Abstract: Polyurethane polishing pads are often used for polishing hard and brittle materials such as optical glass. The morphology and the wear of polishing pads directly influence the polishing accuracy and efficiency. Experimental studies were conducted on the micro-morphology and wear behavior of polyurethane polishing pads during different polishing time and their effects on material removal rate and surface roughness were analyzed. The results showed that the material removal rate and surface roughness are 0.977μm/min and 153.67nm respectively when the spindle speed is 8000r/min， the feed speed is 0.0150mm/s and the axial ultrasonic amplitude is 5μm. Polyurethane polishing pads have relatively little wear in the first 30 min， the surface of the polishing pads is filled with abrasive particles and optical glass debris， as the polishing time increases， damaging the porous structure of polishing pads. The surface of the polishing pads gradually hardens and loses its elasticity. Meanwhile， the abrasive particles and the debris invading the surface of the polishing pads will prevent the renewal of the abrasive particles in the contact area during the polishing， resulting in a reduction in the polishing quality.

Key words: ultrasonic vibration-assisted polishing (UVAP); micro-morphology; wear of polishing pads; optical glass (BK7); polyurethane polishing pad