Key technology research on magnetorheological finishing based on suppression of surface mid-spatial frequency ripple errors

Abstract

A high-energy laser system imposes demanding requirements on the total frequency range of its optical components, mainly the mid-spatial frequency (MSF) error. This error will seriously reduce the optical performance of this system. In order to suppress the MSF ripple error of optical components after magnetorheological finishing (MRF), the influence of the rotation angle of MRF removal functions on the surface MSF ripple error was explored by computer simulation at first. Subsequently, the suppression effect of magnetorheological ribbon fluctuation on surface MSF ripple errors was simulated. Finally, the fused silica components were scanned uniformly under the conditions of different rotation angles and the same MRF ribbon fluctuation. The simulation analysis and experimental results demonstrated that the same removal function had multiple preferred angles under different line feed spacing values. When the preferred angle is reached for the removal function, the surface MSF ripple error of the machined component can be significantly reduced. However, the MSF ripple error cannot be eliminated by simply rotating the preferred angle during MRF. Nevertheless, this part of the MSF ripple error can be swamped by the additional material removal caused by the magnetorheological ribbon fluctuation, which can significantly improve the surface quality of the component. Therefore, the MSF ripple error on the component surface can be eliminated by controlling the rotation angle of the removal function and the fluctuation of the magnetorheological ribbon. This method can significantly improve the root mean square (RMS) of surface MSF ranges and reduce the surface MSF error of high-power laser components.