Study on workpiece surface forming mechanism by successive discharges during USV-MF complex–assisted WEDM-LS process

Abstract

Ultrasonic vibration and magnetic field complex–assisted techniques have been used in low-speed wire electrical discharge machining (USV-MF complex–assisted WEDM-LS) to improve workpiece surface quality. In this paper, a novel approach, which is based on a three-dimensional successive discharge model, is proposed to investigate the interaction between the workpiece surface forming and the vibration of a wire electrode. The influence of USV-MF complex–assisted technique on workpiece surface forming and vibration of a wire electrode is considered by modifying the parameters in this model. During the simulation, the discharge location, which is determined by the minimum gap width in each step, makes it possible to calculate the vibration of a wire electrode in the successive discharge process. Workpiece surface topographies are obtained at the end of simulation, as well as the vibration responses of the wire electrode and the distribution of discharge locations. The simulation results show that the USV-MF complex–assisted technique can increase the vibration amplitude of the wire electrode by 1.12%. The surface roughness values decrease more than 10% and the distribution uniformity of discharge location increases in the USV-MF complex assisted WEDM-LS process. The simulation results are verified by experiments and simulation error of surface roughness value is less than 5% compared with the experimental results. The analysis shows that the servo feed speed increases more than 50% with surface quality unaltered in the USV-MF complex–assisted WEDM-LS process.