Magnetorheological finishing (optics)

Article By:

Dumas, Paul QED Technologies, Rochester, New York.

Last reviewed:2005

DOI:https://doi.org/10.1036/1097-8542.YB051760

Magnetorheological finishing (MRF) is revolutionizing the way that optics are manufactured. The process utilizes polishing slurries based on magnetorheological fluids, which exhibit an increase in viscosity in the presence of a magnetic field. These fluids are mixed, pumped, and conditioned in their liquid states, then converted to a semisolid state to create a stable and conformable polishing pad when applied to the workpiece surface. Material removal rates can be adjusted over a wide range by changing various MRF process parameters, enabling the removal, with each iteration, of more than 10 micrometers of material, or as little as 10 nanometers. MRF offers a deterministic and flexible polishing and final figuring process that can simultaneously improve surface form, roughness, and integrity (by minimizing subsurface damage and residual stress in the crystal lattice of the lens from grinding), and it can be used on a wide variety of materials and part geometries.

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