| 摘要 |
PURPOSE:To improve the efficiency of electric discharge work by detecting the working voltage of a plurality of electrodes and workpiece to be fed through same drive shaft then controlling the returning direction with the maximum level while the feeding direction with minimum level. CONSTITUTION:A plurality of electrodes are fed through same drive shaft while independent working power source is connected to each electrode to perform electric discharge machining. The working voltages 441-444 across each electrode and workpiece are detected to decide the maximum level 44H and minimum level 44L. When the minimum level 44L exceeds over the referential level Vo the electrode is fed toward the workpiece while when it is lower than Vo the electrode is controlled to return. The servo voltage for feed control is exchanged to be the maximum level 44H for the feeding direction while to be the minimum level 44L for the returning direction. When employing the maximum and minimum feeding speed, the machining efficiency can be improved. |
