微透镜阵列单点金刚石车削补偿技术

Single point diamond turning and compensation for micro-lens array

为了提高微透镜阵列单点金刚石车削的加工精度与一致性,提出了加工误差的理论模型,并针对其补偿方法进行了理论分析和实验研究。将微透镜阵列加工等效为自由曲面加工,通过建立单点金刚石慢刀伺服切削模型,计算了理论曲面在每一个切削点处沿切削方向的曲率半径;结合刀具等效倾斜角模型和机床加工时延模型,进一步得到了慢刀伺服切削微透镜阵列误差面形的理论预测值。然后,使用原位测量设备测量处理得到实际加工误差,将面形误差理论值与实际加工误差测量值比较,并将面形误差理论值预补偿到加工程序中。实验结果表明,面形误差理论值与实际加工误差测量值具有一致性,两者偏差在[-0.7μm,0.3μm];补偿加工后微透镜阵列的PV值从5.4μm降低到0.6μm。所提出的微透镜阵列的单点金刚石车削加工与补偿方法能够预测误差面形,显著提升面形精度与一致性。

To improve the efficiency and consistency of machining micro-lens arrays using single point diamond turning,a theoretical model of surface residuals was proposed in this study.A compensation method for the model was then studied.The micro-lens array was regarded as a freeform surface.The radius of curvature at each cutting point along the cutting direction was calculated by establishing an slow slide servo(SSS)cutting model.Combined with the tool equivalent tilt angle and lathe delay models,the theoretical surface residuals of the freeform array in SSS were obtained.Subsequently,the actual surface residuals were measured and processed using in situ measurement.The theoretical and measured surface residuals were then compared and the surface residuals were compensated for in the machining program.The theoretical surface residuals are consistent with the actual ones,with an error range of[-0.7μm,0.3μm].The peak to valley(PV)value is reduced from 5.4μm to 0.6μm after compensation.Therefore,the single point diamond turning and compensation method presented in this study is able to predict the surface residuals and significantly improve machining accuracy and consistency.