The drilling of Al2O3 using a pulsed DC supply with a rotary abrasive electrode by the electrochemical discharge process

The electrochemical discharge machining (ECDM) process has the potential to machine electrically non-conductive high-strength, high-temperature-resistant (HSHTR) ceramics, such as aluminum oxide (Al₂O₃). However, the conventional tool configurations and machining parameters show that the volume of material removed decreases with increasing machining depth and, finally, restricts the machining after a certain depth. To overcome this problem and to increase the volume of material removed during drilling operations on Al₂O₃, two different types of tool configurations, i.e., a spring-fed cylindrical hollow brass tool as a stationary electrode and a spring-fed cylindrical abrasive tool as a rotary electrode, were considered. The volume of material removed by each electrode was assessed under the influence of three parameters, namely, pulsed DC supply voltage, duty factor, and electrolyte conductivity, each at five different levels. The results revealed that the machining ability of the abrasive rotary electrode was better than the hollow stationary electrode, as it would enhance the cutting ability due to the presence of abrasive grains during machining.