Research Of The Effect Of KDP Crystal Anisotropy On The Cutting Surface Roughness

On the high-energy multi-path Inertial Confinement Fusion solid laser driver, laser weapon and other advanced equipment, only the large-size non-linear electrical-optical crystal KDP with high accuracy can be used to make optical frequency multiplication transition and Pockel's switch parts. The basic request of ICF laser driver to the KDP crystal surface roughness is Rms≤5nm. However, the anisotropy of KDP crystal has a great effect on the surface roughness. So, it is important to study the effect of KDP crystal anisotropy on the surface roughness.This paper analyzes the indention and dividing experiments and concludes KDP crystal can be machined with plastic method. A new ultra-precision cutting model is established using the mechanism of cutting surface formation. Then, according to KDP crystal characteristics, a theoretic model of shear angle of KDP ultra-precision machining is built with the principle of the maximum specific energy of shear deformation. We get the rule of cutting force variation in ultra-precision using the KDP characteristics and the cutting angle model above.A dynamic cutting system of cutting tool and work piece is established with machining tool vibration which changes cutting force vibration to relative displacement of cutting tool and work piece. A three-dimension surface roughness model is built according to the surface topography formation in the consideration of tool radius and machining tool vibration. Surface topography of different plane is gotten and the simulation results are analyzed.Finally, the cutting experiments of turning KDP crystal are done on the ultra-precision machining tool of HCM-I and the cutting force in the process is collected. After analyzing the cutting force with FFT, we finds the cutting force vibration caused by anisotropy is obvious and the With the FFT analysis to the cutting force signal at the turning and the regulation of vibration is accord to the cutting force of theoretical computing. The surface roughness vibration of experiments gotten is accord to the simulation results.