Optimization of the Material Removal Rate and Electrode Wear Ratio in Electrical Discharge Machining of Reaction-bonded Silicon Carbide by Response Surface Methodology

Abstract

Reaction-bonded silicon carbide (RB-SiC) is widely used as moulding dies material in many industries thanks to its excellent properties. Nevertheless, because of its high hardness and brittleness, it is extremely hard to be machined with high accuracy and good surface finish. Therefore, electrical discharge machining (EDM) has been chosen as an alternative method to machine the RB-SiC. In the present study, an experimental investigation has been conducted to optimize and validate the EDM parameters on the MRR and EWR of low conductivity RB-SiC in EDM. The new Cu – 1.0 wt. % CNF composite electrode that fabricated via powder metallurgy (PM) process was used as the electrode. The experiments were systematically conducted by face-cubic centre (FCC) approach of response surface methodology (RSM). The mathematical models for MRR and EWR were developed in this study. In addition, analysis of variance (ANOVA) was also figured out to check the significance of the models. Three experiments were conducted as the confirmation test to determine the error percentage of MRR and EWR. Based on the results, only 3.06% and 3.93% errors were determined for both MRR and EWR, respectively. The optimum conditions for multi responses (MRR and EWR) were found to be at a current of 6A, voltage of 22V, and pulse on-time of 12µs. The findings of this study provide an important reference to the manufacturing industries, especially mould and die industry.