磷酸二氢钾晶体的立轴端面可磨性研究

Study on grinding KDP crystal with the vertical spindle face grinding machine

磷酸二氢钾(potassium dihydrogen phosphate,KDP)晶体是公认的性能优良的光学晶体,尤其是大口径(≥400mm)的KDP晶体,是激光核聚变中不可缺少的光学元件之一。KDP晶体从生长到制造成为光学元件,需要经过切割、精密加工、超精密加工及镀膜等多道工序,加工周期长。本研究通过立轴端面磨床对KDP晶体进行磨削加工试验,对比不同粒度的树脂结合剂金刚石砂轮(D7、D36、D91、D151),在不同的加工参数下(主轴转速、工件进给速度、磨削切深),对表面粗糙度Ra、表面微观形貌的影响,研究KDP晶体磨削的可行性,为实现以磨代车(抛),缩短KDP光学晶体元件制造周期奠定基础。

Potassium dihydrogen phosphate(KH_2PO_4 or KDP),an recognized optical crystal,has been widely used in laser nuclear fusion projects due to its good quality of large electro-optic coefficient and large diameter(≥400 mm).From growth to processing into optical element,it requires procedures of cutting,precision machining,ultra-precision machining,coating and so on,and the processing period is long.In this paper,the grinding process of the KDP crystal is carried out using the vertical spindle face grinding machine.The influences of different particle sizes resin bonded diamond wheels(D7,D36,D91,D151)on the surface roughness and surface micro-topography under different processing parameters(spindle speed,feed speed,grinding depth)are compared.The feasibility of KDP crystal grinding is studied which lays the foundation for realization of grinding instead of turning(polishing)and shortening the manufacturing cycle of KDP optical elements.