Pulsed Laser Micro Polishing of Metals using Dual-beam Technology

In this publication laser micro polishing with an additional laser beam for pre-heating of the surface is investigated.The influence of the following process parameters on the surface roughness is examined: Pre-heating laser power, scanning velocity, beam offset of the two laser beams, and intensity distribution of the pre-heating laser beam. The two materials which were used for the experiments (martensitic tool steel and TiAl6V4) showed a different behavior: For martensitic tool steel the micro roughness was increased in comparison to conventional laser polishing with only one laser beam (single-beam technology) due to increasing formation of martensite. For TiAl6V4 the meso roughness of the surfaces was decreased in comparison to conventional laser micro polishing due to longer melt duration, so smoother surfaces wereobtained (up to 36% lower surface roughness for one spatial wavelength regime).