Micro Welding of Thin Stainless Steel Foil with a Direct Diode Laser

Recently, industrial product parts and components are being made smaller to reduce energy consumption and save space, creating a growing need for the micro-welding of thin foil less than 100μm thick. For this purpose, laser processing is expected to be the method of choice because it allows more precise heat control compared with arc and plasma processing. In this report, the practicability of welding thin stainless steel foil with a direct diode laser system was investigated. The elliptically shaped laser beam of the direct diode laser enabled successful butt-welding of thin stainless steel foil 100μm and less in thickness. At a output power of 100W, 100μm and 50μm thick foils could be welded at a high speed of 6.0m/min and 18.0m/min, respectively. They had narrow bead widths of 100μm which was narrower than the beam size of the laser. No spatter or plasma plume was observed when welding without an assist gas. The tensile strength of the weld bead was nearly the same as that of the base material.