in wear of sapphire single crystal have been periodically studied
since the early '60's. It was noted that wear rates for c-cut samples
with small degrees of tilt from surface normal showed a large degree
is an excellent process for studying polishing anisotropies in optical
materials. By examining a series of c-cut sapphire plates using
different MR fluids, we demonstrated that the difference in material
removal rates for polishing "up" or "down" the
basal planes could be significantly reduced by the choice of polishing
A. Kozhinova, S. R. Arrasmith, J. C. Lambropoulos, S. D. Jacobs,
and H. J. Romanofsky, Exploring Anisotropy in Removal Rate
for Single Crystal Sapphire Using MRF, in Optical Manufacturing
and Testing IV, edited by H. P. Stahl (SPIE, Bellingham, WA,
2001), Vol. 4451, pp. 277285.
is easily seen with numerous MR spots.
3-minute spots placed around the part in different directions
with respect to C-axis tilt and the center of the part.
1 and 11 show the same amount of removal, as indicated by
the data and the similar coloration of inside-spot area.
spots 5 (dark blue color) and 6 (light yellow) show a dramatic
difference in spot depth for the same spotting time.