Clamping device for a laser welding device, laser welding device and method for laser welding

Abstract

The invention relates to a clamping device (4) for a laser welding device (1) for laser welding at least two workpieces (5, 6) at several joining points (S1 to Sn), a laser welding device (1) and a method for laser welding two workpieces (5, 6) by means of a laser welding device (1).

Description

[0001] The invention relates to a clamping device for a laser welding device for laser welding, in particular scanner welding, of at least two workpieces.

[0002] Furthermore, the invention relates to a laser welding device with at least one laser welding head and such a clamping device.

[0003] Furthermore, the invention relates to a method for laser welding by means of such a laser welding device.

[0004] Laser welding systems have a laser beam source. A welding head is attached to a robot arm or other manipulator and has welding optics through which the laser beam is focused onto the workpiece. Scanner welding or laser scanner welding is characterized in principle by fast process times. By means of movable mirrors in the welding optics, the laser beam can be moved at high speed within a scan field from one welding point to the next, superimposed on the movement of the welding optics (so-called "welding on the fly"). During a welding process, the workpieces to be joined are usually firmly positioned relative to one another by so-called hold-down devices, for example by being pressed together. Such hold-down devices have a contact surface via which the contact pressure required to join the workpieces can be applied to the workpiece. Conventional individual hold-down devices often have deep orHigh pressure pieces with wide contact surfaces can impair laser beam deflection or a laser beam. However, the movement of the welding optics, especially with a large number of joints, and thus laser beam deflection, is severely restricted by conventional hold-down concepts and designs and the associated shadowing of the laser beam deflection or the laser beam, so that the advantage of the fast process time is lost.

[0005] The invention is based on the object of providing a clamping device for a laser welding device which is improved compared to the prior art, an improved laser welding device and an improved method for laser welding.

[0006] The object with regard to the clamping device is achieved according to the invention by the features specified in claim 1. The object with regard to the laser welding device is achieved according to the invention by the features specified in claim 4. The object with regard to the method is achieved according to the invention by the features specified in claim 5.

[0007] Advantageous embodiments of the invention are the subject of the subclaims.

[0008] The clamping device according to the invention for a laser welding device for laser welding at least two workpieces at a plurality of joining points comprises at least one support frame which has at least one passage opening for a laser beam and a plurality of individual pressure pieces which are spring-mounted in the region of the passage opening, wherein the individual pressure pieces are designed to apply a contact pressure to at least one of the workpieces, the individual pressure pieces each have a passage opening aligned with the passage opening of the support frame for the passage of the laser beam, a joining point is or can be assigned to each individual pressure piece, and each individual pressure piece is separately movable, in particular displaceable or depressible, by a distance relative to the support frame against an associated spring force in order to compensate for height differences of individual joining points on the workpieces.

[0009] The advantages achieved by the invention are, in particular, that a high hold-down effect can be achieved by means of such a clamping device, whereby each joint can be individually loaded via the individual pressure pieces, whereby, in addition, manufacturing tolerances in the component height can be automatically compensated for by the separately spring-mounted individual pressure pieces, without manual adjustment.

[0010] The clamping device according to the invention can form a globally usable clamping tool.

[0011] A laser welding device according to the invention for laser welding, in particular laser scanner welding, of at least two workpieces comprises at least one laser welding head, a component carrier movable relative to the laser welding head and a clamping device arranged between the laser welding head and the component carrier as described above.

[0012] The laser welding head, for example, a welding optic, can be moved across its own scanning field in addition to the laser beam movement. The workpieces are pressed into the clamping fixture from below using a base plate or component carrier, allowing each individual pressure piece to deflect separately by the same amount via its spring element(s), compensating for varying height tolerances at each joint.

[0013] At least one of the support frame's through-holes is adapted to the scanning field of the welding optics. For example, if the welding optics are positioned centrally, the laser beam can be deflected to position several individual pressure pieces. Several individual pressure pieces can be reached through the through-hole in the support frame. The components of the clamping device can be designed to be insulated from one another.

[0014] In the method according to the invention for laser welding two workpieces by means of a laser welding device according to the previous description, the workpieces to be welded together are positioned below the clamping device by means of the component carrier and the component carrier is pressed vertically against the plurality of spring-mounted individual pressure pieces of a firmly clamped support frame, wherein each individual pressure piece is assigned a joining point, each individual pressure piece acts on a joining point on the workpieces and, when pressed against at least one of the workpieces, moves individually by a distance against an associated spring force relative to the support frame, wherein a laser beam of the laser welding head is then guided through the passage opening of the support frame and through the passage opening of the respective individual pressure piece to the assigned joining point.The laser beam is directed to the respective joint by a movable welding optics. This allows multiple joints to be reached precisely.

[0015] Embodiments of the invention are explained in more detail below with reference to drawings.

[0016] Showing: Fig. 1 schematically shows a laser welding device according to the invention in a starting position, wherein the laser welding device comprises at least one laser welding head, a component carrier arranged below the laser welding head and a clamping device arranged between the laser welding head and the component carrier, Fig. 2 schematically shows the laser welding device according to Fig. 1 in a welding position, and Fig. 3 schematically shows a perspective view of the laser welding device according to the invention according to Fig. 1.

[0017] Corresponding parts are provided with the same reference numerals in all figures.

[0018] Fig. 1 schematically shows a laser welding device 1 according to the invention in a starting position P1, wherein the laser welding device 1 comprises at least one laser welding head 2, a component carrier 3 arranged below the laser welding head 2 and a clamping device 4 arranged between the laser welding head 2 and the component carrier 3.

[0019] The clamping device 4 for laser welding at least two workpieces 5, 6, which form, for example, a component assembly 7, at several joining points S1 to Sn comprises at least one support frame 4.1, which has at least one passage opening 4.1.1 for a laser beam L (in Fig. 2) and has several individual pressure pieces 4.2 which are spring-mounted in the area of the passage opening 4.1.1.

[0020] The individual pressure pieces 4.2 each have a through opening 4.2.1 aligned with the through opening 4.1.1 of the support frame 4.1 for the passage of the laser beam L.

[0021] The support frame 4.1 can be clamped or is clamped in a fixed position, for example by means of a clamping element 4.3.

[0022] The component carrier 3 together with the component assembly 7 is adjustable in the direction of the support frame 4.1.

[0023] Each individual pressure piece 4.2 can be assigned or is assigned a joint S1 to Sn on the component assembly 7. Each individual pressure piece 4.2 is separately movable against an associated spring force by a distance Δz (in Fig. 2) is movable relative to the support frame 4.1, in particular displaceable or depressible, in order to compensate for height differences of individual joints S1 to Sn on the workpieces 5, 6.

[0024] Each individual pressure piece 4.2 is spring-mounted on the support frame 4.1 via at least one spring element 4.2.2, for example a compression spring.

[0025] The support frame 4.1 is a support plate with several through-holes 4.1.1 arranged in the longitudinal direction and / or in the transverse direction. The support frame 4.1 has a defined thickness t. The support frame 4.1 is designed to be flexurally and torsionally rigid.

[0026] Fig. 2 shows schematically the laser welding device 1 according to Fig. 1 in a welding position P2.

[0027] The component assembly 7 is inserted from below into the clamping device 4 by means of the component carrier 3 and pressed against the individual pressure pieces 4.2.

[0028] The laser welding head 2, for example, a welding optics, can be moved across its own scanning field in addition to the laser beam movement. The entire component assembly 7 is pressed or pushed upwards from below by means of the component carrier 3 toward the clamping device 4 by a stroke Hz, so that each individual pressure piece 4.2 can deflect separately by the distance Δz via its spring element(s) 4.2.2 in order to compensate for different height tolerances for each joint S1 to Sn.

[0029] The laser welding device 1 according to the invention enables highly precise and process-reliable laser welding of multiple joints S1 to Sn with significantly reduced cycle times. The targeted design for the use of modern laser welding heads 2, for example, modern welding optics with a large scan field, achieves maximum area utilization with minimal mechanical effort.

[0030] Each individual joint S1 to Sn is held down by a separately designed and separately spring-loaded pressure piece 4.2. This ensures a uniform and reliable contact force F across all joining zones and leads to a significant improvement in weld seam quality. Adjustment to height differences and tolerances occurs automatically through the compression of the individual pressure pieces 4.2, without the need for individual readjustment or positioning.

[0031] The entire component assembly 7 is inserted into the clamping device 4, for example, a clamping tool, with a single lifting movement in the vertical direction Z. Manual or automated movement of individual hold-down devices is completely eliminated. This not only results in precise and repeatable positioning but also reduces wear and tear and the complexity of the system.

[0032] Due to its modular design and flexible material selection, clamping device 4 can be combined with current system technology and easily integrated into existing production lines. It is particularly suitable for applications with numerous, extensively arranged joints S1 to Sn, such as those found in the contacting of battery cells with cell connectors.

[0033] A further advantage is the high flexibility with different materials and the adaptability to a wide variety of joining zone geometries and weld seam paths. The individual 4.2 pressure pads can be disassembled individually, allowing for easy maintenance, cleaning, and quick replacement if necessary.

[0034] All components of the clamping device 4 can be designed according to the specific material and application. For example, the support frame 4.1 can be made of steel or aluminum, while the individual pressure pieces 4.2 are made of copper and, if necessary, coated to meet the thermal and mechanical requirements.

[0035] Fig. 3 shows schematically a perspective view of the laser welding device 1 according to the invention according to Fig. 1.

[0036] The support frame 4.1 is a support plate with several through-openings 4.1.1 arranged in the longitudinal direction X and / or in the transverse direction Y. The support frame 4.1 can be or become variable in its width 4.1.2, length 4.1.3 and / or thickness t.

[0037] In one possible embodiment, the individual pressure pieces 4.2 are arranged next to one another and / or one behind the other along a transverse extension and / or longitudinal extension of the at least one passage opening 4.1.1 of the support frame 4.1.

[0038] In a further embodiment, the support frame 4.1 comprises a plurality of through-openings 4.1.1, wherein each through-opening 4.1.1 is assigned a plurality of spring-mounted individual pressure pieces 4.2.

[0039] The laser welding head 2 is arranged above the clamping device 4 and, thanks to its own scanning field, is able to direct the laser beam L through a single passage opening 4.1.1 onto several individual pressure pieces 4.2. List of reference symbols 1 laser welding device 2 laser welding heads 3 component carriers 4 clamping device 4.1 Supporting frame 4.1.1 Passage opening 4.1.2 Width 4.1.3 Length 4.2 Single pressure piece 4.2.1 Passage opening 4.2.2 Spring element 4.3 Clamping element 5, 6 Workpiece 7 Component composite F contact force Hz stroke L laser beam P1 starting position P2 welding position S1 to Sn joint t starch Δz path X Longitudinal expansion direction Y transverse expansion direction Z vertical direction

Claims

[1] Clamping device (4) for a laser welding device (1) for laser welding at least two workpieces (5, 6) at several joining points (S1 to Sn), characterized by - at least one support frame (4.1) which has at least one passage opening (4.1.1) for a laser beam (L) and a plurality of individual pressure pieces (4.2) which are spring-mounted in the region of the passage opening (4.1.1), wherein - the individual pressure pieces (4.2) are designed to apply a contact force (F) to at least one of the workpieces (5, 6), - the individual pressure pieces (4.2) each have a through-opening (4.2.1) aligned with the through-opening (4.1.1) of the support frame (4.1) for the passage of the laser beam (L), - each individual pressure piece (4.2) can be assigned or is assigned a joint (S1 to Sn), and - each individual pressure piece (4.2) can be moved separately against an associated spring force by a distance (Δz) relative to the support frame (4.1) in order to compensate for height differences of individual joints (S1 to Sn) on the workpieces (5, 6). [2] Clamping device (4) according to claim 1, characterized by that the individual pressure pieces (4.2) are arranged next to one another and / or one behind the other along a transverse extension and / or longitudinal extension of the at least one passage opening (4.1.1). [3] Clamping device (4) according to claim 1 or 2, characterized by that the support frame (4.1) comprises a plurality of through-openings (4.1.1), each through-opening (4.1.1) being assigned a plurality of spring-mounted individual pressure pieces (4.2). [4] Laser welding device (1) for laser welding two workpieces (5, 6) at a plurality of joining points (S1 to Sn), comprising at least one laser welding head (2), a component carrier (3) arranged below the laser welding head (2) and a clamping device (4) according to one of the preceding claims arranged between the laser welding head (2) and the component carrier (3). [5] Method for laser welding two workpieces (5, 6) at several joining points (S1 to Sn) by means of a laser welding device (1) according to claim 4, wherein - the workpieces (5, 6) to be welded together are positioned below the clamping device (4) by means of the component carrier (3), - the support frame (4.1) is fixed by means of a clamping element (4.3), - the component carrier (3) is moved in the vertical direction (Z) towards the support frame (4.1) and pressed against the individual pressure pieces (4.2) arranged on the support frame (4.1), - wherein each individual pressure piece (4.2) is assigned a joint (S1 to Sn) and each individual pressure piece (4.2) is moved by a distance (Δz) against an associated spring force relative to the support frame (4.1) when pressed against at least one of the workpieces (5, 6) in order to compensate for height differences at the joints (S1 to Sn), - wherein a laser beam (L) is then guided through the through-opening (4.1.1) of the support frame (4.1) and through the through-opening (4.2.1) of the respective individual pressure piece (4.2) to the associated joint (S1 to Sn).

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