Beam shaping BrightLine Weld: latest application results

Recently, a new laser welding technology called BrightLine Weld has been introduced by TRUMPF. It is based on applying a TruDisk thin-disk solid-state laser with a so called two-in-one fiber delivery optical cable. In combination with a novel system of variable laser power coupling into the inner as well as the outer fiber core, an application-tailored laser power distribution is created. This enables a new degree of freedom through beam shaping for laser keyhole welding. The process benefits are significantly higher achievable feed rates during welding, minimal spatter formation and highest weld seam qualities. This paper presents latest results on welding of steel, aluminum and highly reflective materials such as copper using BrightLine Weld. The welding of gear parts has been performed exploiting the full feed rate performance with highly alloyed steels. Endurance strength tests show that the weld seam characteristics of these novel high-speed welds fulfill state-of-the-art requirements. We also report on results in weld penetration depth monitoring, applying optical coherence topography (OCT) to copper welding samples. Due to the keyhole stabilization in a wide range of feed rates and their respective penetration depths, the keyhole depth monitoring becomes widely applicable and supports the process especially in terms of reliability. Furthermore, an outlook on full penetration welding of tubes and profiles will be given. We will show first application results demonstrating the impact of BrightLine Weld on spatter prevention both on the top and on the bottom side of the weld seam.