Investigation on Electrochemical Discharge Micro-Machining of Silicon Carbide

1. Introduction

With the rapid growth of engineering materials towards the direction from metal to non-metal and thereafter to ceramics and composites, the modern industries have developed an increasing demand for machining of advanced engineering materials irrespective of their hardness, toughness, electrical conductivity and microstructure etc. The improved properties of the materials, however, pose new challenges to the present manufacturing and process engineers, as often haunted by the requirements of machining those materials economically and efficiently. Again, the miniaturization of the products demands newer manufacturing processes and complete machining system for operating in the micron range. But, it becomes troublesome to produce 3-D micro-shapes with ceramics by the conventional machining and manufacturing techniques. Some non-conventional machining processes like LBM, USM and AWJM, etc., can be used for machining the above materials but these machining processes are very expensive. To meet the requirement of machining such important engineering materials in the micron range the machining methods have taken a dramatic shift from the practice of traditional machining to the non-traditional machining and finally, in turn, towards hybrid machining. Electrochemical Discharge Machining (ECDM) process has potential for micro-machining operation on non-conducting as well as harder engineering ceramic materials although it has some limitations (Tsuchiya et al., 1985; Bhattacharyya et al., 1999; Wüthrich and Fascio, 2005; Basak and Ghosh, 1997; Jain et al., 1999). Micro-ECDM is an advanced hybrid machining process that comprises the techniques of Electrochemical Machining (ECM) and Electro Discharge Machining (EDM). In micro-ECDM process, the material removal takes place due to the combined effects of electrochemical (EC) reactions and electrical spark discharge (ESD) action.