抄録
This paper deals with the precusory phenomena of the wire breaking in wire EDM and the effective method for foreseeing the wire breaking.
We found that the waveform of gap voltage and the frequency of discharge changed before the wire breaking.
The precusory phenomena of wire breaking are as follows;
1) The precusory phenomena appeared about 40ms before wire breaking. At this time, the frequency of discharge was measured three or four times as meny as the mean value in the normal EDM process. Moreover, during the about 10ms before wire breaking, discharge concentrated abnormally and the maximum frequency of discharge reached 77 pulse/ms.
2) Considering the relation between the wear of wire electrode and the frequency of discharge, we investigated the cause of wire breaking. In all probability, wire breaking occured when discharge concentrated abnormally at comparativelly small space.
According to these results, the wire breaking can be foreseen and avoided.
