Influence of global and local process gas shielding on surface topography in laser micro polishing (LmP) of stainless steel 410
Abstract Laser micro polishing (LmP) is a new laser based material processing method that has a high potential to overcome common disadvantages of traditional polishing techniques. A special challenge in LmP is the processing of large areas since processing in a process gas atmosphere is deemed necessary to avoid undesired oxidation and minimize surface roughness. Therefore, a new process strategy for LmP on stainless steel AISI 410 was investigated in which a gas nozzle was used to create a local process gas shielding and therefore to significantly increase the field of maximal processing. Using a Nd:YAG high power Q switch laser, we demonstrated that local process gas shielding is feasible for LmP in terms of avoidance of surface defects and achieved micro roughness. In addition, a wide process window in terms of nozzle distances and gas flow exists for LmP. The resulting surfaces are highly reproducible in terms of surface roughness. Besides Argon, Nitrogen is another process gas that is highly suitable for LmP of AISI 410. The use of Nitrogen might therefore significantly lower future production costs in LmP. Finally, spatially resolved LmP was explicitly demonstrated on a textured press plate.