Study of machining characteristics of Nimonic 80A using wire-cut EDM

Wire Electrical Discharge machining (WEDM) is very complex process due to the presence of large number of process variables involved. WEDM is used for machining of hard material parts that are extremely difficult to machine by conventional machining process. The present work investigates the influence of machining parameters on material removal rate (MRR) and cutting speed (CS) for machining of Nimonic 80A using wire-cut electrical discharge machining (WEDM) process. Two important process responses MRR and CS have been studied as a function of four different control parameters namely Pulse-on time (Ton), Pulse-off time (Toff), Input current (IP) and servo gap set voltage (SV). It was found that that and metal removal rate (MRR) and cutting speed (CS) increases with increase in Ton and IP while decreases with increase in Toff and SV. Experimentation was planned using "one factor at a time approach". WEDM is an electro thermal process in which metal is eroded from the workpiece using a series of sparks generated by a thin wire electrode in the presence of dielectric. WEDM can easily machine any conductive metal irrespective of their hardness. Wire-cut EDM process generates a large amount of heating at the machining area which results in melting and vaporization of metal from localized area. The dielectric is fed continuously to the machining area to flush away the eroded particles (Mahapatra and Patnaik, 2007). Figure 1 shows the schematic representation of the WEDM.