Roughness prediction in hatched laser scanning polishing based on critical spatial frequency

Abstract

In the study of laser polishing, the modeling of hatched laser scanning polishing, which must take into account the initial surface micro-morphology and scanning path simultaneously, is still a challenge. To address the problem, this paper presents an improved surface roughness prediction model based on spatial frequency analysis. The initial surface morphology was simplified into a micro-textured surface. And then A 3D FEA heat conduction model of the micro-texture in hatched laser scanning polishing was established to evaluate the melting depth and melting duration in the hatched scanning traces. Subsequently, based on the evaluated melting durations, the critical spatial frequency was calculated and the spatial spectrum of polished surface profile was evaluated. And thus, the profile and the average roughness R_a of the polished surface were determined by inverse Fourier transform. By comparing the predicted result with the measured surface roughness in hatched laser scanning polishing test, it indicates that the proposed model allows for accurate predictions of polished finish with predicted error range from −9.5 % to 8.9 %, which is much smaller than that of other traditional spatial frequency analysis model of laser polishing.