Theoretical and experimental investigation on material removal mechanism in dual-rotation polishing of fused silica glass

Abstract

Fused silica glass is utilized extensively in various optical components owing to its excellent optical properties, but its high hardness and brittleness make it difficult to process with high surface accuracy and low subsurface damage. To solve this problem, a series of experiments is carried out to explore the mechanism of material removal during dual-rotation polishing of fused quartz glass. A predictive model is proposed to predict the material removal rate and the microtopography of polished surface. This model considers fundamental physics of the dual-rotation polishing process, for instance, the surface micro-topography and the pressure distribution of the polishing pad, the brittle–ductile material removal mechanism, the planetary motion during the polishing, and the influence of chemical reactions. The reliability and accuracy of the model are quantitatively evaluated through practical experiments. It is turned out that the simulated results reasonably agree with the experimental data. In addition, simulation experiments show that a Gaussian removal function with a strong central peak can be obtained when the eccentricity is 0.9 and the rotating speed ratio is between −10 and −1. This indicates that the theoretical model can be successfully applied to the prediction and optimization of polishing processes.