S.H.Ebrahim1, M.Ghoreishi2
Manufacturing Engineering Group, Mechanical Engineering Department, Khaje Nasir Toosi Univesity , Tehran, Iran
h_ebrahimi@sina.kntu.ac.ir
Abstract
The electro discharge machining (EDM) process provide one of the best alternatives, or sometimes the only alternative, to machining a growing number of high-strength and corrosion and wear-resistant material used in a broad spectrum of industries. In electro discharge machining (EDM), there are several process for material removing however melting is main process for material removal therefore EDM is basically a thermal process. Heat generated in discharge channel, melts end even evaporates the materials. However, for short pulses (discharge duration <5µs) metal doesn’t have enough time to become adequately heated and almost no melting take place, reported in experimental investigation. There are two important phenomena in each discharge heat transfer and electro static force. Electro static force acting important roles in short pulse however heat transfer has main role in long pulse. In this investigation, effect of two dimensional heat transfer model and electrostatic force has been combined and the 'crater depth' has been calculated. The present models can be used for both short pulses and long pulses hold in all working conditions. In the Electro thermal models which have already been presented for specifying heat transfer two Dimensional model has been utilized. However, regarding researches done, it has been proven that level of heat gained in different points in this model is less than its real amount and this leads to considerable mistake in both specifying yield stress which is related to heat and specifying melting point. Since using this method is based on physics, heat of different point is close to real point and its mistake is not significant which is confirmed by the experiments.
Keywords: Electric discharge machining, Two Dimensional heat transfer model, electro static force
1- M.S student, Dep. of Mechanical Engineering, KNToosi university of Technology, Tehran, Iran.
2- Assistant professor, Dep. of Mechanical Engineering, KNToosi university of Technology, Tehran, Iran.
Introduction
