Study of material removal mechanism in wire electro discharge machining wedm process and optimization of performance characteristics

Abstract

Conventional machining operations tend to reach their limitations as newer materials develop. In recent years, the technology of Wire Electro Discharge Machining (WEDM) process has significantly improved to meet the latest requirements in the industry. Its broad capabilities have allowed it to be used in production in aerospace and automotive industries. WEDM process, with a thin wire as an electrode, transforms electrical energy to thermal energy which melts and removes the materials. With this process high hardness materials like alloy steel, conductive ceramics and aerospace materials can be machined. WEDM is a special form of the traditional EDM process in which the electrode is a continuously moving conductive wire. Material is eroded from the workpiece by a series of discrete sparks between the workpiece and the wire, separated by a thin film of di-electric fluid. High material removal rate and a very good surface finish can not be achieved simultaneously. This is an age long problem and continuous efforts are being made by different researchers all over the world to meet such an objective. The literature survey reveals that little research has been conducted to obtain the optimal levels of machining parameters for higher Material Removal Rate (MRR) and lower Surface Roughness (SR), particularly for the materials like hardened steel, Super alloy Inconel 800, Metal Matrix Composites (MMC), newly developed Tool and Die steels. All the above materials are of high hardness used in extreme load conditions such as hot work forging, extrusion etc. The application of these materials are varied such as manufacturing of punching tools, mandrels, mechanical press forging die, plastic mould and die-casting dies, air craft landing gears, helicopter rotor blades, shafts used in space crafts etc. The objective of the present work is twofold. First part is to investigate the effect of the various WEDM parameters on MRR and SR and to arrive at an optimal setting for each material.