Method for producing a welded joint

Abstract

The invention relates to a method for producing a welded joint (4), wherein at least two components (2, 3) are aligned relative to each other, the components (2, 3) are joined together at least section by section to form the welded joint (4), data of a free surface of the welded joint (4) are acquired by means of an optical detection device (5), and parameters of the welded joint (4) are determined by means of an evaluation unit (6) based on the acquired data. According to the invention, it is provided that at least one outer surface (4.1) bounding the edge of the welded joint (4) is generated by adjusting welding and / or melting parameters such that its free surface has a different structure than a free surface of the remaining welded joint (4.2).

Description

[0001] The invention relates to a method for producing a welded joint according to the preamble of claim 1.

[0002] It is generally known that joints on components, such as welds, especially laser welds, are inspected for quality. One possible approach is a camera-based system that analyzes image data of the joint.

[0003] From DE 10 2009 052 529 B4, a method for quality control of a joint between two components is known. The joint is produced by laser beam welding or laser beam brazing using a laser processing head. The laser processing head comprises laser optics by which the radiation of a laser is directed onto a processing point. The laser processing head guides the radiation from the laser in such a way that the processing point moves relative to the components, thereby approaching several points of the joint and creating the joint at each point. After welding or brazing one of the points, a camera captures an image encompassing the point before the next point is welded or the production of another joint begins. To assess the quality, the thermal radiation and heat dissipation of the point and its surroundings are determined from the image.The laser is switched off during the recording or put into a standby state with minimal power that does not interfere with the recording. The recording is made after a partial or complete defocused scan of the weld seam following the welding process.

[0004] The invention is based on the objective of providing a novel method for producing a welded joint.

[0005] The problem is solved according to the invention by a method which has the features specified in claim 1.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] In a process for producing a welded joint, at least two components are aligned relative to each other, the components are joined together at least section by section to form the welded joint, data of a free surface of the welded joint are recorded by means of an optical detection device and parameters of the welded joint are determined by means of an evaluation unit based on the recorded data.

[0008] According to the invention, it is provided that at least one outer surface limiting the edge of the weld joint is generated by adjusting welding and / or melting parameters in such a way that its free surface has a different structure than a free surface of the rest of the weld joint.

[0009] The functionality of optical systems for detecting and evaluating the surfaces of welded joints is severely limited or completely rendered ineffective in the case of highly similar surfaces of the welded joint and the surfaces of at least one component, since boundaries between the welded joint and the at least one component are not clearly detectable and therefore not identifiable.

[0010] Using the present method, it is possible in a simple and reliable manner to modify the structure of the free surface of the outer web, as detected by the optical scanning device, in such a way as to differentiate it from the rest of the weld surface, so that the outer web can be easily and reliably detected in the acquired data. This improves the detection of the weld in the acquired data, in particular allowing for a clearer demarcation of the weld from the at least one component due to an exact representation of the weld's outer contour. Thus, a detailed evaluation of the weld with regard to its area and its connection can be achieved.Consequently, the parameters determined from the acquired data can be improved, enabling particularly precise and reliable determination of quality data and the achievement of exceptionally high product quality. Furthermore, generating the different surface conditions of the weld joint allows for their unambiguous detection, even using cost-effective optical detection devices designed as camera-based systems.

[0011] Modifying the surface structure of the outer web can be easily integrated into the joining process, eliminating the need for additional complex process steps and associated costs. This approach offers excellent integration into existing processes and systems, enabling a high degree of automation. Furthermore, the method allows for the simple integration of quality control into the joining process, or alternatively, this can be performed downstream.

[0012] The process is characterized by its diverse and variable application possibilities, for example, for creating joints on body components and / or connections on electrical components, such as laser-welded battery contacts. The process also exhibits high flexibility with regard to materials and their surfaces or weld joint surfaces and is particularly suitable for creating connections between metallic materials, such as aluminum.

[0013] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0014] This shows: Fig. 1. Schematic top view of a component arrangement with two components, Fig. 2 schematically a top view of the component arrangement according to Fig. 1 after creating a welded joint between the two components in accordance with the state of the art, Fig. 3 schematically a top view of the component arrangement according to Fig. 2 during an optical detection of the weld joint, Fig. 4 schematically a top view of the component arrangement according to Fig. 1 after the creation of a welded joint between the two components, Fig. 5 schematically a top view of the component arrangement according to Fig. 4 during an optical detection of the weld joint, Fig. 6 schematically a sectional view of the component arrangement according to Fig. 4 during the creation of the weld joint between the two components, Fig. 7 schematically a sectional view of the component arrangement according to Fig. 4 after carrying out a first welding process to create the weld joint and Fig. 8 schematically a sectional view of the component arrangement according to Fig. 7 during the execution of a second welding and / or remelting process to produce the weld joint.

[0015] Corresponding parts are marked with the same reference symbols in all figures.

[0016] In Fig. Figure 1 shows a top view of a component arrangement 1 with two components 2, 3, where component 2 is, for example, an electrical single cell and component 3 is, for example, a cell connector.

[0017] To create an electrical and mechanical connection between components 2 and 3, these are connected by generating a Fig. 2. The weld joint 4, shown in more detail below, is joined together. This is done, for example, in a laser welding process in which a Fig. 6. A laser beam LS, shown in more detail, is directed onto a surface of component 3. Component 3 is completely penetrated, and component 2 is partially melted. After solidification of the resulting melt, the weld 4 is formed, and components 2 and 3 are joined as shown in the illustration. Fig. 2 connected to each other.

[0018] To record parameters of the produced weld joint 4, it is recorded using an optical recording device 5, which, for example, includes at least one camera. This is in Fig. 3 shown in more detail.

[0019] If a free surface of the weld 4 and a free surface of the component 3 adjacent to the weld 4 have a similar or at least nearly identical structure, the function of the optical detection device 5 for detecting and evaluating the surfaces of weld 4 is severely limited or completely rendered ineffective. This is because the boundaries between the weld 4 and the component 3 cannot be clearly detected and therefore cannot be identified by the detection device 5.

[0020] In Fig. Figure 4 is a top view of the component arrangement 1 according to Fig. 1 shown after the creation of a welded joint 4 between the two components 2, 3, wherein the welded joint 4 was produced by means of a possible embodiment of a method according to the invention for producing a welded joint 4.

[0021] The weld joint 4 is produced in such a way that an outer web 4.1, which limits its edge, is created by adjusting welding and / or melting parameters such that its free surface has a different structure than a free surface of the rest of the weld joint 4.2. For example, the weld joint 4 and its outer web 4.1 are produced in a laser welding and / or laser melting process.

[0022] This modification of the outer track 4.1 ensures that there is a clear visual demarcation between the outer track 4.1 and the component 3. Thus, the weld joint 4 can be constructed as shown in the illustration. Fig. 5 in the data acquired by the detection device 5 of one component 3 are reliably and precisely detected due to an exact mapping of its outer contour by the outer track 4.1. For this purpose, the optical detection device 5 has, for example, at least one camera, with which image data of the free surface of the weld joint 4 and the free surface of the outer track 4.1 are acquired.

[0023] In particular, the modified outer web 4.1 allows a weld contour to be determined from the data of the acquisition device 5 by a quality assurance system implemented in an evaluation unit 6. An area lying within the weld contour can be completely characterized and defined as a weld. Thus, in an evaluation of the acquired data, parameters of the weld joint 4, such as its dimensions and / or weld imperfections, especially those located in and / or within the outer web 4.1, can be determined, and conclusions can be drawn about the quality of the weld joint 4.

[0024] In Fig. Figure 6 is a sectional view of the component arrangement 1 according to Fig. 4 shown during the creation of the weld joint 4 between the two components 2, 3.

[0025] In this process, a laser beam LS is directed onto a surface of component 3, completely penetrating component 3 and partially melting a surface of component 2. The weld joint 4 and its outer surface 4.1 are thereby created in a welding and / or melting process with the other structure. During the execution of the welding and / or melting process, the welding and / or melting parameters of the laser beam LS are adjusted to generate the other structure in the area of ​​the outer surface 4.1. Thus, a different topography is created in the area of ​​the free surface of the outer surface 4.1 than in the area of ​​the free surface of the remaining weld joint 4.2. For example, the topography of the free surface of the outer surface 4.1 exhibits a higher degree of smoothness compared to the topography of the free surface of the remaining weld joint 4.2.

[0026] After solidification of a melt generated by means of the laser beam LS, the weld joint 4 and its outer surface 4.1 and the components 2, 3 are formed according to the illustration in Fig. 4 connected to each other.

[0027] In the Fig. 7 and Fig. Figure 8 shows an alternative method for generating the welded joint 4 and the outer web 4.1.

[0028] In a first welding process, the weld joint 4 and its outer surface 4.1 with surfaces of the same structure are created, so that a weld joint 4 according to Fig. 7 is created. This means, for example, that the weld joint 4 is initially created in its entirety with the same welding parameters.

[0029] Subsequently, in a second welding and / or melting process, the outer layer 4.1 is modified by passing over it again with the laser beam LS using different welding and / or melting parameters, for example, lower power, so that its free surface exhibits the different structure. During this second pass, the free surface of the outer layer 4.1 can, for example, be smoothed. Reference symbol list 1 Component arrangement 2 components 3 components 4 welded joints 4.1 Outer lane 4.2 other weld joint 5 Detection device 6 evaluation unit LS laser beam QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2009 052 529 B4

[0003]

Claims

Method for producing a welded joint (4), wherein: - at least two components (2, 3) are aligned relative to each other, - the components (2, 3) are joined together at least section by section to form the welded joint (4), - data of a free surface of the welded joint (4) are acquired by means of an optical detection device (5), and - parameters of the welded joint (4) are determined by means of an evaluation unit (6) on the basis of the acquired data, characterized in that at least one outer surface (4.1) limiting the edge of the welded joint (4) is produced by setting welding and / or melting parameters such that its free surface has a different structure than a free surface of the rest of the welded joint (4.2). Method according to claim 1, characterized in that - the remaining weld joint (4.2) and its outer web (4.1) are produced with the other structure in a welding process and - during the execution of the welding process the welding and / or melting parameters are adjusted to produce the other structure in the area of ​​the outer web (4.1). Method according to claim 1, characterized in that - in a first welding process the entire weld joint (4) with the outer web (4.1) and the remaining weld joint (4.2) are produced with surfaces of the same structure and - in a second welding and / or melting process the outer web (4.1) is modified such that its free surface has the other structure. Method according to one of the preceding claims, characterized in that the remaining weld joint (4.2) and the outer web (4.1) are produced in a laser welding and / or laser melting process. Method according to one of the preceding claims, characterized in that the optical detection device (5) has at least one camera, by means of which image data of the free surface of the remaining weld joint (4.2) and the free surface of the outer web (4.1) are detected as data. Method according to one of the preceding claims, characterized in that the dimensions of the welded joint (4) and / or seam imperfections are determined as parameters of the welded joint.

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