A self-learning fuzzy controller for wire rupture prevention in WEDM

Wire breaking is a serious problem in the application of wire electrical discharge machining (WEDM). A WEDM sparking frequency monitoring and control system based on the characteristics of the voltage waveform of WEDM is developed. Two types of wire breaking phenomena are categorised according to the duration of the symptoms: a sudden rise of sparking frequency, and a sluggish rise of sparking frequency. Based on these results, a new self-learning fuzzy controller (SLFC) is proposed. The pulse off-time is regulated in real-time to keep the sparking frequency at a safe level so that wire breaking can be prevented. Experimental results show that this monitoring and control system can control the sparking frequency at an optimal high metal removal rate level without the risk of wire rupture.