Influence of anisotropy of KDP crystal on the surface shape deviation of slice by diamond wire saw

Abstract

KDP crystal is an important functional crystal material used in the fields of laser frequency conversion. Slicing is the first process of KDP crystal processing and the KDP crystal is usually sliced by the diamond wire saw. As KDP crystal is an anisotropic material, the properties of KDP contact with different diamond grits on the diamond wire saw during slicing would be different. The anisotropic properties may lead to the deviation of the diamond wire saw in the thickness direction and form the surface shape deviation of slice. The surface shape deviation would affect the amount of material to be removed and the accuracy of crystal positioning. The commonly used crystal planes of KDP crystal are the (001), the double-frequency, and the triple-frequency crystal plane. In this paper, a model of diamond wire saw considering the anisotropy of KDP crystal is established to obtain the sawing forces, while the anisotropic properties of KDP crystal used in slicing are obtained through coordinate changes. The obtained sawing forces are then applied to the diamond wire saw to obtain the surface shape deviation. Besides, the influence of the tension force on the surface shape deviation is also considered. Based on the established model, the variation rule of surface shape deviation with the feed angle of diamond wire saw is obtained. Results in this paper can reduce the surface shape deviation of slice caused by the anisotropic properties of KDP crystal.