EP2576122A1

EP2576122A1 - Method and device for laser-joining sheet metal parts

Info

Publication number: EP2576122A1
Application number: EP11722396.6A
Authority: EP
Inventors: Steffen Walter; Igor Haschke
Original assignee: Scansonic MI GmbH
Current assignee: Scansonic MI GmbH
Priority date: 2010-05-28
Filing date: 2011-05-25
Publication date: 2013-04-10
Also published as: CN103025470B; DE102010029477A1; WO2011147891A1; US20130087538A1; US8981257B2; JP2013530837A; JP5864557B2; CN103025470A

Abstract

The invention relates to a device and corresponding method for laser-joining sheet metal parts each having a flange, wherein the flanges of the sheet metal parts (2) are to be joined to form a connecting flange. The device comprises a clamping unit (5) for clamping the sheet metal parts (2) to be joined in a primary clamping direction which is transverse to the connecting flange, and a beam guiding unit for a laser beam (1). The device further comprises a compensating axis (9) which tracks the laser beam (1) in accordance with a relative movement between the connecting flange and a guiding machine.

Description

Method and device for laser joining sheet metal parts

The invention relates to a method and a device for laser joining sheet metal parts with flanges, in particular body parts.

For joining, in particular for laser joining, sheets to be joined can be provided with a flange, that is to say an angled edge. In this way, connecting flanges can be produced in which the flanges of the metal sheets to be joined strike each other flat and thus form a joint with a flange plane.

The laser welding of I-seams in the lap joint has long been established in the body shop. For example, welds are made on door entry openings or along roof edges according to this principle. For the most part, so-called "flying optics" are used in conjunction with stationary or accompanying clamping technology To influence corrosion protection layer and thus to improve the near quality. By way of example, only a few methods are mentioned here.

DE 10 2004 044601 A1 discloses a method in which the sheets are overlap-deformed in the overlap by the deliberate attachment of revolving clamping elements in such a way that a degassing gap is produced in order to improve the welding quality. For non-straight seams, e.g. At radii in door corners, a defined gap generation is poorly possible. Multiple impacts are not controllable by the method.

DE 102 48955 B3 discloses a method in which the connection of 3 sheets is possible by the use of two, one from above and one from below laser beams by means of running clamping technique in conjunction with a degassing.

DE 10 2004 041502 A1 discloses a method in which the vapor capillary is stabilized by modulation of the laser radiation and an improved welding result is produced. The determination of the required modulation properties is essentially based on the empirical determination, which requires some effort in determining the modulation characteristics for specific components.

In order to avoid the disadvantages of the I-seams in the lap joint, the welding of fillet welds on the lap joint is often used. In particular, by a special design of the arrangement of the sheets in the overlapping area, the degassing can be improved. DE 102 61507 A1 discloses a method in which the overlapping sheets in the weld area meet at an acute angle to each other and that the weld in the region or close to the curvature of one of the sheets is designed as a fillet weld. In order to realize the required precision in the positioning of the laser spot with respect to the joint for the production of fillet welds, DE 100 06852 C5 describes a method in which the filler material in the form of a wire is used as a mechanical probe element and the wire tip melting off the energy beam is frictionally passed along the material surface is guided. The beam direction when joining sheet metal flange joints in body construction is perpendicular or substantially perpendicular to the flange plane, ie transversely through the sheets to be joined. Accordingly, if the laser flanges are used for laser joining, such as, for example, door-mounted clamping systems or sills, the alignment of the laser beam is parallel or substantially parallel to the direction of force of the clamping or pressing technique. Usual angles are 0 ° ..15 °, maximum angles 20 °.

The known methods of welding sheets in body shop have disadvantages. The frequently used laser welding of I-seams in the lap joint is often characterized by low seam quality due to zinc degassing. In this type of seam connection errors can be difficult or impossible to detect nondestructively. A superficially perfect-looking seam may have connection errors. This risk is particularly great for I-seams in the lap joint. The connection cross-section is limited, the welding depth relatively little reproducible, especially in multi-plate connections. Welding causes damage to the zinc layer on the back of the sheet metal. Due to the practically limited positioning accuracy of laser spot to component, and the required compliance defined joint gaps, the flange dimensions are relatively large.

The still widespread fillet weld on the lap joint is in contrast produced because of improved degassing of zinc fumes in higher quality. At the same time, the seam connections to both joining partners are optically inspectable. However, because of the insufficient positioning accuracy of the laser spot to the component joint, the seam shape often requires a seam guiding system. To increase the connection cross-section often a filler material is applied. The connection cross-section can not be increased beyond the material thickness of the top plate. Due to the necessary welding angle to the component, the clamping technology must ensure appropriate accessibility, which is often only possible in conjunction with relatively large flange dimensions. These relatively large sheet metal flanges are not desirable in connection with the mass reduction and fuel economy sought in vehicle construction. The object of the invention is to provide a possibility for laser joining of sheet metal parts with flanges, in particular body parts, with which can be improved by a frontal welding in the lap, for example on the door entry of body shells, the seam strength and manufacturing, and the flange lengths can be shortened ,

According to the invention this object is achieved on the one hand by a method for laser joining of sheet metal parts and on the other hand by a device for laser joining of sheet metal parts.

The method according to the invention for laser joining sheet metal parts, each with a flange, wherein the flanges of the sheet metal parts are to be joined to form a connecting flange, comprises the method steps:

Clamping of sheet metal parts in the region of the connecting flange in a direction transverse to the connecting flange main clamping direction and at the same time frontal welding to the connecting flange by directing a laser beam substantially parallel to the connecting flange and transverse to the main clamping direction on a front side of at least one of the flanges of the sheet metal parts to be joined, wherein the processing point along the connecting flange is guided in a seam guiding movement relative to the sheet metal parts to be joined in the main tensioning direction and / or in the spacing direction.

The device according to the invention for laser joining sheet metal parts, each with a flange, comprises: a clamping device for clamping the sheet metal parts to be joined in a direction transverse to the connecting flange clamping direction and a beam guiding device for a laser beam, which is formed, a laser beam substantially parallel to the connecting flange and transversely to To direct clamping direction on a front side of at least one of the flanges of the sheet metal parts to be joined. The device further comprises a compensating axis which, when the device is connected to a guiding machine, tracks the laser beam according to a relative movement between the connecting flange and the guiding machine.

The compensation axis is a compensation mechanism that can be realized both mechanically and visually. According to a mechanical embodiment, a compensating axis is realized by a movable connection between optical components and the guiding machine. According to an optical embodiment, a compensating axis is realized by a seam guide by means of movable optical elements, such as mirrors or lenses.

According to one embodiment, those parts of the device which jointly move the clamping device and machining points in which the laser beam impinges on the connecting flange are connected by means of at least one compensating axis to a part fastened to the guiding machine.

By means of such a device, the flanges of the sheet metal parts to be joined can be joined to a connecting flange by means of laser joining and the metal sheets are connected to one another in the region of the joint joint formed by their abutting flanges.

The use of high and ultra high strength automotive materials to reduce mass makes it necessary to increase the bond cross-sections of the joint because of the reduced strength at the joint. The method according to the invention makes it possible, on the basis of the more favorable seam geometry, to increase the connection cross-sections with the same sheet thickness and to make the seam inspectable. The process and clamping technique can be designed so that the realization of minimum flange dimensions is possible because of the more favorable arrangement. At the same time by a particular embodiment of the method, an alternating welding of multi-plate connections in a single operation is possible without increasing the process time, which provides additional freedom in implementing particularly safe and cost-effective joining concepts. The invention is based on the finding that the seam strength and production in laser joining sheet metal parts with flanges can be improved in particular in bodywork and simultaneous shorter flanges are made possible by the welding of the laser beam parallel or substantially parallel to the impact plane in flush or largely flush position of the Sheet edges are carried out with simultaneous use of provided in the machining head follower clamping technology and the integrated seam guide, which is particularly advantageous when welding flange connections to door entrances or window openings in the body.

The compensation mechanism preferably has a compensation axis compensating for a positioning error and a device for tracking the joining sequence. Positioning errors may be caused, for example, by the guide machine, which moves the device as a whole. The positioning by the guide machine, for example, an industrial robot, then does not have to be quite so accurate.

Preferably, the clamping device has clamping means which engage in operation of the device to be joined sheet metal parts and which are connected to the beam guiding device such that there is a tactile seam guide. The clamping means in this case have a dual function, namely on the one hand the clamping of the sheet metal parts to be joined in the region of the connecting flange to be created and on the other they serve to guide the laser beam. For this purpose, the clamping means are indirectly or directly, in particular mechanically connected to the beam guiding device.

Alternatively or additionally, the device may comprise means for optical seam guidance. In this case, the device preferably has a reception beam path which is coaxial with the laser beam and an internal or external illumination unit assigned to it. Particularly preferred is a device which has two independent lighting units, which are assigned to the receiving beam path.

The beam guiding device preferably has at least one deflection element for deflecting the laser beam in the main tensioning direction of the tensioning elements, to be able to track in the main tension direction of the clamping elements around that processing point at which the laser beam strikes the metal sheets to be joined. The deflection element preferably comprises at least one rotationally driven mirror for tracking the processing point. The embodiment with at least one deflection element is preferably carried out with a coaxial reception beam path and with one or two illumination units associated therewith.

Moreover, it is advantageous if the beam guiding device has at least one optical element which is able to influence the steel angle with which the laser beam is perpendicular to the main tensioning direction F, in such a way that a switching between different beam angles is possible in the region of a possible processing point , In this case, it is particularly preferred if the beam guiding device has one or more mirrors which are arranged so that a switching between different beam angles is possible in the region of a possible processing point. In this case, two or more mirrors are preferably arranged in such a way that, when switching between different beam angles, the optical path of the laser beam from the focusing lens to the processing point is approximately the same length. Different optical path lengths can also be compensated, if necessary, by movement of the focusing lens or other optical elements.

It should be noted at this point that the beam angle corresponds to the lateral angle drawn in the example described below.

According to an advantageous embodiment, the tensioning means may comprise at least two floating tensioning rollers or alternatively have a pressure roller.

With regard to the method, it is preferred if the welding takes place substantially parallel to the flange plane and substantially perpendicular to the direction of a clamping force F acting during clamping. Angles between beam and flange plane in the range of plus minus 60 degrees are possible. Preferred are angles in the range of plus minus 45 degrees. Particularly preferred are angles between 15 degrees and minus 15 degrees.

Preferably, the laser beam is guided along the connecting flange in a seam guiding movement relative to the sheet metal parts to be joined, and at the same time the position modulation of the position of a machining point at which the laser beam impinges on sheet metal parts to be joined takes place in at least one spatial direction.

Preferably, a control of the position of a processing point is also provided, on which the laser beam impinges on sheet metal parts to be joined, wherein the control is carried out in dependence on a measured by a sensor joint geometry.

The invention will now be explained in more detail by means of embodiments with reference to the figures. From these shows:

Figure 1: a schematic sketch of a front weld on the lap joint as Zweibelchverbindung;

Figure 2: a lap joint with Stirneinschweißung as Dreibelchverbindung;

Figure 3 is a plan view of the lap joint of Figure 2;

Figure 4: a lap joint with Stirneinschweißung as Zweibelchverbindung with offset of the right sheet with respect to the processing point;

Figure 5: a device for front welding at the lap joint, in the

Tensioning rollers simultaneously scan the lateral position of the component and a compensating movement takes place by an integrated compensating axis;

Figure 6: an alternative device for face welding at the lap joint, with floating mounted, counteracting tension rollers that meet the function of a compensation axis in conjunction with an automatically positionable mirror; Figure 7: a detail of the illumination of the embodiment shown in Figure 6; and

8 shows a further preferred embodiment for laterally inclined reciprocal welding with two additional mirrors

The Stirneinschweißung at the lap joint as Zweibelchverbindung takes place according to a schematic sketch (Figure 1). A laser beam 1 strikes two metal sheets, each with a flange, which are to be joined, at the planned processing point 4, which is usually located at the joint of the two metal sheets 2, ie where the two flanges of the metal sheets to be joined meet. Clamping means 5 as part of a clamping device cause a force transversely to the parting plane of the flanges 2. By the action of the laser beam 1 forms between the compressed flanges a weld 3, which is characterized by a relatively large connection cross-section. The main clamping direction F, ie the direction of the acting clamping force, of the counteracting pairs of forces runs in contrast to the prior art substantially perpendicular to the parting plane of the flanges. 2

The weld may be made as a continuous joint or stitched seam.

The precise alignment of the laser beam 1 on the processing point 4 is performed by the device. A part of the device is fixedly connected to a guiding machine, for example an industrial robot, while other parts are movable relative to the guiding machine and thus allow a seam guide through the device.

Due to the high demands on the positioning accuracy, a seam guide is required. In the device according to the invention, this can be done both mechanically tactually by means of integrated mechanical or optical seam guidance in conjunction with integrated compensation axis. The compensation axis may misalignments of the device and sheets to be joined to each other due to inaccuracies of positioning by the Guide machine and / or the sheets to be joined compensate and avoids damage to guide machine, component or device.

In the simplest case, the positioning of the laser beam 1 takes place via the tensioning means 5, by means of a beam guiding device, e.g. a beam guiding optics, and the clamping means are mechanically or otherwise coupled such that a deflection of the clamping means causes a corresponding deflection of the laser beam. This is at least one lateral seam guide (in the Y direction, see Figure 5) possible, which is usually sufficient. With a corresponding embodiment of the device by means of two compensating axes and corresponding design of the clamping means, the seam guide would also be possible in the spacing direction (in the Z direction, see FIG. 5).

An optical seam guide in conjunction with at least one controllable compensation axis allows a non-contact scanning of the joining position independently of the relative position of the clamping means to the processing point. At the same time, the position of the laser beam can be changed during use of controllable compensation axes during the machining process and adapted to the machining conditions. Furthermore, an optical seam guiding sensor system, for example by means of a light-section method, permits a measurement of the joint gap and possibly an adaptation of machining parameters.

Fig. 2 shows a lap joint with Stirneinschweißung as Dreibelchverbindung. It is preferably designed as a stitching, since in the welding breaks of the left connection, the welding of the right connection (dashed lines) can take place. By rapidly switching the laser beam 1 between the two processing positions 4, 4 ', a continuous relative movement as a total movement of the device, generated by means of guide machine, come between machining head and component for use. For switching the laser beam, a controllable compensation axis can be used with a corresponding inventive embodiment.

In Fig. 3 is a plan view of the three-plate connection of Fig. 2 is shown. The welds are offset to each other. The switching time between the Machining positions leads to gaps between the stitches. This principle can also be used for the welding of 4 or more layers of sheet metal, since the accessibility for the laser beam is given and the impact can be swept over almost simultaneously by the laser beam. Here, too, running clamping means 5 cause the sheets 2 to be pressed together. The seam is guided by means of integrated optical seam guidance in conjunction with at least one compensating axis integrated in the device.

The reduction of the laser spot to about half the sheet thickness is a good way to minimize zinc burn-off and to obtain the corrosion protection and at the same time to improve the strength through greater penetration depth. Such a small laser spot requires the use of a seam guide, but causes less process heat with less resulting distortion, the reduction of necessary laser power and the increase of the process speed with the same or even higher connection cross-section. The trailing clamping technology is required to ensure the contact of the components and to minimize the seam incidence. At the same time, it is possible to dispense with stationary clamping technology. The welding of the front side makes it possible to sweep the zinc layers of the abutting sheets during joining with the so-called keyhole in the joining zone so that the resulting zinc vapor can flow largely unhindered upwards through the so-called keyhole. The ejections as they occur at an I seam at the overlap with zero gap, are avoided. An elaborate Entgasungsunterstützung can thus be omitted.

Fig. 4 shows a lap joint with Stirneinschweißung as Zweibelchverbindung with offset of the right sheet with respect to the processing point 4. In the event that the sheets do not flush with each other and thus form no common face, quite deliberately a lateral angle 6 away from the protruding sheet can be adjusted , as shown in Fig. 4 in section. This makes it possible to avoid shading of the laser beam by the protruding part of the sheet 2 'and still achieve the required connection cross-section at the bottom of the joint. This can also be transferred to multi-sheet connections. The following is a description of various embodiments of the device according to the invention.

Figure 5 shows an embodiment in which tension rollers as a clamping means and part of a clamping device simultaneously scan the lateral position of the flanges to be joined sheets and a compensating movement is carried out by an integrated compensating axis.

FIG. 6 shows a further embodiment in which a floating mounting of the oppositely acting tensioning rollers in conjunction with an automatically positionable mirror fulfills the function of a compensation axis.

FIG. 7 shows a detail of the illumination of the embodiment described in FIG. Right in the view from the front and the left in the view from the side.

FIG. 8 shows a further preferred embodiment for laterally inclined reciprocal welding with two additional mirrors which, at different angles of incidence, respectively allow approximately the same optical path of the laser beam from the focusing lens to the processing location.

A possible embodiment of the invention is shown in FIG. A laser beam is supplied to the device by means of glass fiber via a fiber plug 10 and collimated by a lens 1 1. The beam feed can alternatively take place via a free jet and the lenses can be replaced by other beam-shaping elements, such as mirrors. The part of the device which contains the beam feed is fixedly connected by means of fastening flange 12 to a guiding machine, for example an industrial robot. The part of the device which mainly carries the focusing device and the clamping means is connected by means of compensation axis 9 with the part attached to the guide machine. The compensating axle 9 preferably contains a spring-loaded, stable middle position. The collimated laser beam passes coaxially through the balance axis 9. A displacement of the movably mounted parts thus does not affect the focusing properties of the laser beam. The focusing device in this possible embodiment comprises a second, focusing lens 13. The focused laser beam 1 strikes an adjustable mirror 14 and is directed from there, between the, the plates laterally clamping, roller-shaped clamping means 5, to the joint. The clamping means may be formed as rollers, rollers or as a clamping finger. The clamping means 5 are attached to symmetrically exciting clamping arms 15. The clamping force is transmitted symmetrically to the clamping means 5 by means of pneumatic tensioning drive 16 via positive guide 17 and clamping arms 15. This can alternatively be done for example by means of hydraulic or electric drive. The symmetrical movement of the clamping means centers the laser beam between the flanges 2 of the sheets to be welded. The adjustable mirror 14 serves to adjust the relative position of the laser beam to the processing point 4 according to the machining process. A changed position of the component formed by the sheets to be joined is compensated by the compensating axis 9 in the Y direction by linear displacement of the components of the device movably mounted in relation to the guiding machine. Alternatively, rotational compensation axes are also conceivable. The tracking of the joint is carried out here by means of the clamping means 5 indirectly via the symmetrical mechanical scanning of the flange geometry, taking into account the material thickness of the flange forming sheets 2. Within a component changing thicknesses of the sheets or multiple connections are not or limited fügbar by this simple mechanical device. Here it helps to equip the adjustable mirror 14 with at least one actuator and to make it by means of a suitable control to a positionable mirror to make an automatic switching between the joints or with different sheet thicknesses adjustment of the processing point adapted to the sheet thicknesses for multiple connections ,

FIG. 6 shows a further preferred embodiment, in which the floating mounting of the clamping arms with counteracting clamping means in conjunction with the automatically positionable mirror fulfills the function of a compensating axis and in which the seam guide instead of the mechanical scanning by the rollers by means of an optical sensor takes place, which is integrated in the machining head. Alternatively it would be a leading conventional optical seam guide sensor can be used, wherein an integrated sensor has the advantage of compensating for positioning error of the positionable tilting mirror, because the working laser beam and the sensor beam path are guided together and extend coaxially. At the same time, the accessibility to the component and the protection against contamination improve. The mechanical positive guidance of the embodiment shown in Fig. 5 is replaced by a control engineering positive guidance, which at the same time easily offers the possibility during the process of changing the position of the laser spot.

The laser radiation is supplied to the device via the fiber connector 10, collimated by collimating lens 1 1, passed over a highly reflective for the laser beam 1 partially transparent mirror 25 to the focusing lens 13 and a pivoting mirror 18 to the processing point 4. The pivoting mirror 18 has a dynamic, precise positioning drive 24. The clamping means 5 are fastened to clamping arms 15, which are floatingly mounted in this embodiment by means of rotary compensating axis 9. The clamping force generated by the pneumatic tensioning drive 16 is transmitted symmetrically via clamping arms 15 to the clamping means 5 and the sheets 2 to be welded. The illumination beam path 20 emanating from the illumination device 19 at an angle of preferably 15 to 35 degrees to the laser beam 1 serves to produce a line projection 21 on the surface of the component in the vicinity of the processing point 4. In FIG. 7, the line projection is isolated Detail, right in the view from the front and left shown in the view from the side. The incidence of the line projection 21 takes place within the field of view of the receiving beam path 22 leading in front of the processing point 4 in the processing direction 23. The light scattered by the component diffused light over the substantially to the laser beam 1 coaxial reception beam path 22 via the positionable pivoting mirror 18, by the focusing lens 13th , partially transmissive mirror 25 and imaging lens 26 projected onto the image sensor 27. The evaluation of the image of the so-called light section and the conversion into sensor position values takes place in the image evaluation device 28. The illumination device 19 with the line projection 21 in conjunction with imaging lens 26, image sensor 27 and image evaluation device 28 form the integrated optical seam guide sensor. The position of the laser beam relative to The image of the light section can be calibrated and does not change due to the coaxial principle when the pivoting mirror 18 is moving. The position of the processing point 4 in lateral and distance directions is calculated in the control device 29, taking into account the mirror position of the pivoting mirror 18 and the measured values of the light section. At the same time, the control device 29 implements a stock control for seam tracking, in which the positioning of the pivoting mirror takes place in such a way that the calibrated position of the machining beam and the nominal position of the measured impact geometry coincide. A lateral position deviation that may result from deviations of the programmed guideway from the component geometry is compensated by the floating mounting of the compensation axis 9 and by the integrated seam guide sensor by means of pivoting mirror 18. There is also a certain constraint. The control device 29 also allows the pivoting mirror 18 can be positioned so that the laser beam with offsets along the joint can be performed. The activation, feedback and the parameterization of the functions of the device is made possible via the provided external interface 30 of the control device 29. Protective mechanisms such as protective glass and Crossjet are not shown and are required for industrial use.

FIG. 7 shows a particularly preferred embodiment whose basic operating principle is identical to the embodiment in FIG. In addition, two mirrors 31 a and 31 b are arranged so that the laser beam can radiate to the component at two different angles to the flange plane. In this example of a three-flange connection, the outer plates are the two plates 2 ', 2 "projecting beyond the inner plate 2. In this case, the positioning drive 24 not only serves as an actuator for focus correction for seam tracking, but also as a changeover switch, compared with the embodiment shown in FIG for the processing of the connection of inner sheet 2 with left protruding sheet 2 'and inner sheet 2 with right protruding sheet 2 "with simultaneous switching of the angle of incidence. To avoid process-damaging shading, the laser beam (as also shown in FIG. 4) must each have a lateral angle away from the metal sheet projecting beyond the joining point, onto the sheet metal Irradiate component. To solve the problem, two additional mirrors are arranged in this embodiment such that the one deflecting mirror 31 a from the pivoting mirror in position A 18a outgoing laser beam 1 a to the processing point for position A 4a of the connection between the left outer sheet 2 'and the inner plate 2 and the other deflection mirror 31 b directs the laser beam 1b originating from the pivoting mirror in position B 18b to the processing point for position B 4b of the connection between the right outer sheet 2 "and the inner sheet 2. The overall arrangement is designed such that the optical system Paths of the laser beams 1 a and 1 b between the focusing lens 13 and the respective processing points 4a and 4b are approximately the same, in the sense of an area which has no influence on the machining process If more beam angles are required for machining, more mirrors can be arranged analogously. The illumination device 19 with the line projectio n 21 in conjunction with imaging lens 26, image sensor 27 and image analyzer 28 form the integrated optical seam guide sensor, wherein the image of the line projection 21 of the processing point for position A 4a through the one mirror 31 a and the image of the line projection 21 of the processing point for position B 4b the other mirror 31 b is imaged on the image sensor 27 via the pivoting mirror in the respective position 18 a and 18 b and the imaging lens 26. Alternatively, more than one lighting device can be arranged. Active illumination and reception beam paths must be calibrated together. Under different processing situations, such as orientations of the device to the component, the plurality of illumination devices in conjunction with the coaxial beam path can act as independent sensors, so that a better illumination of the joint or done too much shadowing by the overhanging sheets can be avoided. In addition, this embodiment of the device is equipped with a device for shifting the laser focus in the beam direction. For this purpose, the focusing lens 13 is arranged movably and can be positioned by the controller 29 via a corresponding focusing drive 32. Alternatively, other elements in the optical system can be used to influence the focus position in the beam direction. The focusing drive 32 also makes it possible to adjust the beam spot size to the process or the joint gap at the same time. Of the Positioning drive 24 can also be used to modulate the lateral position. With biaxial design of the drive or use of another mirror, a modulation is also possible in the direction of travel. Coating and process-adapted motion overlays are thereby possible.

List of Reference Numbers Designation

1 laser beam

1 a laser beam for position A

1 b laser beam for position B

2 sheet metal

2 ', 2 "protruding sheet

3 weld

4, 4 'processing point

4a Machining point for position A

4b Processing point for position B

5 clamping devices

6 lateral angles

7 mechanical seam guide

8 optical seam guide sensor

9 compensation axis

10 fiber connectors

1 1 collimating lens

12 mounting flange

13 focusing lens

14 Adjustable mirror

15 tension arm

16 tensioning drive forced control

swivel mirror

a Swivel mirror in position From swivel mirror in position B

Illumination unit Illumination beam path

line projection

Receptive beam path Reception beam path for position Reception beam path for position B

Machining direction positioning drive

semitransparent mirror

imaging lens

image sensor

Image evaluation device

Control device interface

a Deflection mirror for position Ab Deflection mirror for position B

focusing drive

Main clamping direction

Claims

claims

1 . Apparatus for laser joining of sheet metal parts (2) each having a flange, wherein the flanges of the sheet metal parts (2) are to add to a connecting flange, wherein the device comprises a clamping device (5) for clamping the sheet metal parts (2) to be joined in a transverse to the connecting flange extending main tensioning direction and a beam guiding device for a laser beam (1), which is designed to direct a laser beam (1) substantially parallel to the connecting flange and transversely to the clamping direction on an end face of at least one of the flanges of the sheet metal parts (2) to be joined, characterized in that the device further comprises a compensating axis (9) which, when the device is connected to a guiding machine, tracks the laser beam (1) according to a relative movement between the connecting flange and the guiding machine.

2. Apparatus according to claim 1, characterized in that the compensation axis (9) is realized mechanically or optically.

3. Apparatus according to claim 1 or 2, characterized in that those parts of the device which the clamping device and processing points (4), in which the laser beam (1) impinges on the connecting flange, move together, by means of at least one compensating axis (9) a part attached to the guide machine (12) are connected.

4. Device according to one of claims 1 to 3, characterized in that the device has a device for tracking the joining progress and the compensating mechanism comprises a positioning error compensating compensating axis (9).

5. Apparatus according to claim 1 to 4, characterized in that the clamping device comprises clamping means (5) which engage in operation of the device to be joined sheet metal parts (2) and which are connected to the beam guiding device such that there is a tactile seam guide.

6. Device according to one of claims 1 to 4, characterized in that the device comprises means for optical seam guide.

7. The device according to claim 6, characterized in that the device has a laser beam to the (1) coaxial reception beam path and an internal or external illumination unit associated therewith.

8. The device according to claim 7, characterized in that the device comprises two independent lighting units which are associated with the receiving beam path.

9. Device according to one of claims 1 to 8, characterized in that the beam guiding device at least one deflecting element (14, 18, 18 a, 18 b, 25, 31 a, 31 b) for deflecting the laser beam (1) in the main clamping direction of the clamping elements (5 ) in order to be able to track in the main tensioning direction of the clamping elements that machining point (4) at which the laser beam strikes the metal sheets (2) to be joined.

10. The device according to claim 9, characterized in that the deflecting element has at least one rotationally driven mirror (14, 18, 18 a, 18 b, 25, 31 a, 31 b) for the tracking of the processing point (4).

1 1. Device according to one of claims 1 to 10, characterized in that the beam guiding device has at least one optical element, with which a beam angle with which the laser beam (1) extends to a direction perpendicular to the main tensioning direction (F) plane, is to be influenced in such a way, that in the range of a possible processing point (4) switching between different beam angles is possible.

12. The device according to claim 1 1, characterized in that the beam guiding device has as an optical element one or more mirrors, which are arranged so that in the range of a possible processing point a switching between different beam angles is possible.

13. The apparatus of claim 1 1, characterized in that the beam guiding device comprises two or more mirrors as an optical element, which are arranged such that when switching between different beam angles each have an approximately equal optical path of the laser beam from a focusing lens to the processing point results.

14. A method for laser joining sheet metal parts (2), each having a flange, wherein the flanges of the sheet metal parts are to be joined to a connecting flange, comprising the steps of: concurrent clamping of bleaching parts in the region of the connecting flange in a main direction of tension extending transversely to the connecting flange and at the same time end-side welding on the connecting flange by directing a laser beam substantially parallel to the connecting flange and transversely to the main clamping direction on an end face of at least one of the flanges of the sheet metal parts (2) to be joined, characterized in that the machining point (4) along the connecting flange in a seam guiding movement relative to the mating sheet metal parts (2) is guided in the main direction of tension and / or in the distance direction.

15. The method according to claim 14, characterized in that one of the seam guide movement superimposed position modulation of the position of a processing point (4) at which the laser beam impinges on sheet metal parts to be joined (2) takes place in at least one spatial direction.

16. The method according to any one of claims 14 to 15, characterized in that a control of the position of a processing point (4) at which the laser beam (1) to be joined to sheet metal parts (2) impinges and / or steel modulation and / or adjustment of the laser power depending on a measured by a sensor joint geometry.