Optimisation of Process Parameters during Manufacturing of Miniature Spur Gears by CNC Wire Cut Electric Discharge Machining

Abstract

In this present investigation, the manufacturing of miniature spur gears, made of Inconel-718 by Wire cut Electric Discharge Machining (WEDM), has been carried out. Inconel-718 has some important characteristics, such as good strength and good resistance against corrosion etc. WEDM is the most innovative and cost effective process for cutting of spur gears to obtain better surface finish and accuracy. The most important output response is Material Removal Rate (MRR) during WEDM Process. The main input variables that affect the output response are Pulse on time, Pulse off time and gap voltage. These effective process parameters 54have been selected based on the literature survey. The experiments have been done by selecting L9 Orthogonal Array and results have been optimised with the Taguchi Methodology. Significant process parameters have been identified by ANOVA. Statistical results at a 95% confidence level, show that the Pulse on time, Pulse off time and gap voltage have percentage contribution of 94.03%, 2.41%, and 2.29%, on MRR respectively. The result shows that the maximum MRR of 2.746 mm3/min has been obtained by the Taguchi's optimisation method. From the results obtained by ANOVA, it has been found that the Pulse on time is the most significant parameter. Contour plot has been used to determine the desirable MRR and corresponding operating conditions during the manufacturing of miniature Spur Gears.