| 摘要 |
PURPOSE:To prevent accidents due to damage of an electrode, by detecting the degree of insulation of an insulative machining fluid existing in the gap between the electrode and a workpiece and by comparing thus detected value with a reference value to control the current peak value of pulses applied across the interpole gap. CONSTITUTION:A control instruction signal generating device 17 superposes high frequency alternate voltage from a rower sources 18 during a deionizing period or the quiescent time of pulse voltage applied between a wire electrode 2 and a workpiece 1 from a machining power source 15, and a current detector 6 detects interpole leakage current running due to the lowering of insulation of the machining fluid 3 which is caused by machined chips, so that thus detected current is compared with a preset reference value to discriminate the interpole condition. With the result of the discrimina tion a control instruction signal is fed to a control device 14 and the machining power source 15, and if there would be any risk that the degree of insulation of insulative machining fluid 3 is lowered so that abnormal electric discharge occurs, the current peak value of pulses applied across the interpole gap from a machining power source 15 is controlled. Thus, it is possible to prevent breakage of the wire electrode without the machining rate being lowered.
|
