Electric discharge machining apparatus
AssigneeFanuc Corporation
InventorsMasao MURAI, Akihiro SAKURAI
Life of this patent
Estimating the term…
Abstract
A voltage measurement circuit is connected between an electrode and a workpiece by a parallel cable through a resistor to measure a machining gap voltage. The parallel cable, like a television antenna feeder line, is formed such that two conductive wires are parallel fixed by an insulating and flexible material such as rubber or resin with a predetermined distance. The interline distance of the parallel cable is increased to decrease a stray capacitance of the cable, so that a high-frequency voltage in finish machining can be measured by the voltage measurement circuit without being attenuated. The resistor is connected to suppress oscillation of a voltage input to the voltage measurement circuit.
Claims3
An electric discharge machining apparatus which has a voltage measurement circuit for measuring a machining gap voltage between an electrode and a workpiece during machining and controls an electric discharge state and feeding of the electrode on the basis of a measurement result obtained by the voltage measurement circuit, wherein
- two measurement cables including a measurement cable for connecting the voltage measurement circuit to an electrode and a measurement cable for connecting the voltage measurement circuit to the workpiece are arranged to be parallel fixed by insulating and flexible material with a distance not less than four times a radius of the measurement cable, and a resistor is inserted to the electrode and the workpiece side in the measurement circuit.
An electric discharge machining apparatus which has a voltage measurement circuit for measuring a machining gap voltage between an electrode and a workpiece during machining and controls an electric discharge state and feeding of the electrode on the basis of a measurement result obtained by the voltage measurement circuit, wherein
- one terminal of a resistor capacitance divider which connects a first and a second RC parallel circuit, obtained by connecting a resistor and a capacitor in parallel to each other, in series to divide a machining gap voltage between the electrode and the workpiece and outputs the divided voltages is connected to the electrode, and the other terminal is connected to the workpiece,
- the machining gap voltage is measured by the voltage measurement circuit through the resistor capacitance divider, and
- a capacitance of a second RC parallel circuit connected to the voltage measurement circuit is set as a stray capacitance held by a measurement cable connected to the voltage measurement circuit.
Dependencies are inferred from the claim text.