WO2012079945A1

WO2012079945A1 - Workpiece with an orientation aid for a laser welding device with an edge sensing device

Info

Publication number: WO2012079945A1
Application number: PCT/EP2011/070836
Authority: WO
Inventors: Robert Meyer; Markus Berger; Volker Frey; Dietmar Salg
Original assignee: Endress+Hauser Gmbh+Co. Kg
Priority date: 2010-12-15
Filing date: 2011-11-23
Publication date: 2012-06-21
Also published as: DE102010063113A1

Abstract

In order to ensure exact positioning of a welding laser beam even in the case of unfavourable edge forms or contours of a first workpiece (130) intended to be welded to a second workpiece (140), the invention proposes that an orientation aid (134) for an automatic edge sensing device should be provided on the first workpiece (130), at a predefined distance (136b) from the edge (132) to be welded.

Description

WORKPIECE WITH AN ORIENTATION AID FOR A LASER WELDING DEVICE

WITH EDGE DETECTION DEVICE

The invention relates to a workpiece which is to be welded at its edge to a second workpiece by means of an automatic laser welding device with an edge detection device.

Laser welding apparatuses of this type usually comprise a laser, a moving unit and an optical system for guiding the laser beam, at the end of which the processing and focusing optics are seated. The motion system either moves the laser beam over the workpiece or the workpiece under the laser beam. The laser beam can also be moved over the workpiece after focusing with a mirror scanner. Furthermore, laser welding devices are known which work in combination with an automatic edge detection device. For this purpose, the workpiece to be welded is optionally illuminated and optically scanned (scanned) in order to detect the desired edge at which the workpiece is to be welded to another workpiece. Taking into account a predetermined distance of the edge detection device to the welding device, the laser beam for welding to the desired position of the weld, here: the edge to be welded, set or moved. The same applies to firmly positioned welding device when the workpiece is moved under the laser beam.

It has been shown in practice that under certain circumstances the optical edge detection can not or only partially detect the desired edge of the workpiece and thus the laser beam can not be correctly positioned. However, the accuracy of the edge detection determines the accuracy of the positioning of the laser for welding. In this respect, an exact edge detection is essential for the desired weld. The invention is therefore based on the object, even with unfavorable edge shapes or contours of a workpiece to be welded to ensure an exact positioning of the laser beam. This object is according to the invention in a workpiece which is to be welded at its edge to a second workpiece by means of an automatic laser welding device with edge detection means by an attached on the workpiece at a predetermined distance from the edge orientation aid for the edge detection device solved.

In a preferred embodiment of the invention, the

Orientation on the workpiece at least one groove which is mounted on or in the surface of the workpiece.

In another embodiment of the invention, geometric dimensions of the groove or grooves are chosen such that the edge detection device of the welding device can uniquely identify them.

In a further embodiment of the invention in which a plurality of grooves are used as an orientation aid, the grooves have different widths on the workpiece. In still another embodiment of the invention, wherein a plurality of grooves are used as an orientation aid, the grooves have different depths on the workpiece.

In yet another embodiment of the invention having a plurality of grooves on the workpiece as an orientation aid, the distances of the grooves from each other include an encoded instruction for the welding device with respect to the welding parameters used. The advantage of the invention is that in a simple manner, the positioning of a laser beam for welding from the detection of the welded edge of the workpiece is independent. This is achieved by applying an easy-to-install orientation aid on the workpiece itself with minimal effort, providing a clear scan and thus accurate positioning of the workpiece

Laser beam allowed.

The invention will be described and explained in more detail below with reference to various embodiments of the invention shown in the accompanying drawings. Showing:

Fig. 1 a is a schematic diagram of two workpieces with rounded

Edge;

Figure 1 b is a schematic diagram of two workpieces, of which a workpiece has a chamfered edge.

Figure 1 c is a schematic diagram of two workpieces, of which a workpiece has a compressed edge.

Fig. 2 is a perspective sketch of two cylindrical components; Fig. 3 shows a first embodiment of the invention

Workpiece together with an automatic laser welding device with edge detection device;

Fig. 4 shows a second embodiment of the invention

Workpiece;

Fig. 5 shows a third embodiment of the invention

Workpiece;

Fig. 6 shows a fourth embodiment of the invention

Workpiece;

Fig. 7 shows a fifth embodiment of the invention

Workpiece; and

Fig. 8 shows a sixth embodiment of the invention

Workpiece. Figs. 1 a to 1 c are illustrative of possible

Problems with edge detection of workpieces. Here, two workpieces 10 and 20 are shown, which at their edges 12 and 22 by an automatic laser welding device with each other

to be welded, wherein an edge detecting means controls the positioning of a laser beam used for welding (see also Figs. 3, 7 and 8). Due to manufacturing tolerances and incorrect handling in practice different problems with edges of workpieces, which lead to undesirable difficulties in the exact positioning of the laser beam. However, the accuracy of the edge detection determines the accuracy of the positioning of the laser for welding. In this respect, an exact edge detection is essential for the desired weld. In Fig. 1 a, the two workpieces 10 and 20 rounded edges 12 and 22. For relatively large radii or different radii at the edges 12 and 22 of the workpieces 10, 20, the exact position of the edge 12 and 22 of the edge detecting device is difficult to detect. A similar problem occurs when the edge 12 of a first

Workpiece 10 has been provided with a chamfer, while the edge 22 of the second workpiece 20 is rounded. Even with such

Constellation, which is shown here in Fig. 1 b, has been shown in practice that the exact edge detection can not always be guaranteed.

Another practical case where the edge detection does not always give the desired results is illustrated in Figure 1c. For one of the workpieces, here: the first

Workpiece 10, the edge to be welded 12 has been poorly machined or compressed, so that it is in its contour beyond the edge 22 of the second workpiece 20 addition. This "compression" is indicated in Fig. 1 c by "16". As opposed to a "normal" edge, this kind of upsetting 16 produces an unusual shadow that is an exact one Detection of the edge and thus prevents an exact positioning of the laser.

Figures 1 a to 1 c are for general illustration and are schematic diagrams. The workpieces 10, 20 shown therein may be rectangular, square, cylindrical or tubular workpieces or any combinations thereof that are to be welded at their edges. Yet another case of possibly defective edge detection is shown in FIG. Here, two cylindrical workpieces 30 and 40 are illustrated which, due to manufacturing tolerances, have different outside diameters at their edges 32 and 42 which are to be welded together. Again, it has been shown in practice that the exact edge detection can not always be guaranteed.

In Fig. 3, a first embodiment of the invention

Workpiece illustrated by the selected in Fig. 1 a representation. A first workpiece 50 is shown along with a typical automatic laser welder 70 with an edge detector 76. Also, this first workpiece 50 is to be welded at its edge 52 with an edge 62 of a second workpiece 60 by the laser welding device 70. In order to enable an exact edge detection by an edge detection device 76, a groove 54 is provided according to the invention on the first workpiece 50 at an exactly predetermined distance from its edge 52 as an orientation aid for the edge detection device 76. The groove 54 is, as well as in the following embodiments of the invention, in its width 58 and / or depth designed so that it is detected by the automatic edge detection device 76 accurately and clearly.

Due to the width 58 of the groove 54, different distances 56a, 56b result for the desired positioning of the laser beam of the laser beam. Welding device 70, depending on which edge of the groove 54 as

Reference edge is selected. In the in Fig. 3 is also a

Movement device 74 of the laser welding device 70 shown in sketchy, is moved by and on which the laser 72 with focusing device in dependence on the desired distance 56a or 56b on the seam 52 to be welded.

The automatic laser welding device 70, its edge detection device 76, its laser 72 and movement unit 74 or the optical system for focusing and guiding the laser beam are not the subject of the invention and are well known to those skilled in the art. They are for simplicity in Figs. 3, 7, 8 only indicated.

In Fig. 4, a second embodiment of the workpiece according to the invention is illustrated with reference to the representation selected in Fig. 1 b. For ease of illustration, the automatic laser welding apparatus 70 with an edge detector 76 shown in FIG. 3 is not shown here. If below on the

automatic laser welding apparatus 70 and the edge detecting means 76 is referred to, as shown in Fig. 3 is meant.

A first workpiece 80 is intended to be welded at its edge 82 to an edge 102 of a second workpiece 100 by the laser welder 70 (see FIG. 3). In order to enable an exact edge detection by an edge detector 76, in this

Embodiment of the invention, two grooves 84 and 86 on the first workpiece 80, each provided at an exactly predetermined distance 88a and 88b to the edge 82 as an orientation aid for the edge detection device 76. Both grooves can be the same width, wherein at least one width 99 of the innermost (relative to the edge 82 to be welded) groove 84 is designed so that it is accurately and clearly detected by the automatic edge detection device 76. Due to the width 99 of the first groove 84 and the width of the second groove 86, different distances 88a-88d result for the desired positioning of the laser beam of the laser welding device 70 over the edge 82, depending on which edge of the grooves 84, 86 as a reference edge for the Edge detector 76 is selected. By the second groove 86 and in particular by the thus predetermined distance 88e between the two grooves 84, 86 can here in contrast to

Embodiment of the invention as shown in FIG. 3, a coding for the laser 72 are set, which controls special, variable welding parameters of the laser 72. Prerequisite is a corresponding programming or configuration of the edge detection device 76 in

Interaction with the laser 72.

In Fig. 5, a third embodiment of the workpiece according to the invention is illustrated with reference to the representation selected in Fig. 1 c. For ease of illustration, the automatic laser welding apparatus 70 with edge detecting means 76 shown in Figs. 3, 7 and 8 is not shown here. Referring now to the automatic laser welder 70 and the edge detector 76, what is illustrated in Figs. 3, 7, 8 is meant.

A first workpiece 110 is to be welded at its edge 12 to an edge 124 of a second workpiece 120 by the laser welding device 70 (see FIGS. 3, 7, 8). In order to enable an exact edge detection by an edge detection device 76, two grooves 1 14 and 122 are again provided in this embodiment of the invention, however, wherein the first groove 1 14 in the first workpiece 1 10 and the second groove 122 in the second workpiece 120 are cut. The advantage of this embodiment is that an exact edge detection is possible even with inaccurately placed edge detection device 76. The edge detection device 76 can either on the first workpiece 1 10 or on the second workpiece 120 start. Taking into account the direction of travel or scanning direction of the edge detection device 76 can be detected with detected first groove 1 14 or when detected second groove 122 with the known

Distances 1 16a, 1 16b of the first groove 1 14 to edge 1 12 and the

Distances 126a, 126b of the second groove 122 to the edge 122 of the laser 72 of the laser welding device 70 (see Fig. 3, 7, 8) are accurately positioned.

FIG. 6 illustrates a fourth exemplary embodiment of the workpiece according to the invention based on the representation of two cylindrical workpieces 130 and 140 selected in FIG. 2, which have different outer diameters at their edges 132 and 142 due to manufacturing tolerances and which are to be welded together. Again, to simplify the illustration, the automatic laser welder 70 with edge detector 76, shown in Figs. 3, 7 and 8, is not shown. As an orientation aid for the edge detection device 76 (see FIGS. 3, 7, 8), similar to the first embodiment of the invention shown in FIG. 3, a groove 134 which revolves because of the cylindrical shape of the first workpiece 130 is provided here. Due to the width of the groove 134, different distances 136a, 136b result for the desired positioning of the laser beam of the laser welding device 70 over the edge 132 of the first workpiece 130 to be welded, depending on which edge of the groove 134 as

Reference edge for the edge detector 76 is selected.

In Fig. 7, a fifth embodiment of the workpiece 150 according to the invention is illustrated. On a representation of the second

Workpiece with which the first workpiece 150 is to be welded at its edge 152 has been omitted here for simplicity. The first workpiece 150 is again shown in FIG. 7 together with the typical automatic laser welding apparatus 70 described earlier with edge detector 76 and moving unit for moving of the laser 72. In order to enable an exact edge detection by the edge detection device 76, a first groove 154 is provided on the workpiece 150 at exactly predetermined distance 158a to the edge 152 as an orientation aid for the edge detection device 76. In addition, and at a precisely predetermined distance 158b to the first groove 154, a further, second groove 156 is cut into the workpiece 150.

The illustrated in Fig. 7 fifth embodiment with the two grooves 154, 156 is similar to the embodiment of the invention shown in Fig. 4. The difference of the embodiment of FIG. 7 is in the

different width and / or depth of the grooves 154, 156. In addition to the already described above for Fig. 4 described improved edge detection by two grooves in the workpiece different width and / or depth of the grooves 154, 156 provide a further possibility of coding for special The prerequisite is a corresponding programming or configuration of the edge detection device 76 in cooperation with the laser 72. FIG. 8 shows in FIG. 7 a sixth exemplary embodiment of the invention

sketched according to the invention 160

illustrated. In a representation of the second workpiece, with which the first workpiece 160 is to be welded at its edge 162, has also been omitted here. Again, the typical automatic laser welder 70 with edge detector 76 is again illustrated. For exact edge detection by the edge detection device 76, a larger groove than previously described is provided on the workpiece 160, which is provided from a first groove 164 and second groove 166 directly connected thereto.

As illustrated in FIG. 8, the two grooves 164, 166 form a stepped, stepped groove as an orientation aid for the edge detection device 76. This results in different distances 168a, 168b and 168c of the individual, unspecified edges here to be welded to the edge 162 of the workpiece 160. As already described above, by the edge detecting means 76 at detected first groove 164 or detected second groove 166 with the predetermined distances 168a, 168c of the grooves 164, 166 are accurately positioned to the edge 162 of the lasers 72 of the laser welding apparatus 70. Due to the stepped groove formed in the workpiece 160 by the two grooves 164, 166, different widths and / or depths of the grooves 164, 166 offer a further possibility of coding for special, variable welding parameters of the laser 72. Prerequisite is a corresponding programming or configuration of the laser Edge detector 76 in cooperation with the laser 72nd

The embodiments of the invention described above have individual features. However, it is quite possible that

different features of the various orientations of the embodiments of the invention with each other in others

To combine embodiments of the invention.

Reference numeral list

1. Workpiece Fig. 5 110 1. Workpiece

Edge of (10) 112 edge of (100)

Bevel 114 I

Compression 116a distance

2nd workpiece 116b distance

Edge of (20) 120 2. Workpiece

1st cyl. Workpiece 122 2. Groove

Edge of (30) 124 edge of (120)

2nd cyl. Workpiece 126a distance

Edge of (40) 126b distance

1. Workpiece Fig. 6 130 1. Workpiece

Edge of (50) 132 edge of (130)

Groove (Orient Help) 134 Groove

a distance 136a distance b distance 136b distance

Width of (54) 140 2. Workpiece

2nd workpiece 142 edge of (140)

Edge of (60) Fig. 7 150 1. Workpiece

Laser Schweißvorr. 152 edge of (150)

Laser 154 1. Groove

Movement unit 156 2. Groove

Edge 158a distance acquisition no.

, Workpiece 158b distance

Edge of (80) Fig. 8 160 1. Workpiece

1st groove 162 edge of (160)

2. Groove 164 1. Nuta Distance 166 2. Nutb Distance 168a Distance C Distance 168b Distance Distance 168c Distance Distance

Width of (84)

0 2nd workpiece

2 edge of (100)

Claims

claims

1 . A workpiece (50; 80; 1 10; 130; 150; 160) which is provided at its edge (52; 82; 1 12; 132; 152; 162) with a second workpiece (60; 100; 120; 140) by means of an automatic workpiece Laser welding device (70) with edge detection means (76) to be welded, characterized by a on the first workpiece (50; 80; 1 10; 130; 150; 160) at a predetermined distance (56a, 56b; 88a, 88c 1 16a 1 16b; 136a; 136b; 158a; 168a, 168c) being attached to the edge (52; 82; 1 12; 132; 152; 162)

Orientation aid (54; 84, 86; 1 14, 122; 134; 154, 156; 164, 166) for the edge detection device (76).

2. Workpiece according to claim 1, characterized in that the orientation aid comprises at least one groove (54; 84, 86; 1 14; 134; 154, 156; 164, 166) which is disposed on or in the surface of the workpiece (50; 80; 1 10; 130; 150; 160) is mounted.

3. Workpiece according to claim 1 or 2, characterized in that geometric dimensions of the groove or grooves (54; 84, 86; 1 14, 122; 134; 154, 156; 164, 166) are selected such that the edge detection device (76) of the welding device (70) can uniquely identify them.

A workpiece as claimed in claim 2 or 3, characterized in that a plurality of grooves (84, 86; 154, 156; 164, 166) are used as an orientation aid having different widths on the workpiece (50, 80, 110, 130) ; 150; 160).

5. A workpiece according to claim 2, 3 or 4, characterized in that the plurality of grooves (84, 86; 154, 156; 164, 166) have different depths.

6. workpiece according to one of claims 2 to 4, characterized

characterized in that the spacings (88e, 158b) of the plurality of grooves (84, 86, 154, 156) relative to each other are an encoded instruction for the

Welding device (70) with respect to welding parameters to be used.