Sonication of tool electrode for utilizing high discharge energy during ECDM

The use of high applied voltage during the electrochemical discharge machining (ECDM) process forms a thick gas film and generates high discharge energy on film breakdown. This results in polarization and evaporation of electrolyte at the tooltip. Consequently, the ECDM process results in a low depth of penetration (DOP) with a large hole overcut (HOC). The present investigation is an attempt for utilizing high discharge energy during the ECDM process using sonication of tool electrode. The experimental results reveal that sonication regulates the gas bubble departure radius and thereby controls the gas film thickness. Besides, an increase in the electrolyte concentration reduces the gas film thickness and results in the generation of high-intensity and high-frequency electric discharges. Sonication results in improved electrolyte replenishment and sludge removal. A mathematical model is developed to understand the effect of process parameters on the gas bubble departure radius. Also, the present investigation compares ultrasonic-assisted electrochemical discharge machining (UAECDM) and the general ECDM process. Sonication of tool electrode during UAECDM process exhibit improvement in material removal rate (MRR) by 11.13%, DOP by 27.17% and reduction in HOC by 23.10% over the ECDM process.