Surface evaluation and evolution during hydrodynamic effect polishing for quartz glass.

Hydrodynamic effect polishing (HEP), a noncontact machining process, can realize the processed surface roughness as small as atomic level. To investigate the subsurface structure, the HEP processed quartz glass surface was etched by the hydrofluoric acid solution. It has been proved that HEP is a polishing method with the ability to process the surface with atomic-level flatness and damage-free surface/subsurface. It has been found that the microplastic scratches on the lap prepolished glass were obviously exposed when the thin redeposition layer was removed. Then the scratches were gradually removed and surface roughness decreased quickly as the removal depth increased. The surface becomes very smooth and the surface roughness maintains at an atomic level when the subsurface damage is removed clearly. The experimental results demonstrated that the defects such as the scratches parallel to the rotational axis of the wheel were firstly removed during the polishing process, and then the defects vertical to the wheel rotational axis were removed.