大口径高陡度离轴非球面精磨阶段的数控加工

Computer controlled manufacturing during fine grinding stage of highly steep off-axis asphere with large aperture

对大口径高陡度离轴非球面的数控加工过程中遇到的矢高变化率太大、磨头去除特性改变等技术难题进行了深入细致的研究,并提出了相应的解决方法。首先,通过坐标变换降低高陡度离轴非球面的矢高变化率;然后,给出了磨头沿非球面的法线方向进行数控加工的具体实施方法;最后,对轮廓检验的结果进行修正,使之在法线方向投影,从而使数控加工能更加准确有效地控制面形误差收敛。给出了数控加工实例,精磨阶段达到面形精度PV:10.502 8μm,RMS:0.829 3μm。结果表明,提出的方法在工程中完全可行,并有较高的收敛效率。

By studying and discussing on the technical puzzles of the high sagitta variation rate and the seriously changed removal characteristic of lap in computer controlled optical surfacing of highly steep off-axls aspheres with large aperture, the practicable solutions are given. Decreasing the sagitta varia- tion rate through coordinates transforming, the computer controlled manufacturing method that the lap grinds along the normal of the asphere is carried out, then, revising the figure testing result to project it on the asphere＇s normal, and the revised result is used in computer controlled optical manu- facturing to converge the figure error more precise and effective. Finally, a manufacturing example is given in the final figure precision of PV. 10. 502 8 μm and RMS.0. 829 3 μm during fine grinding stage. The results show that the methods are practical and have even higher convergence efficiency.