重畳波による超硬合金の放電加工
1981 年 14 巻 28 号 p. 10-19
詳細
1981 年 14 巻 28 号 p. 10-19
A specially designed transistorized pulse generator, which produces a superimposed short pulse on a fundamental rectangular pulse, is applied for machining tungsten carbide alloy with a copper tool electrode in a kerosene dielectric. The polarity of the tool electrode is positive.
The results obtained are as follows.
(1) In EDM of tungsten carbide alloy, the successive discharge is exceedingly stable and most of the discharges ignite before the gap voltage reaches no load voltage. Subsequently, the average ignition delay time is close to zero.
During about 10μs at the beginning of each discharge, the transient extraordinary phenomenon with both high voltage and high frequency oscillation is observed on the waveform of gap voltage.
(2) As the current intensity of discharge reduces, the successive discharge becomes unstable. It is found from this experiment that the high current pulse with short duration, superimposed at the beginning of each discharge, is sufficiently available to stabilize the successive discharge with low current.
(3) The effect of the superimposed pulse on the electrode erosion remarkably exerts only in the early stage of discharge, and the removal rate of tungsten carbide alloy can be markedly increased by using the superimposed pulse in comparison with ordinary rectangular pulse.
