Background: Microelectrodes have been widely used in the fields of microfabrication,
measurement and medical applications. Electrochemical etching machining is a better method for fabricating
microelectrode, and the multi-stepped electrode is easily fabricated to very small size. However,
the rotary accuracy of multi-stepped electrode fabricated by conventional electrochemical etching is not
high, because of the installation error of electrode and the uneven machining gap between the electrode
and tool cathode. Various relevant papers and patents have studied different methods to improve the
machining accuracy and efficiency of electrodes.
Objective: In order to achieve the high-efficiency machining of multi-stepped cylindrical microelectrode
with high rotary accuracy, a new electrochemical etching process (rotating electrochemical etching)
Methods: Firstly, the effect of machining current on the change of electrode diameter was deduced
based on the principle of electrochemical etching. Secondly, the experiments proved that the rotation
can improve the current change rate and the effective initial current and thus improve the machining
efficiency. Following this, the influence of rotation on the rotary accuracy of electrode was analyzed,
and the efficient method, which uses different rotation speeds combination, was proposed to fabricate
multi-stepped cylindrical microelectrodes with high rotary accuracy. Thirdly, the influence of machining
parameters such as the rotation speed, the voltage and the cut-off current, on the shape and size of
electrode was analyzed.
Results: Finally, a set of three-stepped cylindrical microelectrodes, which have the terminal diameter of
less than 15µm and coaxial error within 1µm, was successfully fabricated using the optimized machining
parameters. Compared with the conventional electrochemical etching process, the machining efficiency
Conclusion: It has been proved that rotating electrochemical etching is a better method to improve the
machining efficiency and rotary accuracy of microelectrodes.