Both multi-mode and single-mode lasers are well established in welding applications. In micro welding, single-mode lasers are often used while multi-mode lasers are more common when it comes to welding tasks in the macro range.
In this work, a 500 W multi-mode and a 1,000 W single-mode fiber laser were compared concerning their practicability in terms of micro welding. For this reason, stainless steel foils in thicknesses of 25 µm and 50 µm were overlap welded with focal diameters between 22 µm and 204 µm using 2D scanning systems. The process boundaries were described and process behavior was determined by examining welding regime, melt flow-induced seam imperfections, and specific energy demand while welding.
Additionally, measurements of hardness and tensile tests illustrate usage properties and constraints of both fiber laser concepts in micro welding.