Theoretical model and experimental analysis of non-uniform material removal during full-aperture polishing

Full-aperture polishing is a key process in the fabrication of large flat optical elements with a high-precision surface figure. Controlling of the surface figure, which is primarily dependent on the material removal distribution, during the polishing process is challenging. In this study, a novel model is proposed to calculate the material removal distribution and the resultant surface figure. The model determines the material removal amount of points on the workpiece by considering the kinematic parameters and pressure distribution along the sliding trajectory relative to the pad. Moreover, the pressure distribution during the polishing process is acquired from the mechanical and morphological characteristic of polishing pad. With this model, the final surface figures under several polishing conditions were simulated and were found to be in close agreement with the experimental results.