Effect of surfactants and additives on electrical discharge machining of Reaction Bonded Silicon Carbide

In this paper, a comparative study of Electrical Discharge Machining (EDM) on Reaction Bonded Silicon Carbide (RB-SiC) by using different types of surfactants and additives powder has been carried out. The EDM oil type Low Smell (LS) used in the experiment was mixed with different surfactants namely Span 20, Span 80, Span 83 and Span 85. Additives powder that were used to verify the machining performance are Carbon Nanofiber (CNF), Carbon Nano Powder (CNP) and Carbon Powder (CP). These powders are different in terms of size and shape. In this study, the change of material removal rate (MRR), electrode wear ratio (EWR), surface roughness and spark gap was investigated. The result shows that the surfactant and additives added dielectric fluid not only improves MRR and spark gap, but also reduces the EWR. The addition of surfactant might prevent the agglomeration of powders, and caused the powders dispersed well in the dielectric fluid. Therefore, electro discharge frequency will be increased, leading to a higher MRR and spark gap. However, the improvement of surface finish is not significant after addition of surfactant. For comparison, combination of surfactant Span 80 and CNF is more significant in improving machining efficiency of RB-SiC compared to the others type of surfactant and additives.