Study On Distributing Characteristics And Figuring Method For Medium-high Frequency Errors In Deterministic Optical Manufacturing

Compared with the traditional optical machining methods, the deterministic optical manufacturing technology can obviousy improve the machining accuracy and efficiency of optical mirrors. However, more medium-high frequency (MHF) errors will produce in this process due to the utilization of small polishing tools. These errors will severely influence the optical performances, thus they must be strictly controlled.In this dissertation, the influences of MHF errors on optical performances are analyzed with different frequencies and distributions, and the control ability on MHF errors is studied when the machining parameters are different in the magnetorheological finishing (MRF) process. The main contents are as follows:1) The relationship between deterministic manufacturing errors and typical optical performances are studied. The frequency bands of errors are divided by using two- dimensional discrete wavelet transform method, and the influences of MHF errors on optical performances are analyzed on emphasis.2) According to the characteristics of derministic optical manufacturing, the distributing region, the changing feature and the producing cause of different frequency errors are analyzed. Aimed at the distributing characteristics, the MHF errors are decomposed into local sub-region errors and annular sub-region errors, and the influences of different sub-region errors are analyzed.3) The MHF errors are quantificationally evaluated by using power spectral density function in deterministic optical manufacturing, the control ability of processing parameters is analyzed on different frequency errors in the MRF process, and the result will provide a guideline on the improvement of MHF errors.4) The machining experiments on typical plane mirror and spherical mirror are accomplished by choosing suitable processing parameters in MRF process. The measuring results show that the accuracy of machined mirrors are very high, the MHF errors are effectively controlled, and the PSD satisfy the requirements of ISO on the condition of precision polishing.