Path segment division and feed-rate solution in ion beam figuring

For high-precision deterministic processing, the equal profile of dwell-time and an adaptive step size algorithm are presented in this paper to solve processing path feed-rate. Firstly, we analyze the issues that exist in the conventional and other step algorithms. And then, for these issues, the adaptive step size algorithm is introduced. Finally, a f600 mm plane reflector element is taken to be an instance. The result shows that after four combinations of processing, the surface accuracy of peak-valley (PV) value and the root mean square (RMS) value was reduced to 4.81 nm (/131.6) and 0.495 nm(/1278.4) from 110.22 nm (/5.7) and 13.998 nm (/45.2) (=632.8 nm) respectively in the 98% caliber of the element. By using the new algorithm in our ion beam figuring machine, we obtained a reflector optical element whose PV value was less than /70 in 100 mm caliber.