Surface modification of SKD 61 by electrical discharge coating (EDM/EDC) with multilayer cylindrical electrode and jatropha curcas as dielectric fluid

Electrical Discharge Machining (EDM) is the most extensive non-conventional material removal processes used. In recent years, EDM researchers have been explore several sparking efficiency improvement methods including some unique experimental concepts that begin from the EDM traditional sparking phenomenon. This paper reports the use of layered cylindrical electrodes combined with jatropha curcas as dielectric fluid which is not widely used in the EDM process. The results are compared with the EDM process using kerosene dielectric fluid and single electrode (conventional). Dielectric fluid jatropha curcas is expected to substitute the commonly used dielectric fluid. Dielectric strength was tested by the impulse method. Furthermore, the EDM process is measured using surface roughness and microhardness of white layer values at various cutting conditions on the material SKD 61 as an indicator. The highest value of white layer hardness using jatropha curcas dielectric fluid is provided by three layers of electrodes, whereas the lowest is resulted of two layers of electrodes. Meanwhile, the use of kerosene dielectric fluid, the highest hardness value is achieved by two layers of electrodes, and the lowest is produced by three layers of electrodes. This study shows that jatropha curcas dielectric fluid is potential to be used in the EDM process since it produces a smoother surface and higher white layer hardness value.