Control switching for spark erosion machining gap - uses parameters of pulse applied between workpiece and tool electrodes for defining machining gap

摘要

The adjustment of the working gap in spark erosion machining installations is controlled by defining the working gap, using parameters of each voltage pulse applied between the tool and workpiece electrodes. The parameters are the ignition time of the discharge and the voltage value between the electrodes during the current pulse. The parameters of one discharge to the next are stored. The parameters are summated, and a proportionality factor is allocated to each parameter. The sum represents the value to be held constant during the machininq process. The summation of the stored parameters is interrupted when a short circuit, or a light arc discharge, occurs in the working gap. The control circuit converts the ignition time values of discharges into voltage values. The voltage during the current pulse between the electrodes is measured and stored by a second circuit, incorporated into the control one.