计算机控制光学表面成形技术的驻留时间算法

为了提高镜片的加工精度与效率,利用计算机控制光学表面成形技术(CCOS)的抛光方法对光学镜片进行抛光全过程动态仿真。根据Preston方程建立材料去除函数模型,对抛光过程中压力、转速以及工件与抛光磨头相对半径比对抛光去除速率的影响进行分析。为建立球面镜片的动态全过程仿真,结合卷积原理,推导加工残余误差与去除函数和驻留时间三者间的线性关系,根据镜片的对称性,将元素个数从2m+1点简化为m+1点,以提高运算效率。最后为获得仿真最小残余误差,采用非负最小二乘法求解驻留时间。结果表明,材料去除速率函数类似于高斯分布,抛光后能使镜片面形误差收敛,对模拟表面进行仿真,半径为100mm的镜片其初始表面形貌粗糙度的均方根值从0.467μm收敛到0.028μm,轮廓最大高度从6.12μm收敛到1.48μm。对实测表面进行加工仿真同样令其表面形貌粗糙度的均方根值从3.007μm收敛到0.107μm,轮廓最大高度从160.73μm收敛到13.76μm,因此提出的驻留时间求解方法对于球面镜片抛光全过程动态仿真有一定的可行性。

Dwell time algorithm for computer controlled optical surfacing technology

In order to improve the precision and efficiency of the lens manufacture,this paper describes that the optical lenses using computer controlled optical surfacing technology (CCOS) performs the whole process of dynamic simulation.The material removal function model is established according to Preston equation to analyze the influence of pressure,rotating speed and the ratio of radius of the workpiece and the spherical polishing tool over the material removal rate.To establish a dynamic simulation of the whole process of the lens,considering the principle of convolution to derive a linear algebraic equation of the residual error,removal function and dwell time and its symmetry,we can reduce the number of points from to that improves operational efficiency.Finally,a non-negative least squares method gives a solution to minimize residual error.The results showed that the material removal rate was similar to a Gaussian distribution function.It can make that the lens surface shape error converges after polishing.Structure surface's radius is 100mm,and its initial root-meansquare is 0.467m converging to 0.028 μm.Peak value converges from 6.12μm to 1.48 μm.The simulation of the measured surface also make its initial RMS from 3.007 μm converge to 0.107μm and PV converge from 160.73 μm to 13.76 μm.Thus,the proposed dwell time solving method is feasible for whole process of dynamic simulation of spherical polishing.