Performance Characteristics of Dry Edm

INTRODUCTION

One of the aspects stimulating development of

manufacturing techniques and processes is the

increasing need of accuracy, quality of machining and

quality of surface layer after machining. Very important,

especially recently, factors are also demands on creating

machining methods not harmful for environment. One of

the ways of developing environment friendly EDM was

focused on reduction of amount of hydrocarbon/organic

based dielectric fluids. It was usually performed by

exchanging them with pure, water or low concentration

water solutions. The synthesis of using environmentallyfriendly

dielectrics for EDM was presented by Leao and

Pashby [1]. There are presented advantages and

drawbacks of using hydrocarbon and water based

dielectrics.

Recent investigations in the field of material machining -

mainly cutting processes are aiming at development of

dry or "almost dry". In these works, researchers are

focused on reduction of coolants volume, by exchanging

them with gases or mixture of gas and coolant.

Resignation of liquids during machining process may

bring many advantages concerning: easier machine

construction (the same lower cost of machine itself),

lower costs of machining and looking forward to the

future, better preparation for stricter low regulations. The

benefits of dry machining processes, described by

Weinert et all [1], presented in the Figure 1.

Figure 1: Benefits of dry machining [1]

Dry EDM is a 'green' environment friendly EDM technique

in which instead of mineral oil based liquid dielectric, gas

at high pressure is used as the dielectric medium. This

method brings advantages in process performance, like

lower tool wear, lower residual thermal stresses and

higher precision.

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