Magnetorheological Jet Finishing of Conformal, Freeform and Steep Concave Optics

Conformal, freeform and steep concave optics represent important shapes that are difficult or impossible to finish using conventional techniques due to mechanical interferences and steep local slopes. One way to polish these optics is by using a jet of abrasive/fluid mixture. Widely used abrasive water jet machining is not applicable for precision polishing because of natural jet instability, which gives an unstable removal function. Theoretical and experimental results in this paper show how this problem can be addressed with a magnetically stabilized jet of magnetorheological fluid. Polishing results demonstrate the suitability for this technique for precision finishing of complex shapes.