Method and welding equipment for producing a welded joint

Abstract

The invention relates to a method (11) for producing a welded joint (2) for joining two components (3, 4), - in which the two components (3, 4), each having an end-face connecting surface (7, 8), are arranged next to each other in a welding device (5) such that the two connecting surfaces (7, 8) are next to each other, - in which a spatial position of the two connecting surfaces (7, 8) is measured, - in which the welding process is carried out to create the welded joint (2) in such a way that the welded joint (2) connects the two joining surfaces (7, 8) together, - in which a spatial shape and spatial position of the produced weld joint (2) are measured, - in which a spatial actual shape of the produced weld joint (2) is determined from the measured shape and position of the produced weld joint (2) in conjunction with the measured position of the joining surfaces (7, 8), - in which it is determined whether the weld produced (2) is a good or bad weld by comparing the actual form of the welded joint (2) with forms of good and bad welded joints (2) stored in a database (9).

Description

[0001] The present invention relates to a method for creating a welded joint for joining at least two components. The invention also relates to a welding system for carrying out the method.

[0002] When producing welded joints, attention must be paid to the high quality of the welded joints to ensure, among other things, the desired strength and fatigue strength of the welded joint. Depending on the welded joint, other factors may also be crucial for a high-quality welded joint, such as a permanently guaranteed electrical connection between the components. This is even more true for machine-made welded joints. Accordingly, quality control of the welded joints is regularly performed to identify good and bad welds. Poor welds may result in scrap or require rework.

[0003] DE 10 2022 101 093 A1 discloses a method for determining at least one geometric result variable and / or at least one quality characteristic of a weld seam on at least one workpiece. The weld seam is scanned using a measuring beam during laser beam welding of the weld seam in order to determine data points. The measuring beam is moved along at least one measuring path on the weld seam, with the determined data points indicating a height and / or depth of the weld seam relative to a workpiece surface of the at least one workpiece. Subsequently, the at least one geometric result variable and / or at least one quality characteristic are determined by evaluating the previously determined data points.In the known method, the quality of the weld seam to be created is monitored during the creation of the weld seam, making it an online process that, in particular, makes it possible to adjust welding parameters based on the determined result variables and / or quality characteristics during the welding process. This method is suitable for welded joints that require a comparatively long time to produce, such as longer welds. This method is therefore less suitable for small or short, particularly spot welds, which are manufactured mechanically and in series, particularly in short cycle times.

[0004] The present invention addresses the problem of providing an improved or at least a different embodiment of a method or welding system for creating a welded joint for joining two components, which is characterized in particular by improved manufacturing quality. Furthermore, a reduction in scrap is sought.

[0005] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The invention is based on the general idea of ​​comparing the actual shape of the currently produced weld with a multitude of stored shapes of good and bad welds. This allows for a simple and quick determination of whether the produced weld is a good or bad weld.

[0007] In detail, it is proposed that the two components, each having a front-end connecting surface, be arranged next to one another in a welding device in such a way that the two connecting surfaces are next to one another, whereby in particular the components can lie directly against one another there. Ideally, the two connecting surfaces are spaced from one another by a technical zero gap. Even with components that lie directly against one another, a residual gap cannot be avoided due to surface roughness, which is referred to as a technical zero gap. The spatial position of the two connecting surfaces is then measured. A welding process is then carried out to create the welded joint in such a way that the welded joint connects the two connecting surfaces. Any possible gap or residual gap is bridged.A spatial shape and a spatial position of the created weld are then measured. A spatial actual shape of the created weld is then determined from the measured shape and position of the created weld in conjunction with the measured position of the connecting surfaces. In this way, the spatial position of the two connecting surfaces is subtracted from the spatial position of the created weld in such a way that the spatial actual shape is neutralized with regard to the spatial position of the two connecting surfaces. In a subsequent step, by comparing the actual shape of the created weld with shapes of good and bad welds stored in a database, it is determined whether the created weld is a good or a bad weld.Since the method according to the invention checks the welded joint to be inspected by comparing the actual shape with stored shapes, this inspection can be carried out relatively quickly. Consequently, this method can also be easily implemented in automated series production.

[0008] The measurement of the spatial position of the two connecting surfaces and / or the measurement of the spatial shape and the spatial position of the produced weld joint can be carried out optically, for example by means of a camera or by means of a laser scanning or a laser scan.

[0009] According to an advantageous embodiment, a number of welding parameters can be determined depending on the measured spatial position of the two connecting surfaces, wherein the welding device is adapted to the measured spatial position of the two connecting surfaces using the determined welding parameters before the welding process to create the welded joint is carried out. By taking the current spatial position of the two connecting surfaces into account when adjusting the welding device, tolerances in the manufacture of the two components and in the arrangement of the two components in the welding device can be compensated. This can improve the quality of the produced welded joint. It is noteworthy here that the positioning of the two components is not intervened in, but only the welding parameters of the welding device are adjusted.This adjustment can be carried out more quickly and accurately than, for example, adjusting the position of the two components within the welding device.

[0010] In an advantageous embodiment, the database can store the stored shapes of good and poor welds, as well as the spatial positions of the joining surfaces before the respective good or poor weld was created, as well as the welding parameters used when creating the respective weld. The welding parameters can then be determined depending on the measured spatial position of the two joining surfaces by comparing the measured spatial position of the two joining surfaces with the stored spatial positions of good welds. In this way, the welding parameters used to adjust the welding device are determined based on known spatial positions that have led to good welds in the past. In this way, the quality of the weld to be created can be improved.

[0011] According to an advantageous embodiment, the stored welding parameters of the good weld joint for which the corresponding stored spatial position of the two connecting surfaces is closest to that of the measured spatial position of the two connecting surfaces can be used as welding parameters for adapting the welding device to the measured spatial position of the two connecting surfaces. In other words, the good weld joint is searched for in the database in which the spatial position of the two connecting surfaces before the weld joint is produced has the greatest correspondence with the currently measured spatial position of the two connecting surfaces of the weld joint currently being produced. In this way, the quality of the weld joint to be produced can be improved.

[0012] In another advantageous embodiment, the welding parameters can include, for example, an angle of incidence of a laser beam and / or a focus position of a laser beam of the laser-based welding device. This allows the welding device to be particularly easily adapted to varying spatial positions of the two joining surfaces to be welded together.

[0013] For example, the two connecting surfaces in the welding fixture can be located at different absolute positions with respect to an X-axis and / or a Y-axis and / or a Z-axis. Likewise, the two connecting surfaces can be located at different positions relative to each other with respect to an X-axis and / or a Y-axis and / or a Z-axis. Likewise, a possible gap between the two connecting surfaces can be of different sizes.

[0014] According to another advantageous embodiment, the determination of whether the created weld is a good or bad weld can be made using shape data of the actual shape, which is compared with shape data of the stored shapes. Based on the stored shape data, the stored shape whose shape data best matches the shape data of the actual shape can then be determined. The created weld can then be identified as a good weld if the determined stored shape whose shape data best matches the shape data of the actual shape is assigned to a stored good weld.Likewise, the generated weld can be identified as a poor weld if the determined stored shape whose shape data best matches the shape data of the actual shape is associated with a stored poor weld. Accordingly, the classification of the generated weld as a good or poor weld can be performed quickly and easily.

[0015] In another advantageous embodiment, the determination of whether the welded joint is good or bad can be carried out using artificial intelligence, which is trained using a large number of welded joints that have already been created and classified as good or bad. The use of artificial intelligence allows a particularly large amount of data to be taken into account, which increases the reliability of the quality inspection.

[0016] According to an advantageous embodiment, it can be provided that when determining whether the welded joint produced is a good or bad weld, in the case of a bad weld, a defect category can also be determined into which a defect in the bad welded joint falls. Depending on the defect category, different consequences can follow. In the case of simple defects, such as small deviations in shape, it can be provided, for example, that the welded components are subjected to reworking. In the case of larger defects, such as deviations in shape that indicate inclusions of air or gas or foreign particles, the welded components can be identified as scrap if necessary and disposed of accordingly.Likewise, in the case of certain defects, it may be stipulated that a welding system in which the process presented here is being performed is stopped in order to eliminate the cause of the defect in the weld joint for future welds. In particular, it may also be stipulated that the type of defects occurring and their frequency are continuously recorded. Furthermore, it may be stipulated that the welding system is only stopped when defects of a certain category occur with a certain frequency.

[0017] Accordingly, according to an advantageous embodiment, it can be provided that several defect categories of different defects are taken into account when classifying the poor welded joints.

[0018] A welding system according to the invention for producing a welded joint for connecting two components comprises a welding device for producing the welded joint, a measuring device for measuring the spatial position of the connecting surfaces and for measuring the spatial shape and spatial position of the produced welded joint, a database in which shapes of good and bad welded joints are stored, and a control device which is coupled to the welding device, to the measuring device and to the database and which is configured to carry out the method described above.

[0019] In the present context, a ‘configuration’ is synonymous with a ‘design’ and / or ‘arrangement’ and / or ‘programming’, so that the phrase ‘configured so that’ is synonymous with the phrase ‘designed and / or arranged and / or programmed so that’.

[0020] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0021] It is understood that the features mentioned above and those to be explained below can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention as defined by the claims. Components mentioned above and those to be mentioned below of a higher-level unit, such as a device, apparatus, or arrangement, which are designated separately, may form separate parts or components of this unit or be integral areas or sections of this unit, even if this is shown differently in the drawings.

[0022] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0023] They show, schematically, Fig. 1 to 3 each show a highly simplified schematic diagram of a welding system during different steps of a process for producing a welded joint, Fig. 4 a highly simplified view of two components before creating the weld joint, Fig. 5 a view in Fig. 4, but after creating a good weld joint, Fig. 6 and Fig. 7 views as in Fig. 5, but after creating a poor weld, Fig. 8 is a flow chart explaining a process for manufacturing the welded joint.

[0024] According to the Fig. 1 to 3 comprises a welding system 1, which serves to create a welded joint 2 for connecting two components 3, 4, a welding device 5 for creating the welded joint 2, a measuring device 6 for measuring a spatial position of end-face connecting surfaces 7, 8 of the two components 3, 4 as well as for measuring a spatial shape and spatial position of the welded joint 2. Furthermore, the welding system 1 comprises a database 9 in which the shapes of good and bad welded joints are stored. The database 9 is in the Fig. 1 to 3, each indicated by a rectangle drawn with a broken line within the welding device 5. In addition, the welding system 1 comprises a control device 10, which is Fig. 1 to 3 is also indicated by a rectangle drawn with a broken line within the welding device 5. The control device 10 is coupled in a suitable manner via corresponding lines (not shown) to the welding device 5, to the measuring device 6 and to the database 9. Furthermore, the control device 10 is configured to carry out a method 11, which is described below with reference to Fig. 8 is explained in more detail.

[0025] Accordingly Fig. 8, the method 11 for producing the welded joint 2 for connecting the two components 3, 4 comprises a production phase 12 and a learning phase 13 preceding the production phase 12. The production phase 12 will be discussed in more detail below.

[0026] First, the two components 3, 4 are arranged next to one another in the welding device 5 or in a holder 14 or clamping device 14 of the welding device 5, in such a way that the two end-face connecting surfaces 7, 8 are located next to one another. Preferably, the components 3, 4 lie directly against one another, at least in the region of the connecting surfaces 7, 8. Likewise, the connecting surfaces 7, 8 can be separated from one another or spaced from one another by a gap 15, ideally a technical zero gap. The two components 3, 4 can, for example, be straight end pieces of electrical conductors that are to be mechanically and electrically connected to one another by means of the welded joint 2.

[0027] In a step 16 of the production phase 12 of the process 11, which is also Fig. 1, a spatial position of the two connecting surfaces 7, 8 is measured. For this purpose, a measuring beam 17 of the measuring device 6 can scan the connecting surfaces 7, 8. In particular, the spatial position of the two connecting surfaces 7, 8 with respect to a reference point of the welding device 5 is recorded. The spatial position is recorded in the form of spatial coordinates, which can in particular include values ​​for an X-axis, a Y-axis and a Z-axis. A corresponding Cartesian coordinate system is shown purely as an example in Fig. 1 and also applies to the Fig. 2 and Fig. 3. Accordingly, the two components 3, 4 are spaced apart from each other with respect to the X-axis.

[0028] In a later step 18, which is also in Fig. 2, a welding process is carried out to create the welded joint 2. The welding process is carried out in such a way that the welded joint 2 connects the two connecting surfaces 7, 8. Any gap 15 that may be present is bridged. Fig. 2 shows a laser beam 19, with which the welded joint 2 is created. Accordingly, the welding device 5 operates here with a laser beam 19 to create the welded joint 2.

[0029] In a further step 20, which is also in Fig. As shown in Figure 3, a spatial shape and a spatial position of the produced weld joint 2 are measured using the measuring device 6. Here, a measuring beam 17 again scans the weld joint 2.

[0030] In a subsequent step 21, it is determined whether the produced weld 2 is a good or a bad weld 2. For this purpose, a spatial actual shape of the produced weld 2 is first determined from the measured shape and position of the produced weld 2 using the measured position of the connecting surfaces 7, 8. This actual shape of the weld 2 is thus adjusted or neutralized with regard to the spatial position of the connecting surfaces 7, 8.

[0031] Subsequently - but shown here in the same step 21 - the actual shape of the created weld joint 2 is compared with the shapes of good and bad weld joints 2 stored in the database 9. This comparison can then be used to determine whether the created weld joint 2 is a good weld joint or a bad weld joint. If it is determined in step 21 that the created weld joint 2 is a good weld joint 2, a step 22 follows in which it is determined that the welded components 3, 4 are OK. If, however, the comparison in step 21 shows that the weld joint 2 is a bad weld joint 2, a step 23 determines that the welded components 3, 4 are not OK.This result can then lead to the rejection of the welded components 3, 4 or to reworking of the weld joint 2.

[0032] Between step 16, in which the spatial position of the two connecting surfaces 7, 8 is measured, and step 18, in which the welded joint 2 is created, an intermediate step 24 can be provided in which several welding parameters are determined depending on the measured spatial position of the two connecting surfaces 7, 8 and in which the welding device 5 is adapted with the determined welding parameters to the measured spatial position of the two connecting surfaces 7, 8. This means that the welding process is then carried out with the welding device 5 adapted to the current welding parameters.

[0033] For example, in addition to the stored shapes of good and bad welds 2, the database 9 can also store the spatial positions of the connecting surfaces 7, 8 before the respective good or bad weld was created, as well as the welding parameters used when creating the respective good or bad weld 2. The welding parameters usable for adjusting the welding device 5 can now be determined by comparing the measured spatial position of the two connecting surfaces 7, 8 with the stored spatial positions of good welds 2 in order to find the one within the stored good welds 2 for which the spatial position of the two connecting surfaces 7, 8 is closest to the currently measured spatial position.Subsequently, the stored welding parameters of that good weld joint 2 in which the associated stored spatial position of the two connecting surfaces 7, 8 is closest to that of the measured spatial position of the two connecting surfaces 7, 8 are used as welding parameters for adapting the welding device 5 to the measured spatial position of the two connecting surfaces 7, 8.

[0034] Welding parameters that can be set on the welding device 5 for producing the welded joint 2 are, for example, an angle of incidence of the laser beam 19 and / or a focus position of the laser beam 19, for example with respect to the Z-axis, and / or an area to be covered by the laser beam, for example in the X-axis and the Y-axis and / or the laser power to be applied.

[0035] The determination in step 21 as to whether the welded joint 2 produced is a good or bad welded joint 2 is expediently carried out using shape data of the actual shape, which are compared with shape data of the stored shapes.

[0036] Fig. 4 shows the two components 3, 4 before the welding connection. Fig. The coordinate system shown in Figure 4 also applies to the Fig. 5 to 7. In the Fig. 5 to 7, the welded joint 2 is established. As can be seen, the welded joint 2 connects the two components 3, 4 in the area of ​​the connecting surfaces 7, 8, thereby bridging any gap 15 or zero gap that may be present. Fig. 5 shows an example of a good weld 2+, while the Fig. 6 and Fig. 7 show two examples of deteriorated welds 2-. According to Fig. 5 shows the good weld joint 2+ of the Fig. 5 a permissible extension in the Z-axis, whereby the position of the connecting surfaces 7, 8 before the weld 2 is made is used as a reference. The good weld 2+ also protrudes to a permissible extent in the Y-axis and in the X-axis (not visible here) beyond the components 3, 4 or their end-face connecting surfaces 7, 8.

[0037] The bad weld 2- the Fig. 6, for example, protrudes too far beyond the connecting surfaces 7, 8 in the Z-axis and protrudes too far beyond the corresponding connecting surface 8 in the Y-axis in the area of ​​component 4. In addition, within the poor weld joint 2- in Fig. 6 Inclusions 25 are indicated, which may be formed by gases or impurities. In the case of a poor weld joint 2-the Fig. 7 the weld joint 2- remains below a desired height in the Z-axis.

[0038] The dimensions of the welded joint 2 along the spatial axes thus constitute the actual shape data. Likewise, impurities 25, which are measurable as unevenness on the surface of the welded joint 2, constitute the actual shape data.

[0039] The determination carried out in step 21 as to whether the created weld joint 2 is a good or bad weld joint 2 is then carried out using shape data of the actual shape, which is compared with shape data of the stored shapes. Based on the stored shape data, the stored shape whose shape data shows the greatest match with the shape data of the actual shape is now determined. The created weld joint 2 can then be identified as a good weld joint 2+ if the determined saved shape whose shape data shows the greatest match with the shape data of the actual shape is assigned to a stored good weld joint 2+. The created weld joint 2, on the other hand, can be identified as a bad weld joint 2- if the determined saved shape whose shape data shows the greatest match with the shape data of the actual shape is assigned to a stored bad weld joint 2-.

[0040] The determination performed in step 21 as to whether the welded joint 2 produced is a good or bad welded joint 2 can be carried out in particular using artificial intelligence. This artificial intelligence is taught during the teaching phase 13 of the method 11. In a step 26, limit sample components are welded in order to produce good and bad welded joints 2, whereby samples and examples of bad welded joints 2 are produced with all known defect types. At the same time, before the respective welded joint 2 is produced, the spatial positions of the connecting surfaces 7, 8 are measured. In addition, the welding parameters set during the welding process are recorded. Likewise, the welded joint 2 produced in this process is measured with regard to its spatial shape and spatial position.

[0041] In a subsequent step 27, the produced welds 2 are categorized according to their quality using conventional methods, for example, through metallurgical processes and X-ray examinations. In a further step 28, the exemplary good and bad welds 2 are then taught, thereby training the artificial intelligence.

[0042] During the training of the artificial intelligence, the poor welds 2 can also be categorized with regard to the defects of the poor welds 2. The categorization of the different defects within the poor welds 2 enables improved quality monitoring during the production phase 12. In particular, this allows unavoidable production defects in series production to be distinguished from system defects, such as damage to the welding device 5 or the measuring device 6. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2022 101 093 A1

[0003]

Claims

[1] Method (11) for producing a welded joint (2) for connecting at least two components (3, 4), - in which the two components (3, 4), each having a frontal connecting surface (7, 8), are arranged next to one another in a welding device (5) in such a way that the two connecting surfaces (7, 8) are located next to one another, - in which a spatial position of the two connecting surfaces (7, 8) is measured, - in which the welding process for producing the welded joint (2) is carried out in such a way that the welded joint (2) connects the two connecting surfaces (7, 8) to one another, - in which a spatial shape and spatial position of the produced weld (2) are measured, - in which a spatial actual shape of the produced welded joint (2) is determined from the measured shape and position of the produced welded joint (2) in conjunction with the measured position of the connecting surfaces (7, 8), - in which it is determined whether the produced weld joint (2) is a good or bad weld joint (2) by comparing the actual shape of the produced weld joint (2) with shapes of good and bad weld joints (2) stored in a database (9). [2] Method (11) according to claim 1, characterized by , - that welding parameters are determined depending on the measured spatial position of the two connecting surfaces (7, 8), - in which the welding device (5) is adapted to the measured spatial position of the two connecting surfaces (7, 8) using the determined welding parameters. [3] Method (11) according to claim 2, characterized by , - that in the database (9), in addition to the stored shapes of good and bad welds (2), the spatial positions of the connecting surfaces (7, 8) before the respective good or bad weld (2) is created, as well as the welding parameters used when creating the respective weld (2) are stored, - that the welding parameters are determined as a function of the measured spatial position of the two connecting surfaces (7, 8) by comparing the measured spatial position of the two connecting surfaces (7, 8) with the stored spatial positions of good welded joints (2). [4] Welding system (1) for producing a welded joint (2) for connecting two components (3, 4), - with a welding device (5) for producing the welded joint (2), - with a measuring device (6) for measuring the spatial position of the connecting surfaces (7, 8) and for measuring the spatial shape and position of the welded joint (2) produced, - with a database (9) in which shapes of good and bad welds (2) are stored, - with a control device (10) which is coupled to the welding device (5), to the measuring device (6) and to the database (9) and which is configured to carry out the method (11) according to one of the preceding claims.

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