A novel high efficiency magnetorheological polishing process excited by Halbach array magnetic field

Magnetorheological polishing is a potential process for the low-damage manufacture of optics, semiconductors, and related devices. However, due to magnetic materials’ size and magnetic field strength limitations, a high-efficiency material removal rate can hardly be achieved in practical application. This work presents a novel high-efficiency magnetorheological polishing process, which employs Halbach array as magnetic field excitation to improve the processing efficiency. The Halbach array provides a large-area, high-intensity magnetic field, which is verified by finite element simulation and experiments. The force analysis of carbonyl iron particles in the magnetic field revealed the distribution of polishing pressure and polishing marks. The polishing performance of the process as well as the distribution of polishing pressure and polishing marks were investigated by polishing experiments. The effects of process parameters on the removal rate and surface roughness have also been systematically investigated. The novel magnetorheological polishing process can achieve 3.8 times material removal rate compared with the previous process. In the polishing processes of fused silica, the surface roughness reduced from 1979.154 nm to 0.544 nm in 60 min. To sum up, Halbach array could significantly improve the efficiency of magnetorheological polishing while preserving polishing quality.