With electro-discharge machining (EDM), complicated shapes in hard materials can be produced with good accuracy and surface finish. The surface roughness which is influenced by discharge energy is known to be one of the most important parameter in the final EDM processing.
In this thesis characteristics of the surface roughness are investigated by time series analysis. A second order differential equation is developed, which represents the surface roughness model. The parameter of this equation is identified by the EDM profile measurements of the surface machined under various Pulse frequency, Average Ampere and Capacitance which affect the discharge energy. The model is physically interpreted by obtaining the Natural frequency, the Damping ratio and the Root mean square of the surface roughness model.