Estimation of MRR and thermal stresses in EDM process: a comparative numerical study

In this work, a new finite element (FE) EDM model was established to estimate the material removal rate (MRR) and thermal stresses in the AISI 316L and AISI D2 steels. Numerical simulation of EDM process was performed using dynamic coupled thermo-mechanical analysis considering plane-strain assumption. Different thermal loading conditions were tested during numerical simulation of the discharge phase while altering heat input size function. Time-dependent plasma channel radius forms with and without discharge current effect have been investigated for each material. The appropriate discharge radius function was identified for each grade of steel based on the comparison of numerically predicted MRR-discharge current diagrams with experiments from previously published work. It was found that the heat input size functions that take into account the effect of discharge current are the most suitable for the prediction of the MRR. Moreover, thermal stresses were predicted via a cooling analysis. The confrontation between experiment and the computed thermal stress profiles for the AISI 316L in the same erosion regime was deemed satisfactory.