An integrated approach for tool design in ECM

Abstract

In practice the costly trial and error approach of designing and experimentally testing complex-shaped tools in electrochemical machining (ECM) is still followed. This results in low productivity of tooling design in ECM. This, coupled with the initial high cost of ECM set-up, high wages of skilled operators and very high cost of components to be machined are the main obstacles to realizing the full industrial potential of ECM. The paper reviews different models proposed for the analysis problems (anode shape prediction) and design problems (tool design) in ECM. These models based on the cos θ method, complex variable approach, empirical and nomographic approach, finite differences method, finite element technique, and boundary element method vary in the methodology employed to solve the Laplace equation (the cos θ method, and empirical and nomographic approaches do not use the Laplace equation), assumptions, applications, merits and limitations. The interdependence of different parameters, which is the main cause of the low success in tool design for ECM, is illustrated. The finite element formulation for tooling design in electrochemical machining is outlined. Results of two-dimensional tool design for electrochemical drilling are presented. Experiments were conducted using an aqueous solutions of NaCl as electrolyte, low alloy steel castings and low alloy steel forgings as work materials, and brass as the tool material. The shape and size of the tools used during experimentation have been found to be in agreement with design. The paper also proposes an integrated approach for computer-aided tool design in ECM. The scheme emphasizes the need for incorporating the optimization model, decision support system and a computer-aided process planning system in the tool design package. The integration of a simulation system for the computer-based testing and verification of a designed tool is also discussed.