Abstract—In this paper an attempt has been made to correlate the usefulness of electrodes made through powder metallurgy (PM) in comparison with conventional copper electrode during electric discharge machining. Experimental results are presented on electric discharge machining of AISI D2 steel in kerosene with copper tungsten (30% Cu and 70% W) tool electrode made through powder metallurgy (PM) technique and Cu electrode. An L18 (21 37) orthogonal array of Taguchi methodology was used to identify the effect of process input factors (viz. current, duty cycle and flushing pressure) on the output factors {viz. material removal rate (MRR) and surface roughness (SR)}. It was found that CuW electrode (made through PM) gives high surface finish where as the Cu electrode is better for higher material removal rate. Keywords—Electrical discharge machining (EDM), Powder Metallurgy (PM), Taguchi method, Material Removal Rate (MRR), Surface Roughness (SR). I. INTRODUCTION LECTRICAL DISCHARGE MACHINING is a thermo-electrical material removal process, in which tool electrode shape is reproduced mirror wise into a work material, with the shape of the electrode defining the area in which the spark erosion will occur [1]. It has been widely used to produce dies, molds, aerospace, automotive industry and surgical components [2]. It is also useful for machining brittle materials, as there is virtually no contact between the tool and work-piece. In EDM, the material is removed primarily through the conversion of electrical energy into thermal energy through a series of successive sparks between the electrode and the work piece in a dielectric fluid. The thermal energy is consumed in generating high temperature plasma, eroding the work piece material. Moreover there is no direct contact between the electrode and the work piece which eliminates mechanical stresses chatter and vibration problems during machining. Naveen Beri is with Department of Mechanical Engineering, Beant College of Engineering & Technology, Gurdaspur, Punjab, India. (e-mail: nav_beri74@yahoo.co.in). S. Maheshwari, is with Division of Manufacturing Process & Automation Engineering, Netaji Subash Institute of Technology, Dwarka, New Delhi, India. (e-mail: ssaacchhiinn@gmail.com). C. Sharma is with Department of Mechanical and Automation Engineering, IGIT, Kashmiri Gate, Delhi, India. (e-mail: chitrabisht@rediffmail.com). Anil Kumar is with Department of Mechanical Engineering, Beant College of Engineering & Technology, Gurdaspur, Punjab, India. (phone: +91- 9417286270 ; fax: +911874-221463; e-mail: ak_101968@yahoo.com). The recent developments in the field of EDM have progressed due to the growing application of EDM process and the challenges being faced by the modern manufacturing industries, from the development of new materials that are hard and difficult-to-machine such as tool steels, composites, ceramics, super alloys, hastalloy, nitralloy, waspalloy, nemonics, carbides, stainless steels, heat resistant steel, etc. Typically, the major cost and time components in die and mould machining by EDM are in the electrode fabrication, which can account for over 50% of the total machining cost [3]. Typical materials, used as EDM electrodes include copper, brass, chromium, tungsten, steel, copper-tungsten and copper chromium alloys [4,5,6]. Conventional methods of fabricating the electrodes include stamping, coining, grinding, extrusion, drawing, and more commonly, turning, milling, incurring long processing time and material wastage especially if a complex geometry or profile is required [4]. EDM research has concentrated on achieving faster and more efficient metal removal rate coupled with a reduction in tool wear and improved surface characteristics [7, 8, 9]. The majority of work has been done using mechanically formed tool electrodes and the present EDM user is compelled to search for alternative tooling such as powder metallurgy (PM) method of electrode fabrication which is more economic and faster to manufacture. A complex electrode made by conventional method can cost around 100 times more than a simple square electrode. However, in the PM route a large number of tool electrodes can be made from a single die and punch assembly, resulting in an overall reduction of EDM tooling cost. Therefore, PM turns out to be a viable alternative to produce tool electrode in which the desirable properties of different materials can be combined. Moreover, the thermal, electrical, mechanical and micro structural properties of PM tool electrodes can be effectively controlled by the process variables such as compacting pressure and sintering temperature. These will affect density and pore shape. An example is an alloy of CuW made through PM where tungsten particles are uniformly embedded in highly conductive copper matrix. The electrodes made by using powder metallurgy technology from special powders have been used to modify EDM surfaces in recent years, to improve wear and corrosion resistance. Gangadhar e.t. al. [10] reported surface deposition by EDM in a liquid dielectric using PM compact tool electrode. Deposition of tungsten carbide on flank and rake of a HSS toll using PM electrode containing 40%WC and 60% Fe (zinc sterate as lubricant) with reverse polarity and kerosene as dielectric resulted in low variation in cutting forces. Soni and Chakraverti [11] found that appreciable amount of elements Naveen Beri, S. Maheshwari, C. Sharma, Anil Kumar Performance Evaluation of Powder Metallurgy Electrode in Electrical Discharge Machining of AISI D2 Steel Using Taguchi Method E World Academy of Science, Engineering and Technology International Journal of Mechanical and Mechatronics Engineering Vol:2, No:2, 2008 225 International Scholarly and Scientific Research & Innovation 2(2) 2008 scholar.waset.org/1307-6892/40 International Science Index, Mechanical and Mechatronics Engineering Vol:2, No:2, 2008 waset.org/Publication/40