Analytical and experimental study of material removal mechanism in turning process by ultrasonic-assisted wire electrical discharge

The increased material removal rate in ultrasonic-assisted wire electrical discharge turning (by∼2 times)was attributed to compressive and rarefying wave front in dielectric and discharge column sliding into plasma channel and molten crater due to applying lateral ultrasonic vibration on the wire. A single discharge was analytically and experimentally studied and the effective forces and factors on plasma channel including Lorentz force¡ increase of pressure and surrounding vapor ionization of plasma channel¡ elongation of molten crater due to lateral displacement of wire and creation of positive and negative pressures of the ultrasonic wave on molten crater were investigated. Experiments were performed in different machining parameters of voltage and power with and without ultrasonic vibrations. By using ultrasonic vibration¡ the plasma density was increased due to decrease of bubble growth. The current density was increased and pressure drop in the end of discharge was increased. As a result¡ a great amount of the material was exploded out of the crater due to bulk boiling. The plasma channel sliding was elongated the molten crater on workpiece surface¡ which leads to material removal increase.