Modeling and Applications of Electrochemical Machining Process

Abstract

Electrochemical Machining (below ECM) is one of advanced machining technologies and has been developed and applied in highly specialized fields, such as aerospace, aeronautics, defense and medical industries. In recent years, ECM is used in other industries such as automobile and turbo-machinery because of the following advantages. That is, it has no tool wear, and it can machine difficult-to-cut metals and complex geometries with relatively high accuracy. However, ECM still has some problems to be overcome. The efficient tool-design procedure, electrolyte processing, disposal of metal hydroxide sludge are the typical issues. In order to solve these problems, a numerical simulation is considered to be a powerful tool. However, the numerical code that can satisfactorily predict the flow field and the machining process has not been developed because of the complex flow natures such as the three-dimensionality, hydrogen bubble/metal sludge generation (i.e. three-phase effect), temperature increase and flow separation. In present paper, summery of my PhD works is mentioned, about modeling and applications. Modeling for ECM process takes into account metal dissolution, electrolyte flow, void fraction distribution of hydrogen bubbles generated from the tool cathode, thermal, electric potential, and electric conductivity. Especially, two types of method are used for the coupling between gas- and liquid-phase in electrolyte. One is one-way coupling method; only the electrolyte flow affects the void fraction distribution of hydrogen bubbles. The other is two-way coupling method; considering the interaction between the electrolyte flow and the void fraction distribution. In the two-way coupling method, considering bulk density distribution in the electrolyte flow path due to hydrogen bubble, Low-Mach-Number approximation is used for simulations. For applications with our numerical code, simulations for machining 3-D compressor blade are performed. Blade geometry is successfully predicted and we can obtain some guideline of ECM process.