JPH04258379A - Profile welding method - Google Patents

Abstract

PURPOSE:To execute profile control even if a groove shape of a weld zone changes by tack welding, etc., in the profile control of a weld line in automatic welding equipment. CONSTITUTION:The position of the weld line is stored by a sensor at the time of tack welding. At the time of main welding, the position of the weld line is read by the sensor and a welding torch is allowed to follow this. At this time, whether or not the groove shape obtained by the sensor is the normal shape is discriminated and when it is normal, the groove position can be recognized and the welding torch is allowed to follow this. When this groove shape is abnormal, since the groove position cannot be determined, this is recognized as a tack welded part and the welding torch position is determined by referring to the stored weld line position. Namely, the stored weld line position is compared with the weld line position read by the sensor (starting position of the tack welded part) to obtain the deviated quantity and the weld line position stored is shifted by the deviated quantity to use it as the weld line position.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the profile of a welding machine in automatic welding.

0002

[Prior art] Sensing and control in arc welding (
Published by Welding Society Welding Method Research Committee, iSBN4-9
06110-23-1) from page II-4 to II-8
As described on the page, there is a known method of detecting the groove shape using laser light and controlling the profile of the welding torch.

0003

[Problem to be solved by the invention] This control is performed on the premise that a groove of a constant shape continues in the entire area to be welded, and when there are parts with different shapes in the middle due to tack welding etc. It wasn't taken into consideration. In other words, changes in the groove shape of the welded part, such as when the temporary welding part is in the middle of the welded part, are not taken into consideration, and the welding machine's tracing operation is not performed normally in areas other than the regular groove shape. There was a problem with it disappearing.

An object of the present invention is to accurately trace a weld line without being affected by changes in the shape of the weld.

[0005]

[Means for Solving the Problems] The present invention provides a method for determining the welding line by comparing image data from a sensor preceding the welding torch with reference data of the groove when the welding position cannot be determined. The method is characterized in that the amount of deviation of the stored welding line position is determined from the position and the position from the image data, and the welding torch is moved by shifting the stored position of the welding line using this deviation amount. do.

[0006]

[Operation] If the position of the groove of the weld line cannot be determined due to tacking or the like, welding is performed using a previously memorized position of the weld line. In this case, if only the memorized values are used, the tolerance will become large, so find the amount of deviation between the memorized weld line position and the position according to the image data (the position immediately before the tack weld), and Shift the current position.

[0007]

[Embodiment] An embodiment of the welding apparatus of the present invention will be described below with reference to FIGS.
This will be explained with reference to FIG.

In FIG. 2, the welding device is used to weld workpieces 9a and 9.
It consists of a table 11 on which is placed a table 11, a gate-shaped traveling body 13 that runs along rails 12a and 12b installed on both sides of the table 11, and a welding device installed on the traveling body 13. The traveling body 13 has a frame 15 that is movable in a direction perpendicular to the running direction of the traveling body 13, and can be moved along a rail 17 by a motor 16. A known welding torch 20 and a known sensor 30 are installed on the frame 15. The welding torch 20 and the sensor 30 are installed on a frame 25 that is installed on the frame 15 so as to be movable up and down. 26 is a motor for lifting and lowering. 29 is a known welding machine, and 40 is a control device having a tracing device.

FIG. 3 shows a configuration for profile control. Sensor 30 is located in front of welding torch 20 in the welding progress direction. The sensor 30 includes a laser light source 31 that emits light toward the welding part, a reflecting mirror 32, and a camera 33. The light reflected at the welding part is reflected by a mirror 32 toward a camera 33. The image data obtained by the camera 33 is processed by the profiling control device 41 of the control device 40, and the position of the weld line is determined. The operation program 43 has input welding conditions, control information for starting and ending welding, and the moving order and path of the head of the torch 20. The positioning control device 44 corrects the path given by the operation program 43 using the welding line position information obtained by the profiling control device 41, and causes the motor drive device 45 to move the motor 16,
26 etc., the torch 20 is positioned.

An example of the welding procedure is shown in FIG. The works 6a and 6b are set in the welding device (S10), and the operation program 43 and the normal shape data 42 of the groove are input (S20). Prior to the main welding, temporary welding is performed at predetermined intervals at the welded portions of the works 6a and 6b. During this welding, the sensor 30 and the like are in operation, and the position of the welding line is read by the sensor 30 and the tracing control device 41.
The positions given by the operation program 43 are corrected and temporary attachment is performed at predetermined intervals, and the positions of the welding lines are stored (S30). Then, after the temporary attachment is completed, main welding is performed (S40). Figure 1 shows the flow of the profiling operation during main welding. Import the image captured by camera 9 (S10
0). For example, when there is no tack welding on a V-groove weld line, the linear light from the laser light source 31 is taken in as a bright line having a shape as shown in FIG. This bright line shows the cross-sectional shape of the weld, and allows the width and depth of the groove to be read. The normal shape data 42 consisting of the shape, width, depth, area, etc. of the welded part given in advance is compared with the captured image data (S110). If the welding position can be determined based only on image data, it is determined that the shape is normal, and in the case of a V groove, the position of the deepest part of the V is calculated as the welding position (S120). Figure 6,
As shown in FIG. 7, if the groove is filled with the tack KW and the welding position cannot be determined from the image data, it is necessary to determine the position of that part using other data. Therefore, as shown in Fig. 7, the weld line position Y1 read during temporary welding and the weld line position Y during main welding are
The difference from 0 is calculated (S140), and the position Y1 is shifted by that amount to become the welding position Y0 (S150). The welding position thus determined is corrected for the difference between the irradiation position of the laser light source 7 and the position of the torch 20 (S160), and the torch is positioned (S180).

Regarding the distance between the welding torch 20 and the sensor 30, it is preferable that the distance be short in the section where the groove is normal, and be large in the section where the groove is irregular (temporarily attached part). Since it is known from the pre-stored data that the vehicle is approaching the temporary attachment portion, the sensor 30 is moved in advance when the vehicle approaches the temporary attachment portion. This leading distance is made larger than the tacking length. This determines the start and end positions of the tack, and thereby determines the path of the welding torch in the tack section.

0012

According to the present invention, even if there is a part in the middle where the welding position cannot be determined from the shape of the welded part due to tack welding, etc., the welding position can be determined with high accuracy. In profile control, it is possible to eliminate the influence of changes in the shape of the welded part due to tack bonding, etc.

Furthermore, by changing the welding conditions such as voltage and current based on the result of determining the shape of the welded part as claimed in claim 6, the tacked part can be welded under conditions suitable for the welding part. Enables high quality welding.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of tracing control according to an embodiment of the present invention.

FIG. 2 is a perspective view of a profile welding device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a profiling control device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a work procedure.

FIG. 5 is a diagram showing bright lines of a television image.

FIG. 6 is a diagram showing the state of bright lines in a television image.

FIG. 7 is an explanatory diagram of position determination in the temporary attachment part.

[Explanation of symbols]

9a, 9b...Workpiece, 20...Welding torch, 30...Sensor, 41...Profiling control device.

Claims (1)

[Claims] Claim 1: In a tracing welding method, the welding position is determined by comparing image data in front of the welding torch with reference data, and the welding position is determined by comparing the image data with the reference data. If it cannot be determined, the amount of deviation between the stored welding line position and the image data position is determined, and the stored welding line position is shifted by this deviation amount. A profile welding method characterized by moving a welding torch.