Effects of the properties of workpiece, electrode and dielectric fluid in micro-EDM drilling process

In the last years, the miniaturization of the components took place in many industrial sectors such as automotive, aerospace, biomedical. Significant industrial efforts were made to support this new manufacturing trend in order to propose effective solutions. In this scenario, Electrical Discharge Machining (EDM) finds use for a variety of drilling applications in automotive, aerospace, biomedical sectors on different materials such as stainless steels, titanium alloys and others metals regardless of their mechanical properties. The material removal occurs thorough electrical discharges between the electrode tool and the workpiece in a dielectric fluid. Dielectric, electrode and workpiece are the main factors involved during the discharges. Aim of this paper is to analyse the effects of the physical and thermal properties of the dielectric fluid and material of electrode and workpiece on the process performance of micro-EDM drilling operation. Two traditional (water and mineral oil) and an unconventional (vegetable oil) dielectrics were tested on sheets of stainless steel and titanium alloy using both brass and tungsten carbide electrodes. The performance were evaluated considering the material removal rate, the tool wear ratio and the geometrical characteristics of the holes. The results were correlated to the properties of the dielectric, electrode and workpiece. The results can be useful to both improve the knowledge and allow the optimization of the process.