Fabrication Of Polycrystalline Cubic Boron Nitride Tool Based On Femtosecond Laser

There are a large number of friction pairs in the core parts of the power system and transmission system of the car.These friction pairs will not only reduce the fuel economy of the car,but also shorten the service life of the car.Modern tribology thinks that machining some special microstructure on the surface of the object can effectively reduce the friction loss between the objects.The new type of bindless polycrystalline cubic boron nitride has higher hardness and thermal stability than ordinary polycrystalline cubic boron nitride.Therefore,based on the new polycrystalline cubic boron nitride material,the superhard polycrystalline cubic boron nitride tool was prepared by femtosecond laser micromachining system.In this paper,the deep mechanism of the removal of polycrystalline cubic boron nitride by femtosecond laser is studied,and the specific process of the removal by femtosecond laser is analyzed theoretically.By means of femtosecond laser monopulse experiment,the theoretical model of ablative threshold is derived,and the ablative threshold of polycrystalline cubic boron nitride monopulse is calculated.By means of femtosecond laser linear groove experiment,the influence law between the incident power,scanning speed and depth and width of the linear groove of femtosecond laser is studied,and the morphology and formation mechanism of the linear groove are theoretically analyzed.By means of femtosecond laser cutting edge experiment,the surface quality of the cutting edge is theoretically analyzed,and the influence law of femtosecond laser on the cutting edge roughness and cutting edge sharpness under different parameters is analyzed by detecting the surface roughness and cutting edge sharpness of the cutting tool.Based on removal mechanism of femtosecond laser,the machining scheme of polycrystalline cubic boron nitride cutter was designed,the interference phenomenon of femtosecond laser was solved,the machining direction,incident direction and the machining sequence of front and rear cutter surfaces of femtosecond laser were determined.Finally,the polycrystalline cubic boron nitride arc-edge tool was prepared andits quality was tested.The results showed that the blunt circle radius of the tool edge was0.67μm and the average roughness of the tool surface was Ra 217 nm,which met the design requirements.