Upscaling laser polishing of large 3D surfaces

Laser polishing (LP) is considered as one of the enabling technologies primed to replace time-consuming manual polishing operations. During laser polishing, a thin layer of material is melted as a result of laser irradiation. Since molten metal is characterized by the melt pool relocation capabilities, laser polishing results in a significant decrease of surface roughness. Experiments on flat stainless-steel metal plates with a 1200W fiber laser lead to a surface roughness as low as Sa = 320nm (90% roughness decrease) with a processing time of approximately 40s/cm². The aim of this study is first to demonstrate the potential for the upscaling of process speed. Upscaling laws based on power density and energy density will be discussed. Experiments are carried out to assess the upscaling from 1200W to a 10kW fiber laser in order to improve processing time. We can expect to reach a processing time of 5s/cm², a diminution by 4 to 6 times comparing to the current process. Under appropriate process parameters, certain classes of metallic materials are suitable for LP and can reduce their average surface roughness by more than 90 %.