Wire-Electrical Discharge Machining

Wire-electrical discharge machining (EDM) is a non-traditional machining process in which a pulsed voltage difference between a wire electrode and a conductive work piece initiates sparks which erode work piece material. Removing material in such a way is often advantageous when the work piece material would be difficult to machine with traditional machine tools due to high strength, hardness, toughness, etcetera (Newton, 2008). Due to the process itself, EDM are able to produce any complex shape but at the loss of surface integrity and some other after effect like Kerf width, Heat affected zone and etc. However, the selection of cutting parameters for obtaining higher cutting efficiency or accuracy in WEDM is still not fully solved, even with the most up-to-date CNC WEDM machine. It is due to the hard to expect nature of the process of Wire EDM. As a result, the relationships between the cutting parameters and the process performance are hard to model accurately. The problems arise although the machine itself is very up to date and some people hardly make a research out of it.

Nowadays, the application demands for a material that has best properties in term of strength, corrosion and other properties. The composition of material is then made according to the specific properties demanded. But, the properties also bring disadvantages on what process should be chose to manufacture the material so the composition of the material should be studied earlier before making any decision. The ease and economy with which INCONEL alloy 718 can be fabricated, combined with good tensile, fatigue, creep, and rupture strength, have resulted in its use in a wide range of applications. The examples of applications that use Inconel 718 as their mai...

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CHAPTER 2

Literature Review

2.1 Introduction

2.1.1 Wire EDM

Electrical Discharge Machine (EDM) is mainly used to cut a very intricate shape which other machines can’t do. Somehow, it’s only usable on the metal based product since electric is the main source for the cutting of product. The process of cutting the metal product is very complicated since lots of factor need to be considered in order to achieve a perfect finish product. The basic process of EDM is that a spark is generated between two electrodes which are tool and work piece. The spark will occur at the narrowest gap between the two electrodes. The sparks generated are very high and the cycle time for each spark is very short. Due to high temperature of the spark, the spark area melts in an instant and vaporized. The residue is then removed by the dielectric fluid contained inside the machining area.