Cutting area responsive EDM method and apparatus with cyclically interrupted pulse trains

摘要

EDM method and apparatus in which the electrical-discharge machining pulses are triggered by the application across the machining gap of a succession of pulse trains of discrete pulses whose durations and intervals may be preset for optimum machining conditions (e.g. surface finish). The instantaneous machining area is detected and a time element, such as the duration of each pulse train or the interval between pulse trains or both, is controlled so as to maintain the current density substantially constant in spite of changing machining areas during the machining process.