大口径碳化硅反射镜高效磨削实时补偿技术

Real-time compensation of high efficiency grinding for the large aperture mirror

碳化硅陶瓷作为光学材料已在空间相机反射镜中得到了广泛应用,而在碳化硅反射镜磨削加工过程中,砂轮会产生径向磨损,导致砂轮的形状精度发生较大变化,这将直接影响碳化硅反射镜的加工精度和加工周期。为保证磨削质量,需要对砂轮磨削产生的误差进行补偿。通过工艺试验,获得不同加工参数和加工时间下的误差补偿值,再利用五轴联动数控机床并结合UG(NX)软件快速建立母线误差曲线的补偿模型,从而实现整个磨削过程中的磨削误差实时补偿。针对Φ1.6m口径碳化硅同轴非球面反射镜,经过磨削补偿加工后的反射镜面型误差PV为27.4μm,RMS为5.5μm,实现了轻质碳化硅光学元件的安全、高效、高精度磨削加工。

As an optical mirror material,silicon carbide ceramics has been widely used in space camera.But in the grinding process of silicon carbide mirror,the grinding wheel will have great change in the shape accuracy due to the radial wearing,which has a direct impact on the silicon carbide mirror processing cycle.In order to ensure the grinding quality,it is necessary to compensate wearing error.The error compensation value under different processing parameters is obtained by tests;And the compensatory model of error curve on generatrix was established by using the five-axis CNC machine combined with UG(NX)software.It is applicable to realize the real-time compensation of grinding errors.ForΦ1.6 m silicon carbide coaxial aspheric mirrors,the surface form accuracy attained to PV 27.4μm and RMS 5.5μm after error compensation processing,which means that a safe,high efficiency and high precision grinding for the lightweight silicon carbide was achieved.