ELECTRODE FEED SPEED CORRECTING DEVICE FOR ELECTROLYTIC PROCESSING MACHINE

摘要

PURPOSE:To hold a gap between processing electrodes at a proper value, by a method wherein, when a change factor of a current flowing through the gap between the processing electrodes exceeds the upper limit of a preset allowable range, the feed speed of the processing electrode is decreased, and when it is below a lower limit, the feed speed is increased. CONSTITUTION:Based on a voltage, regulated by a regulator 6, serving as a speed reference, a processing electrode 1 is fed in the direction of a workpiece 2 according to a processing progress with the aid of an electric motor 7. In which case, a voltage proportioning a current flowing through a gap between the electrodes 1 and 2 is generated at both ends of a shunt 9, and voltage signals therefrom are converted into a frequency pulse through a V-F converter 11 for counting. A ratio between a preceding and a present value per a unit time by means of a signal from a control device 18, is determined through the working or resistors 13a, 13b, D/A 14a, 14b, and a divider 15. An output therefrom is compared with reference values REF 1 and REF 2 responding to a ratio of 1.1 or 0.9, when the output exceeds 1.1, an electrode feed speed is decreased by means of a comparator 16a and a drive device 24a, and when below 0.9, the speed is increased. This constitution holds a gap between processing electrodes at a proper value, and prevents the occurrence of shortcircuit.