Modeling and optimization of crater size generated during micro- EDM of Ti alloy using Response surface method

Abstract

This paper opted for Box Behnken design approach to plan for experimental trial of micro electro discharge machining of Ti Alloy with the aim for modeling of crater size generation. Box Behngken design array used capacitance, voltage and tool rotation speed as input parameters. Using this design array, experimental trial was conducted on Ti alloy, where blind hole of 30micron depth was fabricated using micro EDM. Following that, machined surfaces were cleaned and observed using Scanning electron microscope. An important machining performance parameter crater size was measured using GIMP software from the SEM image. These experimental data of crater sizes were used to generate mathematical model with the help of MINITAB software. Response Surface methodology (RSM) was exploited to present the output parameters dependency on the input parameters. Response surface plot generated by GNU plot from this mathematical model presented the combined effect of input parameters on the crater size. It is also observed that, predicted values of crater size are in good agreement with the experimental real value. This study concludes that Box-Behnken design and response surface methodology could efficiently be applied to generate a model for calculating crater size created during micro EDM when the discharge energy is not so low.