Influence of electrode temperature on electric erosion pit morphology during cool electrode EDM

Abstract

The mechanism of material removal through cool electrode electrical discharge machining (EDM) was investigated in this study by using single pulse discharge method. The influence of electrode temperature on the electric erosion pit morphology on the surface of the electrode and workpiece was analyzed. Finite element simulation was conducted on the temperature field between the electrode and workpiece under different electrode temperatures, and the simulation results were verified through a single pulse experiment. Under the same single pulse discharge parameters, when the electrode temperature was −20, 20, and 60 °C, the electric erosion pit diameter on the electrode surface increased to 290, 350, and 403 μm, respectively; the change in electric erosion pit diameter on the workpiece surface was small, and the corresponding values were 690, 705, and 718 μm. However, the bulge of the electric erosion pit on the surface of the workpiece became increasingly obvious, and the surface became unsmooth. The results of the single pulse experiment and the finite element simulation were identical. A comparative experiment involving the machining of Ti-6Al-4V titanium alloy was conducted with cool electrode and conventional EDM. Electrode wear, surface roughness, and machining efficiency were analyzed. Compared with that in conventional EDM, electrode wear decreased by 24.5%, the material removal rate increased by 14.16%, and surface roughness decreased by 14.14% in cool electrode EDM. Reducing the electrode temperature changed the electric erosion pit morphology on the electrode and workpiece surface, reduced electrode wear, improved surface processing quality, and increased processing efficiency.