Probing 3M Trizact abrasive pads in the polishing and super-polishing phase of fused silica

Abstract

The use of 3M<SUP>TM</SUP> Trizact<SUP>TM</SUP> diamond tiled abrasive pads was proven as a cost-effective pre-polishing technique. Thanks to the low subsurface damages introduced it allows to speed up the polishing phases, reducing the amount of material to be removed. Nowadays, different kind of abrasive pads are available on the market and some of these are dedicated to the last phases of the surface finishing. In this paper, we present the results obtained with 3M<SUP>TM</SUP> Trizact<SUP>TM</SUP> Hookit<SUP>TM</SUP> Film Disc 268XA as last step of the polishing phases. The test activity has been carried out on fused silica samples prepared with initial R<SUB>q</SUB> around 50 - 70 nm. In particular, we focused on the wear rate of the pads, the material removal rate and the micro-roughness evolution, in dependence of several parameters as the amount of water, pH, velocity and pressure. The removal rate depends on the status of the abrasive pad and on the polishing conditions, while the micro-roughness of the surface can be decreased well below 1nm rms on millimetre scale. Moreover, a combined process of bonnet pre-polishing followed by 3M<SUP>TM</SUP> Trizact<SUP>TM</SUP> polishing has been proven as a cost-effective solution to realize super-polished optical surfaces.