Magnetorheological Finishing of SiC Aspheric Mirrors

ABSTRACT Many high-precision optical components are made of glass, but they can also be made of a wide variety of other materials. For example, reaction-bonded silicon carbide (RB-SiC) has recently been used to make optical parts for poor working conditions due to its distinct properties such as low density, high hardness, and low thermal expansion coefficient. Thus, in order to rapidly manufacture high-precision aspherical mirrors made from RB-SiC, a novel aspheric manufacturing system equipped with magnetorheological finishing (MRF) technology is described in this paper, which incorporates a host of features and has unprecedented processing versatility. The system has four degrees of freedom, and can realize manufacture or measurement based on the Cartesian coordinate or polar coordinate systems. To achieve good surface accuracy, the polishing wheel combines self-rotation movement with corotation. The prepolishing and fine polishing processes can be done on the same machine by changing different process...