JPH03196920A - Removing device for core of wire electric discharging machine - Google Patents

Abstract

PURPOSE:To shorten a stand by time necessary for a core removing work and to drastically shorten the processing time on the whole, by starting the transfer for removing a core immediately irrespective of the lapse of time, at the stage of the sufficient suction force necessary for pulling out of a core being secured. CONSTITUTION:A 1st transfer means positions a suction pad 24 at the target position located on a core 31 and the suction pad sucks the core. A 2nd transfer means transfers the suction pad positioned at the target position to a core scrapping position to remove the core from a work 30. After completion of the positioning by the 1st transfer means, an operation permit signal C1 is output to the 2nd transfer means immediately in the state of a pressure sensor detecting the atmosphere below the specific value to start the transfer of the core. Accordingly, the stand by time necessary for the core removing work is shortened and the working time on the whole is drastically shortened. An alarm signal is then output when an operation permit signal C2 is ceased during the operation of the 2nd transfer means and the drop of the core under transfer is immediately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a core removing device for a wire electrical discharge machine.

Conventional technology When a machined shape is cut out with a wire electrical discharge machine, a core is produced.

If this core is left as it is, it will get in the way of the wire electrical discharge machining that is to be performed subsequently, so it is removed each time using a core removing device provided in the wire electrical discharge machine. However, with conventional core removal equipment, there was no established means for detecting the operating status of the core removal equipment or automatic control using this, so the core removal work took an excessive amount of time. There were problems such as problems with the table feeding of the wire electric discharge machine and failures in the core removal device being repaired, making it difficult to reliably perform long-term automatic operation.

For example, in a normal core removal device, a suction pad is positioned at a target position on the core and then suction is applied for 2 to 3 seconds.
This was considered the completion of the suction process, so even if the suction process was performed normally, there was a minimum wait of 2 to 3 seconds before moving on to the process of removing the core from the workpiece. When cutting out a large number of processed shapes, this waiting time accumulates and results in a significant waste of time. There is no guarantee that normal adsorption will occur.
If the transporting means is fed without the core being completely removed, there is a possibility that interference with the electric discharge machine or the core removal device may occur, causing damage to various parts. Furthermore, if the suction pad is positioned overlapping the machining start hole of the core, it will not be possible to secure sufficient suction force to attract the core, and this failure will be automatically recovered. This makes it difficult to continue the subsequent processing.

In addition, in conventional core removal devices, whether or not the core removed from the workpiece is attracted to the suction pad is detected by a proximity sensor installed on the suction pad side that detects the proximity of metal. In some cases, the proximity sensor may malfunction due to interference with the suction pad or metal members constituting peripheral devices, making it impossible to properly detect the suction state of the core during the transfer process. We are also currently researching a system in which a passing sensor installed at the core disposal position detects whether or not the core has been transferred to the core disposal position, that is, whether or not the core has fallen off during the transfer process. However, in this case, dropping of the core is detected at the final stage of transport, and even if the core falls off during the transport, the transport means is fed to the end, and the core is not removed. Interference with the feeding mechanism cannot be prevented.

Problems to be Solved by the Invention The purpose of the present invention is to eliminate the drawbacks of these conventional techniques and to remove the core of a wire electrical discharge machine that can reliably perform long-term automatic operation without wasting time. The goal is to provide equipment.

Means for Solving the Problem After the first transfer means completes positioning, the pressure sensor detects an atmospheric pressure below a predetermined value, and immediately outputs an operation permission signal to the second transfer means to start transferring the core. let

By using a pressure sensor that detects the atmospheric pressure inside the suction pad, malfunctions caused by interference from metal members are eliminated, and the suction state of the core is properly detected and the transfer of the core is started.

By outputting an alarm signal when the operation permission signal is interrupted while the second transfer means is in operation, dropping of the core during transfer is immediately detected.

Furthermore, if the operation permission signal is not output even after a predetermined period of time has elapsed after the completion of positioning by the first transfer means, a small correction is made to the target position and a positioning signal is output again to the first transfer means. , position the suction pad at a target position different from the previous one.

Operation The first transfer means positions the suction pad at a target position on the core, and the suction pad attracts the core.

The second transfer means transfers the suction pad positioned at the target position to the core disposal position and removes the core from the workpiece.

After the positioning by the first transfer means is completed, the core is removed by immediately outputting an operation permission signal to the second transfer means to start the transfer of the core when the pressure sensor detects the atmospheric pressure below a predetermined value. The waiting time required for work is reduced, and the overall work time is significantly reduced.

Since the suction state of the core is detected by a pressure sensor that detects the atmospheric pressure inside the suction pad, the detection means will not malfunction due to interference from metal members (and the suction state of the core will be properly detected).

If the operation permission signal is interrupted while the second transfer means is in operation, an alarm signal is output, and dropping of the core during transfer is immediately detected, making it possible to avoid interference between the dropped core and the drive unit. This makes it possible to prevent damage to the electric discharge machine and core removal device.

Furthermore, if the operation permission signal is not output even after a predetermined period of time has passed after the first transfer means completes positioning, the suction pad is repositioned by making a small correction to the target position and outputting a positioning signal. , the suction force of the suction pad is restored and the core removal work can be continued.

Example Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

1 to 3 are diagrams showing the hardware of the wire electrical discharge machine 1 and the core removing device 11 of the embodiment. Column 3. Upper arm 4. An NC control device 6 is provided which also serves as part of the control means for the lower arm 5 and the core removing device 11. On the table part 2, a workpiece stand 7 is movable in X-axis and Y-axis directions set on a horizontal plane.

At the tip of the upper arm 4, an upper guide section 8 equipped with a UV-axis drive device is provided so as to be movable up and down along two vertical axes, and a wire 9 is inserted through this.

The upper guide part 8 is equipped with an automatic wire connecting device 29. An upper wire guide 10 and a core removal device 11 are attached.

A lower wire guide 12 is provided at the tip of the lower arm 5 at a position facing the upper wire guide 1o.
An automatic wire unloading device 51 is provided inside.

The wire 9 is routed from a supply reel 13 to each guide roller 14 .as shown. Tension roller 15. Furthermore, upper wire guide 10. The wire passes through the lower wire guide 12, passes through the automatic wire unloading device 51 of the lower arm 5, reaches the feed roller 16, and is stored in the wire collection box 17.

Reference numeral 18 is a core storage device provided at the core disposal position.

As shown in FIGS. 2 and 3, the core removing device 11 includes a main body portion 199, a rotating arm 20, and a support portion 22 at the tip of the lower nozzle.

The main body part 19 is fixedly attached to the upper guide part 8,
The base of the rotating arm 20 is supported by a horizontal shaft 23, and
A first transfer means includes a drive mechanism for the rotating arm 20 using an air actuator inside, and uses these shafts 231, rotating arm 20, etc. to position the suction pad 24 at a target position on the core, and a first transfer means for positioning the suction pad 24 at a target position on the core. Positioned suction pad 2
4 to the core disposal position.

The tip of the rotating arm 20 is bent into a hook shape, and four suction pads 24 are provided on the tip surface of the rotating arm 20 in close proximity to each other. The hook-shaped bend allows the suction pad 24 to be located at the bottom of the upper wire guide 10 when the pivot arm 20 is pivoted downward (FIG. 3).

Each suction pad 24 is made of synthetic resin with flexible elasticity and is connected to the vacuum device 21 through a tube 25 and a pressure sensor provided for each suction pad 24, and is connected between the tubes 25. The pressure sensor detects the atmospheric pressure inside each suction pad 24. In addition, in FIGS. 4 and 5, the pressure sensor sw1. connected between the tubes 25 of the first and second suction pads 24. Only sw2 is illustrated, and the others are omitted. Pressure sensor SWl,
SW2... is a detection signal A when an atmospheric pressure below a predetermined value (260 TORR in the embodiment) is detected.

B..., and these detection signals are input to each of the AND gate 32 and the OR gate 33. Therefore, the AND gate 32 sends an operation permission signal C that allows the second transfer means to start operating when the internal pressures of all the four suction pads 24 become below a predetermined value.
1, and if the partial pressure of even one of these suction pads 24 is below a predetermined value, the OR gate 33 outputs another operation permission signal C2 that allows the second transfer means to continue operating. It will be output. Operation permission signal C1, C
2 is input to the NC control device 6 via the input/output circuit 34.

The support portion 22 in the lower wire guide 12 is formed by enlarging the periphery of the nozzle opening to form a surface parallel to the workpiece placement surface.

The core storage bag rR18 is a box-shaped container with an opening 26 and is removably arranged on the table part 2 so as to move with the table, and the opening 26 allows the upper wire guide 10 to move relative to the table part 2. In other words, the movable area of the upper wire guide 10 and the upper guide part 8
The suction pad 24 is disposed in a region between the movable regions of the suction pad 24, which is attached to the suction pad 24 and moves relative to the suction pad 24.

In addition, in FIGS. 2 and 3, the reference numeral 29 is an automatic wire connecting device, the reference numeral 30 is a workpiece, and the reference numeral 31 is a core.

During wire electrical discharge machining, the rotating arm 2 of the core removing device 11
0 is in the retracted position rotated upward as shown in FIG.

Hereinafter, the operation of the core removing device 11 will be explained with reference to a flowchart (FIG. 6) showing an outline of the core removing process stored in the NC control device 6.

In this process, wire electrical discharge machining progresses according to the machine program stored in the NC control device 6, the core 31 is cut out, the electrical discharge power is cut off, and at the same time the automatic wire connection device 29 is activated to cut the wire 9. , the wire is removed from between the upper and lower wire guides 10, 12, and the core 31 is placed on the support portion 22 of the lower wire guide 12, and then activated.

The NC device 6 that has started the core removal process calculates the positions X and Y1 on the core 31 at which the suction pad 24 should be positioned based on the positional deviation between the wire 9 and the suction pad 24, and uses these coordinate values. Adsorption position memory register R(X), R(
Y), initializes the retry counter C (step 501), feeds the table section 2, and positions the suction pad 24 at the position indicated by the suction position storage registers R(X) and R(Y). , the rotating arm 20 is rotated downward to lower the upper guide portion 8 and press the suction pad 24 to the initial target position (step 502).

Next, the vacuum device 21 is driven to start suctioning the core 31 by the suction pad 24, and at the same time, the timer T is set and started for an allowable time until the suction is completed (step 5).
03), it is determined whether the operation permission signal C1 has been inputted or not (step 504), and if the operation permission signal CI has not been inputted, it is determined whether the allowable time until the completion of suction has elapsed or not (step 505). ), the process returns to step SO4 and the same process as above is repeated.

Even if the allowable time until suction completion has elapsed, the operation permission signal C1 remains
Otherwise, at least one of the internal suction pads 21 may be positioned in an inappropriate position, such as over the machining start hole of the core 31, and the suction pads 21 may not have enough space to pull out the core 31. This means that the adsorption force is not maintained. Therefore, the NC device 6 determines whether or not the value of the retry counter C has reached the allowable value N for the number of retries (step 511). If the value of the retry counter C has not reached the allowable value N for the number of retries, the retry is performed Increment the value of counter C, and increment the value of suction position storage register R (
X), R(Y) are added with minute correction amounts ΔX and ΔY to correct the target position where the suction pad 24 should be positioned (step 512), the drive of the vacuum device 21 is stopped, and the rotating arm 20 is and return the upper guide part 8 to the retracted position (
Step 513), Step SO2 to Step SO5
The suction pad 24 is repositioned by executing the process described above, and the suction pad 24 is placed in a state where sufficient suction force required for pulling out the core 31 is obtained. Note that if the operation permission signal C1 is not input even after the permissible time until suction completion has elapsed, the same glue try process as described above is repeatedly executed until the value of the retry counter C reaches the permissible value N of the number of retries. If the operation permission signal C1 is not input even when the value of the retry counter C reaches the allowable value N, it is determined that recovery from the failure is impossible, an alarm signal is output, and the drive of the vacuum device 21 is stopped (step 514).

If the operation permission signal C1 is input before the value of the retry counter C reaches the allowable number of retries N, and the sufficient suction force required to pull out the core 31 is secured, the upper guide part 8 is After raising the core 31 and pulling it out from the workpiece 30, which has been attracted to the suction pad 24, and rotating the rotary arm 20 upward about the horizontal shaft 23, the workpiece table 7 of the table 2 is fed. Transfer to the core storage device 18, which is the core disposal position, is started (step 507).

Until the transfer of the core 31 is completed, the operation permission signal C is
2 is input, that is, whether at least one thing inside the suction pad 24 is adsorbed to the core 31, that is, whether or not the core 31 has fallen off or not is constantly checked. (Steps 808 to 509), and when the input of the operation permission signal C2 is interrupted and dropping of the core 31 is confirmed, an alarm signal is output and the drive of the vacuum device 21 is stopped (Step 514). When the core 31 is normally transferred to the core storage device 18, after stopping the drive of the vacuum device 21 (step 510), the table section 2 is fed to the next machining start hole in the workpiece 30, and the automatic operation is performed. The wire 9 is automatically connected by the wire connecting device 29, and the next wire cutting process is continued.

According to this embodiment, as soon as sufficient suction force required to pull out the core is secured, the transfer of the core is immediately started regardless of the passage of time, which is necessary for core removal work. This reduces the waiting time and the overall processing time, and it is also useful in cases where the suction pad is improperly positioned and air leaks, making it impossible to ensure sufficient suction power. Since this method corrects the target position of the suction pad and performs suction again, it is possible to automatically recover from this type of failure. In addition, since the suction state of the core is detected by a pressure sensor that detects the air pressure inside the suction pad, the detection means will not malfunction due to interference from metal parts, and the suction state of the core can be accurately detected. Moreover, since an alarm signal is outputted immediately when a dropping of the core during transportation is detected, interference between the dropped core and the driving section can be prevented.

In the embodiment, the correction amounts ΔX and ΔY used to correct the positioning of the suction parallax lower 24 are fixed values, but these values and their directions may be set on the program according to the machining shape etc. . Further, the operation permission signal C1 that permits the start of operation of the second transfer means does not necessarily have to be output only when all pressure sensors are turned on.
Depending on the suction power of each suction pad 24, the size of the core, etc.
The output may be output when a predetermined number or more of pressure sensors are turned on. That is, it is a structural requirement that the output is performed at a stage when sufficient suction force required for pulling out the core is secured. The operation permission signals C1 and C2 are supplied to the AND gate 32. Although it is designed to be outputted via the OR gate 33, there is no problem in performing these logical processes on the NC control device 6 side.

The above is one example.

The core removing device 11 is not limited to the above configuration, including the configuration of the core holding section.

Effects of the Invention According to the core removal device of the present invention, once sufficient adsorption force required for pulling out the core is secured, transfer for core removal starts immediately regardless of the passage of time. This reduces the waiting time required for the core removal operation and significantly reduces the overall processing time, and also prevents the suction pad from being improperly positioned and causing air leakage, resulting in insufficient suction force. If the suction pad cannot be secured, the target position at which the suction pad should be positioned is corrected and the suction process is executed again, making it possible to automatically recover from failures due to poor suction. In addition, since the pressure sensor that detects the atmospheric pressure inside the bow bud detects the adsorption state of the core,
The detection means will not malfunction due to interference from metal parts, and the adsorption state of the core can be properly detected. Moreover, if a dropout of the core is detected during transfer, an alarm signal will be immediately issued. Since this is output, interference between the dropped core and the drive unit can be prevented by stopping the feeding mechanism and the like.

Therefore, long-term automatic operation can be reliably performed without wasting time or damaging the electrical discharge machine.

[Brief explanation of drawings]

Fig. 1 is a perspective view, Fig. 2 is a front view, Fig. 3 is a partially sectional front view, Fig. 4 is a view showing the installation state of the pressure sensor, and Fig. 5 is a block diagram. 6 are flowcharts showing an outline of the core removal process. 1... Wire electric discharge machine, 6... NC control device, 9
... Wire, 11 ... Core removal device, 18 ... Core accommodation device, 20 ... Rotating arm, 21 ... Vacuum device,
23... Shaft, 24... Suction pad, 25... Tube, 30... Work, 31... Core, SWI, S
W2...pressure sensor, C1, C2...operation permission signal, C...retry counter, N...permissible value of number of retries, ΔX, ΔY...correction amount. 1st curse 2nd diagram

Claims (2)

[Claims] (1) A first transfer means that positions the suction pad at a target position on the core, and a second transfer means that transfers the suction pad positioned at the target position on the core to a core disposal position. In the wire electric discharge machine, a pressure sensor detects the atmospheric pressure inside the suction pad, and after the positioning by the first transfer means is completed, the pressure sensor detects the atmospheric pressure below a predetermined value, and then the pressure sensor detects the atmospheric pressure inside the suction pad. While the operation permission signal is output, if the operation permission signal is not output even after a predetermined time has elapsed after the completion of positioning by the first transfer means, or the operation permission signal is interrupted while the second transfer means is in operation. A core removing device for a wire electric discharge machine, characterized in that the device is provided with a control means for outputting an alarm signal when the core is removed. (2) A first transfer means that positions the suction pad at a target position on the core, and a second transfer means that transfers the suction pad positioned at the target position on the core to a core disposal position. In the wire electric discharge machine, a pressure sensor detects the atmospheric pressure inside the suction pad, and after the positioning by the first transfer means is completed, the pressure sensor detects the atmospheric pressure below a predetermined value, and then the pressure sensor detects the atmospheric pressure inside the suction pad. While outputting an operation permission signal, if the operation permission signal is not output even after a predetermined period of time has elapsed after the completion of positioning by the first transfer means, a slight correction is made to the target position on the core. A positioning signal is output to the first transfer means, and when the pressure sensor does not detect an air pressure below a predetermined value even after the positioning signal is output a predetermined number of times, and when the second transfer means is in operation, the operation permission signal is sent. A core removing device for a wire electric discharge machine, characterized in that it is provided with a control means for outputting an alarm signal when the core removal device is interrupted.