ABSTRACT
Surface roughness is an important constituent of the surface characteristic of the machined component. Wire electrical discharge machining (WEDM) is a widely accepted process for machining of nickel-based material. This material is important in high-temperature applications; they are also known as heat-resistant material. Nickel-based material is the only material to retain high strength even after continuous exposure to extremely high temperatures with excellent surface stability. Because of these properties, the machining of these materials is difficult. New and alternate methods of machining have propelled researchers to develop and use new processes of machining, which promoted the use of WEDM process. The pulse on-time, pulse off-time, wire tension and wire feed are the input process parameters of WEDM. In this paper, an attempt has been made to investigate the effect of the WEDM parameters on the surface roughness of Monel 400 alloy using brass wire with a diameter of 0.25 mm as electrode.
The experiments were conducted based on four factors on five level central composite designs. The mathematical model was developed using response surface methodology (RSM) technique. The effects of input process parameters are discussed. The optimized process parameters were identified. The results show that the surface roughness increases with an increase in pulse on-time and decreases with pulse-off time and wire tension. The average deviation between predicted and measured value was close to the target value. The minimum surface roughness of 1.49 µm was obtained using the process parameter combination of pulse on-time 10μs, pulse off-time 6μs, wire tension1000 g and wire feed 5 m / min.
