Influence of process gases in welding with diode lasers

In laser welding of metals normally inert gases or mixtures of them are used, due to several reasons. Better welding results have been achieved just by changing the shielding gas in diode laser welding. By changing from helium to the active gas “Linde - LASERMIX” side-wall fusion and depth of penetration were greatly improved. For instance penetration changed from surface to deep penetration. It is shown in high speed films in the presentation that differences in weld pool behavior are responsible for these phenomena. Because of our results, diode laser welding can be used in a new practical way in the industry, not achieved earlier. A research program had been started at Linde Technology Center in cooperation with the Institute for Machine Tools and Industrial Management (iwb), of the TU Muenchen. Results demonstrate that the type of gas has a much stronger influence on welding results when using high power diode lasers (HPDL) compared to the established laser systems.