DE20111394U1 - welding equipment - Google Patents

Description

DESCRIPTION Welding device

The invention relates to a welding device, in particular a laser welding device with the features in the preamble of the main claim.

Such a laser welding device is known from DE-A 195 01 866. It consists of a laser welding unit with a pressure finger, onto the tip of which an alternative pressure piece with a differently shaped contact surface for the workpieces can be attached if required. The pressure piece then acts on the workpieces instead of the pressure finger. The change to takes place offline when the laser welding device is at a standstill and requires an interruption of the welding process. The change requires manual intervention and cannot be done automatically.

EP 0 892 692 Bl shows another laser welding device. It consists of a robot-guided frame on which a laser welding unit and a pressure roller acting on the metal sheets are movably mounted by means of a pressure device. The pressure device consists of a compensation slide mounted longitudinally on the frame and a slide drive with a pneumatic cylinder. The pressure device is used to press the pressure roller onto the workpieces with a predetermined force, whereby any guidance inaccuracies of the robot or workpiece tolerances can be compensated. In line or path welding, the laser welding device is guided by the robot along a predetermined path over the metal sheets. In the case of straight or only slightly curved paths, there is no

Difficulties. However, problems can arise with tight radii, e.g. in the corners of the sheets when reorienting the pressure roller or with possible elevations or depressions in the sheets and corresponding steps in the movement path. The pressure roller is often unable to follow these problem areas with sufficient accuracy. With elevations or depressions in the path, there is also the problem that the pressure roller cannot easily follow these contour changes, which may also cause the focus of the laser beam to be adjusted in an undesirable way, which can lead to poorer welding results.

From the literature reference EMMELMANN, C, et al.: Nd. YAG not only for the fine, in: Laser-Praxis, Supplement to Hanser Fachzeitschriften, June 1993, p. LS 15, LS 16, Figure 2, differently designed laser welding devices for different purposes for track welding and stitch seam welding are known. In one version they are equipped with a telescopic roller and in the other version with a picker.

If the intended use changes, the complete laser welding units are replaced.

It is an object of the present invention to provide an improved welding device.

The invention solves this problem with the features in the main claim.

The claimed welding device is able to counteract the problems that occur in the welding area by using one or more additional pressure elements that can be exchanged in the operating position and during welding. The pressure element that is best suited to the problem area to be processed is then brought into the operating position. This allows the contact pressure to be adjusted in the required manner

even in problem areas. In addition, undesirable defocusing is avoided. In addition, appropriately shaped additional pressure elements can be used to achieve optimal adaptation to the respective workpiece geometry. For this purpose, it is advantageous if the various pressure elements have different shapes and/or different sizes of their pressure areas. In the preferred embodiment, two pressure elements are present, which consist of a freely rotating pressure roller and a narrow pressure finger.

The individual additional pressure element can have one or more additional axes of movement. It is particularly advantageous if there is relative mobility in the feed direction between the laser beam and the additional pressure element. This allows a weld seam to be set while maintaining the contact pressure in a stationary manner. For this purpose, it is recommended to provide the pressure finger with an evasive device.

In addition, the pressure finger can also have a tilting axis with a reset device, with which it can compensate for any positioning or guidance inaccuracies of the robot and optimally adapt to the workpiece geometry.

The welding device is preferably designed as a laser welding device with a laser unit, e.g. a solid-state or diode laser. Alternatively, it can also be another welding device in which the welding energy is generated by means of a welding beam, e.g.

is transmitted over a distance to the workpiece by means of an arc.

The arrangement and adjustment of the multiple pressure elements is possible in any suitable manner. A particularly advantageous embodiment provides a common movable holder in the form of a

Swivel unit with a suitable feed drive, e.g. a swivel-mounted pneumatic cylinder. It is recommended to arrange the holder with the various pressure elements on the compensation slide of the pressure device in order to compensate for inaccuracies in the robot's guidance in the pressing direction or workpiece tolerances. This arrangement is also advantageous with regard to the avoidance device because the contact pressure allows the pressing finger to remain stationary on the workpiece, while the laser beam can be moved in the feed direction to form a weld seam in the further robot movement.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention is illustrated by way of example and schematically in the drawings. In detail:

Figure 1

a front view of a
Laser welding device with a pressing device and two different pressing elements which can be exchanged in the operating position in a first operating position.

Figure 2

Figure 3:

the arrangement of Figure 1 in a second operating position with changed pressure elements,

a side view of the arrangement of Figure 1 in the direction of arrow III,

Figure 4

an enlarged detailed view of the marked section in Figure 3 and

Figure 5 and 6:

Schematic representations of the relative movement between laser beam and pressure finger in operating position.

In Figures 1 to 4, a welding device (1) is shown, which is designed here as a laser welding device, which is equipped with a laser welding unit (9), e.g. a solid-state laser, a diode laser or the like. Alternatively, the welding device (1) and its welding unit (9) can also be of a different type and design, wherein the welding energy is also transmitted over a certain distance by welding beam (10), e.g. in the form of an arc or in another way. This can also be a

It can be a hybrid device that works in a combined manner with a laser beam (10) and an arc. In the sense of the invention, a welding device (1) is also understood to mean a soldering device or another heat treatment device that transmits the energy by laser beam (10), arc or in another way while bridging a distance.

The laser welding device (1) shown is used for welding, soldering or similar other heat treatment of at least one workpiece (3). The workpiece (3) is only indicated schematically in Figures 1 to 4. This involves, for example, two or more metal sheets lying on top of one another, which are to be pressed together in the welding area (4).

The welding device (1) is moved in any suitable manner by a guide device, e.g. a multi-axis articulated arm robot (2) in the feed direction (26). Alternatively, this can also be any other type of manipulator, e.g. a cross slide or a manipulator with combined rotary and translatory axes. In Figure 1, the hand of a robot (2) is broken off and shown schematically.

The welding device (1) has a pressing device (6) which is used to press the sheets (3). The pressing device (6) has at least one compensating slide (7) which is mounted on a frame (5) of the welding device (1) which is rigidly connected to the aforementioned robot hand and is movable in one or more axes. In the embodiment shown, the compensating slide (7) has a translational axis which is directed normal to the sheet surface and in the embodiment shown runs essentially vertically. The compensating slide (7) is moved by a suitable feed device (8), here a slide drive with

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a pneumatic cylinder moves up and down. The slide drive (8) exerts a force F on the sheets or the workpiece (3).

The welding unit, specifically the laser welding unit (9), is attached to the compensation slide (7). For the sake of clarity, only the laser optics or focusing unit and the laser beam (10) of the laser welding unit (9) are shown.

The pressing device (6) also has several pressing elements (11, 12) which can be exchanged for one another in the operating position (27) on the workpiece (3). In the preferred embodiment, two pressing elements (11, 12) are present, one of which is designed as a freely rotatable pressing roller (11) and the other as a narrow pressing finger (12). The two pressing elements (11, 12) have pressing areas (13, 14) of different sizes and shapes with which they act on the workpiece (3) or the sheets in the operating position (27). The pressing finger (12) preferably has a flat or "spherically rounded" pressing surface (14).

The pressing elements (11, 12) are arranged together on a holder (15), which in turn is preferably connected to the compensating slide (7). The holder (15) can alternatively also be rigidly attached to the frame (5). The two pressing elements (11, 12) are attached to the holder (15) at a distance from one another and at different angular positions. The holder (15) is in turn movably mounted in one or more axes and allows an exchange or change of the pressing elements (11, 12) between the operating position (27) and a rest position by means of a movement corresponding to the axes. For this purpose, the holder (15) has a suitable feed device (17).

In the illustrated and preferred embodiment, the holder (15) is designed as a swivel unit which is mounted on the compensating carriage (7) with a swivel axis (16) preferably aligned transversely to the laser beam (10) and the feed direction (26). The holder (15) can have edges or side surfaces that are angled to one another and is essentially diamond-shaped in the illustrated embodiment. Adjustable stops (20) can be present on the side surfaces, which are arranged at an angle to one another and come into limit stop with the frame (5) in two different swivel positions. These swivel positions define the operating position of the two pressing elements (11, 12). Figures 1 and 2 show various swivel and use positions. In Figure 1, the pressing finger (12) is in the operating position (27) on the workpiece (3), with the pressing roller (11) swiveled away to the side. In the pivoting position of Figure 2, the pressure roller (11) is in the operating position (27), with the pressure finger (12) pivoted away to the side.

In the embodiment shown, the feed device (17) for the holder (15) is designed as a pneumatic cylinder which is attached with its upper cylinder bearing (18) to the compensating slide (7) or, if necessary, to the frame (5). The lower articulation point (19) of the piston rod is connected to one end of the holder (15) at a lateral distance from the pivot axis (16). The cylinder (17) assumes two end positions. In the retracted position shown in Figure 1, it pulls the holder (15) with the left stop (20) into the first pivot position. In the extended position, it brings the holder (15) into the second pivot position shown in Figure 2.

The additional pressing element (12) can have one or more additional axes of movement. In particular, in the preferred embodiment, there is relative mobility between the laser beam (10) and the pressing element (12) in the direction of movement or feed direction (26) of the welding device (1). For this purpose, the pressing element (12) is preferably connected to an evasive device (21).

In the embodiment shown, the pressure finger (12) is attached to a linear slide (28) which is mounted on a sliding guide (22) which is connected to the holder (15) and which can move back and forth parallel to the workpiece surface or to the feed direction (26) by means of the deflection device (21). The deflection device (21) also has a restoring spring (23) which is supported at one end on the linear slide (28) or on the pressure finger (12) and at the other end on a suitable stop on the holder (15).

The spring (23) is designed here as a compression spring, which tries to push the pressure finger (12) in the feed direction (26) along the sliding guide (22).

Figures 5 and 6 illustrate the design and function of the additional pressing element (12) or pressing finger and the deflection device (21). The workpiece (3) has the recess or bead (30) shown in Figures 5 and 6, which is so narrow or possibly so deep that the pressing roller (11) cannot pass through it in a suitable manner. The pressing area (14) of the pressing finger (12) is adapted to the shape of the bead and is narrower than the pressing roller (11). It has a shape and size corresponding to the bead '("3O) so that it fits well into the bead (30) with little play, for example as in the embodiment shown, and presses the sheets (3) together under the effect of the pressing force F.

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As soon as the welding device (1) reaches the bead (30) while following its feed path (26), the holder (15) is rotated and the pressure roller (11) is replaced with the pressure finger (12). To do this, the robot (2) can briefly lift the welding device (1) if necessary. The pressure finger (12) is then inserted into the bead (30) and pressed into place.

The pressing finger (12) with its pressing area (14) is preferably positioned relative to the laser beam (10) in such a way that the laser beam (10), as shown in Figure 5, is located at the rear end of the pressing surface (14) in the direction of movement (26). In this position, the welding device (1) is moved further in the feed direction (26) by the robot (2) while maintaining the pressing force F exerted by the carriage drive (8). The pressing finger (12) remains in its position in the bead (30) by frictional connection and/or positive connection, with the laser beam (10) traveling along the pressing surface (14) due to the robot movement in the feed direction (26) and producing a linear weld seam, for example. The avoidance device (21) allows the holder (15) and the sliding guide (22) to move accordingly against the force of the spring (23) supported and compressed on the pressing finger (12).

As soon as the end position according to Figure 6 is reached, the pressure finger (12) is exchanged for the pressure roller (11), which is better suited for linear movements and sliding pressure on the workpiece (3). The welding process can then be continued in the direction of movement (26). When changing, the spring (23) relaxes and pushes the pressure finger (12) back into the end position shown in Figure 2.

- 10 -

As Figures 1 and 3 illustrate, the pivot axis (16) of the holder (15) is preferably located exactly in the vertical movement axis of the compensation slide (7) or the center line of the laser beam (10). In the operating position (27), the pivot roller (11) is also located exactly vertically below the pivot axis (16) and in a central position to the laser beam (10). Figure 2 shows this arrangement. Figure 1, on the other hand, illustrates the preferably eccentric positioning of the pressure finger (12) relative to the laser beam (10). The pressure finger (12) can also be angled forwards at an angle as shown in Figures 3 and 4.

As Figures 3 and 4 show, the pressure finger (12) also has a second additional axis in the form of a tilting axis (24) with a reset device (25). The tilting axis (24) is aligned parallel to the swivel axis (16) and transverse to the laser beam (10). This allows the pressure finger (12), which is positioned in the axis area by disc springs, to adjust itself by means of a tilting movement and thereby compensate for any positioning and guidance inaccuracies of the robot (2) or workpiece inaccuracies. The reset device (25) is designed here as a spring catch, which returns the pressure finger (12) to its vertical starting position when the load is released.

The holder (15) can be designed in one or more parts according to Figure 3. In the embodiment shown, it consists of a base plate (31) with the pivot bearing (16), to which a mounting plate (32) with the aforementioned diamond shape is attached in a suitable manner with precise positioning by means of a screw connection or the like. The sliding guide (22) with the linear slide (28) attached to it is located on the mounting plate (32). As Figures 3 and 4 make clear, the holder (15) is preferably located on the side facing the welding area (4).

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facing front of the compensating slide (7). The cylinder (17) is mounted on the rear of the slide, with the articulation point (19) having a protruding arm.

The laser device (1) can be equipped with one or more additional devices (29) of any desired suitability. Figure 1 shows, for example, a shielding gas supply device in a broken-off view. Furthermore, one or more suitable sensor arrangements for tracking the movement path or seam path can be present (not shown). Likewise, for example, a supply device for an additional wire (not shown) can also be present.

The embodiment shown can be modified in various ways. Firstly, the holder (15) can be designed in any other way and can also have one or more other types of movement axes. It can also be attached to the frame (5) instead of to the compensation slide (7). The feed device (17) can be designed in any other way. In addition, more than two pressure elements (11, 12) can be arranged on the holder (15). In a further modification, it is possible to assign each pressure element (11, 12) its own movable holder. Furthermore, the welding device (1) can basically also dispense with the compensation slide (7) in the embodiment shown. The compensation option in the feed direction or normal to the workpiece surface can be completely omitted or created in another way, e.g. by a spring connection between the frame (5) and the robot hand (2).

The number and arrangement of the additional axes of the other pressure elements (12) are also variable. These additional axes can alternatively be omitted. Further variations exist

9·

- 12 -

with regard to the shape and arrangement of the additional pressing elements (12). Instead of pressing fingers, these can also be smaller pressing rollers or other suitable types of pressing elements.

- 13 LIST OF REFERENCE SYMBOLS

1 welding device, laser welding device

2 robots

3 Workpiece, sheet metal

4 Welding area

5 Frame

6 Pressing device

7 Compensating slide

8 Feed device, carriage drive

9 Welding unit, laser welding unit

10 Welding beam, laser beam

11 Pressure element, pressure roller

12 Pressing element, pressing finger 13 Pressing area, pressing surface

14 Pressure area, pressure surface

15 Bracket

16 Movement axis, swivel axis

17 Feed device, cylinder 18 Bearing, cylinder bearing

19 Articulation point

20 stop

21 Alternative facility

22 Sliding guide
23 Spring

24 Tilting axis

25 Reset device, spring catch

26 Direction of movement

27 Operating position 28 Linear slide

29 Additional equipment, protective gas supply

30 Recess, bead ■3-1 Base plate

32 Mounting plate
35

F Contact force

Claims (15)

1. Welding device with a welding unit ( 9 ) and a pressing device ( 6 ) with several exchangeable pressing elements ( 11 , 12) acting on one or more workpieces ( 3 ), characterized in that the pressing elements (11, 12 ) are arranged separately from one another and are movably mounted, wherein the pressing elements (11 , 12 ) are arranged so as to be exchangeable with one another in the operating position ( 27 ) during welding operation. 2. Welding device according to claim 1, characterized in that the welding device ( 1 ) is designed as a laser welding device with a laser welding unit ( 9 ). 3. Welding device according to claim 1 or 2, characterized in that the pressing elements ( 11 , 12 ) have pressing areas ( 13 , 14 ) of different sizes and/or different shapes. 4. Welding device according to claim 1, 2 or 3, characterized in that one pressing element ( 11 ) is designed as a pressing roller and the other pressing element ( 12 ) is designed as a narrow pressing finger. 5. Welding device according to one of the preceding claims, characterized in that the further pressing element ( 12 ) has a flat or spherical pressing surface ( 13 ). 6. Welding device according to one of the preceding claims, characterized in that the welding beam ( 10 ) and the further pressing element ( 12 ) are arranged to be movable relative to one another in the feed direction ( 26 ) in the operating position ( 27 ). 7. Welding device according to one of the preceding claims, characterized in that the further pressing element ( 12 ) has an evasive device ( 21 ) movable in the feed direction ( 26 ). 8. Welding device according to one of the preceding claims, characterized in that the further pressing element ( 12 ) is arranged on a linear slide ( 28 ), wherein the avoidance device ( 21 ) has a relatively stationary sliding guide ( 22 ) and a restoring spring ( 23 ). 9. Welding device according to one of the preceding claims, characterized in that the further pressing element ( 12 ) has a tilting axis ( 24 ) aligned substantially transversely to the feed direction ( 26 ) and arranged on the linear slide ( 28 ) and a return device ( 25 ). 10. Welding device according to one of the preceding claims, characterized in that the pressing elements ( 11 , 12 ) are mounted together on a movable holder ( 15 ) provided with a feed device ( 17 ). 11. Welding device according to one of the preceding claims, characterized in that the pressing device ( 6 ) has at least one compensating slide ( 7 ) with a feed device ( 8 ) which is mounted and supported on a frame ( 5 ) of the welding device ( 1 ) so as to be movable in one or more axes. 12. Welding device according to one of the preceding claims, characterized in that the welding unit ( 9 ) and the holder ( 15 ) with the pressing elements ( 11 , 12 ) are arranged on the compensating carriage ( 7 ). 13. Welding device according to one of the preceding claims, characterized in that the holder ( 15 ) is designed as a pivoting unit with a pivot axis ( 16 ) arranged on the compensating slide ( 7 ), wherein the feed device ( 17 ) is designed as a cylinder, the bearing ( 18 ) of which is arranged on the compensating slide ( 7 ) and the articulation point ( 19 ) of which is arranged on the holder ( 15 ). 14. Welding device according to one of the preceding claims, characterized in that the pivot axis ( 16 ) is arranged in the region of the feed axis of the compensating slide ( 7 ). 15. Welding device according to one of the preceding claims, characterized in that the sliding guide ( 22 ) of the avoidance device ( 21 ) is arranged on the holder ( 15 ).