Wire electrical discharge machine and electrical discharge machining method

Patent metadata

Field	Value
Publication number	US-11534844-B2
Application number	US-201916655641-A
Country	US
Kind code	B2
Filing date	Oct 17, 2019
Priority date	Oct 23, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A wire electrical discharge machine includes: a gap voltage detector for detecting a voltage across an electrode gap; a first voltage control unit for applying a first voltage to the electrode gap; a discharge determiner for determining whether or not the electrode gap is in a discharging state during application of the first voltage; and a second voltage control unit for supplying a machining current through the electrode gap when the electrode gap is in a discharging state. After a supply of the machining current to the electrode gap, even when a discharge is induced by the next application of the first voltage to the electrode gap, the second voltage control unit prohibits application of a second voltage to the electrode gap.

First claim

What is claimed is:

1. A wire electrical discharge machine which performs electrical discharge machining on a workpiece by using electrical discharges generated by applying voltage across an electrode gap formed between a wire electrode and the workpiece, comprising:
a first power circuit including a capacitor and configured to induce an electrical discharge by applying a first voltage across the electrode gap;
a second power circuit configured to supply a machining current through the electrode gap by applying a second voltage across the electrode gap;
a gap voltage detector configured to detect the voltage across the electrode gap;
a first voltage control unit operatively coupled to the first power circuit, the first voltage control unit programmed to apply the first voltage to the electrode gap in an intermittent manner by controlling the first power circuit;
a discharge determiner configured to determine whether or not the electrode gap is in a discharging state during application of the first voltage, based on the detected voltage across the electrode gap; and
a second voltage control unit operatively coupled to the second power circuit, the second voltage control unit programmed to supply the machining current through the electrode gap when the electrode gap is determined to be in a discharging state unless machining current was supplied after the previous discharging state,
then the second voltage control unit is programmed to not supply the machining current through the electrode gap, wherein the first voltage control unit is programmed to apply the first voltage to the electrode gap
where the electrode gap gets into the discharging state during subsequent application of the first voltage after the machining current was not supplied through the electrode gap previously, the second voltage control unit is programmed to supply the machining current through the electrode gap.

2. The wire electrical discharge machine according to claim 1 , wherein when the voltage across the electrode gap becomes lower than a predetermined voltage during the application of the first voltage, the discharge determiner determines that the electrode gap is in a discharging state.

3. An electrical discharging method for performing electrical discharge machining on a workpiece with a wire electrical discharge machine by using electrical discharges generated by applying voltage across an electrode gap formed between a wire electrode and the workpiece, wherein the wire electrical discharge machine includes: a first power circuit including a capacitor and applying a first voltage across the electrode gap to induce an electrical discharge; a second power circuit applying a second voltage across the electrode gap to supply a machining current through the electrode gap; and a gap voltage detector detecting the voltage across the electrode gap,
the electrical discharging method comprising:
a first voltage control step of applying the first voltage to the electrode gap in an intermittent manner by controlling the first power circuit;
a discharge determination step of determining whether or not the electrode gap is in a discharging state during application of the first voltage, based on the detected voltage across the electrode gap; and
a second voltage control step of supplying the machining current through the electrode gap by controlling the second power circuit when the electrode gap is determined to be in a discharging state,
wherein after a supply of the machining current to the electrode gap, even when a discharge is induced during next application of the first voltage to the electrode gap, the second power circuit is prohibited from applying the second voltage to the electrode gap in the second voltage control step so as not to supply the machining current through the electrode gap,
where the electrode gap gets into the discharging state during further application of the first voltage after the machining current has not been supplied through the electrode gap last time, the machining current is supplied through the electrode gap.

4. The electrical discharge machining method according to claim 3 , wherein in the discharge determination step, when the voltage across the electrode gap becomes lower than a predetermined voltage during the application of the first voltage, it is determined that the electrode gap is in a discharging state.

Assignees

• Fanuc Corp

Inventors

• Hasegawa Yasuo

Classifications

• B23H7/08

  Wire electrodes · CPC title

• B23H1/022 Primary

  for shaping the discharge pulse train (B23H1/024 takes precedence) · CPC title

• B23H7/04

  Apparatus for supplying current to working gap; Electric circuits specially adapted therefor · CPC title

• B23H11/00

  Auxiliary apparatus or details, not otherwise provided for · CPC title

• B23H7/02 Primary

  Wire-cutting · CPC title