JPH0512091B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a wire electrical discharge machining device that, when a wire electrode is broken, returns the wire electrode repaired at the machining start position to the original broken position. This is related to controlling the feeding speed of the wire electrode during the process.

[Conventional technology]

FIG. 2 is a schematic configuration diagram showing a conventional wire electric discharge machining apparatus. In the figure, 1 is a wire electrode, 2
is the workpiece, 3 is the machining start position on the workpiece 2,
4 is a wire electrode winding motor, 5 is a main tension brake, 6 is a pretension motor, 7
is a rotation detector, 8 is a collection roller, 9 is a pinch roller, 10 is a lower roller, 11 is a wire electrode supply motor, 12 is an upper roller, 13, 14 are pinch rollers, 15, 16, 17, 18, 19 are pulleys ,
20 is a wire electrode supply bobbin, 21 is a pipe guide clamp, 22 is a pipe guide, 23 is a collection box, and 24 is a disconnection position of the wire electrode 1 on the workpiece 2.

In the wire electric discharge machining apparatus as described above, a pulsed electric discharge is repeatedly generated between the workpiece 2 and the wire electrode 1, and the workpiece 2 is cut by the discharge energy. By the way, since the wire electrode 1 is usually composed of a thin metal wire, the wire electrode 1 is often broken due to an abnormal situation occurring during electrical discharge machining. In such a case, the X-axis and Y-axis table drive motors (not shown) are automatically started, and the wire electrode 1 is automatically repaired at the processing start position 3 on the workpiece 2. . Thereafter, the repaired wire electrode 1 is returned to the original disconnection position 24 while passing through the gap of the already processed locus of the workpiece 2. In that case, wire electrode 1
The feed rate is controlled at the same speed as the cutting process. The feeding speed of the wire electrode 1 is determined by controlling the rotational speed of the wire electrode winding motor 4. The rotational speed of the wire electrode hoisting motor 4 is made variable depending on the magnitude of the current flowing through the wire electrode hoisting motor 4, but the control range is normally controlled by hand between 1 and 16 notches. It is made variable within a range.

[Problem that the invention seeks to solve]

Since the conventional wire electric discharge machining apparatus described above is configured as described above, when the wire electrode 1 is cut during machining, the wire electrode 1 can be repaired at the machining start position 3 on the workpiece 2. After that, when returning the wire electrode 1 from the machining start position 3 to the original disconnection position 24, the wire electrode 1 passes through the gap in the machining trajectory of the workpiece 2, but normally Since the shape to be machined on the workpiece 2 is very complex, the distance between the wire breakage position 24 of the wire electrode 1 on the workpiece 2 and the machining start position 3 becomes long. However, since the feed speed of the wire electrode 1 during that time is controlled at the same speed as the speed during machining, there was a problem that the wire electrode 1 was wasted.The present invention solves this problem. This wire was developed to solve the problem, and can automatically control the feed speed of the wire electrode when restoring the repaired wire electrode to its original broken position, thereby suppressing unnecessary wear and tear on the wire electrode. The purpose is to obtain electrical discharge machining equipment.

[Means for solving problems]

The wire electrical discharge machining apparatus according to the present invention can prevent
The wire electrode is repaired at the machining start position, and the feed speed of the wire electrode when the repaired wire electrode passes through the gap in the machining trajectory and returns to the original broken position is determined while machining the workpiece. The feed speed of the wire electrode is automatically controlled to be slower than the feed speed during cutting.

[Effect]

In the wire electrical discharge machining apparatus of the present invention, by providing a means for automatically controlling the feed rate of the wire electrode, the feed rate of the wire electrode is automatically controlled in unmanned operation, thereby eliminating wasteful consumption of the wire electrode. can be prevented.

〔Example〕

FIG. 1 is a block diagram showing a feed speed control circuit for a wire electrode hoisting motor used in a wire electrical discharge machining apparatus which is an embodiment of the present invention. In the figure, 4 is a wire electrode winding motor, 25 is a current control circuit, 26 is an NC (numerical control) device, and 27
is NC tape.

The structure of the wire electric discharge machining apparatus which is an embodiment of the present invention described above is almost the same as the conventional apparatus shown in FIG. A series of operations for returning the wire electrode 1 to the original disconnection position 24 and continuing the electric discharge machining before the disconnection using the wire electrode 1 again will be omitted.

Now, the feeding speed of the wire electrode 1 is the collection roller 8.
determined by the rotation speed of The collection roller 8 is connected to the wire electrode winding motor 4, and the rotational speed of the wire electrode winding motor 4 is controlled by a feed speed control circuit for the wire electrode winding motor 4 shown in FIG. Therefore, wire electrode 1
After repairing the wire electrode 1 at the processing start position 3 during cutting, the repaired wire electrode 1
When returning the wire to the disconnection position 24,
NC device 26 inputted by NC tape 27
The program inside works and the signal is sent to the current control circuit 25.
The above program is set so that the feeding speed of the wire electrode 1 during normal cutting is ignored and a minute current flows to the wire electrode winding motor 4. If the program in the NC device 26 is stored so as to perform the above-mentioned operation, the unmanned operation of the wire electric discharge machining machine can be performed.
Prevents unnecessary wear and tear on the wire electrode 1 when the workpiece 2 is not being subjected to electrical discharge machining, such as when the wire electrode 1 passes through a gap in the machining trajectory and returns to the original disconnection position 24. can do.

Further, after the wire electrode 1 is returned to the wire breakage position 24, the feed rate of the wire electrode 1 becomes the same as that during electrical discharge machining, and the machining performed before the wire breakage is continued from the wire electrode 1 again.

In the above embodiment, when the wire electrode 1 is cut, after the wire electrode 1 is repaired at the processing start position 3, when the repaired wire electrode 1 is returned to the disconnection position 24, the wire electrode winding is performed. Although automatic speed control of the motor 4 has been described, there are other cases where feeding of the wire electrode 1 is required in addition to cutting the workpiece 2, such as end face positioning in setup work, and feeding of the wire electrode 1. It can be similarly applied to cases where vertical alignment is performed.

[Effects of the Invention] As explained above, in a wire electrical discharge machining apparatus, when cutting a wire electrode, the wire electrode that has been repaired at the machining start position is returned to its original cross section by passing through the gap of the already machining trajectory. Since the wire electrode feed speed when returning to the position is automatically controlled to be slower than the feed speed during machining of the workpiece, unnecessary wear and tear on the wire electrode is minimized. This has the excellent effect that expensive wire electrodes can be used efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a feed speed control circuit for a wire electrode hoisting motor used in a wire electrical discharge machining device which is an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing a conventional wire electrical discharge machining device. . In the figure, 1... wire electrode, 2... workpiece, 3... machining start position, 4... wire electrode winding motor, 5... main tension brake, 6...
... Pretension motor, 7 ... Rotation detector, 8 ... Collection roller, 9, 13, 14 ... Pinch roller, 10 ... Lower roller, 11 ... Wire electrode supply motor, 12 ... Upper roller, 15,1
6, 17, 18, 19...Pulley, 20...Wire electrode supply bobbin, 21...Pipe guide clamp, 22...Pipe guide, 23...Recovery box, 2
4...Disconnection position, 25...Current control circuit, 26...
...NC device, 27...NC tape. In addition,
In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A wire electrical discharge machining device that opposes a wire electrode to a workpiece through a minute gap and cuts the workpiece using discharge energy,
When the wire electrode is broken, the wire electrode is repaired at the processing start position, and the repaired wire electrode is returned to the original broken position by passing through the gap of the processed trajectory. A wire electrical discharge machining apparatus characterized by comprising means for automatically controlling a feed rate to be slower than a feed rate during machining of the workpiece.