Electric discharge machine including means for detecting abnormal discharge conditions

DETAILED DESCRIPTION An object of the present invention is to provide, in light of the aforementioned problems, an electric discharge machine capable of determining whether an interpole gap is in a normal or abnormal condition, by analyzing the frequency spectrum of the voltage waveform of the electric discharge across the interpole gap when the electric discharge is caused, in order to distinguish between normal and abnormal electric discharges.
A further object of the present invention is to provide an electric discharge machine wherein elements which may worsen the condition of the interpole gap, such as sludge and chips, are removed by first analyzing the frequency spectrum of the voltage waveform of the electric discharge across the interpole gap when electric discharge is caused in order to distinguish between normal and abnormal electric discharges, and increasing and decreasing the gap between the electrode and workpiece to generate a liquid flow by means of a pumping action in the interpole gap.
Another object of the present invention is to provide an electric discharge machine wherein the value of a pulse voltage applied across the gap between the electrode and the workpiece to normalize conditions in the interpole gap is controlled by analyzing the frequency spectrum of the voltage waveform of an electric discharge across the interpole gap when electric discharge is caused, in order to distinguish between normal and abnormal electric discharges.
Still another object of the present invention is to provide an electric discharge machine wherein the quiescent time of the pulse voltage applied across the gap between the electrode and the workpiece is controlled by analyzing the frequency spectrum of the voltage waveform of the electric discharge across the interpole gap when electric discharge is caused, in order to distinguish between normal and abnormal electric discharges and to normalize the conditions in the interpole gap.
Still another object of the present invention is to provide an electric discharge machine wherein a reference voltage used to control the gap between the electrode and the workpiece is controlled by analyzing the frequency spectrum of the voltage waveform of the electric discharge across the interpole gap when electric discharge is caused in order to distinguish between normal and abnormal discharges and to normalize conditions in the interpole gap