* Corresponding author. Tel.: +91-9416358678 E-mail: kamaljangra84@gmail.com (K. Jangra) © 2011 Growing Science Ltd. All rights reserved. doi: 10.5267/j.ijiec.2011.04.005 International Journal of Industrial Engineering Computations 2 (2011) 479–490 Contents lists available at GrowingScience International Journal of Industrial Engineering Computations homepage: www.GrowingScience.com/ijiec Simultaneous optimization of material removal rate and surface roughness for WEDM of WC- Co composite using grey relational analysis along with Taguchi method Kamal Jangra a* , Sandeep Grover a and Aman Aggarwal b a Department of Mechanical Engineering, YMCA University of Science and Technology, Faridabad, India b Mechanical and Automation Engineering Department, Maharaja Agrasen Institute of Technology, Sector-22, Rohini, Delhi 110085, India A R T I C L E I N F O A B S T R A C T Article history: Received 20 January 2011 Received in revised form April, 20, 2011 Accepted 20 April 2011 Available online 24 April 2011 In this paper, wire electrical discharge machining of WC-Co composite is studied. Influence of taper angle, peak current, pulse-on time, pulse-off time, wire tension and dielectric flow rate are investigated for material removal rate (MRR) and surface roughness (SR) during intricate machining of a carbide block. In order to optimize MRR and SR simultaneously, grey relational analysis (GRA) is employed along with Taguchi method. Through GRA, grey relational grade is used as a performance index to determine the optimal setting of process parameters for multiple machining characteristics. Analysis of variance (ANOVA) shows that the taper angle and pulse-on time are the most significant parameters affecting the multiple machining characteristics. Confirmatory results, proves the potential of GRA to optimize process parameters successfully for multi-machining characteristics. © 2011 Growing Science Ltd. All rights reserved Keywords: Tungsten carbide composite Wire electrical discharge machining Taguchi method Grey relational analysis Multi-characteristics optimization 1. Introduction The cemented carbides such as WC-Co are typically used in tool and die industries because of their excellent hardness and strength. It is hard to machine material, produced by sintering of WC powder with the binder (typically Co or Ni) at temperature near the melting point of the metal (Kim et al., 2005). The formation of liquid phase during sintering enhances the densification process and hence increases the hardness of the composite. Machinability of WC-Co composite is very important in die and tool manufacturing as it may affect different manufacturing phases including product design, process planning, machining operations etc. Processing of WC-Co composite is very difficult with conventional machining method due to its high hardness. Machining of WC-Co, using CBN tools in CNC turning, results in very high cutting forces and very poor surface finish (Liu et al., 200). Ultrasonic machining method (Nath et al., 2009) may yield better machining results as compared to conventional machining process but complex and precise shapes are very difficult to generate. Similar difficulties occur with grinding operation. Electrical discharge machining (EDM) method is the best alternative to machine hard and non- conductive composites (Kucukturk & Cogun, 2010). Wire electrical discharge machining (WEDM) is a special form of EDM, which has the capability to produce intricate shapes and profiles in composite materials with a high degree of accuracy. In WEDM, the erosion mechanism is described as melting and/or evaporation of the surface material by the heat generated in the plasma channel. A spark is