Frequency spectrum features of material removal function in optical manufacturing

This paper proposes a novel wheel-shaped grinding/polishing tool, which is designed to be controlled on both the self-rotation around its axis and the co-rotation around vertical axis Z at the specified speeds respectively. Therefore, the surface material of the workpiece can be removed by virtue of self-rotating motion. On the other hand, the co-rotating motion will also change the manufacturing orbit continually. To analyze the characteristics of the tool, material removal in the manufacturing zone on the workpiece surface is first established through theoretical modeling. Subsequently, a good evaluating method, i.e. power spectral density, for analyzing the frequency spectrum features of material removal function in computer-controlled optical grinding and polishing is introduced in detail. By simulation, the power spectral density of the material removal function was cut into several parts, some frequency with low amplifies of material removal function were removed, and the modified material removal function reflected the actual processing status, which was helpful in removing some residual high frequency errors on the surface of the workpiece. Finally, the high amplitude such as at high frequency of 110mm ^-1 and 210mm^-1 was reserved and some other low amplitude frequencies were removed.