Quasi-Homogenous Model of Electrochemical Machining of Turbine Engine Parts

In order to increase the efficiency of jet engines hard to machine nickel-based and titanium-based alloys are in common use for aero engine components such as blades and blade integrated disks (BLISK). Electrochemical Machining (ECM) provides an economical and effective method for machining high strength and heat-resistant materials into complex shapes with high material removal rate without tool wear and without inducing residual stress. This article presents the physical and mathematical models of electrochemical shaping used in the manufacture of turbine engine parts. The modelling is based on the assumption that the multi-phase mixture filling the gap is treated as two-phase quasi-homogenous medium. The model describes the workpiece shape evolution in time, distribution the local gap size, flow parameters such as the static pressure and the velocity, temperature and void fraction as result of gas generation. The major features of the numerical computer program are briefly described with a selected example of machining a typical turbine blade. The results of computer simulation of effects of setting parameters ECM on accuracy-machined profile are discussed. The improvement of accuracy has been reached by using described sequence of ECM and Pulse ECM processes.

Modeling of process of copying of a ledge form on an electrode-tool at electrochemical machining

Problems of modeling of a non-stationary electrochemical shaping are reduced to the solution of two boundary problems for definition of analytical functions of the complex variable: conformal mapping of the parametrical plane on physical and partial derivatives on time of interelectrode space points coordinates. Each of functions is obtained in the form of the sum of known function with singularities and two unknown functions defined by Schwartz or Keldysh – Sedov's formulas. One of unknown functions is intended for the description of a form of an electrode-tool, the second – the processed surface. Results of the numerical solution of problems with an electrode in the form of a circle and a plate are presented.