Control method of polishing errors by dwell time compensation

A method for controlling the spatial-frequency errors in computer controlled optical surfacing process (CCOS) is brought forward. The mechanism of middle and high spatial-frequency errors in polishing is studied, error factors are assorted, and the wear function of polishing tool, concentration changing function of slurry and system revised function are established. Then the Preston function is modified, and a dwell function algorithm is established based on the discrete last-squares method. The application shows that, the method can reduce residual errors on optical surface, and thus improve the CCOS precision.