High-frequency power feeder circuitry and supply for electrical discharge machining

摘要

An EDM method and apparatus for supplying successive trains of discrete elementary machining pulses to an EDM gap wherein a high-frequency AC power generally of the frequency of the discrete elementary machining pulses is generated in a high-frequency generating unit disposed remote from the machining gap. The power is transmitted directly in the unrectified AC form along a feeder cable to the proximity of the machining gap whereat a switching rectifier is provided connected to a tool electrode and workpiece across the machining gap via respective conductors of a minimum length. The rectifier operates to cyclically interrupt the transmitted high-frequency AC while concurrently rectifying same, thereby providing successive trains of the discrete elementary machining pulses for direct application across the EDM gap. A discharge state sensor is also disposed in the direct proximity of the gap for sensing the discharge characteristics occurring in the EDM operation a pulser provides a control signal which acts on pulsing for the switching rectifier to modify the cyclic interruption of the transmitted AC and to control production of the successive trains of elementary discharge pulses.