Fixed diamond abrasive polishing method of glass substrate using diamond sheet

–Effect of initial surface texture of substrate and coolant on polishing characteristics–

Abstract

A fixed abrasive polishing method using a diamond sheet with a fine-tuned coolant is applied in the production of industrial glass substrates. While it is known empirically that the initial surface texture of glass substrate and the coolant affect the polishing characteristics, such as the removal rate and surface roughness, there have been insufficient systematic evaluations of the process. Focusing on these two parameters, experimental verification was performed using a double-sided polisher. The initial surface texture of the substrate was evaluated based on the transmission of white light, and the coolant characteristics were estimated by the luminance of the liquid film due to the appearance of bubbles formed on the lower platen during polishing with the upper platen removed. The results showed that the initial surface texture of the substrate has a marked effect on the removal rate, and that the removal rate was reduced the closer the initial surface texture was to a mirror surface. Furthermore, obtaining a high removal rate became more difficult when the liquid film formed on the lower platen approached white. This white color was considered to be generated due to the bubbles formed during polishing and to be related to sludge discharge performance from the platen.