WIRE ELECTRIC DISCHARGE MACHINE HAVING WIRE ELECTRODE TENSION CONTROL FUNCTION

• US 20140291295A1
• Filed: 04/01/2014
• Published: 10/02/2014
• Est. Priority Date: 04/02/2013
• Status: Abandoned Application

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: KASAI, Hirotsugu
• Application Number:
  US14/231,817
• Publication Number:
  US 20140291295A1
• Time in Patent Office: Days
• US Class Current: 219/69.12
• CPC Class Codes: B23H 1/00 Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
• CPC Class Codes: B23H 7/06 Control of the travel curve of the relative movement between electrode and workpiece
• CPC Class Codes: B23H 7/065 Electric circuits specially adapted therefor
• CPC Class Codes: B23H 7/10 Supporting, winding or electrical connection of wire-electrode
• CPC Class Codes: B23H 7/104 Wire tension control
• CPC Class Codes: G05B 2219/45221 Edm, electrical discharge machining, electroerosion, ecm, chemical

Abstract

In a taper machining using a wire electric discharge machine, a difference between a target tension value and an actual tension value of a wire electrode is fed back to a controller to determine input current values to a wire electrode feed motor and a wire electrode deliver motor, thereby adjusting the tension value of the wire electrode. When the taper angle of the wire electrode exceeds a given value, the control gain of the tension of the wire electrode for determining the input current value to the motor is lowered to prevent the wire electrode from oscillating.

Claims

1. A wire electric discharge machine having a wire electrode tension control function, the wire electric discharge machine comprising:

a motor that feeds a wire electrode to a workpiece;

a tension detection unit that detects a tension of the wire electrode;

a controller that controls the tension of the wire electrode;

upper and lower wire guides that hold the wire electrode above and below the workpiece; and

upper and lower wire guide units that move the upper and lower wire guides to incline the wire electrode;

wherein

the wire electric discharge machine performs machining of the workpiece by inclining the wire electrode and relatively moving the workpiece and the wire electrode, and

the wire electric discharge machine further comprising;

a tension control gain storage unit that stores control gains of the tension of the wire electrode in association with inclination angles of the wire electrode;

an inclination angle obtaining unit that obtains the inclination angle of the wire electrode; and

a tension control gain setting unit that reads the tension control gain corresponding to the obtained inclination angle of the wire electrode from the tension control gain storage unit and sets the read tension control gain;

wherein

the controller controls the tension of the wire electrode using the set tension control gain.

2. The wire electric discharge machine having a wire electrode tension control function according to claim 1, wherein the control gain is stored in the tension control gain storage unit in association with any one of a diameter of the wire electrode, a material of the wire electrode, a material of the upper and lower wire guides, or a combination thereof, and the inclination angle of the wire electrode.

3. The wire electric discharge machine according to claim 1, wherein

the inclination angle obtaining unit obtains the inclination angle of the wire electrode when a relative position of the upper and lower wire guides is changed, when the inclination angle of the wire electrode is changed, at each of predetermined times, or at predetermined time intervals, and

the tension control gain setting unit reads the tension control gain corresponding to the obtained inclination angle of the wire electrode from the tension control gain storage unit and sets the tension control gain.