Fabrication of small aspheric moulds using single point inclined axis grinding

• A single point inclined axis grinding protocol was developed for fabrication of aspheric moulds, which enabled improved profile accuracy.
• The selection criteria of cylindrical wheels for avoiding the interference were proposed.
• The compensation method focused on centreing and tool wear error was developed and proven to be effective.

Single point inclined axis grinding techniques, including the wheel setting, wheel–workpiece interference, error source determination and compensation approaches, were studied to fabricate small aspheric moulds of high profile accuracy. The interference of a cylindrical grinding wheel with the workpiece was analysed and the criteria for selection of wheel geometry for avoiding the interference was proposed. The grinding process was performed with compensation focused on two major error sources, wheel setting error and wheel wear. The grinding results showed that the compensation approach was efficient and the developed grinding process was capable to generate small aspheric concave surfaces on tungsten carbide material with a profile error of smaller than 200 nm in PV value after two to three compensation cycles.