JPH05305525A - Control device for wire winding up of wire electric discharge machine - Google Patents

Abstract

PURPOSE:To appropriately adjust winding up speed so as to prevent breaking of a wire electrode, and enable the end of wire to be correctly positioned. CONSTITUTION:Whether the winding up speed of a wire electrode is high speed over 100mm/s or not is judged at S142. When the winding up speed of the wire electrode is judged to be high speed, a process to gradually increase tension brake is performed for decreasing the winding up speed at S144. Meanwhile, at S146, whether the winding up speed of the wire electrode is under 100mm/s and lower than 80mm/s or not is judged. When the winding up speed is judged to be decreased, a process to gradually decrease tension brake is performed for increasing the winding speed at S148.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire winding control device for a wire electric discharge machine, which repeats electric discharge between a wire electrode and a workpiece.

[0002]

2. Description of the Related Art Conventionally, a wire electric discharge machine of this type has a mechanism for automatically re-extending a broken wire electrode because the wire electrode may break during machining.

In order to automatically re-stretch the wire electrode, it is necessary to position the broken wire electrode. Therefore, various devices for positioning the wire end have been proposed. For example, when the wire breakage sensor detects wire breakage, the supply bobbin winds the wire electrode and the drive roller or the like sends the wire electrode in the direction opposite to the wire traveling direction, and the wire end detection sensor breaks the wire. There is a device for positioning the wire end by stopping the feeding of the wire electrode in the opposite direction when the end of the wire electrode is detected.

However, in such a device, when the wire electrode is wound up, a slack of the wire electrode may occur and the wire may be derailed from the roller or the like. Therefore, the applicant of the present application describes in Japanese Patent Application No. 3-201983. We have proposed a wire winding control device for a wire electric discharge machine that has a simple structure and can prevent slackening of the wire electrode during winding to prevent derailment.

[0005]

However, even such an improved technique is not always sufficient for a higher demand for automation. That is,
The supply bobbin for supplying and winding the wire electrode has a problem that the winding force and the weight are different because the winding diameter and the weight of the supply bobbin vary depending on the amount of the wound wire electrode. In other words, if the required hoisting force is set when the diameter of the supply bobbin is large, if the diameter of the supply bobbin becomes smaller, the hoisting force will be unnecessarily increased and the hoisting speed will increase excessively. Had the problem of derailing from the roller. There is also a problem that if the winding speed is too high, accurate positioning cannot be performed even if the wire end is detected.

The present invention has been made to solve the above problems, and the wire of a wire electric discharge machine that appropriately adjusts the winding speed to prevent derailment of the wire electrode and enables accurate positioning of the wire end. An object is to provide a hoisting control device.

[0007]

In order to achieve this object, the present invention, as illustrated in FIG. 1, discharges electric discharge between a wire electrode and a work piece which is the other electrode. In a wire winding control device of a wire electric discharge machine that winds the wire electrode when the wire is broken, the wire speed detecting means M1 for detecting the moving speed of the wire electrode and the wire breakage of the wire electrode are detected. Wire break-up detecting means M2 and wire winding means M for urging the wire electrode by urging the wire electrode in a direction opposite to the traveling direction during processing.
3, a wire tension generating means M4 disposed between the wire winding means M3 and the workpiece to apply passage resistance to the wire electrode to generate tension in the wire electrode, and the wire breakage detection. When the wire breakage of the wire electrode is detected by the means M2, the wire tension generating means M4 is driven according to the moving speed of the wire electrode detected by the wire speed detecting means M1 to wind up the wire electrode. The wire winding control device of the wire electric discharge machine is characterized by further comprising wire speed control means M5 for adjusting

[0008]

In the present invention having the above-mentioned structure, the wire tension is arranged between the wire winding means M3 for urging and winding the wire electrode (opposite to the traveling direction during processing) and the workpiece. In the generating means M4, a passage resistance is applied to the wire electrode to generate tension in the wire electrode, and electric discharge is performed between the wire electrode and the work piece which is the other electrode to process the work piece. There is.

When the wire breakage detecting means M2 detects the wire breakage of the wire electrode, the wire speed controlling means M5 causes the wire tension generating means M4 in accordance with the moving speed of the wire electrode detected by the wire speed detecting means M1. The winding speed of the wire electrode is adjusted by driving and controlling.

That is, according to the present invention, the speed of the wire electrode wound up when the wire is broken is detected, and the passing resistance of the wire electrode is adjusted to control the wire electrode winding speed so that the moving speed becomes an appropriate value. It is a thing.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a wire winding control device of a wire electric discharge machine embodying the present invention will be described below with reference to the drawings. As shown in FIG. 2, the wire electric discharge machine of the first embodiment feeds the wire electrode 1 in the wire feeding direction (arrow A direction) at the time of machining, and between the wire bobbin 10 and the brake roller 16. A pre-tension generating mechanism 2 that generates a tension applied to the wire electrode 1, an assertive force generating mechanism 3 that generates a tension applied to the wire electrode 1 between the brake roller 16 and the drive roller 35, and a disconnection of the wire electrode 1. And a wire breakage / speed detection mechanism 4 that detects the winding speed of the wire electrode 1, a wire end detection sensor 5 that detects the end of the wire electrode 1 that has been broken, and a wire recovery mechanism 6 that houses the used wire electrode 1. It consists of

Next, each mechanism will be described in detail. The pre-tension generating mechanism 2 stops the rotation of the wire bobbin 10 around which the wire electrode 1 to be fed is wound, the back tension motor 11 that urges the wire bobbin 10 in the wire winding direction (arrow B direction), and the back tension motor 11. It is composed of an electromagnetic brake 12,
Torque is applied in the wire winding direction by the back tension motor 11 so that the wire electrode 1 stretched between the wire bobbin 10 and the asserting force generating mechanism 3 does not sag.

At the time of processing, the wire electrode 1 is sequentially pulled out from the wire bobbin 10 toward the asserting force generating mechanism 3 side. On the other hand, at the time of disconnection, the electromagnetic brake 12 momentarily stops the rotation of the wire bobbin 10, and then the wire bobbin 10 is operated. It functions so that the wire electrode 1 is wound up.

The asserting force generating mechanism 3 includes a pinch roller 15,
It consists of the brake roller 16 and the tension brake 17, and the friction torque generated by the tension brake 17 is
It is converted into tension by the brake roller 16 and the pinch roller 15 that sandwich the wire electrode 1. That is, the tension brake 17 that generates the friction torque by the excitation of the magnetic powder applies the assertive force to the wire electrode 1 stretched along the workpiece 18.

The disconnection / speed detection mechanism 4 is mounted coaxially with the tension brake 17 of the assertion force generation mechanism 3 and has an interrupter 20 formed with a large number of slits.
And a photo sensor 21 mounted near the interrupter 20. That is, when the wire electrode 1 is broken at the P position, for example, the tension brake 17 is temporarily stopped. Therefore, by detecting the stop of the interrupter 20 synchronized with the rotation of the tension brake 17 by the photo sensor 21, Electrode 1
This is to detect the disconnection of.

Further, in the wire breakage / speed detection mechanism 4, as shown in FIG. 3, the winding speed of the wire electrode 1 is divided into two, H side (high speed side) and L side (low speed side). The output simple speed detection circuit 39 is connected. This speed simple detection circuit 39 switches ON / OFF of the signals output from the H side and the L side according to the frequency generated by the rotation of the slit (that is, the winding speed of the wire electrode 1), and an electronic control unit (ECU). In the present embodiment, for example, when the winding speed of the wire electrode 1 is 80 mm / s or more, the output on the L side is turned on, and the output is 100 mm.
When / s or more, the output on the H side is also turned on.

The wire end detecting sensor 5 is arranged between the asserting force generating mechanism 3 and the workpiece 18, and the cut end of the wire electrode 1 which is rewound in the direction of arrow B passes through this sensor 5. It will notify you when you do. The wire collecting mechanism 6 includes a drive roller 35 that drives the wire electrode 1 in the direction of arrow A, a servomotor 36 that drives the drive roller 35, a pinch roller 37 that sandwiches the wire electrode 1 together with the drive roller 35, and a used roller. And a recovery basket 38 for accommodating the wire electrode 1. That is, the wire electrode 1 is pulled out from the wire bobbin 10 by being wound by the drive roller 35 during processing, and travels in the direction of arrow A.

Further, in this embodiment, in order to control the traveling of the wire electrode 1 described above, the ECU 4 as shown in FIG. 4 is used.
0 is provided. This ECU 40 is a well-known RAM4
0a, ROM 40b, CPU 40c, input / output port 40
I / O port 40
The back tension motor 11, the electromagnetic brake 12, the tension brake 17, and the servomotor 36 are connected to d via a drive circuit (not shown). Also,
In addition to the photo sensor 21 and the wire end detection sensor 5, the I / O port 40d outputs H-side and L-side signals (indicating high and low speeds) to the ECU 40 according to the output from the photo sensor 21. The speed simple detection circuit 39 is connected.

The wire winding control device of the wire electric discharge machine of this embodiment operates under the control of the ECU 40 as follows. This operation will be described based on the flowcharts of FIGS. 5 and 6 and the timing chart of FIG. 7. First, when the workpiece 18 is processed, in step (hereinafter referred to as S) 100, the back tension motor 11 is turned on, and the wire bobbin 10 is biased in the direction opposite to the traveling direction of the wire electrode 1.

Then, in S110, it is determined whether or not the wire electrode 1 is broken based on the output from the photosensor 21 of the wire breakage / speed detection mechanism 4, and the breakage of the wire electrode 1 is detected here. If so, the process proceeds to S120. S1
At 20, as shown in FIG. 7, the electromagnetic brake 12 is momentarily excited to brake the back tension motor 11 to stop the rotation of the wire bobbin 10 in the wire feeding direction. That is, when the wire breaks, the rotation of the assertive force generating mechanism 3 is stopped, but since the wire bobbin 10 sends out the wire electrode 1 by inertia, the wire bobbin 10 is prevented from sagging due to this sending out. It stops the rotation.

In the subsequent S130, the tension brake 1
The excitation state of No. 7 is changed from the large set value H to the small set value L. That is, the frictional force of the tension brake 17 is reduced so that the wire electrode 1 can be moved smoothly. As a result, the tension brake 17 is released, so that the wire bobbin 10 can be reversely rotated by the back tension motor 11 at a rotation speed N ₂ lower than the rotation speed N ₁ at the time of wire feeding, and as a result, the wire electrode 1 is rotated. It is rewound in the direction of arrow B.

In subsequent S140, the speed simple detection circuit 39
The winding speed of the wire electrode 1 is controlled based on the output of. Here, the control routine of the winding speed of the wire electrode 1 performed in S140 will be described with reference to FIG.

First, in S142, the simple speed detection circuit 3
Whether the output on the L side of 9 is on and the output on the H side is on, that is, the winding speed of the wire electrode 1 is 100 mm / s.
It is determined whether or not the speed is higher than the above. Here, if an affirmative decision is made, the operation proceeds to S144, while if a negative decision is made,
Proceed to S146.

In S144, since the winding speed of the wire electrode 1 is high, a process of gradually increasing the exciting force of the tension brake 17 is performed in order to reduce the winding speed, and the present process is temporarily terminated. On the other hand, in S146, it is determined whether or not the H-side output of the speed simple detection circuit 39 is off and the L-side output is off, that is, the winding speed of the wire electrode 1 is lower than 100 mm / s and 80 mm / s. It is determined whether or not it has fallen below s. If an affirmative decision is made here, S1
On the other hand, when the determination is negative, the process ends.

At S148, since the winding speed of the wire electrode 1 is decreased, in order to increase the winding speed,
A process of gradually reducing the exciting force of the tension brake 17 is performed, and the present process is temporarily terminated. That is, the above S14
The processes of 2 to S148 are processes for maintaining the winding speed of the wire electrode 1 within a predetermined range based on the outputs of the speed simple detection circuit 39 on the H side and the L side.

Returning to FIG. 5, in S150, the wire electrode 1 to be rewound based on the output of the wire end detection sensor 5 is rewound.
Is detected, that is, whether the wire end has been rewound to a predetermined position. If the wire end is detected, the process proceeds to S160. On the other hand, if the wire end is not yet detected, the steps S142 to S1 are performed.
The process of 48 is repeated to keep the winding speed of the wire electrode 1 constant.

At S160, in response to the detection of the wire end,
The driving of the back tension motor 11 is stopped, the rewinding of the wire electrode 1 is stopped, and this processing is once ended. At this time, since the wire electrode 1 is rewound at a predetermined moderate speed, the wire end accurately stops at a predetermined stop position.

As described above, in this embodiment, when the wire electrode 1 is detected to be disconnected, first, the wire bobbin 10 is momentarily stopped and the tension brake 17 is loosened to move the wire electrode 1 in the direction of arrow B. Rewinding to.
At the same time, the winding speed of the wire electrode 1 is detected, and the exciting force of the tension brake 17 is controlled according to the winding speed to adjust the winding speed of the wire electrode 1 to a predetermined appropriate speed. There is. Then, when the wire end is detected thereafter, control for stopping the rewinding of the wire electrode 1 is performed.

Therefore, even if the winding diameter or weight of the wire bobbin 10 changes and the winding force fluctuates, the wire electrode 1 can be wound at a preferable low speed when the wire electrode 1 is broken. There is a remarkable effect that it is possible to prevent derailment from the pulleys and rollers. Further, since the winding speed can be adjusted appropriately, there is an advantage that the wire end can be reliably detected and accurate positioning can be performed.

Next, the second embodiment will be described. The wire winding control device of the wire electric discharge machine of this embodiment is shown in FIG.
As shown in FIG.
1, an assertion force generation mechanism 42, a wire breakage / speed detection mechanism 43, a wire end detection sensor 44, a wire recovery mechanism 45, a speed simple detection circuit (not shown), etc. The difference is that it does not have a brake. Therefore, in this embodiment, as shown in FIG.
The control shown in the flowchart of FIG. 10 and the timing chart of FIG. 11 is performed. The description of the same parts as those in the above-mentioned embodiment will be omitted.

First, at the time of processing, the wire electrode 50 is fed in the direction of arrow A, the back tension motor 51 is driven in S200, and the wire electrode 5 is continued in S210.
It is determined whether 0 is disconnected. If it is determined that the wire is broken, the tension brake 53 is loosened in S220. As a result, the wire electrode 50 is wound in the arrow B direction by the wire bobbin 54 driven by the back tension motor 51.

At the subsequent S230, S232 to S in FIG.
As indicated by reference numeral 238, the winding speed of the wire electrode 50 is controlled by increasing or decreasing the exciting force of the tension brake 53 in the same manner as in the above embodiment. Then, in S240 of FIG. 9, it is determined whether or not the wire end is detected, and if it is determined that the wire end has reached the predetermined position, the winding of the back tension motor 51 is stopped in S250. Then, this process is once terminated.

As described above, in the present embodiment, the electromagnetic brake as in the above embodiment is used to stop the rotation of the wire bobbin 54 at the time of wire breakage, but at the time of wire breakage, the wire electrode 50 is simply moved by the back tension motor 51. Just rewind. Therefore, when the feed rate during processing is low, the deflection of the wire electrode 50 is small, and such a configuration is sufficient.

Further, since the winding speed of the wire electrode 50 is appropriately controlled, there is a feature that the wire electrode 50 does not derail and the wire end can be accurately positioned. Further, since the structure is simple, there is an advantage that the cost can be reduced and the failure is hard to occur.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that the present invention can be carried out in various modes within the scope of the gist of the present invention.

[0036]

As is apparent from the above detailed description, according to the present invention, when the wire breakage detecting means detects the wire breakage of the wire electrode, the moving speed of the wire electrode detected by the wire speed detecting means. According to the above, the wire speed control means drives and controls the wire tension generation means to adjust the winding speed of the wire electrode.

Therefore, since the winding speed of the wire electrode can be controlled so that the moving speed of the wire electrode at the time of disconnection becomes an appropriate value, the wire electrode moves even if the diameter or weight of the supply bobbin changes. The speed does not become excessive, and therefore the wire electrode does not derail from the roller or the like.
Further, since the moving speed of the wire electrode during winding is appropriate, it is easy to detect the wire end, and therefore, there is a remarkable advantage that the wire end can be surely positioned.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating the present invention.

FIG. 2 is an explanatory diagram showing the overall configuration of the device of the first embodiment.

FIG. 3 is an explanatory diagram showing a speed simple detection circuit for the wire electrode 1 according to the first embodiment.

FIG. 4 is a block diagram showing an electronic control unit of a first embodiment.

FIG. 5 is a flowchart showing the overall control of the first embodiment.

FIG. 6 is a flowchart showing the control of the winding speed of the first embodiment.

FIG. 7 is a timing chart showing the control timing of the first embodiment.

FIG. 8 is an explanatory diagram showing an overall configuration of a second embodiment.

FIG. 9 is a flowchart showing the control of the second embodiment.

FIG. 10 is a flowchart showing the control of the winding speed of the second embodiment.

FIG. 11 is a timing chart showing the control timing of the second embodiment.

[Explanation of symbols]

 M1 ... Wire speed detecting means M2 ... Wire disconnection detecting means M3 ... Wire winding means M4 ... Wire tension generating means M5 ... Wire speed controlling means 1, 50 ... Wire electrode 2, 41 ... Pre-tension generating mechanism 3, 42 ... Claim force Generation mechanism 4, 43 ... Wire breakage / speed detection mechanism 5, 44 ... Wire end detection sensor 6, 45 ... Wire collection mechanism 10, 54 ... Wire bobbin 11, 51 ... Back tension motor 12 ... Electromagnetic brake 17, 53 ... Tension brake 21 ... Photo sensor 39 ... Simple speed detection circuit

Claims (1)

[Claims] 1. A wire winding control device for a wire electric discharge machine which discharges electric current between a wire electrode and a work piece which is the other electrode to work the work piece and winds the wire electrode when the wire is broken. In, a wire speed detecting means for detecting the moving speed of the wire electrode, a wire disconnection detecting means for detecting disconnection of the wire electrode, and the wire electrode is urged in a direction opposite to the traveling direction during processing. A wire hoisting means for hoisting, and a wire hoisting means arranged between the wire hoisting means and the workpiece,
Wire tension generating means for applying a passage resistance to the wire electrode to generate tension in the wire electrode; and, when the wire breakage detecting means detects wire breakage of the wire electrode, the wire speed detecting means detects the wire breakage. Wire winding control of a wire electric discharge machine, comprising: wire speed control means for driving the wire tension generating means to adjust a winding speed of the wire electrode according to a moving speed of the wire electrode. apparatus.