非球面表面形状的线测量技术

On-Machine Measurement of Aspherical Surface Profile

描述了一种在超精密磨削机床上基于误差分离法的非球面表面形状精密测量系统 .首先 ,论述了一般用于平面形状测量的两点法不能直接用于非球面形状测量的原因在于测头的设置误差会引起很大的形状测量误差 .提出了先通过两点法测量平面形状得出机床的运动误差 ,然后对测量非球面形状的另外一个测头的输出进行补偿以得出正确的非球面形状 .用此系统测量了一个直径为 3 0mm的非球面镜头的表面形状 .

This paper describes accurate surface profile measurement of an aspherical lens on an ultra-precision grinding machine using the error separation technique. At first, it is verified that the two-probe method, which has been previously developed for separation of the surface profile and the scanning error in on-machine measurement of flat surface profiles, cannot be directly employed for aspherical surfaces because of the large measurement error associated with the alignment of the probes. A measurement model is then developed for solving this problem. In the model, the scanning error is accurately measured by the two-probe method, which employs two probes (Probes A and Probes B) to scan a flat surface. Another probe (Probe C) is employed to scan the aspherical surface. The accurate profile of the aspherical surface can then be obtained through extracting the scanning error from the output of Probe C. A technique in data processing of the two-probe method is also applied to the measurement of the scanning error. Experiments of scanning error measurement and aspherical profile measurement are conducted on a commercially available ultra-precision grinding machine.