等距面误差对抛物面廓形精度的影响

在抛物面加工中,对工件的已加工表面上引起的等距面误差进行了理论分析和计算。用三点法求出理论曲线的最小平移距离,再用两点距离法建立磨具加工面上各点误差的数学模型,该模型适合各类二次曲线磨具等距线误差的计算。实验结果表明磨具等距线误差变化范围为 0~0.7 μm,成形精度能满足大多数工件的面形精度要求,且磨具两端的最大误差为0.624 14 μm,同时,等距面误差随刀具或磨具的磨损量,以及抛物面的曲率的增大而增大,结果证明了该方法的有效性。

Effect of equidistant surface errors on parabolic shape accuracy

In machining a parabolic shape workpiece, equidistant surface errors will be produced on the machined workpiece surface. This paper analyses and calculates this error. The minimal distance of theoretical curve is gained by the three-point method, and the mathematical model of all points of the lapping tool’s surface is established by the two-point method, which can be applied in calculating equidistance-curve error of all the conic of lapping tool. The simulation results indicate that equidistance-curve error of lapping tool changes from 0 to 0.7 μm, which can satisfy surface precision requirement of the most components. The maximal error of beginnings and ends of lapping tool is 0.624 14 μm, and the equidistant surface error increases with tool wearing and abrasives tool wearing and curvature of parabolid increasing. The results show the validity of this method.