JP3013904B2 - Automatic wire connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic wire connecting apparatus, and more particularly, to an automatic wire connecting apparatus capable of early and surely detecting the result of automatic wire connection.

[0002]

2. Description of the Related Art In general, a wire electrode extending in a substantially vertical direction generates a discharge phenomenon between a wire electrode and a workpiece to cut the workpiece like a thread saw. Electric discharge machines are already known. This type of electric discharge machine is provided with an automatic wire connection device that automatically connects a cut wire electrode at the start of machining, at the time of wire breakage during machining, or the like. In this device, for example, after feeding the wire from the automatic wire feeder toward the lower guide portion for a predetermined time, it is necessary to confirm whether the wire reaches the wire discharge portion and the normal operation is enabled. In the wire sending section, an optical or mechanical wire disconnection detector for detecting whether or not tension is normally applied to the wire electrode is provided. It is detected whether or not there is looseness, and if looseness has occurred, it is determined that the wire electrode is not normally connected, and again,
The connection operation is performed. As another conventional apparatus, an apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 2-53529 is known. This apparatus is provided with a pair of seats below a delivery roller a of an automatic wire feeder as shown in FIG. A buckling sensor b is provided, and when the tip of the fed wire electrode 4 normally passes through the workpiece (not shown) and the lower guide c, the buckling sensor b does not sense anything, and is normally connected. As shown in FIG. 3, when the tip of the wire electrode 4 buckles against the workpiece or the lower guide c as shown in FIG. 3, the buckled wire electrode becomes the buckling sensor b.
As a result, the connection is regarded as having failed, and a retry operation is performed. Further, as another conventional device, as disclosed in Japanese Patent Application Laid-Open No. 2-76629, a wire passage detecting means for detecting passage of a wire electrode is provided on a lower guide portion, and the wire electrode contacts the lower guide portion. In this case, it is determined that the wire connection has been made normally.

[0003]

Incidentally, of the above-mentioned conventional apparatuses, an apparatus using a wire disconnection detector and an apparatus disclosed in
In the apparatus disclosed in JP-A-53529, if the time for sending out the wire electrode is too long, a considerable amount of the wire electrode is already sent out when it is determined that the wire connection has failed. When a thin wire (0.1 mmφ or less) is used, the wire may become entangled, making it impossible to re-execute the connection. Further, in the device using the buckling sensor, when the thin wire as described above is used, the stiffness of the wire itself is low, and when the buckling occurs as shown in FIG. There is a problem that sufficient deformation for contacting the wire electrode 8 with the wire electrode 4 cannot be obtained. Further, in the conventional device shown in the above-mentioned document, since the wire passage detecting means made of a conductor is in contact with the wire electrode fed during processing, a groove is formed at the tip of the conductor detecting means due to friction. And unexpected tension is applied to the wire electrode,
Alternatively, there is a case where the tip of the detecting means and the wire electrode are in contact with each other and the wire position is shifted in the lateral direction, thereby affecting the processing accuracy. The present invention has been devised in view of the above problems and effectively solving them. SUMMARY OF THE INVENTION It is an object of the present invention to be able to detect the result of automatic connection at an early stage and to prevent the wire detecting means from being worn by a wire electrode .
In addition, there is no fluctuation in tension due to contact
It is an object of the present invention to provide an automatic wire connection device that can be used .

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an automatic wire connecting apparatus provided in a wire electric discharge machine for electric discharge machining of a workpiece while supplying a wire electrode by a wire supply means. In, wire feeding means for feeding the wire electrode to the lower guide portion side,
Provided on the lower guide portion and in contact with the wire electrode
It is located in the vicinity of the current-carrying body made possible and extends at a predetermined timing during automatic connection with respect to the wire feeding direction.
The wire detecting means includes a wire detecting means which is out of the way at the time other than the automatic connection and a control means for controlling the wire feeding means in accordance with a detection result of the wire detecting means.

[0005]

According to the present invention, the wire electrode is supplied from the wire supply means during the automatic wire connection, and the wire feed means feeds the wire electrode while guiding it to the lower guide portion side. At this time, the wire detecting means provided in the vicinity of the lower guide portion is located at a position slightly shifted in the horizontal direction from the feeding direction of the wire electrode, that is, the vertical direction, and a predetermined time has elapsed after the start of the wire feeding operation. Then, the wire detecting means is extended to detect the presence or absence of the wire electrode, and it is determined whether or not the connection is successful. Here, when sending the wire electrode, the wire detecting means may be extended in advance. Further, when the pulley of the wire electrode is provided with a slight offset with respect to the vertical direction, the wire electrode is offset in the horizontal direction when the connection is successful, and directly contacts the wire detection means. In this way, if the wire connection is successful, in the former case, the wire detecting means is returned to the original position to break the contact with the wire electrode, and in the latter case, the detecting means is moved in the horizontal direction. By moving, the contact with the wire electrode is similarly cut off, and thereafter, electric discharge machining is started.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the automatic connection device according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an automatic wire connection device, and FIG. 5 is a schematic diagram showing the entire wire electric discharge machine to which the present invention is applied. As shown in FIGS. 1, 5 and 6, first, the wire electric discharge machine 2 includes a wire sending section 6 for sending the wire electrode 4, and an upper guide section 10 for guiding the sent wire electrode 4 to the workpiece 8. When,
It is mainly composed of a lower guide portion 12 for receiving a wire electrode that has passed through the workpiece 8 and a wire discharging portion 14 that discharges the wire electrode that has passed through the lower guide portion 12. Specifically, the wire sending section 6 has a wire bobbin 16 on which a long wire electrode 4 is wound and back-tensioned, and the wire electrode 4 pulled out from the wire bobbin 16 is a cylindrical roller 18 and a guide 20. Through the guide roller 22, the guide roller 22 and a guide pulley 24 arranged in parallel with the guide roller 22 are wound once in a figure-eight shape, and the wire electrode 4 passing through the guide pulley 24 is After passing between the roller 22 and the pinch roller 26 and further passing through the felt roller 28, it passes through the guide roller 30 and is directed downward in the vertical direction. In the middle, a disconnection detection limit 32 for detecting a wire disconnection and a brush 34 for removing dust adhering to the wire are provided.

The wire electrode 4 is connected to an upper guide portion 10,
It passes through the workpiece 8 and the lower guide part 12 sequentially and is introduced into the wire discharge part 14. Specifically, the wire discharging unit 14 has a pulley 34 supported by the lower arm 32, and the used wire electrode 4 passing through the pulley 34
After passing through the inside of the acrylic pipe 36, it is introduced into the suction part 40 provided in the column 38, and is configured to suction the wire electrode 4 using the pressure of water. This suction unit 40
The wire electrode is sent out by a wire feed roller 42 and discharged from a wire discharge port 44 to a wire collection box 46. Then, the lower guide portion 1
2 is provided with a fixed die 60, for example.
The configuration is such that the wire electrode 4 can pass through the die 60. Below this, for example, a fixed type electric conductor 62 is provided.
, So that electricity can be supplied to this. The wire electric discharge machine configured as described above is provided with an automatic wire connection device. Specifically, as shown in FIG. 1, the automatic wire connection device 50 includes a wire feeding means 52 for feeding the wire electrode 4 to the lower guide portion 12 side.
A wire detecting means 54 provided in the vicinity of the lower guide portion 12 and provided so as to be able to protrude and retract in the feeding direction of the wire, and a wire as a wire supplying means in accordance with a detection result of the detecting means 54 It is mainly constituted by a control section 56 for controlling the sending section 6 and the wire feeding section 52.

The wire feeding means 52 has a feeding roller 64 for holding the wire electrode 4 as shown in FIG. 6. Below this, a pipe 66 for inserting the wire electrode is provided. The upper end of the pipe 66 is connected to a tube 68 made of, for example, polyurethane, through which water flows to facilitate insertion of the wire electrode into the pipe 66. A slide belt 70 for sliding the pipe 66 in a vertical direction is stretched between a pair of belt rollers 72, 72 on the side of the pipe 66. The wire detecting means 54 provided in the vicinity of the lower guide portion 12 includes a detector 74 made of a conductor having good conductivity such as copper.
And a cylinder 76 that makes the detector 74 protrude and retract in the direction in which the wire electrode 4 is located.
The detector 74 is insulated from its surroundings, and a wiring 78 is connected to the detector 74.
This wiring 78 is connected to the control means 56 via a power supply 80, a detection relay 82 and the like on the way.
When the wire electrode 4 comes into contact with the wire 78, the wire 78
And the wire electrode 4 to form a closed loop so that a detection signal flows to the control means 56.
The control means 56 is adapted to send a control signal to, for example, a drive system of the wire bobbin 16 of the wire sending section 6, and when the automatic connection fails, the sent wire electrode 4
To retry and retry.

Next, the operation of the apparatus configured as described above will be described. First, during normal processing, the wire feed roller 42 of the wire discharger 14 is driven to rotate, so that the wire electrode 4 is fed from the wire bobbin 16 of the wire feeder 6 at a predetermined speed, for example, 10 cm / sec. Then, after passing through the guide roller 30, the wire feeding means 52, the upper guide portion 10, the workpiece 8, and the lower guide portion 12 while a predetermined tension is applied by the tension roller 22, the acrylic pipe 36 of the wire discharge portion 14, After passing through the suction part 40 and the like, the wire is discharged from the wire discharge port 44 into the wire discharge box 46. And the wire electrode 4
Electric discharge is generated between the workpiece 8 and the wire electrode 4 by the electric power supplied from the current-carrying body 62 which comes into contact with the workpiece, thereby performing machining. During the electric discharge machining, the detector 74 of the wire detecting means 54 is immersed in the cylinder 76 so that the detector 74 and the wire electrode 4 are separated from each other to prevent the detector 74 from being worn. are doing. If the wire breaks for some reason, first, a cutter (not shown) provided below the wire feeding means 52 is provided.
Cuts the wire electrode, and discharges the remaining wire electrode in the workpiece 8. At this time, the wire electrode 4 slightly returns due to the back tension applied by the wire sending section 6, and the tip thereof is located in the middle of the pipe 66 of the wire feeding means 52. Then, the wire electrodes are fed between the feed rollers 64 and 64 with the wire electrode 4 interposed therebetween, and at the same time, the pipe 66 itself is moved downward by the slide belt 70 at the same speed as the descending speed of the wire. Then, while performing this movement, the tube 68
The water is made to flow downward into the pipe 66 to make the wire feed more smoothly. Then, the upper guide portion 12 composed of the split guide is opened, the pipe 66 descending into the upper guide portion 12 is inserted, and the lowering of the pipe 66 is stopped immediately before the pipe 66 comes into contact with the workpiece 8.

On the other hand, the wire electrode 4 is sent out without stopping, and the workpiece 8 and the lower guide 12
Pass through the pulley 34 of the wire discharge section 14 and the acrylic pipe 36, and reach the wire feed roller 42 with the suction pipe 40 utilizing the suction power of water.
Here, when a predetermined time, for example, at least the time required for the lower end portion of the wire electrode 4 to pass through the position where the detector 74 is passed has elapsed after the driving of the wire feed rollers 64, 64, the control means 56 Drives the cylinder 76 to extend it into the passage for the wire electrode. It has been empirically determined that the wire electrode passing through the lower guide portion 12 is almost 100% safely sandwiched by the wire feed roller 42 and successful connection is established.
When the wire 4 is extended and comes into contact with the wire electrode, a detection signal flows to the control means 56 via the wire electrode 4 and the wiring 78, and the control means 56 receiving the signal deems that the connection is successful. Then, the detector 74 is immersed and separated from the wire electrode 4. Thereafter, normal electric discharge machining is started. However, since the detector 74 and the wire electrode 4 are separated from each other as described above, the detector 74 does not wear, and the tension does not fluctuate due to the contact. The workpiece 8 can be accurately machined.

On the other hand, when the detection element 74 is extended and no detection signal is generated without contact with the wire electrode 4, the control means 56 regards the connection failure as failure and immediately switches the wire bobbin 16 or the like. By rotating the wire electrode 4 in the reverse direction, the fed wire electrode 4 is rewound to prevent it from becoming entangled. afterwards,
The connection operation is performed again in the same procedure as described above. In the above embodiment, the detector 74 is initially immersed, and when a predetermined time has elapsed from the start of the connection operation, the detector 74 is extended to detect the presence or absence of the wire electrode 4. However, the present invention is not limited to this. For example, the detector 74 may be extended from the beginning of the connection operation, and when the presence of the wire electrode 4 is detected, the detector 74 may be immersed as described above. Of course. Further, in the above embodiment, the lower guide part 12 is fixed die 60
Also, the case where the feed direction of the wire electrode 4 is directed substantially downward in the vertical direction has been described. However, the present invention is not limited to this. For example, an apparatus in which a movable die is used instead of the fixed die 60 Can be applied to
The present invention can also be applied to a device in which the feed direction of the wire electrode 4 is slightly offset in the horizontal direction from below in the vertical direction. Further, in the above embodiment, the apparatus for sucking and discharging the wire electrode 4 has been described. However, the present invention is not limited to this. In addition, the apparatus is configured to discharge the wire electrode 4 by a belt as shown in FIG. It can also be applied to the example of the device. That is, the lower guide portion 100 has the fixed side split guide 102 and the movable side split guide 104, and is configured to be moved by the compact cylinder 106. The electric conductor 108 is attached so as to move integrally with the movable split guide 104,
The current conductor 108 is configured to come into contact with the wire electrode 4 when the second and 104 are closed.

[0012] On the other hand, the wire discharging portion is connected to the upper belt 110.
And the lower belt 112, and the wire pull-in pulley 11
The right end of the wire electrode 4 is offset by a dimension A with respect to the vertical direction in which the wire electrode 4 hangs down.
Is located at a position where the detector 120 contacts the detector 120.
Is installed insulated from surroundings. And this detector 1
Reference numeral 20 denotes the electric conductor 108 and the movable side split guide 104.
The detector 120 is configured to move so as to move integrally with the connecting member 122, and to move away from the wire electrode 4 when the movable guide 104 moves so as to be closed. I have. According to the above configuration, if the connection operation is successful, the wire pull-in pulley 1
The wire electrode 4 drawn into contact with the detector 120 is offset by the dimension A, thereby the control means 56 is turned off.
Can recognize the success of the connection operation. Then, the compact cylinder 106 is driven to move the movable side split guide 10.
When the conductor 4 is closed and the electric conductor 108 is brought into contact with the wire electrode 4, the detector 120 moves integrally with the wire electrode 4 away from the wire electrode 4. Therefore, the detector 120 does not come into contact with the wire electrode 4 during the electric discharge machining.
The same effect as in the first embodiment is obtained. Further, in the present embodiment, it is not necessary to provide a separate cylinder or the like as a drive source of the detector 120, and the drive source for moving the movable side split guide or the like, that is, the compact cylinder 106 can be shared. Further, in another embodiment shown in FIG. 7, an example of a device in which a movable guide is used integrally with the electric conductor 108 has been described. However, the present invention is not limited to this, and a fixed guide is used. The case can also be applied. In this case, the electric conductor 108 is configured to integrally work with the detector 120.

[0013]

In summary, according to the present invention, the following excellent effects can be obtained. Wire detection means is provided on the lower guide part and can contact the wire electrode
In the wire feeding direction
To the specified timing during automatic connection
Because it was immersed at times other than the time of connection, even if the connection failed, it can be detected immediately, and therefore, especially when using a thin wire, it does not get entangled,
Since retry is possible, the connection ratio can be improved. Further, at the time of normal electric discharge machining, since the detector and the wire electrode do not come into contact with each other, not only can the wear of the detector be prevented but also the fluctuation of the tension due to the contact can be eliminated, and the machining accuracy can be improved. .

[Brief description of the drawings]

FIG. 1 is a schematic view showing an automatic connection device according to the present invention.

FIG. 2 is a diagram illustrating a state when connection is successful.

FIG. 3 is a diagram showing a state when connection fails.

FIG. 4 is a diagram showing a state when connection fails using a thin line.

FIG. 5 is a schematic view showing a wire electric discharge machine.

FIG. 6 is a schematic view showing a wire feeding means of the automatic wire connection device.

FIG. 7 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 wire electric discharge machine 4 wire electrode 6 wire sending section (wire supply means) 8 workpiece 10 upper guide section 12 lower guide section 14 wire discharging section 50 automatic wire connection device 52 wire feeding means 54 wire detecting means 56 control Means 62 Conductor 74 Detector 76 Cylinder

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23H ^7/ 02-7/10

Claims (1)

(57) [Claims] 1. A wire feeder for feeding a wire electrode to a lower guide portion in an automatic wire connection device provided in a wire electric discharge machine for performing an electric discharge machining of a workpiece while supplying a wire electrode by a wire supply means. Means , provided on the lower guide portion , and capable of contacting the wire electrode.
Is positioned near the current-carrying member that has been activated, and extends at a predetermined timing during automatic wiring in the wire feeding direction.
A wire detecting means which is submerged except at the time of the automatic connection, and a control means for controlling the wire feeding means in accordance with a detection result of the wire detecting means. Wiring device.