Experimental research on plane lapping of fused silica glass substrate

The lapping of fused silica glass substrate is a basic process of its super smooth polishing. Free abrasive was used in rough grinding and fine finishing fused quartz glass on one side. The effects of abrasive mass fraction, rotation speed of grinding disc, flow rate of grinding fluid and grinding time on surface quality and material removal rate of fused quartz glass were studied. The results show that the material removal rate increases first and then decreases with the increase of abrasive mass fraction, grinding disc speed and grinding fluid flow rate. With the extension of processing time, the surface roughness R_a gradually reaches a stable level. The surface roughness R_a of fused quartz glass substrate reaches 0.11 μm at conditions of the mass fraction of abrasive particles 4%, the flow rate of abrasive fluid 20 mL/min, the speed of abrasive disc 60 r/min and the processing time 30 min. When fine finishing fused silica glass substrates, the surface roughness R_a of the substrates is the lowest after 50 minutes processing with 3 μm-sized CeO₂ particles, which is 4.11 nm.