Response of the melt pool and vapour capillary on dynamic beam shaping in the kHz regime during laser welding

Beam shaping technologies provide the possibility to distribute the optical energy of the laser beam on the workpiece in multiple ways. One of the latest technologies is coherent beam combining (CBC) of 32 fiber lasers, which allows quasi-instantaneous switching of beam shapes during laser material processing with frequencies up to 10 MHz. A study was performed for laser welding of stainless steel 1.4301, to investigate the influence of the switching frequency between two beam shapes on the capillary shape. Therefore, the beam shape was switched between a single spot and four spots, which leads to a maximum intensity variation. Frequencies between 10 Hz and 10 kHz were investigated. The results show, that the melt pool shape and the capillary shape follow the switching frequency until a limit frequency.