A novel approach to plasma channel radius determination and numerical modeling of electrical discharge machining process

In this investigation, a single discharge of electrical discharge machining (EDM) has been simulated using finite element method (FEM) to obtain the temperature distribution on the workpiece surface. The dimensions of discharge crater on workpiece surface were calculated using temperature distribution profile, and a FEM model for material removal rate was developed for EDM process. Also, the plasma channel radius was obtained by a newly developed mathematical model and used at simulation stage. Considering the maximum error of 8.2%, between the recast layer thickness obtained by numerical and experimental approaches, the numerical results were used to study the influences of pulse current and pulse duration as input parameters on plasma efficiency in ejection of the molten materials from molten puddles on machined surface and recast layer thickness. The results showed that enhancement of pulse current leads to increasing plasma flushing efficiency and increasing pulse duration decreases plasma flushing efficiency and enhances recast layer thickness.