Author(s)

D. Curry, A. Sherlock, A. Mount & R. Muir

Abstract

Electrochemical machining (ECM) is a manufacturing process based on the principles of electrolysis. It machines irrespective of workpiece hardness and, as a result, it is used in the manufacture of parts requiring the use of hard alloys such as airfoil blades. Die-sinking ECM involves a shaped tool being moved closer towards the workpiece. Material removal takes place under the influence of an electric field. Once material removal rates are equal to the tool feed rate the process is said to have reached equilibrium. At equilibrium the workpiece is an approximate inverse of the tool shape. Under ideal ECM conditions, a number of process parameters are assumed to be constant. Industrially however, conditions are rarely ideal, and it may not be desirable to machine until equilibrium. This paper presents a time-dependent simulation that includes a model of one of the changing parameters, the overpotential, which is the voltage required to drive the electrochemical reactions at the workpiece and the tool. Previous work has shown that this condition varies throughout the course of machining. Validation is performed against experimental results, and comparisons are made against simulation under ideal conditions. Keywords: electrochemical machining (ECM), simulation, time-dependent, finite-element analysis, overpotential, non-ideal, non-equilibrium. 1 List of Symbols V0 Overpotential n Valency Vt Applied voltage A Area of workpiece electrode κ Conductivity I Current z Gap dh Material removed

Keywords

electrochemical machining (ECM), simulation, time-dependent, finite-element analysis, overpotential, non-ideal, non-equilibrium.