Multi-channel aerosol dielectric electrical discharge machining ablation based on discrete electrode

Abstract

The electrical discharge machining (EDM) ablation processing energy comes from the chemical energy released by metal combustion, which is much higher than in conventional EDM. In singular pulse voltage, only one discharge channel induces and activates metal substrate. Thus, the processing energy is concentrated, which impedes the improvement of material removal efficiency and workpiece surface quality. Multi-channel EDM ablation in aerosol dielectric is proposed in this study. Multi-channel discharge induces multi-spot ablation, which not only expands the scope of the ablation region and improves the machining efficiency of EDM ablation, but also disperses the discharge energy and enhances the surface quality of EDM ablation. The discrete electrode in which the method is based contained multiple copper tube electrodes. Each electrode was electrically insulated and connected to the pulse generator through a resistance. It generated multi-channel discharge in singular pulse voltage. In this study, the mechanism of multi-channel discharge was elucidated, and the machining characteristics of multi-channel aerosol dielectric EDM ablation were evaluated. On the basis of the results of the experiment by using Cr12 die steel as the workpiece, it was concluded that relative to that in aerosol dielectric EDM ablation, the material removal rate in multi-channel aerosol dielectric EDM ablation was improved by 92%. This rate was 3.12 times higher than that obtained in multi-channel inner jetted EDM and nearly 10 times higher than that in inner jetted EDM. The surface quality was improved as well.