DE102017201730A1 - Method of welding and welding device - Google Patents

Abstract

The invention relates to a method and a device for welding, in which at least two components (5, 6) are positioned in a joint arrangement with respect to one another and are materially connected to one another by a weld seam (9), using a welding device (1) based on control parameters (5). ST) at a weld (8) in the components of a molten bath is generated and the weld (8) relative to the components (5, 6) is moved. According to the invention, an observation window (11; 18) on the components is detected by means of a time-of-flight detection device (10; 16) which at least partially leads the welding point (8) and corresponding image data (B1) are generated by evaluating the Time-of-flight image data (B1) are determined corresponding topography data (T) of the component assembly, and the control parameters (ST) of the welding device are adapted based on the topography data (T).

Description

The present invention relates to a method for seam welding according to the preamble of claim 1 and a welding device.

During welding, the material of the components to be joined at the joint is heated above the liquidus temperature. The molten phases of both components mix and solidify after cooling to a cohesive connection. For welding seams u.a. the metal inert gas welding and laser welding common welding methods. Gas shielded metal arc welding is an arc welding process in which the consumable filler wire is continuously fed to the molten bath. The joint is simultaneously flowed around by a protective gas. Depending on the protective gas used, gas metal arc welding is also referred to as metal active gas (MAG) or metal inert gas (MIG) welding. In laser beam welding, a focused laser beam of high power density is directed to a joint, which melts the irradiated material. By performing a relative movement between the laser beam and the tool, the molten bath is moved over the components. The cooling melt solidifies and bonds the components welded together firmly.

Through the use of seam guiding systems, it is also possible, in particular, to carry out welds on component edges, for example for the formation of fillet welds. In addition to tactile methods, a seam-tracking system operating according to the light-section method is, for example, from the document DE 10 2006 004 919 A1 known. In advance of the welding position of a welding laser, a laser line is projected onto the components. The projected image is captured by a camera and evaluated for line offset. By determining the line offset, the edge profile can be determined.

Especially in laser beam welding, which is usually performed without filler material, however, the determination of the edge profile alone is not sufficient to ensure the necessary process reliability can.

Against this background, it is the object of the present invention to show a way how the process reliability during welding and in particular during laser welding can be improved.

The object is achieved by a method according to claim 1 and a device according to claim 11. Further advantageous embodiments of the invention will become apparent from the dependent claims.

The invention relates to a method for welding in which at least two components are positioned in a joint arrangement with respect to one another and are connected to one another in a material-locking manner by a weld seam. For this purpose, a molten bath is produced with a welding device on the basis of control parameters at a weld in the components and the weld is moved relative to the components. According to the invention, an observation window on the components is detected by means of a time-of-flight detection device, which at least partially leads the welding point, and corresponding image data are generated. By evaluating the time-of-flight image data, corresponding topography data of the component arrangement are determined and the control parameters of the welding device are adapted on the basis of the topography data.

According to the invention, a time-of-flight (TOF) detection device is used for seam detection or seam tracking. The TOF detection device may e.g. be implemented as a TOF camera by means of a PMD (photonic mixer) area sensor. The TOF detection device illuminates the components in the observation window by means of a light pulse and determines for each pixel, the time that the light needs to the component and back again. From the TOF image data, the distance to the component can thus be determined for each pixel, and topography data can be generated which reflects the surface shape of the components in the observation window. The topography data may e.g. be prepared as a data set or as a three-dimensional pictorial representation.

Advantageously, with the TOF detection device, the entire observation window can be recorded at once, a line-by-line scanning is not necessary. The data collected are available in near real time. In addition, with the TOF technology, a high resolution up to the HD range is possible. Thus, very high quality and meaningful data is obtained from the joint, which is used to adjust in real time the control parameters with which the welding process is controlled.

The determined topography data can in one embodiment reflect the course of a component edge. The exact knowledge of the edge profile enables the exact positioning of the weld or the laser beam relative to the components, e.g. in fillet weld or I-seam on the butt joint and makes a tactile seam guidance unnecessary.

Furthermore, the topography data can reproduce the gap dimension of a joint gap between the components. This can be used, for example, to adjust the feed rate of the additional wire or, for example, to adjust a beam oscillation of a laser beam. The laser beam welding has due to the small beam diameter and the relatively small melt pool only a small gap bridging, but which can be improved, for example, by oscillation of the laser beam. The evaluation of the TOF image data with respect to the gap size allows, for example, a targeted adaptation of the beam oscillation.

Similarly, the topography data may represent a trim angle of at least one of the components, e.g. the trim angle of the top sheet at a lap joint.

The image data of the TOF detection device may also be evaluated to determine a plurality of the above-described types of topography data or other topography data, e.g. Distance from the component.

Preferably, based on the determined topography data, the position of the weld or laser beam is adjusted relative to a component edge, or the welding parameters are adjusted, e.g. the welding current, the feed rate, the wire feed or when using a laser beam, the focus position, focus diameter, Oszillationsart, size and frequency or welding speed or both the position of the weld or the laser beam and the welding parameters are adjusted.

In one embodiment, the method can also be used to subsequently perform a quality assurance of the weld produced directly to the welding process. For this purpose, image data are recorded in a tracking section following the weld by means of a time-of-flight detection device and evaluated with regard to the quality of the weld seam. The image data enable a high-resolution three-dimensional representation of the weld produced and form the basis for a high-quality optical seam inspection. The assessment of the quality of the weld can e.g. be carried out by trained personnel or in an automated form, e.g. by comparing the image data with reference data sets. Defects in the weld can then be found immediately after the welding process.

The trailing observation section can be detected by the same TOF detection device with which the image data in the leading area is also recorded. In this case, the trailing observation section is part of the observation window, which then includes both the area before the weld and a subsequent area. In this case, the TOF detecting device may be e.g. equipped with a filter to filter away laser process light.

In one embodiment, the detection of the trailing observation section is performed with a second TOF detection device whose detection area is at least partially directed as a second observation window onto the trailing area.

Preferably, the image data of the observation window and - as far as detected - of the second observation window continuously detected during the duration of the weld. The observation windows preferably move along with the progressive weld seam.

The components are preferably metal components. A metal component is in particular a sheet metal part, e.g. from an aluminum or steel sheet, which may also be a casting or profile part. The components may preferably be vehicle components, e.g. Body components or body parts, suspension components etc.

Advantageously, the method provides and evaluates image data in real time, which enables a significantly improved seam guidance and regulation of the welding process parameters. Existing dimensional deviations can be detected in advance of the weld and the welding parameters adjusted accordingly. In addition, there is the possibility of an optical evaluation of the seam immediately after their production, what u.a. opened the possibility of a "repair" in the same operation. As a result, the process reliability can be increased.

Preferably, the method is used to adapt the control parameters of a laser welding device or a metal inert gas welding device, but in principle can also be used for other welding devices.

Furthermore, a welding device is specified, which is suitable for carrying out the method according to the invention. The welding apparatus includes a control device configured to generate a weld pool in the components to be joined based on control parameters, and to move the weld relative to the components. Furthermore, the welding device includes a time-of-flight detection device whose detection range can be directed to an observation window, at least the welding point partially leading and can be detected with the image data of the observation window, and an evaluation that uses the time-of-flight image data generated topography data of the components in the observation window, based on the determined topography data adapts the control parameters and is in a controlled connection with the control device.

The evaluation device can furthermore be set up to generate an optical representation of the seam topography from image data acquired in a monitoring section following the weld, and / or to evaluate the quality of the weld seam. For evaluating the weld quality, e.g. the image data are compared with reference data or characteristics are determined.

If the trailing observation section is to be detected as a separate second observation window, then the welding device can optionally have a second time-of-flight detection device whose detection area can be directed onto the second observation section trailing the weld.

In a preferred embodiment, the welding device is a laser beam welding device and further includes a laser source and a suitable optics for generating the welding laser beam. Preferably, the laser beam welding apparatus may be a laser remote welding apparatus. In laser remote welding, the long working laser beam, e.g. more than 40 cm, moved over the components by means of a scanner optics. The laser-remote welding enables high working speeds even with complex weld seam geometries. To retain these advantages, the TOF sensing device (s) is preferably integrated with the optics-bearing remote head.

If the welding device is a metal inert gas welding device, it also includes a welding torch with wire feed and power supply for generating the arc and an inert gas supply.

The welding apparatus can be used to carry out the method described above and, as such, achieves the same technical effects and advantages as described for the method.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood with reference to the drawings and in conjunction with the following description of the embodiments. If the term "can" is used in this application, it is both the technical possibility and the actual technical implementation.

• 1 eine beispielhafte Schweißvorrichtung zur Erläuterung des Verfahrens und
• 2 eine alternative Ausgestaltung einer Schweißvorrichtung zur Durchführung des Verfahrens.

Embodiments will be explained below with reference to the accompanying drawings. Therein show in schematic view:

• 1 an exemplary welding apparatus for explaining the method and
• 2 an alternative embodiment of a welding device for performing the method.

1 shows a schematic diagram of a welding device 1 in the form of a laser remote welding device with which the method according to the invention can be carried out. From a laser source, not shown, laser radiation is in a scanner device 2 coupled in and over movable mirrors 3 and a focusing and deflecting unit 4 as a focused welding laser beam S on the components to be welded 5 . 6 directed. The control of the beam movement and parameters takes place by means of a control device 7 which is in operative association therewith with the beam-forming and -moving device components.

The components to be welded 5 . 6 in the form of sheet metal components are arranged in the lap joint and are to be welded with a Stirnkehlnaht. For this purpose, the laser beam S on the components 5 . 6 directed where he is at the weld 8th produces a molten bath. The weld 8th is through the components 5 . 6 moves, causing the weld 9 formed. The welding direction is through the arrow R specified. At the end of the weld 9 the laser beam S is switched off.

The welding device 1 still has a TOF camera 10 on that in the scanner device 2 is integrated. The detection range of the TOF camera 10 is oriented such that an observation window 11 is detected, both a leading the welding point observation section 12 as well as a trailing observation section 13 detected.

The TOF camera 10 is operated during welding and continuously captures image data B1 . B2 from the observation window 11 , The image data B1, B2 are sent to an evaluation device 14 transfer. From the image data B1 of the leading observation section 12 become topography data T generated the component surfaces. This topography data T give, for example, the position and the course of the component edge, the trim angle of the upper sheet 5 and a gap width between upper and lower plate. The topography data T become used the control parameters ST with which the control device 7 the weld controls to adjust in the manner of a control connection.

Furthermore, the image data B2 , which in the trailing observation section 13 are used to assess the seam quality. For this purpose, the evaluation device generates 14 a visual representation of the seam topography and evaluates the quality of the weld 9 by comparing the image data B2 with reference data or by determination of parameters. The assessment of the seam quality can then be sent to an evaluation interface 15 eg a computer or screen.

2 shows an alternative embodiment of the welding device 1A with two TOF cameras 16 . 17 , As far as the device and component assembly in 2 with the in 1 match, the same reference numerals are used and it applies the above-described also for 2 , A first TOF camera 16 is oriented so that its coverage area on a first observation window 18 directed, that of the weld 8th precedes. The first TOF camera 16 delivers the image data B1 for topography determination of the component arrangement and for adaptation of the control parameters ST for the welding process. A second TOF camera 17 is oriented so that its coverage area on a second observation window 18 directed, that of the weld 8th at least partially trailing and in which the seam is already formed. The second TOF camera 17 provides the image data B2, which are used to assess the weld quality.

The detection areas of the TOF cameras are preferably in the welding direction R moved.

The scanner device 2 may be arranged stationary or movable, for example, on a handling device, not shown, such as a robot. The type of impact shown and the type of weld are exemplary. The method and apparatus are also suitable for joining other seam shapes and / or joint types, eg I-seam on butt joint, etc.

The embodiments are not to scale and are not restrictive. Modifications in the context of expert action are possible.

LIST OF REFERENCE NUMBERS

1, 1A

welder

2

Scanner device

3

mirror

4

Focusing / deflecting

5.6

components

7

control device

8th

weld

9

Weld

10

TOF camera

11

observation window

12, 13

observation section

14

evaluation

15

interface

16, 17

TOF camera

18, 19

observation window

B1, B2

Bidldaten

T

topography data

ST

control parameters

R

welding direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006004919 A1 [0003]

Claims (13)

Method for welding, in which at least two components (5, 6) are positioned in abutment with one another and are materially connected to one another by a weld seam (9), for which purpose a welding device (1) can be used at a welding point (8) using control parameters (ST) ) in the components a molten bath is generated and the weld (8) is moved relative to the components (5, 6), characterized in that by means of a time-of-flight detection device (10; 16) an observation window (11; 18) is detected on the components that the welding point (8) at least partially leads, and corresponding image data (B1) are generated, - by evaluating the time-of-flight image data (B1) corresponding topography data (T) of the component arrangement are determined, and Control parameters (ST) of the welding device due to the topography data (T). Method according to Claim 1 in which the topography data (T) reflect the course of a component edge. Method according to one of the preceding claims, in which the topography data (T) reproduce the gap dimension of a joint gap between the components. Method according to one of the preceding claims, in which the topography data (T) represent a trim angle of at least one of the components. Method according to one of the preceding claims, in which, on the basis of the determined topography data (T) - The position of the weld (8) relative to a component edge and / or - The welding parameters are adjusted. Method according to one of the preceding claims, in which TOF image data (B2) for a monitoring section (12; 19) following the weld (8) are furthermore generated and evaluated with regard to the quality of the weld seam. Method according to one of the preceding patent claims, in which the image data (B2) of the observation section (19) following the welding point are generated by means of a second time-of-flight detection device (17). Method according to one of the preceding claims, in which the image data (B1) of the observation window and / or the image data (B2) of the trailing observation window are detected continuously during the duration of the welding. Method according to one of the preceding claims, in which the components (5, 6) are vehicle components. Method according to one of the preceding claims, in which the welding device is a laser welding device or a metal inert gas welding device. Welding device for carrying out the method according to one of Claims 1 to 10 , comprising: a control device (7) arranged to generate, based on control parameters (ST), a molten bath at a weld (8) in the components (5, 6) to be joined, and the weld (8) relative to the components a time-of-flight detection device (10, 16) whose detection range can be directed to an observation window (11, 18) which at least partially leads the welding point (8) and can be detected with the image data (B1) of the observation window, an evaluation device (14) which generates topographical data (T) of the components on the basis of the time-of-flight image data (B1), adapts the control parameters (ST) of the welding device on the basis of the determined topography data (T) and in a control connection with the control device ( ST) stands. Welding device after Claim 11 , further comprising a second time-of-flight detection device (17) whose detection range can be directed to a second observation window (19) at least partially following the weld, wherein the evaluation device (14) determines the time-of-flight image data (B2) of the second time-of-flight detection device (17) generates an optical representation of the Nahttopographie and / or evaluated the quality of the seam. Welding device according to one of Claims 11 or 12 , which is a laser remote welding device, a tactile laser welding device or a metal arc welding device.

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