Multiphysics Simulation Of Electrochemical Machining Process

Electrochemical Machining (ECM) is a metal removing method by anodic dissolution process, where the workpiece and the tool are actually the anode and the cathode of an electrolytic cell, respectively. In contrast to mechanical machining, the tool and workpiece are not in direct contact. Thus there is little tool wear and the hardness of the metal is of no importance. Moreover, the workpiece will not be affected by mechanical or thermal stresses. Its physical properties remain unchanged during the process. Despite its advantages and successful applications of ECM in industry, the design of the ECM processes remains a challenge. The complex behavior of electrochemical processes subjects ECM to several drawbacks, one of the most critical problems is achieving a high degree of accuracy. The prediction of the final shape of a work-piece obtained by ECM is difficult.Computer simulation method plays an important role in the solution of this problem. Simulation can be used to design form of electrochemical machining, optimization of experimental parameters, not only shortens the electrochemical machining preparation cycle, and economical and efficient to improve the processing quality, therefore the electrochemical machining process simulation is necessary. Electrochemical machining is a complicated field coupling process, involving the electric field, flow field, bubble, electrochemical polarization and a combination of many factors such as temperature, so how to accurately and the more comprehensive simulation coupling process, has become a difficult problem in electrochemical machining simulation. In this paper, by using COMSOL software, the study of electrochemical machining process system, a more field coupling model is put forward to complete electrochemical machining process simulation, and the accuracy of the model is verified by experiment, the concrete research content is as follows:(1) First of all, using the arbitrary Lagrangian- eulerian method (ALE) and redrawing of the grid method to complete the 3d model of workpiece forming dynamic simulation, the method can exactly the dynamic shape of workpiece and can extract at any time under the surface information such as coordinates, etc.(2) Completed the machining gap, electrochemical polarization and concentration polarization in electric field simulation of the current distribution in one, two, three times. Secondary current distribution in the use of polarization curves measured by electrochemical workstation, experimental data processing performed by MATLAB. By contrast, found that current density with from one to three times of simulation, the distribution flatten out, this is mainly caused by the polarization resistance, so the same time to simulate the depth of the workpiece forming for decreasing trend.(3) In order to further improve the model, and completed the flow field, current efficiency and pulse power under the action of the workpiece forming dynamic simulation. Flow field of gas-liquid two phase flow and processing process of hydrogen gas lead to changes in the rate of air bubbles, changes the bubble rate makes the conductivity distribution and, in turn, affects the artifact removal in quantity. Current efficiency and pulse function simulation makes simulation model is more close to the actual production, the pulse signals of different frequency, duty cycle for the workpiece forming simulation, found that the duty ratio is smaller, the more often high forming quality, the better, it perfectly match with the actual production.(4) In order to verify the exactness of the multiple field coupling model, has carried on the contrast experiment and simulation. Here choose tube electrode electrochemical machining experiment, completed on the developed by electrolytic process machine. From overall molding effect to specific parameters such as the groove width, found in contrast to such as external contour curvature radius, this simulation model can accurately simulate actual processing, so the model can be used in the development of electrochemical machining and optimize. Cathode is studied by using the model, the simulation of mask, mask under the action of the workpiece forming quality is higher and the thickness of the mask for forming the impact is not big, therefore in the case of ensure the mask should try to reduce the thickness of the mask.