Polishing pad aging studies on computer controlled optical surfacing finishing for large-scale sapphire optical window

摘要

Polishing pad becomes aging after finishing for a while, by reason of friction and wear, or polishing particles deposition,which will reduce polishing effects, increase polishing effects and make a low polishing quality. When the ultra-hardnessof sapphire material needs high pressure and high rotate speed parameters, which will accelerate aging of polishing pad.When large scale sapphire optical window is finished by computer controlled optical surfacing (CCOS) method, thepolishing pad aging problem is an important confinement factor for high quality of polishing. In this paper, we confirmedthe stable polishing period and aging time node of pitch pad and polyurethane pad by polishing experiments. For pitchpad, time aging nodes are between 50min and 75min with polishing pressure 0.1Mpa and 0.2Mpa and between 25minand 50min with polishing pressure 0.4Mpa. For polyurethane pad, the time aging nodes are over 75min with polishingpressure 0.1Mpa and 0.2Mpa and between 50min and 75min with polishing pressure 0.4Mpa. The aging time ofpolyurethane pad is later than that of pitch pad. Increasing polishing pressure will help increase material removal rate,but will accelerate aging of polishing pad