CONTACT DETECTION APPARATUS FOR WIRE ELECTRICAL DISCHARGE MACHNE WITH CAPABILITY TO VARY APPLIED GAP VOLTAGE

• US 20130277335A1
• Filed: 02/28/2013
• Published: 10/24/2013
• Est. Priority Date: 04/24/2012
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: TAKAYAMA, Yushi, KAWAHARA, Akiyoshi, MATSUNAGA, Tomoaki
• Granted Patent: US 9,314,859 B2
• Time in Patent Office: Days
• US Class Current: 219/69.12
• CPC Class Codes: B23H 1/02 Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
• CPC Class Codes: B23H 2500/20 Methods or devices for detecting wire or workpiece position
• CPC Class Codes: B23H 7/04 Apparatus for supplying current to working gap; Electric circuits specially adapted therefor
• CPC Class Codes: B23H 7/18 for maintaining or controlling the desired spacing between electrode and workpiece

Abstract

A contact detection apparatus for a wire electrical discharge machine includes a voltage application unit adapted to apply a detection voltage to detect contact between a wire electrode and a workpiece; a contact determination unit adapted to determine contact or non-contact between the wire electrode and the workpiece based on changes in the detection voltage applied by the voltage application unit; and a voltage value changing unit adapted to change a voltage value of the detection voltage applied by the voltage application unit.

Claims

1. A contact detection apparatus for a wire electrical discharge machine comprising:

a voltage application unit adapted to apply a detection voltage to detect contact between a wire electrode and a workpiece;

a contact determination unit adapted to determine contact or non-contact between the wire electrode and the workpiece based on changes in the detection voltage applied by the voltage application unit; and

a voltage value changing unit adapted to change a voltage value of the detection voltage applied by the voltage application unit.

2. The contact detection apparatus for a wire electrical discharge machine according to claim 1, further comprising:

a data table storage unit adapted to store a data table containing voltage values of the detection voltage in association with materials of the workpiece; and

a voltage value determination unit adapted to determine the voltage value of the detection voltage based on the data table as well as on the material of the workpiece set as a machining condition.

3. The contact detection apparatus for a wire electrical discharge machine according to claim 1, further comprising:

a data table storage unit adapted to store a data table containing voltage values of the detection voltage in association with materials and sizes of the wire electrode; and

a voltage value determination unit adapted to determine the voltage value of the detection voltage based on the data table as well as on the material and size of the wire electrode set as machining conditions.

4. The contact detection apparatus for a wire electrical discharge machine according to claim 1, wherein the voltage value changing unit changes the voltage value by switching over a plurality of power supplies and/or resistance values using a switching unit.

5. The contact detection apparatus for a wire electrical discharge machine according to claim 1, wherein the voltage value changing unit is a variable-voltage value power supply.