Background: Deep micro-holes are important structures which are widely used in many engineering
fields. However, deep micro-holes machining, especially on difficult-to-cut materials, has always
been a problem. The Electrochemical Micro Machining (EMM) process is a good selection for the fabrication
of deep micro-holes on difficult-to-cut materials, and various relevant patents and scientific papers
have been discussed.
Objective: In order to realize the fabrication of deep micro-holes, an electrochemical drilling process with
high-efficiency is introduced.
Method: Firstly, a numerical simulation of the gap flow field is carried out. Simulation results show that
with the increase of the electrode rotating speed, the gas film, which has a good insulation effect around
the electrode increases rapidly, thereby eliminating the taper and improving the machining localization
significantly. At the same time, the enhanced mass transfer is performed well, which can improve the
machining efficiency significantly. Secondly, the influences of some predominant parameters such as
rotating speed, feed rate, applied voltage and pulse frequency on machining localization were analyzed.
Results: Finally, a row of deep micro-holes with no taper, which have a diameter of less than 400μm, an
aspect ratio of more than 10, are fabricated successfully on the nickel-based superalloy.
Conclusion: It is proved that the use of the micro electrochemical drilling process with a high-speed spiral
electrode for fabricating deep micro-holes has considerable potential and broad application prospects.