Research On Key Technologies Of Aluminium-based Silicon Carbide Two-dimensional Ultrasonic Vibration Assisted Lapping

In recent years,the requirements for precision machining of aluminum-based silicon carbide(SiCp/Al)have been continuously improved.Because aluminum-based silicon carbide has the advantages of high strength,low density and high wear resistance,it is widely used in many fields,such as aerospace,automotive and electronics.However,aluminumbased silicon carbide is a typical difficult-to-machine material.The traditional processing method can improve the surface quality,but the processing time is long and the processing cost is high,which undoubtedly increases the difficulty of precision processing.Twodimensional ultrasonic vibration lapping technology has unique advantages in difficult-tomachine materials.Its intermittent lapping can reduce the grinding force,reduce the temperature of the lapping area,further reduce the surface roughness and obtain the ideal material removal rate.At the same time,the processing time is reduced and the processing cost is reduced.In this paper,the processing characteristics of the two-dimensional ultrasonic vibration device are firstly studied.Based on the Kinetic energy theorem and the Hertz contact theory,a two-dimensional ultrasonic vibration-assisted lapping force model is established.Then,finite element simulation is used to simulate the removal form of material,surface defect type.Grinding force is changed with processing parameters.The influence of machining parameters on surface roughness and material removal rate is studied by twodimensional ultrasonic vibration-assisted lapping experiments.Finally,the workpiece surface defect types and lapping head wear patterns are observed and analyzed by a scanning electron microscope and a ultra-depth-of-field three-dimensional microscope.The main research contents of this paper are as follows:(1)Two-dimensional ultrasonic vibration-assisted lapping processing mechanism is studied.The two-dimensional ultrasonic vibration device of characteristics is studied.The machining characteristics and removal mechanism of two-dimensional ultrasonic vibrationassisted lapping are analyzed.Lapping force is broken down into chip forming force,particle breaking force and friction force.A two-dimensional ultrasonic vibration-assisted lapping force model is established by the Hertz contact theory,Kinetic energy theorem and Griffith strength theory.(2)Two-dimensional ultrasonic vibration-assisted lapping of aluminum-based silicon carbide removal characteristics is studied by using simulation.The surface defect formation mechanism and chip types of two-dimensional ultrasonic vibration-assisted lapping of aluminum-based silicon carbide are simulated using finite element simulation.The removal advantages of two-dimensional ultrasonic vibration-assisted lapping and the influence of machining parameters on surface quality are studied by simulation.The influence law of machining parameters on lapping force is revealed.(3)Two-dimensional ultrasonic vibration-assisted lapping of aluminum-based silicon carbide is investigated experimentally.Two-dimensional ultrasonic vibration-assisted lapping experiments are designed.The advantages of improving the surface quality of aluminum-based silicon carbide by two-dimensional ultrasonic vibration-assisted lapping are investigated.The influence of processing parameters on material removal rate and surface quality is revealed.The lapping head damage pattern is analyzed.The advantages of reducing the damage of the lapping head by two-dimensional ultrasonic vibration-assisted lapping are studied.