Process monitoring of electrochemical micromachining

Electrochemical micro-machining (ECμM), utilises very small inter-electrode gaps (< 20 μm) in order to obtain the accuracies necessary. The narrow gaps make the control of the process much more complex than normal ECM. Furthermore, difficulty in gap flushing leads to an increased tendency to cause electrical discharges, which is highly detrimental to the process. In order to formulate spark prevention and gap control strategies, this paper investigates the discharge mechanism in narrow electrolytic gaps. A monitoring method using radio frequency emission is given, which together with the current and voltage signals, identifies more clearly the events occurring within the gap.