ORIGINAL ARTICLE An experimental investigation of cylindrical wire electrical discharge turning process Mohammad Jafar Haddad & Fereshteh Alihoseini & Mostafa Hadi & Meysam Hadad & Alireza Fadaei Tehrani & Aminollah Mohammadi Received: 14 January 2009 / Accepted: 10 June 2009 / Published online: 28 June 2009 # Springer-Verlag London Limited 2009 Abstract The cylindrical wire electrical discharge turning (CWEDT) process was developed to generate precise cylin- drical forms on hard, difficult to machine materials. A precise, flexible, and corrosion-resistant submerged rotary spindle was designed and added to a conventional five-axis CNC wire electrical discharge machine (EDM) to enable the generation of free-form cylindrical geometries. The hardness and strength of the work material are no longer the dominating factors that affect the tool wear and hinder the machining process. In this study, the effect of machining parameters on surface rough- ness (R a ) and roundness in cylindrical CWEDT of a AISI D3 tool steel is investigated. The selection of this material was made taking into account its wide range of applications in tools, dies, and molds and in industries such as punching, tapping, reaming, and so on in cylindrical forms. Surface roughness and roundness are chosen as two of the machining performances to verify the process. In addition, power, pulse off-time, voltage, and spindle rotational speed are adopted for evaluation by full factorial design of experiments. In this case, a 2 2 ×3 2 mixed full factorial design has been selected considering the number of factors used in the present study. The main effects of factors and interactions were considered in this paper, and regression equations were derived using response surface methodology. Finally, the surfaces of the CWEDT parts were examined using scanning electron microscopy (SEM) to identify the macro-ridges and craters on the surface. Cross sections of the EDM parts were examined using the SEM and microhardness tests to quantify the sub-surface recast layers and heat-affected zones under specific process parameters. Keywords CWEDT . Surface roughness . Roundness . DOE 1 Introduction Electrical discharge wire cutting, more commonly known as wire electrical discharge machining (WEDM), is a spark erosion process used to produce complex 2D and 3D shapes through electrically conductive workpieces by using wire electrode. The sparks will be generated between the workpiece and a wire electrode flushed with or immersed in a dielectric fluid. Good accuracy and fine surface finishes make WEDM particularly valuable for machining of stamping dies, extrusion dies, and prototype parts. These sparks generate craters and the recast layer on the surface of the electrical discharge machine (EDM) workpiece. With- out WEDM, the fabrication of precise workpieces requires many hours of manual grinding and polishing [1]. The concept of CWEDT is illustrated in Fig. 1 [2]. A rotary axis is added to a conventional five-axis wire EDM machine in order to produce cylindrical forms. The initial shape of the Int J Adv Manuf Technol (2010) 46:1119–1132 DOI 10.1007/s00170-009-2171-z M. J. Haddad (*) : A. F. Tehrani : A. Mohammadi Manufacturing Engineering Division, Department of Mechanical Engineering, Isfahan University of Technology, Isfahan, Iran e-mail: m.j.hadad@gmail.com F. Alihoseini Statistical Science Division, Mathematical Science Department, Isfahan University of Technology, Isfahan, Iran M. J. Haddad : M. Hadi Manufacturing Engineering Division, Islamic Azad University, Branch of Dehaghan, Isfahan, Iran M. Hadad Agricultural Economics Group, Ramin Agricultural and Natural Resources University, Ahvaz, Iran