Electrochemical Machining of Curvilinear Surfaces of Revolution: Analysis, Modelling, and Process Control

The paper presents the authors' model for the adaptive control of the electrochemical machining (ECM) process of machining the rotary (axisymmetric) elements of any curvilinear shape, using the results of theoretical computer simulation of this process. Computer simulations have been based on the authors' model of the ECM of rotary surfaces of any curvilinear shape. The quasi- 3D ECM model proposed facilitates an analysis of physical phenomena which occur in the interelectrode gap. Mathematical ECM modelling has been based on the application of the equation of the workpiece shape evolution and on the system of partial differential equations resulting from the principle of mass conservation, momentum and the law of conservation of energy describing a flow of the mixture of electrolyte in the interelectrode gap. A solution to the problem has been developed with analytical and numerical integration. For the rotary hemispheric surface, in a set time, the local machining of a change in the interelectrode gap thickness and characteristic physicochemical parameters were determined, especially static pressure distribution, electrolyte flow velocity, temperature and volumetric gas phase concentration as well as current density. The simulation results were experimentally verified by determining the distribution of the shape deviation (WP) calculated from the process computer simulation and after the ECM. Applying the adaptive control of the ECM process has facilitated, based on the simulations made, enhancing the process stability and avoiding the occurrence of critical states.