Performance of Electrochemical Discharge Machining by Forced Discharge Dispersion (2nd Report) Monitoring of Machining Current

Abstract

This paper deals with the monitoring of the current during electrochemical discharge machining (ECDM) with multiple electrodes. A gravity-feed-type unit with six electrodes for ECDM was fabricated. The polarity of the electrodes was set to be negative. While some holes were machined by ECDM on glass, the discharge current was forced to disperse by switching the electrodes to decrease the number of cracks (divided power). The current in the divided power was observed during the machining process and compared with those in the cases of multiple electrodes connected electrically in parallel (equipotential) and of a single electrode. Bubbles were generated by current pulses with a duration of several milliseconds when the voltage was applied. However, they disappeared during pulse intervals. A current pulse with a duration of two to five milliseconds preceded a series of sharp pulses below 200 μs in the single-electrode and divided power methods. Long and low-peak-current pulses frequently occurred, and the current pulses were concentrated at the electrodes at the two ends with equipotential power.