Spiral polishing is a traditional process of computer-controlled optical surfacing. However, the additional polishing
amount is great and the center polishing amount is difficult to control. At first, a simplified mathematics model is
presented for magnetorheological finishing, which indicates that the center polishing amount and additional polishing
amount are proportional to the length and peak value of magnetorheological finishing influence function, and are
inversely proportional to pitch and rotation rate of spiral track, and the center polishing amount is much bigger than
average polishing amount. Secondly, the relationships of "tool feed way and center polishing amount", "spiral pitch and
calculation accuracy of influence matrix for dwell time function solution", "spiral pitch and center polishing amount"
and "peak removal rate, dimensions of removal function and center removal amount" are studied by numerical
computation by Archimedes spiral path. It shows that the center polishing amount is much bigger in feed stage than that
in backhaul stage when the head of influence function is towards workpiece edge in feeding; and the bigger pitch, the
bigger calculation error of influence matrix elements; and the bigger pitch, the smaller center polishing amount, and the
smaller peak removal rate and dimensions of removal function, the smaller center removal amount. At last, the polishing
results are given, which indicates that the center polishing amount is acceptable with a suitable polishing amount rate of
feed stage and backhaul stage, and with a suitable spiral pitch during magnetorheological finishing procedure by spiral
An optical system with double beam interference system was designed to measure the movement of nano-particles in fluid with laser speckle technology. In order to investigate the influence of the scattering light generated from liquid surface on speckle patterns, the liquid surface contour was dynamically detected by WYKO during nano-particle movement. The result demonstrates that the fluctuation of fluid surface is slight. Meanwhile, in order to further analyze this effect, a piece of ground glass was employed. The process of ground glass to be polished to optical glass was studied and tested continuously using WYKO and laser speckle technology. And then, the speckle patterns generated from kerosene fluid surface were studied.
By contrast, the results show that, the fluid surface is transparent to the measurement wavelength. The influence of the surface of fluid can be neglected. Furthermore, the conclusion illustrates that laser speckle technique is an effective and reliable method to study the movement of nano-granular in fluid.