Study On Wire Electrical Discharge Machining (WEDM) With Ultrasonic Vibration Of The Wire

Wire electrical discharge machining(WEDM) is a thermoelectric process whereby material is removed by a succession of electrical discharge occurring between an electrode and a workpiece which are immersed in a dielectric liquid medium(distilled water or kerosene). Through the development over the past half century, the technology has become more maturity and achieved advanced technical standard. It's broad capabilities have allowed it to encompass aerospace,automotive and mould industries and virtually all areas of conductive material machining. Especially, WEDM has played an important role in the fields of machining exotic and high strength and temperature resistive materials with intricate shapes and profiles.Generally, the machining efficiency of WEDM is considered to be rather low, and the breakage of wire would disturb machining process that will obviously increase the production cost, reduce the machining rate and deteriorate the machining precision. This problems are solved through WEDM assisted by ultrasonic vibration of the wire. The mathematical model to describe the vibration state of wire under the action of ultrasonic vibration and discharge force has been established, through which computer simulation has been made to study the influence of ultrasonic excitation on the vibration state of wire and distribution of discharge spots. The machining mechanism and technical rules have been studied through computer simulation and experiment.The conclusions are as follows: (1) high machining efficiency can be be obtained by the compound process, the machining mechanism is: ultrasonic vibration prevent colloid system depositing in the kerf and improve dielectric circulation which facilitates machine-debris removal and dielectric deionization quickly. Therefore, short circui, transition discharging, stabilization electric arc discharging are evidently reduced and high utilization of pulse can be gained. (2) WEDM assisted Ultrasonic vibration can make surface roughness small and machined surface quality super,which is mainly attributed to: stabilization telectric arc discharging and transition discharging evidently reduce, and melted materials cohered on the surface decrease. (3) Ultrasonic vibration can make discharge spots distributed much more evenly along the span of the wire, so the breakage chance of wire can be decreased. That insure machining process more steady, continual and precise. (4) The compound process increase dimensional error of the workpiece, and reduce overall dimensions.The research in this paper will benefite the practice application of the WEDM assisted ultrasonic vibration of the wire. It brings the experiment data for the foundation of the exper system.