Abstract: For the purpose of improving the process stability of electrochemical drilling (ECD), a flow model of the electrolyte along the machining gap is established; the relationship between the electrolyte flow along frontal gap and the process stability is also analyzed. The flow model shows that the side gap, frontal gap and electrolyte flowrate have remarkable influence on the pressure distribution along the frontal machining gap. The related experiments are conducted on the basis of model analysis. Process parameters such as insulation thickness, tool feed rate, and electrolyte pressure are studied and optimized. With optimized parameters, spark and short circuit during the machining process are diminished. Small holes of 7×7 arrays with aspect ratio of 2 are machined by multiple electrodes with good uniformity and stability.

Key words: Electric insulating coatings, Electrochemical drilling, Electrochemical machining, Stability