Papers by Author: Xian Suo Cao

Abstract: Potassium dihydrogen phosphate (KDP) crystal is widely used in navigates spaceflight, national defenses, energy sources and information technology fields based on its excellent nonlinear optical property. Surface quality of KDP crystal influences the property and life time of the device directly. So detection and analysis of the damage induced during machining process, especially on subsurface, should be solved. In this paper, surface damage of the KDP crystal, which machined from #600 grinding wheel with different feed rate, was detected by optical microscope. Cross section and selective etching were used to analyzing the subsurface damage. Because #600 grinding wheel mainly used in coarse grinding and the removal rate is high, the results shown that there was obvious scratch, crack and crushing on the machining surface. When the feed rate is 10+m and 40+m, the subsurface damage depth is 7.41+m and 8.96+m corresponding. This study is a kind of guide for following precision grinding, polishing machining time and removal amount.

Abstract: The KDP (Potassium Dihydrogen Phosphate) crystal, used as an important photoelectron part in the laser nuclear fusion system, is a typical kind of hard-to-machine material because of its soft, brittle, anisotropic property and nano-scale requirement for the shape and plane precision. Based on the experiments of the KDP crystal’s grindability, certain process parameters, such as the wheel granularity, the grinding depth and the workpiece’s feeding speed etc., and their influences on the grinding force and the surface roughness of KDP workpiece are analyzed. Furthermore, some KDP crystal’s typical surface damages in grinding are analyzed and some technical approaches to increasing the ultraprecision machining surface quality of KDP crystal are suggested as well.

Abstract: The functional crystal material Potassium dihydrogen phosphate KH2PO4 (KDP for short) is widely used in navigate, spaceflight, national defenses, energy sources and information technology fields because of its excellent non-linear optical property. However, KDP crystal has some disadvantages such as soft, fragile, hygroscopic, anisotropy, thermally sensitive and low rigidity, which make it a most difficult processing material. In this paper, KDP crystal was machined by the wheel grinding. Some equipment, such as Optic microscope, SEM, ZYGO and Raman spectroscope were used to observe and analysis the KDP crystal surface which was damaged during grinding. The results shows that serious nicks, crashes and the press stress appeared on the surface of the KDP crystal after grinding.