Analysis And Experiment Research On Vibration Characteristics Of Wire Electrode And Temperature Field In Ultrasonic Vibration And Magnetic Field Complex Assisted WEDM-LS

Shape memory alloy(SMA),which is widely used aerospace and biomedical industry,has excellent mechanical properties and high shape memory recovery rate.However,the machining of shape memory alloy with traditional machining method(turning and grinding)is difficult due to its special physical properties and it is difficult to guarantee machining accuracy and surface quality.Low speed wire electrical discharge machining(WEDM-LS),which is a non-traditional machining method without macro cutting force,can machine any conductive materials regardless of mechanical characteristics and has high machining accuracy and quality.Thus,WEDM-LS is fit for the machining of shape memory alloy.However,the machining efficiency of WEDM-LS is low and modern manufacturing industry has higher requirements for the quality of WEDM-LS.Hence,ultrasonic vibration and magnetic field complex assisted WEDM-LS is presented in this paper,through the research on vibration characteristics of wire electrode and temperature field,the mechanism of ultrasonic vibration and magnetic field complex assisted WEDM-LS is studied,combined with experiments,which improves machining efficiency and surface quality significantly.Firstly,force analysis of wire electrode in USV-MF WEDM-LS is conducted then the vibration mathematical model is established.The vibration response is obtained according to the model and the simulation of the vibration of wire electrode is conducted using MATLAB,and the effects of ultrasonic vibration and magnetic field on the vibration of wire electrode are studied.Simulation results show ultrasonic vibration and magnetic field change the vibration shape of wire electrode and the distribution of discharge points is more uniform.Secondly,the movement trajectory of charged particles is obtained based on the force analysis of charged particles in magnetic field assisted WEDM-LS(MF WEDM-LS).The formula of discharge current in MF WEDM-LS is derived based on the length of movement trajectory and the effects of magnetic field on WEDM-LS are studied theoretically.Then,the formula of energy distribution ratio,heat flux and radius of discharge channel are derived according to the formula of discharge current,and the model of temperature field in MF-WEDM is established.Next,the simulation of temperature field is carried out using ANSYS,the effects of pulse width and peak current on the size of discharge crater are studied and compared with traditional WEDM-LS.The prediction models of material removal rate and surface quality are established based on the simulation results afterwards.Finally,experiments of traditional WEDM-LS,USV WEDM-LS,MF WEDM-LS and USV-MF WEDM-LS are carried out,the effects of ultrasonic vibration and magnetic field on WEDM-LS are studied from perspectives of material removal rate,surface roughness and three-dimensional topography.Experiment results show USV-MF WEDM-LS has the best machining performance,which can improve machining efficiency and surface quality at the same time.