Effect of beam diameter on pulsed laser polishing of S7 tool steel

Tool steels such as S7 are often used for molds and dies, an application that requires both an extremely smooth surface and tight geometric tolerances. Pulsed laser micro polishing (PLμP) is a process capable of achieving significant surface smoothing quickly and without removing material. This paper presents the effect of melt pool diameter (laser spot diameter) on surface topography during pulsed laser polishing. How the manipulation of melt pool diameter during three-pass laser polishing can reduce surface roughness is also discussed.