Research On Key Technology Of Ultrasonic Vibration Assisted Milling Of SiCp/Al Composites

As a kind of composite material,SiCp/Al has been widely used in aviation and aerospace systems,automobiles,electronic packaging materials,weapon systems,optical instruments and other high-tech industries due to its high specific strength and stiffness,low density and coefficient of thermal expansion,and has gradually replaced the traditional metal materials.However,SiCp/Al is different from ordinary materials.The addition of SiC particles makes the cutting force large in the actual processing process,which makes the tool wear extremely serious,and finally forms a poor surface quality.Due to the difficult machinability of SiCp/Al composites,the traditional processing method is no longer suitable.Ultrasonic vibration-assisted milling technology,as a kind of ultrasonic vibration cutting technology,can obtain a certain separation time in a vibration cycle to achieve the effect of intermittent cutting.This intermittent cutting feature can reduce cutting force,improve heat dissipation,extend tool life,and obtain better surface quality.This paper selects SiCp/Al as the research object,applies vibration in the direction of the spindle,and then performs ultrasonic vibration milling on it.The research content of the paper mainly includes the following aspects:(1)The kinematics analysis of ultrasonic vibration assisted milling theory is carried out.Based on the circumferential expansion model,the separation characteristics are analyzed,and the separation critical conditions are solved.The contact rate model is established and programmed by MATLAB.The influence of amplitude,frequency,spindle speed and cutter helix angle on the contact rate is analyzed.(2)Establish an ultrasonic milling force model for SiCp/Al composites.The milling force includes the cutting matrix forming force and the particle breaking force.The cutting matrix forming force takes into account the softening effect and contact rate of the ultrasonic vibration on the matrix flow stress and is based on the friction between the two bodies.And three-body rolling wear established the friction angle model of the tool-chip interface.The particle breaking force is established based on Griffith theory,and its force in the radial direction and cutting direction is determined according to the slip line field theory.(3)The cutting simulation analysis of SiCp/Al is carried out based on ABAQUS software.The 3D milling simulation analysis process based on the homogeneous model simulates the milling force under ultrasonic conditions and ordinary conditions,and compares and analyzes the influence of the changes of various cutting parameters.The simulation analysis process of bevel cutting based on the micro model simulates the removal mechanism of the material and studies the surface quality.(4)On a five-axis ultrasonic processing machine tool,the SiCp/Al composite material was subjected to ordinary milling and ultrasonic vibration-assisted milling experiments,and the milling force,groove bottom surface roughness,chip morphology and surface micro morphology were analyzed respectively.