为了满足光学复杂曲面的精密、高效加工, 提出一种利用空化效应促进射流加工效率的光学表面加工方法——纳米胶体自激脉冲空化射流抛光, 并研制了加工系统。采用流体动力学对纳米胶体自激脉冲空化射流抛光中的喷射过程进行了仿真, 获得了周期为0.3 s的自激脉冲射流典型时刻下加工流场的流体动、静压力、速度、空化效应分布规律。进行了纳米胶体自激脉冲空化射流抛光试验, 结果表明该系统能够产生效果良好的自激脉冲空化射流。采用该方法对单晶硅表面进行加工可以得到表面粗糙度为Ra 0.904 nm(Rms 1.225 nm)的超光滑表面, 此加工表面粗糙度质量与相同加工条件下的普通纳米胶体射流抛光相当, 但其加工效率较普通纳米胶体射流抛光能够提升20%左右, 能够满足光学表面高效精密加工的需要。

An optical surface processing method using the cavitation effect, termed as nanoparticle colloid self-induced pulsed cavitation jet polishing (NPCJP), has been proposed to precisely machine complex optical surfaces with enhanced machining efficiency. The NPCJP system has been developed and simulated by fluid dynamics simulation. The dynamic pressure, static pressure, fluid velocity and cavitation effect of the polishing flow field corresponding to a pulse period of 0.3 s, have been determined. NPCJP jet experiments have been performed and the results show that the NPCJP system can effectively produce self-excited pulsed cavitation jet. NPCJP experiment on a single crystal silicon surface show that supersmooth surface with roughness of Ra 0.904 nm (Rms 1.225 nm) can be obtained. The roughness of the surface obtained using the proposed method is equal to that obtained using the conventional nanoparticle colloid jet polishing method, but the processing efficiency of the NPCJP jet polishing method is higher by about 20%. The results show that the NPCJP method can effectively machine complex optical surfaces.