A new Micro-EDM discharge state monitoring method based on impedance-measuring

摘要

Micro-EDM discharge state is usually monitored by measuring the gap average voltage, because it's very simple. Yet according to its principle, the monitoring effectiveness, resolution and threshold voltage would vary with the pulse parameters, i.e. cycle time, pulse width and amplitude. Thus, the gap average voltage measurement (GAVM) method is lacking in adaptability. Aiming at this, a new monitoring method based on impedance-measuring is presented, in which the gap impedance is monitored to identify the discharge states. By this means, when the circuit is settled, the monitoring effectiveness, resolution and threshold voltage would not vary with the pulse parameters. Consequently, the impedance-measuring method could show good adaptability in realistic machining situation where lots of different groups of pulse parameters are needed for different processing requirements. Experimental results show that different discharge states are distinguished by the impedance-measuring circuit and the effectiveness of the impedance-measuring method is proved.