JPH07106498B2 - Wire electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to wire electric discharge machining for automatically cutting the wire electrode by automatically controlling the tension and the melting current of the wire electrode according to the thickness and type of the wire electrode. It relates to the device.

[Prior Art] FIG. 5 is a schematic view showing an example of a wire electrode cutting portion of a conventional wire electric discharge machine. In the figure, (1) is a wire electrode, and (2) is a workpiece to be cut by the wire electrode (1). (3) is a cutter blade for cutting the wire electrode (1), (4) is a pneumatic cylinder connected to the cutter blade (3), (5) and (6) are respectively connected to the pneumatic cylinder (4), and Cutter blade (3)
An air pressure source for advancing and retreating (1), (7) is a receiver for the cutter blade (3) used when cutting the wire electrode (1). (8) is a workpiece (2) and a wire electrode (1)
Power supply that repeatedly generates pulsed discharge between
(9) is a machining start hole provided in the workpiece (2), (1
Reference numeral 0) is a power feeding die provided below the workpiece (2).

Next, the operation will be described. After processing the workpiece (2) with the wire electrode (1), the wire electrode (1) is cut with the cutter blade (3), and the already processed wire electrode (1)
To remove. The cutting of the wire electrode (1) is performed by a pneumatic pressure source (5) on the cylinder (4) connected to the cutter blade (3).
The air pressure is introduced from above, and the cutter blade (3) is moved forward in the direction of the wire electrode (1) to perform the operation with the cutter receiver (7). At this time, the blade angle of the cutter blade and the pressing force are adjusted according to the thickness and type of the wire electrode (1) so that the cut surface of the wire electrode (1) is close to a perfect circle. After that, air pressure is introduced into the air pressure source (6) to retract the cutter blade (3). After the wire electrode (1) is cut, the wire electrode (1) is inserted into the machining start hole (9) of the new workpiece (2) and further into the hole of the power feeding die (10). After that, the discharge energy is supplied from the power source (8) through a series of wire feeding paths to newly cut and process the workpiece (2).

According to the conventional wire electric discharge machine configured as described above, in order to easily insert the wire electrode into the hole of the power feeding die, in order to cut the cut surface of the wire electrode in a state close to a perfect circle, the thickness and type of the wire electrode Therefore, the blade angle and pressing force of the cutter blade must be mechanically adjusted, and its operation is extremely complicated, and the cutting surface is often distorted.In this case, it is difficult to insert it into the hole of the power feeding die. Sometimes it was.

In order to solve such a problem, for example, Japanese Patent Publication No. 61-26
As shown in Japanese Patent No. 455, an invention has been proposed in which a wire electrode is blown. This invention applies an electric current to the wire electrode while applying a tensile force in the axial direction to heat the wire electrode, elongates the wire electrode to form a thin portion in a part of the wire electrode, and stops the application of the tensile force to form the thin wire portion. The diameter part is fused by current heating, and the desired one of the fused wire electrodes is fed to the wire guide to be inserted into the required through hole of the workpiece to set the wire electrode. .

[Problems to be Solved by the Invention] Although the invention configured as described above has various features, it is not only extremely complicated in structure but also for heating the wire electrode depending on the thickness and type of the wire electrode. The current and the magnitude of the current for fusing the wire electrode must be adjusted each time with a variable resistor, and after heating with the above heating current, the switch is opened, and then the fusing current switch is turned on. The operation is extremely troublesome.

The present invention has been made to solve the above-mentioned problems, and it is not necessary to adjust the variable resistor or the like each time according to the thickness and type of the wire electrode, and moreover, the contact section of the wire electrode can be made true. It is an object of the present invention to obtain a wire electric discharge machine capable of cutting in a state close to a circle. In the wire electric discharge machine, the wire electrode may be cut by an abnormal current or the like during electric discharge machining, but the present invention is different from the invention in the case of actively cutting the wire electrode at the end of work. It is about.

[Means for Solving the Problems] A wire electric discharge machine according to the present invention has the following configuration. That is, in the wire electric discharge machine that cuts the work piece by the discharge energy by facing the work piece with the wire electrode with a small gap, the thickness, kind, and fusing of various wire electrodes to be used The wire tension required for fusing the wire electrode to be cut is selected from the memory means by the storage means in which the data table of the required wire tension and current value is stored in advance and the input of the thickness and type of the wire electrode to be cut. Depending on the wire tension determining means to be used and the thickness and type of the wire electrode to be cut,
A current value determining means for selecting and determining a current value required for fusing the wire electrode to be cut from the storage means, a control circuit for applying a tension to the wire electrode based on the wire tension determined by the wire tension determining means, and a current value determination And a disconnecting circuit for supplying a current to the wire electrode based on the current value determined by the means.

Further, the control circuit connects a resistor and a series contact circuit in which a make contact of a relay that is selectively operated by the wire tension determining means is connected to the resistor, and the series circuits are connected in parallel with different resistance values from each other. The parallel circuit and the power supply are connected in series to the input terminal of the drive motor of the roller that applies tension to the wire electrode when disconnected.

Further, the disconnection circuit, a series circuit formed by connecting a resistor and a make point of a relay selectively operated by the current value determining means to the resistor is connected in parallel with a plurality of columns having different resistance values, The parallel circuit and the power supply are connected in series between the upper and lower power supply terminals that come into contact with the wire electrodes when disconnected.

Further, a high-frequency pulse power supply is used as a means for supplying a current to the wire electrode for heating the wire electrode.

[Operation] In the present invention, to cut the wire electrode, first, the thickness and type of the wire electrode to be cut are input. The data of the wire tension and the current value necessary for fusing with respect to the thickness and type of the wire electrode are stored in advance in the storage means, and when the thickness and the type of the wire electrode to be cut are input, the wire tension determination means stores them. The wire tension required for fusing the wire electrode to be cut from the means is selected and determined, and the control circuit is instructed to tension the wire electrode with the determined wire tension. This causes the control circuit to tension the wire electrodes to the indicated wire tension. Further, the current value determining means selects and determines a current value required for fusing the wire electrode to be cut from the storage means, and instructs the cutting circuit to heat the wire electrode at the determined current value. This causes the cutting circuit to heat the wire electrode at the indicated current value. In this way, the optimum values of the wire tension and current value required for fusing according to the thickness and type of the wire electrode are automatically selected and determined, and the fusing of the wire electrode is performed.

Further, a control circuit, a series circuit in which a resistor and a make contact of a relay that is selectively operated by the wire tension determining means are connected to the resistor are connected in parallel in a plurality of columns with different resistance values, By connecting this parallel circuit and the power supply in series to the input terminal of the drive motor of the roller that applies tension to the wire electrode when disconnecting, the optimum value of wire tension can be selected and determined at the same time. The make contact of the relay corresponding to the resistor for closing can be closed, and the responsiveness can be improved.

Further, the disconnection circuit is connected in parallel to the resistor by selectively operating the current value determining means to the resistor, and the parallel circuit and the power supply are connected between the upper and lower power supply terminals that come into contact with the wire electrode at the time of disconnection. By connecting and configuring in series, it is possible to close the make contact of the relay corresponding to the resistor for making the selected current value at the same time as the selection and determination of the optimum value of the current value, and to improve the responsiveness. Can be increased.

Further, by using a high frequency pulse power supply as a means for passing a current through the wire electrode for heating the wire electrode, the current can be concentrated on the surface of the wire electrode, and the skin effect makes the wire electrode closer to a perfect circle. Can be blown into a state. Further, power can be saved as compared with the case of using a DC power supply.

[Embodiment of the Invention] FIG. 1 is a configuration diagram schematically showing an embodiment of the present invention. In the figure, (1) is a wire electrode, and a motor (12)
It is sent out in the direction of the arrow by the wire electrode feed pulley (11) driven by. Reference numeral (13) is a cutting portion of the wire electrode (1), and an upper power supply (14) and a lower power supply (15) arranged in the vicinity of the wire electrode (1) and a cutting circuit (16) for controlling a cutting current. Is equipped with. Reference numeral (17) is a cutting roller for the wire electrode (1), which is connected to a motor (18), and the torque of the motor (18) is controlled by a control circuit (19). (20) is a pressing roller for the wire electrode (1), which is connected to the pneumatic cylinder (21), and by introducing air pressure from the pneumatic pressure source (22) or (23), the direction of arrow (a) or (b). Move to. In addition, (24) is a cutting roller (1
A guide nozzle provided below 7) is provided with a power supply die (25) into which the wire electrode (1) is inserted.

(50) is an NC device (50) for controlling each part of the device of this embodiment
The storage means or memory (51) in which the data table of the thickness and type of various wire electrodes to be used, the Nyer tension and the current value necessary for fusing are stored in advance, and the wire to be cut. By inputting the thickness and type of the electrode, the wire tension required for fusing the wire electrode to be cut is selected and determined from the memory (51), and the tension is applied to the wire electrode with the wire tension determined by the control circuit (19). Depending on the wire tension determining means (52) for instructing to give and the thickness and type of the wire electrode to be cut, the current value necessary for fusing the wire electrode to be cut is selected and determined from the memory (51) and cut. And a current value determining means (53) for instructing the circuit (16) to heat the wire electrode with the determined current value.

FIG. 2 is a circuit diagram of an embodiment of the cutting circuit (16). (3
1), (32), and (33) are make contacts of a relay selectively operated by the wire tension determining means (52), and (3)
4), (35) and (36) are resistors having different resistance values, and the make contact (31), the resistor (34) and the make contact (3
2) and resistor (36), make contact (33) and resistor (35)
And are connected in series to form first to third series circuits, and these series circuits are connected in parallel to form a parallel circuit (30). And this parallel circuit (30)
And the DC power supply (37) are connected in series between the upper power supply (14) and the lower power supply (15) to form a disconnection circuit (16).

FIG. 3 is a circuit diagram of an embodiment of the control circuit (19). Like the disconnecting circuit (16), this control circuit (19) also includes make contacts (41), (42) and (43) of the relay that are selectively operated by the current value determining means (53) and the resistance value. Different resistors (44), (45), (46) are connected in series, and the first to third series circuits are connected in parallel to form a parallel circuit (4
0), and the parallel circuit (40) and the DC power source (47) are connected in series to the input terminal of the motor (18).

The operation of the present invention configured as described above will be described below. Wire electrode (1) after processing the work piece
In order to disconnect, the air pressure is first introduced from the air pressure source (22) into the air pressure cylinder (21) to advance the piston, and the pressing roller (20) connected thereto is moved in the arrow (a) direction. As a result, the wire electrode (1) contacts the upper power supply (14) and the lower power supply (15), and is held between the pressing roller (20) and the cutting roller (17).

Next, the thickness and type of the wire electrode (1) to be cut is input. The data of the wire electrode (1) to be cut is
The data of the wire electrode to be used may be input before the start of processing. The data of the wire tension and the current value required for fusing with respect to the thickness and type of the wire electrode (1) to be cut are stored in advance in the memory (51). Determining means (5
3) Select and determine the current value necessary for fusing the wire electrode (1) to be cut from the memory (51), and heat the wire electrode (1) with the determined current value for the cutting circuit (16). Give instructions. In response to this instruction, the flow value determining means (53) operates the relay corresponding to the resistor (for example, (34)) of the disconnection circuit (16) for setting the selected current value to make the make contact (31). It is done by closing. Thereby, the DC power supply (37), the resistor (34), the make contact (31), the upper power supply (14), the wire electrode (1) and the lower power supply (15).
A closed circuit consisting of is formed, and an optimum current flows from the DC power supply (37) to the wire electrode (1) between the power supply terminals (14) and (15), and the wire electrode (1) is heated by this optimum current. .

Similarly, the wire tension determining means (52) selects and determines the wire tension required for melting the wire electrode (1) to be cut from the memory (51), and the wire tension is determined by the wire tension determined for the control circuit (19). Instruct the electrode (1) to be tensioned. This instruction is performed by operating the relay corresponding to the resistor (for example, (44)) for making the wire tension selected by the wire tension determining means (52) and closing the make contact (41). . As a result, a current flows from the power source (47) to the motor (18) through the circuit including the resistor (44), the torque of the motor (18) is controlled, and the wire electrode feed pulley (11) and the cutting roller (17) are controlled. The tension of the wire electrode (1) between the two is adjusted.

As a result, the wire electrode (1) between the upper and lower power supply terminals (14) and (15) is heated by the current from the cutting circuit (16) and the cutting roller (17) applies an optimum tension to the wire electrode (1). When the electrode (1) reaches a predetermined temperature, it is fused.

In this way, the optimum values of the electric current and the tension for fusing the wire electrode (1) can be automatically selected according to the thickness and the type of the wire electrode (1), whereby the wire electrode (1) can be selected. Since the cut surface of is close to a perfect circle, it can be easily inserted into the feeding die (25).

FIG. 9 is a circuit diagram of another embodiment of the cutting circuit (16) shown in FIG. 4.
In this embodiment, a high frequency pulse power source (37a) is connected instead of the DC power source (37) of the disconnecting circuit (16) shown in FIG.
From this high-frequency pulse power supply (37a), both power supply terminals (14), (1
An optimal high-frequency pulse current is passed through the wire electrode (1) between 5) to heat the wire electrode (1).

With this structure, the skin effect appears on the wire electrode (1) by the high frequency pulse, a cut surface closer to a perfect circle can be obtained, and the power consumption is reduced as compared with the case of using a DC power supply. You can

In the above embodiment, the current value of the cutting circuit (16) and the torque of the motor (18) that drives the cutting roller (17) are
Although the case where the wire electrode (1) is automatically selected according to the thickness and type and the wire electrode (1) is cut at the optimum value has been described, the wire feed motor (12) is also provided with a similar circuit. Good. Further, the disconnection circuit and the control circuit are shown in the case where three series circuits each having a resistor and a make contact having different resistance values are connected in parallel, but the series circuit has a thickness and a kind of wire electrode to be used. It can be increased or decreased as appropriate.

[Effects of the Invention] As is apparent from the above description, according to the present invention, the data table of the thickness, type, wire tension and current value necessary for fusing of various wire electrodes to be used is stored in advance. A storage means, and a wire tension determining means for selecting and determining a wire tension required for fusing the wire electrode to be cut from the storage means by inputting the thickness and type of the wire electrode to be cut,
Based on the wire tension determined by the current value determination means for selecting and determining the current value required for fusing the wire electrode to be cut from the storage means by inputting the thickness and type of the wire electrode to be cut, and the wire tension determined by the wire tension determination means. Since the control circuit for applying tension to the wire electrode and the disconnecting circuit for supplying current to the wire electrode based on the current value determined by the current value determining means are provided,
It is possible to automatically select the optimum value of the wire tension and current value required for fusing according to the thickness and type of wire electrode, and the fusing of the wire electrode can be performed by this automatically selected wire tension and current value. Can be done. For this reason, the cut surface of the wire electrode can be obtained in a state close to a perfect circle, and the wire electrode can be easily inserted into a power feeding die with a small clearance. In other words, it also disappears, and the processing does not stop halfway. Moreover, simply by inputting the thickness and type of the wire electrode to be cut, the wire tension and current value required for fusing according to the wire electrode to be cut are automatically set, so the operation is extremely easy and It is possible to significantly improve the sex.

Further, according to the present invention, the control circuit includes a resistor and a series circuit in which a make contact of a relay selectively operated by the wire tension determining means is connected to the resistor, and the resistance values are different from each other in a plurality of columns. Since the parallel circuit and the power source are connected in series to the input terminal of the drive motor of the roller that applies tension to the wire electrode when disconnected, it is necessary to select and determine the optimum value of wire tension. At the same time, the make contact of the relay corresponding to the resistor for achieving the selected wire tension can be closed, and the responsiveness can be enhanced.

Further, according to the present invention, the disconnection circuit is a series circuit in which a resistor and a make contact of a relay selectively operated by the current value determining means are connected to the resistor so that the resistance values are different from each other in a plurality of columns. The parallel circuit and the power source are connected in series between the upper and lower power supply terminals that come into contact with the wire electrodes when disconnected, so that the optimum value of the current value is selected and selected at the same time. The make contact of the relay corresponding to the resistor for achieving the set current value can be closed, and the responsiveness can be improved.

Further, according to the present invention, since the high-frequency pulse power supply is used as a means for supplying a current to the wire electrode for heating the wire electrode, the current can be concentrated on the surface of the wire electrode, and the skin effect is obtained. The wire electrode can be blown into a state closer to a perfect circle, and power can be saved as compared with the case of using a DC power supply.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing an embodiment of the present invention, FIG. 2 is a circuit diagram of an embodiment of a cutting circuit, FIG. 3 is a circuit diagram of an embodiment of a control circuit, and FIG. 4 is a cutting circuit. Circuit diagram of another embodiment,
FIG. 5 is a block diagram showing an example of a wire electrode cutting portion of a conventional wire electric discharge machine. In the figure, (1) is a wire electrode, (11) is a wire electrode feed pulley, (13) is a cutting part, (14) is an upper power supply,
(15) is a lower power supply, (16) is a cutting circuit, (17) is a cutting roller, (18) is a motor, (19) is a control circuit, (20) is a press roller, (21) is a pneumatic cylinder, ( 25) is a feeding die, (30) and (40) are parallel circuits, (31) to (33),
(41) to (43) are make contacts, (34) to (36), (44)
To (46) are resistors, (37) and (47) are power supplies, (37a) is a high frequency pulse power supply, (51) is a memory (storage means), (5)
2) is a wire tension determining means, and (53) is a current value determining means. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (4)

[Claims] 1. A wire electric discharge machine for cutting a work piece by electric discharge energy, in which a wire electrode is opposed to the work piece with a minute gap therebetween. A storage means in which a data table of wire tension and current values necessary for fusing is stored in advance, and a wire necessary for fusing the wire electrode to be cut from the storage means by inputting the thickness and type of the wire electrode to be cut A wire tension determining means for selecting and determining the tension, and a current value determining means for selecting and determining the current value necessary for fusing the wire electrode to be cut from the storage means by inputting the thickness and type of the wire electrode to be cut A control circuit for applying a tension to the wire electrode based on the wire tension determined by the wire tension determination means, and a current value determined by the current value determination means Wire electrical discharge machining apparatus characterized by comprising a cutting circuit for supplying a current to the wire electrode. 2. The control circuit comprises a resistor and a series circuit in which a make contact of a relay selectively operated by the wire tension determining means is connected to the resistor and the resistance values are different from each other in a plurality of columns. 2. The wire according to claim 1, wherein the wire is connected in parallel, and the parallel circuit and the power supply are connected in series to an input terminal of a drive motor of a roller that applies tension to the wire electrode when disconnected. Electric discharge machine. 3. The disconnecting circuit comprises a resistor and a series circuit in which the resistor is connected to a make point of a relay which is selectively operated by the current value determining means, and the resistance value is different from each other in a plurality of columns. A parallel connection, wherein the parallel circuit and the power supply are connected in series between the upper and lower power supply terminals that come into contact with the wire electrodes when disconnected.
The wire electric discharge machine described. 4. The wire electric discharge machining according to claim 1, wherein a high-frequency pulse power source is used as a means for supplying a current to the wire electrode for heating the wire electrode. apparatus.