Study On Material Removal Mechanism Of Aviation Carbon Fiber Composites In High Speed Milling

Carbon fiber reinforced resin matrix composites are employed in aerospace and other advanced manufacturing fields because of its excellent mechanical properties such as “light weight and high strength”.In the process of machining,CFRP is prone to a series of damage and low cutting efficiency.Due to the constitutive characteristics of composites and the complexity of high speed cutting process,the material removal mechanism of CFRP in high speed milling is not clear.It is a vital issue in the manufacturing to improve the cutting efficiency and surface quality of composites by high speed cutting and to explore the mechanism of high speed cutting of composites.Based on the characteristics of material,fracture mechanics and cutting mechanism,this paper studied the characteristics of cutting force,cutting stress,surface roughness and surface topography in the high speed cutting process of CFRP by means of high speed cutting experiments and finite element simulation,and expounded the influence mechanism of cutting parameters and fiber cutting angle on cutting force and surface quality.Finally,the material removal mechanism of composites in high speed cutting was revealed.In this paper,the high speed milling experiments of unidirectional CFRP in typical orientations were conducted to explore the influence mechanism of fiber cutting angle and cutting parameters on the cutting force.Then,the mapping relationship between fiber cutting angle,cutting parameters and cutting force was established,and the influence weight of each parameter on cutting force was obtained by orthogonal experiments.In the high speed cutting process of composites,the fiber cutting angle and cutting parameters had a significant impact on the cutting force,the cutting force was reduced in the cutting process by the high speed cutting.In view of the 3D-Hashin failure criterion and the degradation mode of material stiffness,the progressive damage finite element model of cutting force in CFRP high speed cutting was established by applying Abaqus.The reliability of the model was verified by cutting experiments,and then the effects of fiber cutting angle on the cutting force,cutting stress and material failure were discussed.The results showed that the model error was less than 5%,and the cutting angle had a significant effect on the cutting force,cutting stress and material failure.In addition,the main mode of material failure was shear failure in the cutting process,and the failure mainly occurred in the cutting area.The machining surface quality of CFRP was characterized by three-dimensional roughness and SEM.Then,the effect of fiber cutting angle and spindle speed on the surface quality of composites were explored,and the chip formation and tool wear in the cutting process of composites were analyzed.Results pointed out that high speed cutting can effectively reduce the surface roughness and improve the surface quality,the fiber cutting angle was the primary factor that led to the difference of surface roughness and surface micro characteristics.Under the cutting edge load,the failure mode of carbon fiber under different stress was distinct.Furthermore,combined the fiber mechanical properties and cutting mechanism,the material removal mechanism for CFRP cutting was revealed.