To achieve ultra-precision optical elements, this paper research on removal-function of bonnet tool polishing from the theoretical and experimental aspects. Firstly, based on the principle of bonnet tool polishing, we calculate the velocity distribution through the geometric relationship, the pressure distribution through finite element model. Then, according to Preston formula, the removal function model is built. Finally, experimental system of bonnet tool polishing is built to accomplish removal-function experiment. And the experimental result indicates that removal-function model is reliable.

Based on the mechanism of magnetorheological finishing(MRF), a material removal model was established. The dwell time function was solved by Jansson-Van Cittert algorithm to accomplish the kernel module design. Thus the control software of aspheric optics in MRF was designed. In order to verify accuracy of the processing control software, experiments were carried out on large aperture aspheric optics and the wavefront error of elements was achieved rapidly convergence. It is proved that the software could control the whole polishing process accurately.

Large aspheric elements in giant laser facility are fabricated using computer controlled rapid polishing technology. The technological parameters are main influencing factors of efficiency. Base on Preston hypothesis, linear relationship of material removal with polishing pressure, polishing velocity and other conditions are established. According to the material removal function model of computer controlled rapid polishing, the removal function is simulated using MATLAB software. The influencing factors of volume removal efficiency are analyzed. In practice, the optimum polishing parameters are eccentricity 0.4, rotational velocity of principal axis 330 rpm, rotational velocity of polishing pad -600 rpm.

In this paper, an on-machine profile measuring system for aspheric ground surface was presented, which involved data processing with improved two-dimensional weighted mean filtering and free form surface fitting. To verify the reliability of this system, a calibration experiment was done by comparing the measuring results of Ф320mm mirror between the WYKO 24 inch interferometer and the on-machine measuring system. The experiment results show that the on-machine measurement is effective and it can provide foundation for compensation machining. By comparing the measurement experiment results of the Keyence LC2430 with the WYKO interferometer, it is demonstrated that the deviation of PV is better than 0.23μm and the deviation of RMS better than 0.08μm.

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