Electric Discharge machining (EDM) is an unconventional electro thermal machining process used for manufacturing geometrically complex or hard material parts that are extremely difficult-to-machined by conventional machining process. The process involves a controlled erosion of electrically conductive materials by the initiation of rapid and repetitive spark discharges between the tool and work piece separated by a suitable gap of about 0.01mm to 0.05mm. The controlled pulsing of direct current between the tool and the work piece produces the spark discharge. The (EDM) process that known today is a result of various researches carried out over the years. This paper presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of (EDM) input parameters on the characteristics of the machined surface and tool wear. The experiments are conducted by varying (EDM) parameters such as current and pulse-on-time. The performance to be measured like material removal rate, tool wear rate, surface roughness, and hardness are assessed.

It is concluded that metal removal rate (MRR), tool wear rate (TWR), surface roughness (Ra) and hardness (HRC) increases with increase in current. But, as the pulse-on-time increases MRR, TWR and SR are decreases. Hardness value increases as pulse on-time increases. The results of this study could be utilized in the selection of optimum process parameters to achieve the desired characteristics of the surface produced by (EDM) when machining (AISI H13) tool steel.