JPS63185533A - Wire cut electric discharge machine - Google Patents

Abstract

PURPOSE:To easily remove a machining chip or the like, accumulating in a machined groove, and to enable a machining speed to be improved, by providing a control circuit which controls a receiving device or a brake device so as to change the moving speed of a wire electrode to be increased and decreased by the fixed time interval. CONSTITUTION:A numerical control (NC) unit 14 supplies a control signal, which adjusts a speed to increase and decrease by the fixed time interval, to a receiving motor 7 controlled by a control power supply circuit 12, correspondingly repeating high and low speed controls for the predetermined time. Accordingly, a wire electrode 1, which moves running, repeatedly changes its moving speed to high and low speeds, but the wire electrode sets its low speed to about the speed of normal feed and high speed to the value of the normal speed or more. And for switching to the high and low speeds, the wire electrode, when it switches its speed to the high speed by the plate thickness of a workpiece 3, switches the speed by the time interval to an extent such that the wire electrode enables its point end to pass through the workpiece 3 from its upper to bottom. This switching time interval is input by an input device 15, in this way, a machine, enhancing a removal effect of a machining chip, accumulating in a machined groove, while improving circulation of machining fluid into a machined part, enables electric discharge machining to be stably performed with less generation of arcing and short-circuiting.

Description

[Detailed description of the invention] field of application of the invention) The present invention relates to improvements in wire-cut electrical discharge machining equipment.

[Prior art and problems]

In a conventional wire-cut electrical discharge machining device, a wire electrode is moved via a guide and is moved at a constant speed and tension using a pulling device and a brake device. The wire electrode moving at a constant speed and the workpiece are placed opposite each other, and a pulse voltage is applied to the opposing gap to repeatedly generate electrical discharge. By controlling the drive and applying a relative machining feed to a predetermined shape, the workpiece is cut into a shape.

The wire electrode used has a wire diameter of 0.05 to 0.3111φ.
For example, Bs1lf of 0.3 m + aφ is used, and in order to reduce the consumption of this thin wire electrode, the moving speed is set at such a level that the electrode does not wear out and break due to discharge.
Machining is performed by setting the traveling speed at the pole to about 41/1n.

However, even if the wire electrode is moved at a speed that does not cause wear and tear as described above and the wire is being moved, concentrated discharges sometimes occur due to machining debris that is generated and accumulated in the machining groove of the workpiece. Processing is interrupted and wire breakage occurs due to short circuits or short circuits.

[Means for solving problems]

The present invention eliminates the above drawbacks and improves processing efficiency by devising the running movement of the wire electrode. It is designed to control a brake device.

〔Example〕

The present invention will be described below with reference to an embodiment of the drawings. Reference numeral 1 denotes a wire electrode, 2 a guide, and the wire electrode 1 and the workpiece 3 that move between these are opposed and machined.

4 is a reel that supplies the wire electrode 1; 5 is a reel that takes up the used wire electrode 1; 6 is a take-up roller;
7, and the pinch low 58
7 Electrode 1 is sandwiched between rollers and driven. A brake roller 9 is driven and controlled by a motor 10, and applies a brake by sandwiching the wire W pole 1 between it and the pinch row 511. 12 is a control power supply circuit for controlling the take-up roller drive motor 1, and 13 is a control 1m source circuit for controlling the brake roller drive motor 10, both of which receive the NCl1jt[1l14niyotte till@ command. 15 is a program input device for N C1i@, 16 is a processing table for fixing the workpiece,
17 and 18 are X and Y axis control motors.

In the above, the wire electrode 1 is supplied from the reel 4, passes through the guide 2, and is wound onto the other reel 5. motor 7
By driving, the take-up roller 6 presses the wire electrode 1 between the pinch rollers 8 and applies a take-up driving force, and the supply side brake roller 9 presses the wire electrode 1 between the pinch rollers 11 by braking of the motor 10 to apply the brake. This applies a predetermined tension and speed to the wire electrode 1 between the guides 2 and causes it to travel. The workpiece 3 faces the wire electrode 1 between the guides 2, and supplies machining pulses from a pulse power source while jetting water machining fluid from a nozzle (not shown).
Machining is performed by repeating pulsed discharge. Motor during processing 17.
A predetermined shape can be cut by controlling 18 by NC and relatively feeding the workpiece 3 in a programmed shape.

Therefore, the take-up motor 7 controlled by the control power supply circuit 12 is not driven at a low speed, but is supplied with a control signal to increase or decrease the speed at regular time intervals from the NC control device 14, and is controlled at high speed for a predetermined period of time accordingly. Repeat low speed control. As a result, the moving wire electrode 1 repeatedly moves at a high speed and then a low speed, but the low speed is about the same as the conventional normal feed speed and the high speed is higher than that. It is effective to switch between high and low speeds depending on the thickness of the workpiece 3 at a time interval that allows the tip of the wire electrode to pass through the workpiece from top to bottom when switching to high speed. This increase/decrease speed and switching time interval are inputted using the input device 115. This gives disturbance to the machining debris deposited in the machining groove, increasing the removal effect, and also improves the flow of machining fluid to the machining area, making it possible to perform stable electric discharge machining with less occurrence of arcs and short circuits.

In the figure, a brake motor 10 is also controlled to increase or decrease by a control power source 13 to increase or decrease the brake. The tension of the moving wire electrode 1 changes as a result of this increase/decrease change, and as strong tension and weak tension act alternately, the wire electrode 1 running between the guides 2 is free from bends, bends, deflections, etc., and this causes concentration. The occurrence of electrical discharge can be prevented, contributing to stable electrical discharge machining.

Next, to explain an example, BS with a wire diameter of 0.311+1φ
When cutting a S K D 11 material with a thickness of 75 II t using a wire at a processing speed of 220 fl12/sin, the moving speed of the wire electrode was set at 51/min.
and 41. When the tension was switched between 1.85 ks and 1.1 kg at 5 Hz, the machining speed increased to about 2901112/workin.

Incidentally, the time interval of speed increase/decrease control by the take-up motor 1 can be switched and controlled depending on the discharge state performed in the gap between the wire electrode 1 and the workpiece 3. Further, the moving speed of the wire electrode can be controlled by controlling a brake, and a powder brake, a friction brake, etc. can be arbitrarily used as the brake. In addition to controlling the movement of the wire electrode, it is possible to increase or decrease the jet pressure of the machining fluid, increase or decrease the current peak value of pulse discharge, or increase or decrease the machining feed rate.

[Effects of the Invention] As described above, the present invention is provided with a control circuit that controls the take-up device or the brake device to increase or decrease the moving speed of the wire electrode at regular time intervals, so that the wire electrode is not deposited in the machined groove. It is easy to remove machining debris, improve the flow of machining fluid to the machining gap, and continue stable machining that prevents concentrated arc discharge and short circuits.This enables highly efficient discharge that increases machining speed. Can be processed.

[Brief explanation of the drawing]

The drawing is a configuration diagram of an embodiment of the present invention. 1...Wire electrode 2...Guide 3...Workpiece 6...Take-off roller 7. ......Take-up motor 8...Pinch roller 9...Brake roller 10...Brake motor 11...・・・
...Pinch roller 12...Motor control power supply circuit 13...
...Motor control power supply circuit 14...
・NC control device patent applicant

Claims (1)

[Claims] In an apparatus for electric discharge machining in which a wire electrode is moved at a predetermined speed and a predetermined tension while passing through a guide and is moved at a predetermined speed and a predetermined tension by controlling a pulling device and a brake device, the moving speed of the wire electrode is controlled for a predetermined period of time. A wire electrical discharge machining device characterized in that a control circuit is provided for controlling the pulling device or the braking device so that the pulling device or the braking device increases or decreases at intervals.