Molecular dynamics simulation and experimental research on fabrication of micro spherical electrode combined by electrochemical etching with spark discharge.

The microstructures with spherical end have been widely applied in micromachining and measurement. In this paper, a microelectrode with spherical end was fabricated combining electrochemical etching with spark discharge machining. Firstly, the formation mechanism of micro spherical electrode was simulated by molecular dynamics LAMMPS, and the energy model of the spherical end was established to guide machining micro spherical electrode. Secondly, on the basis of cylindrical microelectrode, the electrode tip was melted by spark discharge. Simultaneously, the molten electrode formed a spherical end due to surface tension in deionized water. Finally, sets of experiments were carried out to discuss the influence of polarity, applied voltage, and pulse width on the diameter ratio of spherical end to electrode tip. By using optimal machining parameters, the micro spherical electrode with a diameter of 21.25 μm and a coaxial error of 0.9 μm can be obtained, and the diameter ratio is almost 2. [ABSTRACT FROM AUTHOR]