Solid-state laser beam sources offer the possibility of generating very high-brilliance laser beams with low expansion and a high usable intensity at the focal point. New approaches include beam shaping with the use of core and ring fiber and therefore variable power distribution in the laser beam focal point and material interaction area. Especially high-power laser beam welding benefits from beam shaping because of the stabilizing effect on the weld pool. Furthermore, the technical progress regarding beam quality also allows to achieve high Rayleigh lengths and therefore more uniform beam diameter over the whole material thickness.


Investigations on high-power laser beam welding with 24 kW disk laser beam source are conducted for three different materials (mild steel, aluminum alloy, and copper), which are of high interest for welding in different sectors. The influence of the power distribution between core and ring as well as the welding speed on weld geometry (depth and width), weld pool stability and the resulting weld seam quality are investigated. It was shown that the welding process cannot just be scaled up in comparison to welding with lower laser beam power but shows its own challenges. High welding depths that exceed the state of the art could be achieved in one pass.