Analysis On Mechanical Property Of Anisotropy Of Crystal KDP And Simulation Of Cutting Process In The Ductile Mode

As an excellent nonlinear optical crystal, KDP (Potassium Dihydrogen Phosphate is shorted for KDP) crystal is used in laser and nonlinear optics field. But KDP crystal is difficult to machine because the KDP is soft, deliquescent, brittle, strong anisotropy and sensitive to the change of temperature. Presently, KDP crystal is often machined using Single Point Diamond Turning technology in ductile regime. So the study for ductile regime turning of KDP crystal is important to both the basic cutting theory and improving the machining technology of KDP crystal. It is important to research the ductile regime turning of KDP crystal and the influence of anisotropy to cutting deformation and surface quality.In this paper the spherical nano-indentation experiment is proposed by ourselves and carried out to obtain the yield stress and stress-strain curve of crystal KDP. At the same time the friction coefficient with different orientation on (001) plane is studied through the scratch experiment. The finite element method is used to verify the experimental result.In order to research the influence of the material anisotropy to the machining of KDP crystal, the finite element cutting three-dimensional model of KDP crystal with anisotropy is established according to obtained parameter. The cutting process of KDP crystal with different crystal plane and different orientation is simulated by the model. The variation rule of cutting force with different crystal plane and different orientation is studied, the result shows that the cutting force on the planes (100) and (001) has strong anisotropy, there is change of the two periods with the variation of cutting direction form 0°to 180°, and that the value and fluctuation margin of cutting force are all different. The value of cutting force on the plane (110) is constant, it means that the plane (110) is isotropic. The rule of the cutting force accords with the theoretic fluctuate rule of shear angle. The cutting simulation with different cutter's rake angles is done to research its influence to the cutting force and the tensile stress in the cutting field, The simulation shows that the fluctuate of cutting force caused by the anisotropy can be restrained by the smaller cutter's rake angle, and the tensile...