To weld T-Joints with two laser beams simultaneously it is necessary to position both laser foci exact parallel at each side of the workpiece. In addition to that the laser beam must be focused at the joint with high accuracy. If there is a gap a wire feeder must be controlled further in dependency on the gap width. To realize a sensor based solution for welding T-Joints two seam tracking sensors have been integrated into a laser welding cell. They are used to measure the position of the joint relative to the tool center point and the gap width at that position. This measurements are used to position machine axes, to control laser power and wire feeder speed.
The seam tracking has been implemented into the interpolation task of the control by the use of the control’s Profibus interface to guarantee fast reaction times for the process control.