Characterization of Nano-scale Roughness in Single Point Diamond Turned Optical Surfaces using Power Spectral Density Analysis

摘要

Power spectral density (PSD) distribution provides an accurate measure of roughness of an optical surface. This article presents an analysis of optical surface roughness generated by single point diamond turning (SPDT) using PSD. For this study, flat 60 mm diameter aluminium-6061 samples are machined for varying tool feed rates, while keeping the other machining parameters constant. The 1-D PSD distributions are computed from the surface roughness data obtained by mechanical profilometer. The PSD distribution of the surface roughness profile is composed of primarily three periodic components, which are correlated to the tool feed rate, material induced vibrations and machine-tool vibrations. An attempt has been made to identify their individual contributions in PSD estimates. This study helps in improving the surface quality by selecting optimum process parameters.