Simulation Analysis And Experimental Study Of Axially Ultrasonic Vibration Turning

With the development of science and technology,the demand for high-performance materials in national defense,aerospace industry is more and more urgent,and the requirement for dimensional accuracy and processing quality of materials is higher.Because these new materials have high hardness,brittleness and high stress-strain characteristics,traditional cutting could not meet the requirements of processing quality and processing cost.As a new type of machining technology,ultrasonic vibration assisted cutting has good technological effect in improving the surface quality of cutting,reducing cutting force and cutting temperature.It is an important technology in the field of new material processing.Axial ultrasonic vibration assisted turning is to apply a feed direction ultrasonic vibration to the tool on the basis of ordinary turning.changing the contact mode between the cutting edge of the tool and the machined material,which will change the cutting force and the machined surface quality.In this paper,finite element simulation and experimental research methods are used to compare the axial ultrasonic vibration-assisted turning with conventional turning.The effects of cutting parameters and vibration parameters on cutting force and surface integrity are explored.The ultrasonic vibration system was established,and the experimental platform of axial ultrasonic vibration assisted turning was built.The axially ultrasonic assisted vibration cutting process is simplified to a two-dimensional cutting model,and the motion trajectory of cutting edge is studied by using MATLAB software.Through theoretical calculation,the structure size and material of the ultrasonic oscillator are designed,and the stability of the ultrasonic oscillator is analyzed by using simulation software.Through the inherent mode analysis and harmonic response analysis of the ultrasonic oscillator,the amplitude ratio of the ultrasonic oscillator and the displacement response of the output end of the horn are obtained.Constitutive model of machined material,cutter contact friction model and separation criterion of workpiece and chip are established under the cutting simulation software AdvantEdge.Cutting force,cutting temperature and strain rate of ultrasonic vibration turning and traditional turning under two-dimensional cutting simulation are compared,and the influence of ultrasonic vibration on cutting process is analyzed.The influence of cutting parameters and vibration parameters on cutting force is studied by cutting experiments.Using variance analysis,it is proved that the ultrasonic amplitude has a very significant effect on the change of average main cutting force in vibration cutting process.An empirical model of surface roughness in ultrasonic vibration assisted turning was established by orthogonal experiment,and the regression equation and model coefficients were tested.The empirical model has a high accuracy in the range of experimental parameters.The influence of feed,ultrasonic amplitude,cutting speed and cutting depth on surface roughness in the process of ultrasonic vibration is explored.The mechanism of surface residual stress in ultrasonic vibration-assisted turning was analyzed from the viewpoint of thermo-mechanical coupling and plastic deformation effect caused by physical stress in metal cutting.The variation of surface residual stress with cutting parameters and vibration parameters was studied by single factor experiments.It was confirmed that ultrasonic vibration could increase the residual compressive stress of machined surface and improve fatigue resistance and corrosion resistance.By observing the micro-morphology of the machined surface,the axial ultrasonic vibration turning is helpful to remove the scales,scratches,plough grooves and other surface defects in the traditional cutting process,and to improve the quality of the machined surface.