Quilting error correction on large ULE lightweighted optics.

The Q22-950F can finish large flats, spheres, aspheres, off-axis sections, and true freeform geometries optics up to 950mm in diameter.

Magnetorheological finishing presents a unique capability for polishing large lightweighted optics. As a process that exerts very little normal force, MRF can correct "quilting" errors from previous polishing steps without inducing any of its own. In this example, the quilting error from the seven-cell lightweighted structure is clearly visible on the 3mm thick facesheet. After polishing on the Q22-950F, the quilting error was removed. While the customer provided the metrology, QED's subaperture stitching interferometers are capable of measuring flats up to ~340mm and could also have provided this measurement.