Micro-welding of thin foil with direct diode laser

Recently, industrial products parts and components are being made smaller to reduce energy consumption and save space, creating a growing need for micro-welding of thin foil less than 100 mm thick. For this purpose, laser processing is expected to be the method of choice because it allows more precise heat control compared wih 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 100 μm and less in thickness. Foil as thin as 50 μm could be successfully welded with a narrow bead width of 150 μm at a high speed of 18.0m/min. 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.