Surface generation and materials removal mechanism in ultra-precision grinding of biconical optics based on slow tool servo with diamond grinding wheels

Diamond turning, fly-cutting, and milling are the primary manufacturing technologies for generating free-form surfaces; however, they are not sufficiently effective in machining free-form optics on hard and brittle materials. Ultra-precision grinding has been demonstrated to have an outstanding capability in machining difficult-to-cut materials. Therefore, we proposed a novel surface generation technique for free-form optics based on a slow tool servo with diamond grinding wheels (STS-DGW). First, the generation strategies of the wheel path for grinding biconical optics were explored. Subsequently, the generation process of surface topography was theoretically analysed, and the interference between the diamond wheel and biconical optics in the process of surface generation was checked. Eventually, typical biconical free-form optics were fabricated on single-crystal silicon. Submicron profile accuracy and nanometer surface roughness were achieved, and the influence of the processing parameters on the surface topography and material removal mechanism was investigated.