Experimental investigations of energy channelization behavior in ultrasonic assisted electrochemical discharge machining

Abstract

The present work analyzes the energy channelization behavior during the triplex hybrid process of ultrasonic assisted electrochemical discharge machining (UA-ECDM). In this work, a high frequency (35 kHz) low amplitude configuration of ultrasonic vibrations has been employed to investigate the ECDM process. The underlying energy channelization mechanism during the UA-ECDM process has been demonstrated while considering the evidence from high-speed imaging of gas film, discharge signals, optical images, simulation results, structural and compositional analysis of machined work material. The controlled assistance of ultrasonic in the ECDM process shifts the energy paradigm from the edges to the center of the tool electrode. Moreover, in the UA-ECDM process, the material is removed by additional cavitation and high-pressure evacuation actions along with melting, vaporization, and chemical etching phenomenon. An improved frequency of spark discharges indicates the initiation of breakdown phenomena in upward and downward strokes of ultrasonic vibrations. Energy channelization index and specific energy were taken as the performance indicators. The incorporation of ultrasonic vibrations consumed 2.23 times less energy than the ECDM process to remove a unit material per unit time. The energy channelization index with ultrasonic assistance is also improved by five times. The incorporation of ultrasonic vibrations in the ECDM process reduced the heat-affected zone and produced the machined surfaces without the alkali deficient layer. The article reports the parametric effect and their contribution to the response characteristics. The involvement of high electrochemical discharge energy with ultrasonic assistance exhibits better results in higher material removal rate and depth/diameter ratio due to the parallel provision for the evacuation of sludge/debris and electrolyte replenishment in the machining zone.