Optimization of Parameters for Diameter Accuracy in Wire Electric Discharge Grinding for Micro Machining of Tungsten Rods

In this study the process of Wire Electric Discharge Grinding was carried out with a precise, flexible and corrosion resistant submerged rotary spindle which was designed, fabricated and installed in a five axis CNC Wire Electric Discharge Machining in order to produce free form surfaces on micro rods. The tungsten was taken as a work material since it is hard to machine through conventional process. Based on the literature survey the following four factors such as the spindle speed, pulse off time, peak current and wire speed are considered for obtaining high diametrical accuracy. By Taguchi parametric design the array was designed and experimental trials were taken by machining an Ø2.0mm tungsten (W) pin to Ø0.40mm under various set of parameter combinations. The S/N ratio analysis was carried out to find the optimum machining parameters and significant parameters affecting the diametrical accuracy. The analysis of variance was used to analytically verify the significant parameters. Finally it is concluded experimentally and statically that the significant parameters affecting the diameter accuracy are spindle speed and pulse off time.