STUDY OF WIRE BREAKING PROCESS AND MONITORING OF WEDM

Wire rupture in the Wire Electrical Discharge Machining (WEDM) process is a serious problem to manufacturers. A new computer-aided pulse dis crimination system based on the characteristics of voltage waveform du ring machining was developed in this paper. With the use of this syste m, a large amount of sparking frequency data during wire rupture proce ss and under normal working conditions were collected and analyzed. Tw o symptoms of wire rupture were identified: the excess of are sparks, and a sudden rise of the total sparking frequency. The governing mecha nisms of these two types of wire rupture were found from the SEM and E DAX analyses of the ruptured wire electrode. Furthermore, an index to monitor wire breaking was identified, and its relationships with the m etal removal rate and machining parameters were found. Based on the re sults obtained in the paper, a control strategy to prevent wire from r upturing while at the same time improving the machining speed is propo sed. (C) 1997 Published by Elsevier Science Ltd.