Machinability study of metal matrix composites through electrochemical micromachining ecmm

Abstract

Current applications of engineering require materials that are cheaper, stronger and lighter in weight. Aluminium metal matrix composites (AMCs) are noted to supply such tailored property materials required in the field of engineering applications. AMCs are rapid replacement of conventional metallic alloys in many applications as their uses are extended predominantly from automobile, aerospace, defense and other mechanical industries. The conventional machining of AMCs is complex due to the presence of reinforcements which affects the cutting tool and surface quality of the machined components. To overcome these difficulties, non-conventional machining methods are utilized. The greater part of the non- conventional machining processes is thermal oriented, e.g., electron beam machining (EBM), laser beam machining (LBM) and electric discharge machining (EDM) which produces thermal deformation in machined component. Electrochemical machining (ECM) and also chemical machining (CM) processes are thermal-free processes, but CM is applicable only for chemically conductive material. Electrochemical machining (ECM) processes play a significant role in the fabrication of micro components because of their advantages such as higher MRR, no tool wear, good surface finish and better precision control. Electrochemical micromachining (ECMM) has been employed irrespective of difficult-to-cut materials, hard materials and tool wear, and it is one of the non-conventional non-contact machining techniques and hence, ECMM is proposed for machining AMCs. In ECMM the material is expelled by anodic dissolution of electrolytic process, and we should maintain very small machining gap. ECMM is a material removal process, which is the reverse electroplating technique. The workpiece in ECMM is dissolved according to electrolysis laws of Faraday. The workpiece to be machined in this process is made as anode and the tool is vi made as a cathode of an electrolytic cell with a salt solution used as an electrolyte (NaNO3). The positive metal ions