Electromagnetic optimization of the integrated magnetorheological jet polishing tool and its application in millimeter-scale discontinuous structure processing

To meet the special demands in small-scale discontinuous optical surface fabrication, the integrated magnetorheological jet polishing (IMJP) tool with multiple motion degrees is introduced in this paper. Four jetting models are implemented and investigated by means of the IMJP tool for practical manufacture. To ensure steady jetting in a long distance, ideal distribution characteristics of the magnetic field in the structure is proposed, based on electromagnetic theory. The magnetic field distribution is simulated subsequently using the finite element analysis method, and three key parameters in the IMJP tool structure are optimized through the simulations. The actual magnetic flux density is measured and spot polishing experiments are conducted in different standoff distances, verifying the effectiveness of the optimization. A processing experiment of a millimeter scale structure with milling tool marks located on a surface with nonuniform curvatures was conducted using the IMJP tool. The roughness of the polishing region converged to 4.86 nm Ra from a low initial quality after processing, and the tool marks have been efficiently removed. The experimental results reveal the reliability of the setup design and the remarkable roughness convergence ability of the IMJP tool for small complex structures.