MS, University of Cincinnati, 2011, Engineering and Applied Science: Mechanical Engineering

High aspect ratio metallic cylindrical rods having diameters in the sub millimeter range are increasingly being used as micro tools to machine complex micro features including deep hole micro drilling in a wide variety of engineering materials including metals and ceramics. They are also being used in applications such as ultrafine micro needles for intracellular sensing probes and micro robotic manipulators. Accurate and precise micro tools are essential for the micromachining of these highly complex features. Micro tools produced by the well known wire electro-discharge grinding suffer deformation due to the thermal stresses. Therefore, electrochemical machining has been explored as an alternate micro tool manufacturing technique. In this thesis, a micro electrochemical machining system has been designed and built in-house and a mathematical model has been developed to predict the final diameter of the anode based on the velocity of the cathode movement. Experimental verification of the model reveals good correlation with theoretical predictions. Large pulse on-times have successfully been used to fabricate micro tools having diameters of 10 micrometers with aspect ratios as high as 450. Pulse on-time between 5 to 10 ms was found to be an optimum range for successful micromachining using the in-house built micro electrochemical system. Pulse on-times lower than this optimum range result in a conical shape while pulse on-times higher than the optimum range result in a reverse conical shape.

Committee: Murali Sundaram Meenakshi PhD (Committee Chair); Sundararaman Anand PhD (Committee Member); David Thompson PhD (Committee Member) Subjects: Mechanical Engineering