Local material removal mechanism considering curvature effect in the polishing process of the small aspherical lens die

This paper describes a method to obtain the local removal rate for the poli shing process of the small aspherical lens die using a spherical tool. When the small spherical polishing tool traverses an aspherical surface, non-un iform polishing area and local removal rate are locally generated around th e contacting points according to the curvature change of an aspherical surf ace. Therefore, an aspherical surface is divided into multiple patches and the local removal rate on the patches is calculated semi-empirically from t he Preston equation. Formation of the elliptical polishing area is confirme d experimentally and the Preston coefficient is calculated from the central removal depth and dwell time that has a linear relation with the local rem oval depth. Finally, using the equivalent radius of two contact bodies, the curvature effect of an aspherical surface on the polishing area is explain ed. (C) 2001 Elsevier Science B.V. All rights reserved.