Lapping with loose abrasives in lens manufacturing

Abstract

This study deals with lapping process with loose abrasives in large diameter lens manufacturing. Loose abrasive lapping, is a three-body abrasive process in which a fixed load is applied to a plate that presses a slurry consisting of a coolant and abrasive particles onto the optical surface being manufactured. This process is analyzed by examination of the influence of optical glass material parameters on material removal and surface roughness for lens manufacturing conditions. The model established for this analysis uses the concept of lateral fracture, which is based on removal of optical glass material by rolling abrasive particles. The particles remove glass material by lateral cracking. The concept of lateral fracture by rolling abrasive particles is verified as the lapping model, which was found to give a good description of the experimental results. Removal rates and lapping time values at the conventional removal depth are found and which will allow the automation of lapping process for lens manufacturing. The abrasive mineral Barton Garnet was used in the lapping experiments.