Effect of Distilled Water and Kerosene as Dielectrics on Machining Rate and Surface Morphology of Al-6061 During Electric Discharge Machining

Abstract

Electric Discharge Machining (EDM) is widely used for manufacturing complex metal parts. The machining parameters like dielectric fluid, electrode material, current, voltage and pulse rate during EDM are controlled to obtain desired Material Removal Rate (MRR), and it also affects the surface morphology of manufactured components. In this research, the effect of changing machining parameters, dielectric fluid (distilled water and kerosene) and electrode materials (copper and graphite) on the surface morphology of Al 6061 T6 alloy during EDM is investigated. It is observed that the distilled water reacts with the molten aluminum and produces deep pits / voids on the surface due to the liberation of hydrogen gas. A microcrack network is seen radiating from the edge of these pits. It is believed that the very high thermal conductivity of distilled water is responsible for the microcrack network and reduced material removal rate when compared with non-reactive kerosene oil.

Keywords

• dielectric
• surface morphology
• electrode material
• electric discharge machining
• aluminium alloy 6061 T6
• material removal rate
• scanning electron microscope