprises at least one recess; wherein at least one detection means, in particular at least one eddy current sensor, is provided in the at least one recess; wherein the at least one detection means is configured to detect at least one characteristic parameter indicative of the quality of a weld produced in the context of friction welding. HF / HF 240377WO July 17, 2025 13. Holding device according to one of claims 8 to 12, wherein the holding device (24) further comprises clamping elements (38); wherein the clamping elements (38) are preferably configured to hold the at least two workpiece parts (2, 4) in the at least one holding device (24) during friction stir welding; and wherein the clamping elements (38) preferably at least partially form part of the The outer contours of at least two workpiece parts (2, 4) correspond.

14. System for friction stir welding of at least two workpiece parts to form at least one workpiece comprising: at least one holding device (24) according to one of claims 8 to 13 and at least one device for friction stir welding (10). HF / HF 240377WO July 17, 2025

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