Experimental investigation on electrical discharge machining of ceramic composites (Si<SUB align="right">3N<SUB align="right">4-TiN) using RSM

Abstract

In this work, electrical discharge machining (EDM) of silicon nitride-titanium nitride (Si3N4-TiN) composites which have wide application in heat exchangers, wear-resistant parts, and gas turbines were carried out. Si3N4-TiN composites are fabricated by hot pressing and spark plasma sintering (SPS) process. Selection of appropriate machining parameters in EDM is one of the most important aspects taken into consideration as these conditions to determine the important characteristics such as material removal rate (MRR) and electrode wear rate (EWR) among others. The main machining parameters such as gap voltage (V), current (I) and pulse-on time (Ton) were chosen to determine listed technological characteristics. The characteristic features of the EDM process are explored through response surface methodology (RSM) based on design of experiments (DOE). Moreover, L18 orthogonal array based on DOE to conduct of series of experiments has been adopted. From the results, it is evident that the current is the most significant factor as it influences both MRR and EWR. The high current increases the MRR and the less gap voltage reduces the EWR. The square profile machined with the voltage - 50 volts, current - 5 amps and pulse-on time - 500 µsec exhibits high MRR.