| 摘要 |
<p>A wire-cut electrical discharge machine capable of controlling a discharge current to constant. Provided between a main current power source (71) and a capacitor (C) is a current detecting unit (72) which converts electric current (I3) flowing through a closed circuit formed by the main current power source (71) and the capacitor (C) into voltage to detect the same, and the detected result is transmitted to a control unit (500) after it is smoothed by a smoothing circuit unit (73). Also, electric discharge between a wire (49) and a work (36) is detected by a discharge detecting unit (62). A processing unit (52) of the control unit (500) calculates a sum of the electric current (I3) per one cycle of electric discharge machining on the basis of the converted voltage value of the electric current (I3) transmitted through the smoothing circuit unit (73) and the number of electric discharges counted by a counting unit (53). The discharge control unit (55) controls a pulse width of a drive signal (SS) being fed to a main current switches (S2, S3) so that the sum of the electric current (I3) per one cycle of electric discharge machining amounts to a reference value. Accordingly, an appropriate drive signal (SS) can be output taking into consideration temperature changes during an operational lag time of the main current switches (S2, S3), so that it is possible to readily maintain discharge currents (I2a, I2b) at desired values.</p> |
