Weld seam guide for robot-guided welding

Weld tracking systems replace manual teaching when correcting part tolerances

Initial Situation

In assembly lines worldwide, welding robots are more and more involved. The demand for optimum productivity at a consistent quality level is continuously growing, which makes robot welding mandatory in many applications. For corresponding procedures, a path is programmed into the robot, which then is used for all parts to be welded. Due to the tolerances of the objects however, this path may slightly vary from part to part. Furthermore thermal expansion of the material during welding must be taken into consideration, as the resulting warping effect has an influence on the position of the weld seam as well.

Particular Challenges

To correct the effect of the tolerances of the parts, the robot path in conventional applications is usually adjusted, by means of a time consuming manual correction (teaching). The warping effect caused by the thermal expansion however cannot be compensated this way.

QuellTech Solution

For this purpose, QuellTech offers a perfectly tailored seam tracking solution, which is based on a QuellTech 2D-Laserline Sensor of the Q4 family. The method consists in measurement of the real position and width immediately ahead of the welding process. The laser sensor captures the real dimension of the weld bead, and the software used for this process simultaneously sends the nominal position to the robot. The robot performs a correction movement in X or Z position according to this measurement. This way not only the deviation caused by tolerances, but also the warping effect can be compensated – and the weldment takes place exactly at the required position. The QuellTech 2D-Laserline Sensor is specially prepared to the highly disturbing ambient light from the weld process. It can be cooled and protected from weld spatter, so this model proves to be particularly adequate for operation in the harsh environment of the welding process.

Benefits for the Client

By means of the QuellTech 2D- Laserline Sensor Q4 seam tracking solution, the customer can save much time for reprogramming of the robots weld seam track. Thermal warping effect, in contrast to conventional methods, can be corrected as well. This results in an improved weld bead quality, less scrap and higher productivity.