Laser-based surface modification assisted ultra-precision machining of polycrystalline tin

Laser surface modification can improve the processing performance of soft metal materials. In this work, a laser-based surface modification assisted ultra-precision machining method is proposed. A continuous wave fiber laser with a wavelength of 1064 nm is used to achieve surface modification. Based on the self-built laser modification device, the surface modification experiments of polycrystalline tin under different laser power densities were carried out. The depth of the modified layer under different power densities was analyzed, and single-point diamond turning experiments were carried out. The results show that the machined surface roughness obtained by ultra-precision cutting experiments in the modified layer is much lower than that of the unmodified surface. In addition, the causes of surface ablation pools and scratches under high laser power densities are analyzed.