On performance enhancement of electrochemical discharge trepanning (ECDT) process by sonication of tool electrode

In the present work, an attempt has been made to use ultrasonic energy to augment the performance of electrochemical discharge trepanning (ECDT) process. The effect of various process parameters such as applied voltage, pulse on time, tool rotation rate and power rating on quality characteristics (over cut (OC) and depth of penetration (DOP)) of machined work materials has been experimentally investigated. The underlying process mechanism for ultrasonic assisted ECDT (UA-ECDT) process is proposed by considering the high speed images of gas film, mathematical formulations and electrical signals as evidences. A comparative analysis between ECDT and UA-ECDT has also been performed. The experimental results reveal that the integration of ultrasonic vibrations in ECDT process facilitates evacuation of the sludge/debris from the machining zone. Also, it generates thin and stable gas film over the tool electrode. Therefore, the use of UA-ECDT improves the energy channelization index (ECI), and exhibits 10 times more ECI than the ECDT process. The second-order mathematical models have been developed to determine the relationship between input process parameters and quality characteristics (OC and DOP). The developed models are in good agreement with the experimental results and exhibit an average error of less than 3%. Additionally, a desirability approach has been employed to conduct the multiobjective optimization for the minimization of OC and maximization of DOP. The parametric combination of applied voltage of 60 V, pulse on time of 3 ms, tool rotation rate of 42 rpm and power rating of 17% is recommended to perform the UA-ECDT process.