JPS60108218A - Wire electric-discharge machining device - Google Patents

Abstract

PURPOSE:To prevent redisconnection from occurring after repairs, by controlling a discharge energy momentum in time of machining resumption from a disconnection spot of a wire electrode after repairing the snapped wire so as to make it smaller than that of energy in time of the disconnection. CONSTITUTION:In the case where a normal work 1 is machined, all relays 28, 29 and 30 are in a conductive state and therefore pulsative discharge energy is fed to the work 1 and a wire electrode 12 by means of on-off operations in transistors 22, 23 and 24. Repairing the snapped wire, when putting back to a disconnection spot and reopening the machining, a control circuit 18 of a numerical control system 17 outputs a signal, opening the relay 28, and a resistor, where an electric current to be turned to the discharge energy passes, is set to only relays 26 and 27, thereby reducing the electric current. With this constitution, the discharge energy is made smaller than that before the disconnection so that redisconnection of the wire after being repaired is preventable.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a wire electrical discharge machining device in which a wire electrode is opposed to a workpiece through a minute gap, and the workpiece is cut using electrical discharge energy. Regarding this, when the wire electrode is disconnected, the disconnection of the wire electrode after repair is completely prevented.

[Prior art]

Generally, a wire electrode is placed opposite the workpiece through a small gap, and a pulsed electric discharge 2 is generated between the workpiece and the wire electrode.
A wire electrical discharge machining apparatus is known that cuts the workpiece described above using electrical discharge energy that is repeatedly generated. This wire electric discharge machining device can easily perform complex cutting of hard metals and the like.

When performing electric discharge machining on the above-mentioned workpiece, the wire electrode is fed so as to penetrate into the workpiece. 17! c.
This wire electrode is usually made of thin metal, and may break due to an abnormal situation occurring during electrical discharge machining.

When the wire electrode is broken, repair work is performed by moving the machining start position i-, the x-axis table, and the Y-axis table, and replacing the wire electrode with a new one at the machining start position.

After the repair of the wire electrode is completed, the wire electrode is returned to the above-mentioned cutting position by passing through the gap in the vertical machining trajectory while supplying the entire wire electrode intermittently. After this return, the cutting process before cutting should be continued from the above cutting position.

Fully supply machining fluid to the wire electrode and workpiece, and supply the same amount of pulsed discharge energy as before the wire breakage.

Conventionally, when restarting machining after a wire electrode breakage, the same amount of discharge energy as before the wire breakage was supplied.
When this process is restarted, the wire electrode may be broken again, which is a drawback.

[Summary of the invention]

This invention eliminates the above-mentioned drawbacks of the conventional technology, and includes a wire electrode facing the workpiece through a minute gap, and the workpiece being cut using electrical discharge energy. In the event of wire breakage, the workpiece is automatically moved to the machining start position, the wire electrode is repaired at the machining start position, and the wire electrode is then passed through the gap in the reading machining trajectory, and the wire electrode is completely restored. In wire electrical discharge machining equipment that returns to the disconnected position and then generates all the electrical discharge energy to continue machining,
When starting machining at the wire electrode breakage position, the discharge energy supplied to the wire electrode is controlled to be less than the discharge energy at the previous breakage, thereby preventing wire electrode breakage fR'fr after repair. The present invention provides a wire electrical discharge machining apparatus.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows the configuration of a wire electric discharge machining device. In the figure, reference numeral 1 denotes a workpiece, which is placed on an X table 2 and a Y table 3, which are freely movable in a horizontal plane.

Reference numeral 4 denotes a cutting start hole drilled in advance on the surface of the workpiece 1. 5 is a guide that supports the wire electrode 12t, and a Z
It is fixed to an axially movable shaft. 6 is an X-axis table drive motor, and 7 is a Y-axis table drive motor. Bit brake, 9 is a take-up roller, 10 is a supply reel, 11 is a take-up reel, wire electrode 12
It functions to supply. 16 is a machining liquid tank, which contains deionized water and is supplied to the workpiece 1 by a pump 14.

15 is a processing power source, which connects the wire' through the guide 16.
Full discharge energy is supplied to the IfL pole 12 and the workpiece 1. Reference numeral 17 denotes devices (1) to (C), which are composed of a control circuit 18 and a servo circuit 19 that controls a table drive motor. 2o indicates the disconnection position of the wire 'a pole 12.

In the wire electric discharge machining apparatus described above, the wire electrode 12 is opposed to the workpiece 1 through a small gap, deionized water in the machining fluid tank 13 is supplied by the pump 14, and the machining power supply 15 supplies the wire electrode 12 with the workpiece 1. and the workpiece 1 , the X table 2 and the Y table 3 are controlled by the servo circuit 19 , and machining of the workpiece 1 is started from the cutting start hole 4 . Thereafter, when the wire electrode 12 is disconnected at the cutting position 20, the X-axis table drive motor 6 and the X-axis table drive motor 7 are automatically started, and the machine is moved to the machining start position and inserted into the cutting machining start hole 4. Then, the wire electrode 12 is repaired. Thereafter, the wire electrode 12 is returned to the above-mentioned disconnection position 20 while passing through the gap of the vertical machining locus. Thereafter, discharge energy is supplied from the machining power source 15 to continue machining. When the same amount of energy as when cutting the wire electrode 12 is applied as discharge energy to continue this discharge, the wire electrode 12 is cut again.
However, in this case, the amount of discharge energy supplied to the wire electrode 12 when starting machining at the wire breakage position 20 of the wire electrode 12 is controlled to be less than the discharge energy at the previous breakage. This prevents disconnection of the wire electrode 12 after repair.

FIG. 2 shows a specific circuit for controlling the discharge energy as described above. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. 21 is a DC power supply, 22.23
．． 24 is a transistor, 25°26.27 is a current limiting resistor, and 28, 29°30 is a relay. The wire electrode 12 is connected to the workpiece 1 from the DC voltage 21 through a switching transistor 22, 25, 24, a resistor 25, 26, 27, and a relay 28, 29, 30. Also, relay 28.29.30
is turned on by the control circuit 1B (7)
The transistor 22 is configured to be able to perform ttj control.
．． 23 and 24 are configured to be turned ON and OFF by an oscillator OSC.

Normally, when processing workpiece 1, all relays 28
．． 29.30 is conductive, transistor 22.2
3.24 ON-OF'F, pulsed discharge energy is supplied to the workpiece 1 and the wire electrode 12.

When the wire 1st step 12 is broken, the wire 1st step 12 is turned back 1ω as described above. Thereafter, as described above, processing of the workpiece 1 is restarted from the disconnection position 20b of the wire electrode 12 and continued. , for example, opens the contacts of relay 28. As a result, the resistor through which the discharge energy and force current pass has a sign of 2
6.27, the resistance through which the current flows increases, and the current decreases. In this way, when starting machining at the wire electrode breakage position (5), the amount of discharge energy supplied to the wire electrode will be less than the discharge energy at the previous breakage, so this will prevent the wire electrode breakage after repair. It can be prevented.

〔Effect of the invention〕

As described above, this invention has the wire electrode completely facing the workpiece through a small gap, and by electric discharge energy,
When the wire electrode is disconnected, the workpiece is automatically moved to the machining start position, and the wire electrode is repaired at the machining start position.
While passing the wire electrode through the gap in the trajectory of the subsequent reading process, return the wire electrode to the above-mentioned disconnection position,
After that, the entire discharge energy is generated to continue machining (5) In wire electric discharge machining equipment, when machining is started at the wire electrode breakage position, the amount of discharge energy supplied to the wire electrode is ← 1- Ijk'i
It is believed that JX Engineering X has less power than Lugie, and can prevent the wire electrode from breaking after repair, making it possible to perform smooth electrical discharge cutting.

4 f)rliIL Explanation of Drawings Fig. 1 shows a +;4 [human being] of a processing device used to explain an embodiment of this invention; Fig. 2 shows an actual b1n example of this invention. It is a circuit diagram.

1. Workpiece, 12: Wire electrode, 18; Control circuit,
20: Disconnection position.

It should be noted that the same symbol in each 1 and 1 shall be shown as 12 and 12, or 41A and 41A as odd.

Agent: Patent Attorney Sanro Kimura Figure 1 10 ++ 9 15 Figure 2 7

Claims (1)

[Claims] A wire electrode is placed opposite the workpiece through a small gap, and 7
fl [Energy is used to cut the workpiece, and when the wire electrode breaks, the workpiece is automatically moved to the machining start position, and the wire electrode is completely repaired at the machining start position. In a wire electrical discharge machining apparatus, the wire electrode is returned to the above-mentioned disconnection position while the wire electrode is passed through the gap in the machining locus, and then discharge energy is generated to continue machining. A wire electrical discharge machining apparatus characterized in that the amount of electrical discharge energy supplied to a wire electrode when starting machining at a wire breakage position is controlled so that it is less than the discharge energy at the time of a previous wire breakage.