Study on the Pulse Energy Mechanism and Material Removal Characteristics of EDM Based on Magnetic-Levitation Micro-Motion Compensation

Material removal rate and material removal per unit energy are key indicators for evaluating EDM efficiency. By studying the relationship between these indicators and EDM discharge parameters, it is possible to improve machining efficiency and material removal performance. Taking the EDM structure with magnetic-levitation micro-motion compensation as the research object, this paper combines the dynamic levitation position of the moving electrode with the formula of the gap between electrodes and establishes a mathematical model among the macroscopic feed position of the spindle, the dynamic compensation position of the moving electrode, the pulse energy and the heat flux density of the workpiece. It also analyzes the conversion process of single-pulse energy and the Gaussian heat flux density on the workpiece surface. By combining the response surface method, the mapping relationship between electrode discharge parameters and material removal rate, as well as the material removal amount per unit energy, was obtained. Finite-element simulations and single-factor continuous machining experiments show that the MRR is more sensitive to the low-voltage current and pulse interval, whereas the material removal per unit energy exhibits a non-monotonic dependence on the discharge parameters. Specifically, it shows a decreasing trend followed by an increasing trend with increasing low-voltage current and pulse width, whereas the opposite trend is observed with increasing high-voltage current and pulse interval. These results suggest that a moderate low-voltage current, a relatively high-voltage current, a short pulse width, and an appropriate pulse interval are favorable for magnetic-levitation micro-motion-compensated EDM to achieve both high MRR and high material removal per unit energy.