内渐进镜片加工中的过切判据的研究

摘要

Some progressive addition lenses are over cut during the processing.This paper proposes a method.It obtains the least value of the surface curvature radius of the free surface by calculating the parametric equation of the double three spline surface.The least value of the surface curvature radius is calculated by a 3D software.We study the reason of lenses why it can be processed.The result indicates that if the surface curvature radius of some points is less than the radius of machine tool,the surface can not be processed.%针对内渐进镜片在加工过程中出现过切的情况，提出一种判断方法。该方法使用双三次样条曲面参数方程计算自由曲面各点曲率半径最小值，通过三维软件对曲面曲率半径进行计算，研究镜片在机床上实现加工的判据。由分析和计算表明，若曲面加工范围内存在某些点的曲率半径小于给定的机床刀具半径，则机床无法加工内渐进镜片的曲面。