高陡度非球面磨削亚表面损伤深度规律

具有高陡度非球面特性的光学元件可以明显改善光学系统的空气动力学性能, 从而提升和优化系统综合性能。磨削加工方法可以作为此类元件的前期加工工序，而磨削难免会造成零件的亚表面损伤，且在这种高陡度非球面磨削加工中磨削参数是实时变化的，造成整个工件亚表面损伤深度不一致。针对这种情况，建立亚表面损伤预测模型，并结合半球形砂轮磨削的特点，通过理论计算预测非球面磨削亚表面损伤深度分布规律。在此基础上，以热压多晶氟化镁平面为对象进行模拟参数实验，通过磁流变抛斑点法得到各组参数下亚表面损伤深度情况，结果显示损伤深度范围在12.79μm～20.96μm之间，且沿试件半径方向由内向外呈增大趋势，结果与预测模型相吻合。
Deep aspheric optical element can obviously improve the aerodynamic performance of the optical system, thus enhancing and optimizing the comprehensive performance of optical system. The grinding method can be used for primary machining of such elements. However, subsurface damage will be inevitably introduced by this method, and grinding parameters will be changing in real time in the processing of deep aspheric surface, so the depths of subsurface damage of the workpiece are inconsistent. In view of this situation, subsurface damage prediction model was established. Combined with the characteristics of semi-sphere wheels grinding, a theoretical calculation was made to predict distributive regularity of the aspheric grinding subsurface damage depths aspheric characteristics. On the basis of the above work, a simulation experiment on hot-pressing polycrystalline magnesium fluoride plane was carried out. Subsurface damage depths under different conditions of grinding parameters were acquired by the method of magnetorheological finishing spot. Results show that the depth range is between 12.79μm and 20.96μm, which increases from inside to outside along the radius of the workpiece and the results are coincide with previous forecast model.