On-Line Monitor and Control for Wire Breakage in WEDM

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

“…The larger the increase of the total sparking frequency, the shorter the deterioration time, and vice versa. This kind of wire rupture phenomenon has also been found by Rajurkar and Wang [3]. The wire rupture often occurs when the machining parameters, particularly the pulse on-time or off-time, are changed during the machining process.…”

“…It is difficult to design a PID controller for such a complex system. A linear difference equation such as that proposed by Rajurkar and Wang [3,4] may be used as an approximate mathematical model to design a PID controller. However, it should be noted that the model parameters rely heavily on the machining parameters.…”

“…Rajurkar and Wang [3,4] developed an on-line WEDM adaptive control system that monitors and controls the sparking frequency at optimal levels according to the on-line identified workpiece height. Experimental results show that the proposed control system can successfully control the sparking frequency at the optimal value without the risk of wire rupture when cutting a workpiece with variable heights.…”

“…The variations of these parameters and random variations of the gap condition during the machining process often cause wire rupture. Accordingly, the complex dynamics of the WEDM system makes the conventional control scheme [2] and adaptive control [3,4] not applicable to the wide range of variations of machining conditions in WEDM. Hence, it is essential to design a controller which not only has adaptive capability but also robustness to overcome the wire breaking of WEDM.…”

Investigations into Wire Electro-discharge Machining of A6061/Al2O3p Composites

“…According to , during the WEDM of MMCs, wire breakage occurs when the wire comes in contact with non-conducting ceramic particles. However, the wire breakages are generally attributed to high frequency of discharges and concentration of discharges (Rajurkar and Wang, 1991;Kinoshita, 1982). The present study is an attempt to understand the role of ceramic reinforcements in wire breakages.…”