Glass Polishing Experiments Using Magnetorheological Fluids

A pre-prototype magnetorheological (MR) finishing machine has been constructed at the Center for Optics Manufacturing. It consists of an electromagnet, a trough for MR fluid containment and a work spindle (see Figures 1 and 2). A glass part is mounted on the spindle, positioned within the trough and above the magnet pole pieces. Polishing occurs on the surface of the glass as a function of the movement of polishing abrasives through a zone of high pressure, created by the action of the magnetic field on the MR suspension[1]. Polishing slurry in the zone of high pressure is continually refreshed by the rotation of the trough. By rotating the work spindle, an annular ring is polished out on the part (see Figure 3). The entire lens surface is polished out by adjusting spindle tilt (theta, in Figure 2) and dwell time.