An experimental parametric analysis on performance characteristics in wire electric discharge machining of Inconel 718

Abstract

Wire cut electrical discharge machining was identified as a good alternative to conventional machining for machining super alloys that possess low machinability. In the present work, effect of wire tension along with current, pulse on time, and pulse off time on the performance characteristics such as spark gap, surface roughness, amplitude of wire vibration, and cutting rate were studied in wire cut electrical discharge machining of Inconel 718 metal. Experiments were conducted at five levels of the process parameters as per orthogonal array of L25 and their results were collected. These experimental results were analyzed and the interaction effect of wire tension along with current, pulse on time, and pulse off time on performance characteristics was studied using analysis of variance. Response models were developed for the four responses in terms of process parameters and the accuracy of such models was tested. In addition to the above studies, effect of the wire displacement on the kerf size, cutting rate was studied. Spark energy was also estimated for all the experiments and its effect on the performance characteristics was studied. The response models developed in this study were able to predict the experimental results i.e. amplitude of wire vibration, surface roughness, cutting rate, and spark gap with an accuracy of R2 values of 1.0, 0.96, 0.88, and 0.99, respectively. Interaction effect of current and wire tension was found to have the most significant effect on the amplitude of cutter vibration and surface roughness.