Effect of femtosecond laser modification on magnetorheological finishing of magnesium aluminate spinel

Magnesium aluminate spinel materials are widely used as important optical components in harsh environments. High hardness and brittleness lead to low machining efficiency and easily cause surface damage during machining. The different intergranular removal rates of polycrystalline materials result in a visual grain effect after polishing. The efficiency is slow, and polishing ripples occur, especially in magnetorheological finishing (MRF), resulting in the deterioration of the surface quality and performance. We propose a new method for femtosecond laser-surface-modification assisted MRF of spinel and investigate its mechanisms. The results showed that this method significantly improved the spinel MRF efficiency and quality and suppressed the grain effect.