Design of binderless grinding wheel with positive rake angle and fabrication used femtosecond laser ablation for grinding soft and brittle crystals

Abstract

Recent research has proved that precision grinding method can be used for machining the soft and brittle crystals, such as KDP, KTP, and LN et al, achieving much higher process efficiency than the single-point diamond cutting method. However, poor ground surface quality and impurity embedding are encountered when grinding these materials. In this paper, a binderless diamond grinding wheel with positive rake angle of cutting edges is innovatively designed and fabricated by femtosecond laser ablation on CVD diamond. To evaluate the effects of cutting edge rake angle on the grinding performance, two grinding wheels with 5° and 0° rake angles are fabricated. Grinding outputs of these two wheels, including ground surface roughness, surface microstructure and grinding forces for grinding KDP crystal are compared and analyzed. It is found that, positive rake angle effectively improved the ground surface quality, i.e. the ground surface roughness achieved using the wheel with 5° rake angle is about 1/10 of that obtained using the wheel with 0° rake angle. The positive rake angle wheel also effectively reduced the level of grinding forces and specific grinding energy. The grinding forces using the wheel with 5° rake angle are about 2/3 of that with 0° rake angle. It is also found that the wear depth of the binderless diamond grinding wheel with 5° rank angle is about 30 μm, with about 20 μm blade corner radius, and the wear depth of the wheel with 0° rank angle is about 20 μm, with about 10 μm blade corner radius, after removing 1000 mm3 KDP material.