Study On Fabrication Technology Of Nanotwinned Diamond Cutting Tool By Femtosecond Laser

With the continuous development of automotive industry,energy shortage and environmental pollution have become the most difficult problems to be solved.The development of the low friction automobile engine with the surface microstructure is one of the most important ways of energy saving and emission reduction.Ultra-precision turning technology with diamond micro-tools is an ideal way to process the microstructure of engine friction pairs.The hardness of the synthetic nano-twinned diamond(ntD)is two times of the natural diamond and its fracture toughness is extremely high,in addition,its antioxidant temperature is higher than the natural diamond material.In view of the extremely excellent combination property of the nano-twinned diamond,it is of great significance to develop the nano-twinned diamond cutting tools for the antomotive parts processing field.First of all,based on the femotosecond pulse laser processing technology,the theoretical research on femtosecond laser processing nano-twinned diamond have been done in this paper,by taking the nano-twinned diamond as a research object.The principle of femtosecond laser and the mechanism of action of femtosecond laser and diamond are studied,which lays a theoretical foundation for femtosecond laser processing technology of nano-twinned diamond.The single-pulse ablation threshold and multi-pulse ablation threshold model of nano-twinned diamond were deduced by femtosecond laser multi-pulse drilling experiment and the waist radius of the femtosecond laser was calculated.Second,the finite element model of femtosecond laser linear scanning processing nano-twinned diamond was established according to the theory of heat transfer.The temperature field of femtosecond laser processing was simulated by ANSYS software and the effects of different process parameters on the temperature field were studied while the ablation morphology of nano-twinned diamond under different process parameters was obtained.The influence of laser power and scanning speed on ablation morphology was obtained by analyzing the simulation data which provides the technological basis for the femtosecond laser processing experiment of nano-twinned diamond.Finally,the experiment of scanning processing nano-twinned diamond by femtosecond laser under different process parameters was designed.The theoretical calculation of the multi-pulse ablation threshold is verified by experiments.According to the experimental result,the effects of different process parameters on ablation width,depth and surface quality were studied.The optimal combination of process parameters was obtained and the high-efficiency,high-quality femtosecond laser processing technology was obtained.In addition,Based on the process parameters obtained by the linear scanning process experiments,the manufacture of the nano-twinned diamond micro-cutting tool with arc edge have been done and the techniques foundation of femtosecond laser processing technology for nano-twinned diamond micro-tools was established.