Industrial and Management Systems Engineering


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A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Industrial and Management System Engineering, Under the Supervision of Professor Kamlakar P. Rajurkar. Lincoln, Nebraska: December, 2012

Copyright (c) 2012 Farnaz Nourbakhsh


This work presents an experimental investigation of wire electro-discharge machining (WEDM) of titanium alloy. The outstanding characteristics of titanium alloys such as their compatibility and noticeable physical, mechanical and biological performances has led to increased application of them in various industries especially in biomedical industries over the last 50 years. However, due to low thermal conductivity of titanium and its alloys and their reactivity with cobalt in most tool materials, there are some difficulties in machining titanium and its alloys by conventional machining. On the other hand, unconventional machining processes especially Wire Electrical Discharge Machining (WEDM) are more appropriate techniques for machining difficult –to-machine materials like titanium and its alloys. Electrically conductive materials are cut by Wire EDM that uses a wire as electrode in an electro-thermal mechanism. The focus of this thesis is on machining of titanium with WEDM because of the above-mentioned features of WEDM and its suitability for machining titanium and its alloys. In this study the effect of seven process parameters including voltage, pulse width, time between two pulses, servo reference voltage, pulse current, injection pressure and wire tension on process performance parameters such as cutting speed, wire rupture and surface integrity are investigated. In order to analyze the effect of wire type on surface characteristics, Scanning Electron Microscopic (SEM) examination of machined surfaces is performed. This thesis applies Data Dependent System approach (DDS) to analyze the surface profile of titanium work pieces that are machined by both wire types.

Advisor: Kamlakar Rajurkar