ORIGINAL ARTICLE Taguchi analysis of surface modification technique using W-Cu powder metallurgy sintered tools in EDM and characterization of the deposited layer Promod K. Patowari & Partha Saha & Prasanta K. Mishra Received: 6 September 2008 / Accepted: 27 September 2010 / Published online: 16 October 2010 # Springer-Verlag London Limited 2010 Abstract The present study describes an experimental research on surface modification during electrical discharge machining (EDM) by depositing a hard layer over the work surface of C-40 grade plain carbon steel using specially prepared powder metallurgy compact tools. The investigated process parameters were composition, compaction pressure, sintering temperature, pulse on-time, peak–current setting, and duty factor. Measurements of deposited layer thickness, mass transfer rate, tool wear rate, surface roughness and microhardness were undertaken on the EDM-ed specimens. Different studies like X-ray diffraction, optical microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy were carried out to ascertain the characteristics of the deposited layer on the work surface. These analyses confirmed the presence of the tool materials in the work surface layer. At first, an L-16 orthogonal array was applied as Taguchi DOE technique and the ANOVA was done to study the effects of pertinent process parameters. An optimum condition was achieved using overall evaluation criteria. Later on, a detailed study was carried out to get a smooth and regular deposition of material. The characterization of the deposited layer is presented. The deposited layer with a wide range of average layer thickness of 3–785 μm, enriched with tool materials (W and Cu) and with the formation of tungsten carbide, and having microhardness of 9.81–12.75 GPa at the hardest zone was successfully deposited over the work surface. Keywords Electro-discharge machining . EDM . Surface modification . Powder metallurgy compact tools . Taguchi DOE technique . ANOVA 1 Introduction In engineering applications strength, hardness and tough- ness are the bulk properties of the material. In addition to these, the surface properties such as wear resistance, corrosion resistance, and abrasion resistance are also essential properties so that the engineering components, when subjected to aggressive environments like high speed, corrosive media, extreme temperatures, and cyclic stresses, do not fail due to initiated surface degradation. Therefore, a suitable protective coating is necessary to minimize wear, high temperature oxidation, and corrosion. Such stringent requirements have led to rapid advancements in the broad interdisciplinary field of surface-modification technologies. The modifications made to the component surface could be metallurgical, mechanical, chemical, or physical. Surface treatment processes give the desired properties to the material in a variety of ways like modifying the surface without altering the substrate’ s chemistry, by changing the surface layers through altering the alloy chemistry and by adding layers of material to the surface depending on the end-result desired. There are different surface modification P. K. Patowari Department of Mechanical Engineering, National Institute of Technology, Silchar 788010 Assam, India P. Saha (*) Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721302 WB, India e-mail: psaha@mech.iitkgp.ernet.in P. K. Mishra Department of Mechanical Engineering, College of Engineering Pune, Pune 411005 Maharashtra, India Int J Adv Manuf Technol (2011) 54:593–604 DOI 10.1007/s00170-010-2966-y