Study on Robot Application Technology for Laser Welding

The laser welding technology for manufacturing light car body is studied. A industrial robot, a seam tracking system and 4 kW CW Nd:YAG laser are used for robot based laser welding system. The laser system is used 4 kW Nd: YAG laser(HL4006D) of Trumpf and the robot system is used IRB6400R of ABB. The monitoring method of welding quality and seam tracking technology along the butt-joint are studied. The robot laser welding system is equipped with a seam tracker and plasma sensor. The precise positioning (<200 mum) of the laser beam on the welding joint to be welded is obtained by seam tracker. The seam tracking system is SMART-20LS and RAPAL of Servo-Robot and MVS-5 sensor of MVS. The welding joints of steel plate are butt and lap joint. We investigate the parameters which have influence on the welding quality through the plasma intensity signals measuring method. The artificial defects (<o1 mm) in joint are well observed by using the plasma intensity signals measured by the plasma sensor of UV and IR. The laser welding tests for non-linear tailored blank are performed after the observation experiments of bead on plate. Finally, the welding process for non-linear tailored blank and front side member is studied. In this study, the robot based laser welding system is developed for the precision seam tracking and the real-time monitoring of welding quality.