Aspheric Form Generation Using MRF Technology

Case Study Summary

This case study illustrates how Magnetorheological Finishing (MRF) can be used not only for correction but also for inducing aspheric form. A 170 mm diameter BK7 optic with an initial best-fit spherical surface was processed to introduce approximately 16 µm of aspheric departure using a Q-forge platform.

A large 150 mm polishing wheel and D11 MR fluid were selected to maximize removal rate and minimize overall cycle time. MRF achieved material removal rates exceeding 30 µm per minute, making direct aspherization practical without the need for aspheric grinding or pre-polishing steps. After a single aspherization run, the optic was left with a controlled residual error suitable for final figure correction.

This approach significantly simplifies the manufacturing process for precision aspheres. By eliminating specialized grinding equipment and reducing intermediate steps, MRF enables faster turnaround and lower overall production cost for complex optical surfaces.