Material removal mechanism of alumina ceramics with powder-mixed electrochemical discharge-drilling hybrid machining

Engineering ceramics have excellent properties such as high hardness and strength, resistance to high temperature, wear and corrosion, However, these ceramics also pose great challenges to processing techniques. A novel method of powder-mixed electrochemical discharge-drilling hybrid machining (PMECDDM) for alumina ceramics was proposed in this paper. The thermal removal mechanism of alumina ceramics during the hybrid machining process were analyzed. The temperature distribution on alumina ceramics under the action of the single-pulse electrochemical discharge was obtained based on a thermal-fluid coupling multiphysics simulation model. The axial force during the material removal process in mechanical drilling (MD) was comprehensively analyzed. Experiments were conducted under constant force feed condition to investigate the micro-hole machining performance of alumina ceramics by different machining methods. Experimental results revealed that a new form of discharge was generated after the introduction of the micro copper powder into the electrochemical discharge-mechanical drilling hybrid machining process, which increased the local discharge energy and strengthens the softening effect of the discharge on alumina ceramics. Compared to MD, the machined surface of PMECDDM exhibited fewer brittle fracture areas, resulting in improved surface quality. Compared with the conventional electrochemical discharge-drilling hybrid machining (ECDDM), the machining efficiency of PMECDDM was increased by approximately 47 %.