Numerical and experimental study of discharge mechanism in the electrochemical discharge machining process

Electrochemical discharge machining (ECDM) is a modern machining process which can be applied to the special materials with unique properties. Glass and ceramics are major applications of the mentioned process. ECDM includes variant mechanisms of material removal (MR) in which discharge (thermal) mechanism plays the most important role in comparison to other mechanisms. This research introduces a new approach to simulate the discharge phenomenon and the consequent volume of removed material. Despite previous researches which implemented a simple thermal simulation based on Gaussian distribution, the current model considers different constitutive phenomena of discharge (plasma) and presents a more realistic numerical model. Electric current, electromagnetic field, and heat transfer are major effective phenomena on the plasma behavior which are considered in simulations and evaluated simultaneously, for all components of ECDM configuration. Special experiments are designed to validate the predictions of the model. The single discharge mode of the ECDM process is applied and two main parameters of hole diameter and MR are measured to compare with computed results. Consecutive actual images and current signal diagrams determined 37 V as a critical voltage to appear the discharge phenomenon. Results showed that the developed model has errors of 14.33 % and 31.52 % in the prediction of hole diameter and MR, respectively.