Discharge current effect on machining characteristics and mechanical properties of aluminum alloy 6061 workpiece produced by electric discharging machining process

In this study, machining characteristics and mechanical properties of aluminum (Al) alloy 6061 were investigated with variations in discharge currents in electrical discharge machining. The machining characteristics included the electrode wear rate, material removal rate, and roughness. Mechanical properties such as the fatigue life and surface hardness were also discussed in this work. Experimental results showed that better fatigue property of the electrical discharge machined workpiece could be obtained when the discharge current was 15 A; meanwhile, the thickness of the white layer was around 19 µm. The relationship between the thickness of the white layer and the fatigue lifetime had a very strong positive correlation. Furthermore, the repeatability and stability of the machining process were explored by the quality control chart and Shewhart control chart. The results indicated that the electrical discharge machining process under optimum operating conditions was a well-controlled procedure and stable over time.