Modelling of material removal rate in the magnetic field and air-assisted electrical discharge machining

In the present research work, an attempt has been made to develop the mathematical model to predict the material removal rate in the electrical discharge machining process when the assistance of air and magnetic field is provided together. The proposed model incorporates the physical phenomenon occurred during electrical discharge machining such as the plasma column expansion and reduction in the mean free path of electron in the plasma column due to magnetic field. In addition, the model incorporates the effect of air on the material removal rate. The developed model correlates the material removal rate with the process parameters such as the peak current, pulse duration, duty cycle, air pressure and magnetic flux density. The experimental data were used to evaluate the constants for district processing conditions. The relation between air pressure and breakdown voltage in the liquid-air mixed dielectric has been established experimentally. The obtained expression of material removal rate has been validated for the experimental conditions other than that used for obtaining constants. The results show less than 10% error in the prediction by the model over the respective experimental values.