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Advantages And Disadvantages Of Dry Emm

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In dry EDM thin walled pipe has been used as an electrode material. A high velocity air or gas has been entered in to the tool electrode pipe and strike the workpiece through the discharge gap. When small voltage is applied to the electrode gap, high strength electric field has been set up which ionizes the air dielectric present between the electrodes. Strong heat has been generated between the tool and workpiece which causes the breakdown of air [2]. During the breakdown of air, plasma channel has been formed between the electrodes and a high discharge of about 10000° C has been taken place at a least resistance point. This causes both the tool and workpiece melts and forms a crater.
The lower dielectric constant of air media enhances the plasma formation. This unlimited plasma enhancement leads to …show more content…

C. Advantages of Dry EDM
The dry EDM achieves zero tool wear and no corrosion of workpiece [13], lower residual stress, and narrow discharge gap length [12].
D. Disadvantages of Dry EDM
A thin recast layer has been produced on the workpiecec surface which causes poor surface roughness. Lower productivity is the major disadvantages of dry EDM [10].
II. LITERATURE STUDY
The first dry EDM effort is made on 1985 using inert gas to drill small holes. They have used helium and argon gases as a dielectric medium. Later on Kunieda et al. [16] started research on EDM by using oxygen as a dielectric medium and they have found that the dry EDM is environmental friendly and it increases the material removal rate than conventional EDM. After that they have used compressed air with tubular electrode [12]. They have developed 3D milling of Dry EDM and tried the best combination of tool and workpiece with air as dielectric medium [13]. After that many researchers made researches on dry EDM to improve the performance. Some authors attempted near dry EDM process [14], [15] where air and liquid were

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