Taper machining device in wire-cut electrical discharge apparatus

• US 5,012,063 A
• Filed: 09/28/1989
• Issued: 04/30/1991
• Est. Priority Date: 10/05/1988
• Status: Expired due to Term

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Kuriyama, Juzo, Kawanabe, Tasuku
• Primary Examiner(s): Evans, Geoffrey S.
• Application Number:
  US07/413,684
• Time in Patent Office: 579 Days
• Field of Search: 219/69.12, 219/69.2, 219/69.17, 219/69.13, 364/474.04
• US Class Current: 219/69.12
• CPC Class Codes: B23H 2500/20 Methods or devices for detecting wire or workpiece position
• CPC Class Codes: B23H 7/06 Control of the travel curve of the relative movement between electrode and workpiece

Abstract

A taper machining device in a wire-cut electrical machining apparatus. The taper machining device includes an upper wire guide and a lower wire guide defining upper and lower bending points of a wire electrode. The wire electrode slantingly extends under tension between the upper and lower wire guides. One of the upper and lower bending points serves as a reference point and the remaining bending point is movable in a horizontal plane. The movable range of the remaining bending point is understood as being within a circle located at the bottom of a conical body whose apex is coincident with the bending point which serves as the reference point. The conical body has an apical angle twice as large as an allowable maximum inclination angle of the wire electrode.

Claims

1. A taper machining device in a wire electrical discharge machining apparatus for affecting taper machining to a workpiece, comprising:

an upper wire guide and a lower wire guide for supporting a wire electrode in its slanting extension;

upper and lower nozzles integrally provided with the upper and lower wire guides, respectively, for ejecting a machining liquid to the workpiece; and

regulating means;

said wire electrical discharge machining apparatus comprising a worktable extending in a first horizontal plane for mounting the workpiece thereon, a slider extending in a second horizontal plane parallel with said first horizontal plane, drive means for moving the slider in said second horizontal plane and in a vertical direction, the upper wire guide being provided at the slider;

at least one of the upper and lower wire guides and its integrally provided nozzle being horizontally movable, the wire electrode and the workpiece being relatively movable and providing a machining gap therebetween, the wire electrode having an upper bending point at the upper wire guide and a lower bending point at the lower wire guide, and

said regulating means for regulating movement of one of the upper and lower bending points within an imaginary conical body, to thereby avoid mechanical interference between the wire electrode and the upper and lower nozzles, an apex of the imaginary conical body bending defined by a remaining one of the lower and upper bending points as a reference point and the apical angle of the apex being twice as large as an allowable maximum inclination angle of the wire electrode, said regulating means further comprising position detectors for detecting at least one of a vertical and horizontal position of the slider, the position detectors generating signals indicative of said positions, and control means connected to the position detectors for controlling the drive means in response to the signal from the position detectors, said control means comprising;

(a) means for detecting a vertical position of the slider;

(b) first means for computing a wire guide span length between the upper and lower wire guides in accordance with the detected vertical position of the slider;

(c) second means for computing a relative horizontal offsetting length between the upper and lower wire guides when the slider is at the vertical position;

(d) third means for computing a maximum inclination angle at the vertical position of the slider;

(e) comparison means for comparing the maximum inclination angle with the allowable maximum inclination angle of the wire electrode; and

(f) means for driving the drive means when the allowable maximum inclination angle is greater than the maximum inclination angle to change at least one of the parameters consisting of the vertical position of the slider and the relative horizontal offsetting length between the upper and lower wire guides.

2. The control means according to claim 1, further comprising:

means for comparing a current item number (i) with a predetermined item number (i_max), the comparison being made after driving the drive mans; and

means for incrementing the item number when the current item number (i) is lower than the predetermined item number (i_max) for repeatedly executing the computations by the second and third computing means and for executing the comparison by the comparison means.

3. A taper machining device in a wire electrical discharge machining apparatus for effecting taper machining to a workpiece by an electrical discharge from a wire electrode, comprising:

movable and stationary wire guides for supporting the wire electrode, a wire guide span length being defined between the wire guides;

a slider connected to the movable wire guide for moving the wire guide in a horizontal plane and in a vertical direction;

drive means for moving the movable slider in the horizontal plane and in the vertical direction;

means (22) for detecting a vertical position of the slider;

first computing means for computing the wire guide span length in accordance with the detected vertical position of the slider;

second computing means for computing a relative horizontal offsetting length between the upper and lower wire guides when the slider is at the vertical position;

third computing means for computing a maximum inclination angle at the vertical position of the slider;

comparison means for comparing the maximum inclination angle with an allowable maximum inclination angle of the wire electrode; and

means for driving the drive means when the allowable maximum inclination angle is greater than the maximum inclination angle to change at least one of the parameters consisting of the vertical position of the slider and the relative horizontal offsetting length between the upper and lower wire guides.

4. The taper machining device according to claim 3, further comprising means for comparing a current item number (i) with a predetermined item number (i_max), the comparison being made after driving the drive means;

and means for incrementing the item number when the current item number (i) is lower than the predetermined item number (i_max) for repeatedly executing the computations by the second and third computing means and for executing the comparison by the comparison means.