Bringing Pulsed Laser Welding into Production

In this paper, some research and develop-ment activities within pulsed laser welding technology at the Tech-nical University of Denmark will be described. The laser group at the Insti-tute for Manufacturing Technology has nearly 20 years of experience in laser materials process-ing. Inter-nationally the group is mostly known for its contri-butions to the development of the laser cutting process, but further it has been active within laser welding, both in assisting industry in bringing laser welding into production in several cases and in performing fundamental R & D.

In this paper some research activities concerning the weldability of high alloyed austenitic stainless steels for mass production industry applying industrial lasers for fine welding will be described. Studies on hot cracking sensitivity of high alloyed austenitic stainless steel applying both ND-YAG-lasers and CO2-lasers has been performed and is currently in progress in collaboration with a major Danish company, who currently is applying laser welding in several production lines.

Furthermore some case stories from development work on laser welding for industri-al production will be described. One case story describes a current production of hermetic weld seams produced on radiator thermostats applying pulsed laser welding. This application has now been running in several years. 2 laser systems are currently welding each serving two welding stations.

Another case story is describing a high precision assembly technique of a product, where the utilisation of fibre optics has been central in the development of an unique assembly technique, where the parts to be assembled can be manufactured with relative cause tolerances and a simultaneous two beam laser welding can join precisely positioned parts without any distortion of the alignment.