大尺寸轴对称非球面磨削精度建模和分析

Precision Model and Analysis of Large Axisymmetric Aspheric Grinding

运用刚体运动学理论和坐标变换,建立高精度平面磨床的通用误差模型。针对大尺寸轴对称非球面工件的高精度加工要求,采用光栅式平行磨削的加工方式。根据这种非球面磨削方式和高精度平面磨床的结构,给出影响大尺寸非球面加工精度的主要误差因素,并建立基于这些主要误差因素的大尺寸非球面误差模型。对主要单项误差的分析表明,磨床的直线度及定位精度误差和圆弧半径误差是影响面形分布的主要因素,而面形误差值则是各个误差综合作用的结果。通过误差模型可以预测面形误差分布和大小,并可以利用该模型进行补偿加工。加工试验结果表明,该模型能够比较准确地预测面形精度,补偿试验后精度提高,说明利用该模型进行补偿是有效的。

The general error model of high precision surface grinder is presented by using rigid body kinematics theory and coordinate transformation.To meet the machining requirement of large axisymmetry aspheric lens,the grating parallel grinding method is adopted.Considering high precision surface grinder structure and the main error factors affect the machining accuracy of large aspheric,a large axisymmetric aspheric error model is proposed,which can be used to predict surface accuracy and compensation grinding.The main error factors are discussed and it is shown that the straightness error,positioning error and arc radii error are main errors that effect surface error distribution,meanwhile,surface error value is the mixed result of each individual error.The experiments are carried out and in agreement with the theoretical results.The grinding experiment shows that the model can well predict surface accuracy and surface accuracy is improved after compensation grinding