Abstract
To prevent the wire breakage during wire EDM, there must be a reliable spark gap detecting signal which indicate the abnormal wire gap state just before the wire breakage. In this report we compare 3 gap detecting signals, namely the discharging voltage, the ignition delay time and the radio signal during wire EDM. To avoid the influence of wire impedance on the discharging voltage, a method which correct the discharging voltage depending on the discharged location is proposed.
Results show that short circuits pulses, pulses of short ignition delay times and low level radio signal pulses are increasing just before the wire breakage. The detection of discharging voltage is the best method to premonitor the abnormal state of the wire or the gap state to prevent the wire breakage.
