侧铣不可展直纹面模具原理性加工误差计算方法

Algorithm for Calculating Theoretical Errors of Undevelopable Ruled Surface Model in Flank Milling

分析了侧铣不可展直纹面模具的原理性加工误差的来源及特点,提出通过计算被加工表面各点到刀具旋转轴扫掠面的距离以确定误差分布,为刀位主动补偿和后续加工提供了依据。采用有限次离散和平面替代的方法求取点到曲面之间的距离,根据求解精度要求确定曲面最小离散次数,提高了计算效率,平面替代法将问题简化为可精确求解的点到平面的距离问题。实例通过与三坐标测量结果的对比验证了算法的可靠性。

The sources and characteristics of theoretical machining errors for an undevelopable ruled surface model in flank milling are analyzed, and a new algorithm is proposed to determine the error distribution by computing the distance between the points of the ruled surface and the cutter axis swept surface, which provides an important basis for initiative compensating of the cutter positions and farther machining. The distance between a point and a surface is obtained through subdivision and substitutive planes, and the efficiency is improved by determining the minimum subdivision number of a surface depending on the precision requirement, A complex surface is substituted by planes, in order to simplify the case to the computation of distance between a point and a substituted plane, which can be calculated accurately. The reliability of the algorithm is verified by comparing with the 3 coordinates measured result.