Migrating magnetorheological finishing process plans between different optical materials

Determination of the removal function is an important step in magnetorheological finishing (MRF) of optical materials. However, the removal function is difficult to determine if a spot sample of the same material as that needing polish is unavailable, thus preventing establishment of an MRF process plan. A method to resolve this issue is proposed, wherein an MRF process plan for an item of a differing optical material is migrated. The theoretical basis for migration is investigated, and simulations reveal that narrow nonlinear regions of the source and target materials’ removal functions are a necessary condition for adequate convergence rate. The proposed method is experimentally verified by finishing a ZnS part with the process plan of a BK7 optical part of the same geometry, with a convergence rate of 45.7% after four iterations.