| 摘要 |
A wire electrical discharge machining apparatus capable of adequately ascertaining whether the condition of the machining gap is good or bad without lowering the machining speed while preventing damage to the wire electrode. The apparatus includes a high-frequency voltage source that supplies voltage to the gap between applications of DC voltage machining pulses. In response to the application of high-frequency voltage to the gap a current detector and two voltage comparators detect the degree of electric insulation (i.e. dielectric strength) of the machining liquid in the gap. The condition of the gap is determined based upon comparison between the detected degree of electric insulation and a predetermined reference value. In response to the determined condition of the machining liquid gap conditions such as the machining pulse shape, gap width, wire tension, wire feed rate, rate of renewal of the machining liquid, and resistivity of the machining liquid may be changed.
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