Process Simulation-Assisted Fabricating Micro-Herringbone Grooves for a Hydrodynamic Bearing in Electrochemical Micromachining

This study presents the process simulation of fabricating a herringbone groove in a hydrodynamic bearing by electrochemical micromachining (EMM) process. The finite element simulation involved the multiphysics of a chemical reaction, a static electrical field, and electric current density. A dedicated EMM system was established for this study. The groove pattern on the cathode tool was transferred to the internal side of the bearing (anode) by anodic dissolution. The width of the microgroove was selected as a quality index to explore the effects of the process parameters, such as cathode tool, interelectrode gap, voltage intensity, and the pulse rate of the applied voltage, on the electric field distribution and groove fabrication. The experimental results show that the proposed micromachining system has an electrochemical processing rate of k = 1 x 10(-11) m(3)/C, and could complete the micro-herringbone groove fabrication of 11 mu m depth in 0.85 seconds. The simulation results were comparable to those of the experiment. The numerical simulation can be used to design the cathode tool and the parametric selection for the microgroove fabrication of hydrodynamic bearings.