Minimizing polishing times in asphere production by ultra-precision grinding

Abstract

Chemo-mechanical polishing processes that are used to remove grinding marks are a major cost driver in asphere production. Especially when machining glasses that are prone to fracture from grinding subsurface damage can be substantial. As a result, subsequent polishing times can be extremely high. In order to reduce polishing times and increase process stability SwissOptic established an ultra-precision grinding process. Here, we compare process times and surface figure errors for two processes. The first process represents a standard process in asphere production with grinding, polishing and fine correction. The second process adds an ultraprecision grinding step before polishing. As a result, we find that cumulative process times and resulting figure errors are much lower if we apply ultra-precision grinding.