Polishing of ductile cast iron with scan-head guided fiber laser

Present work deals with laser polishing process on GGG70L spheroidal cast iron, which is widely used in die making for the automotive industry. Free graphite in the structure of GGG70L makes difficult the polishing and surface roughness reduction because the high melting temperature. In this work a complete study is presented, where main process parameters are identified and free graphite is eliminated from surface. The quantification of surface improvement is presented in terms of resulting surface roughness, hardness, and heat affected layer thickness. Thus, using optimal parameters, laser polishing with 2D scan head gives satisfactory results on GGG70L cast iron with roughness reduction rates up to 80% and minimum mean roughness R-a of 0.5 mu m.