Title: Experimental investigation on electrical discharge machining of ceramic composites (Si₃N₄-TiN) using RSM

Authors: V.P. Srinivasan; P.K. Palani; L. Selvarajan

Addresses: Department of Mechanical Engineering, Sri Krishna College of Engineering and Technology, Coimbatore, Tamil Nadu, Pin: 641 008, India ' Department of Mechanical Engineering, Government College of Technology, Coimbatore, Tamil Nadu, Pin: 641 013, India ' Department of Mechanical Engineering, Mahendra Institute of Engineering and Technology, Namakkal, Tamil Nadu, Pin: 637 503, India

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 (T_on) 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.

Keywords: electrical discharge machining; EDM; silicon nitride-titanium nitride; Si₃N₄-TiN; material removal rate; MRR; electrode wear rate; EWR; response surface methodology; RSM; design of experiments; DOE.

DOI: 10.1504/IJCMSSE.2018.092541

International Journal of Computational Materials Science and Surface Engineering, 2018 Vol.7 No.2, pp.104 - 115

Received: 25 Sep 2017
Accepted: 19 Oct 2017
Published online: 24 Jun 2018 *

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