Experimental Investigation and Modeling of Friction Coefficient and Material Removal During Optical Glass Polishing

Chemical mechanical polishing is a hybrid polishing technique having different applications in the semiconductor industry, biomedical and optical instrumentation, and defense equipment. The control and accuracy highly depend on the operator's skill due to limited knowledge of material removal behavior. This article attempts to fill this gap through an experimental investigation of friction coefficient and material removal rate as functions of abrasive particle size, normal load, relative velocity, and polishing time during BK7 optical glass polishing. In this article, Taguchi L18 mixed levels full factorial design was used to perform the experiments. Also, a temporal model for material removal rate is developed to study and investigate the mechanism of material removal. The results show the load per particle varies between 0.18 × 10–6 and 4.1 × 10–6 N, which led to the conclusion that material, are removed plastically from the workpiece surface and mechanical actions are dominant over chemical actions in material removal. The values of friction coefficient (μ ~ 0.1) and 3D profilometer images also support this statement. The errors between predicted and experimental results are well within 8% and 12% for friction coefficient and material removal rate, respectively. This study is an important step toward the deterministic optical polishing process, leading to better control of material removal during the polishing of precision optical components.