JPS6029237A - Device for preventing vibration of wire electrode in wire cut electrical discharge machining - Google Patents

Abstract

PURPOSE:To aim at preventing the generation of vibration and as well at absorbing vibration generated, by forcingly contacting a pair or a plurality of contact members made of low-friction materials, with a wire electrode in a clamping condition around the electrode so that vibration is limited. CONSTITUTION:A wire electrode 2 passes through between a movable contact member 14 supported to a movable iron piece 12 and a stationary contact member 15 in a vibration preventing device 10. The wire electrode 1 is magnetically and instantly made into contact with the stationary contact member 15 and the movable contact member 14 in a clamped condition by magnetically exciting a magnetic exciting coil 16 when vibration above a predetermined level generated in the wire electrode 1 in the working part between end part guides 6a, 6b is detected, by magnetically exciting it at predetermined time intervals previously set, or by magnetically exciting it, intermittently with a pulse wave having a frequency which is nearly equal to the resonant frequency of the wire electrode 1, and therefore, at least one of the vibration fulcrums of the wire electrode 1 is displaced from the positions of both guides 6a, 6b toward the positions of the contact members 14, 15 so that generated vibration is damped, ceased or changed into small vibration having a high frequency, thereby vibration is substantially limited.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing vibration of a wire electrode in a wire cut discharge power plant.

Wire-cut electrical discharge machining involves making the wire electrode at the machining section between a pair of positioning guides arranged at intervals, facing the workpiece, and moving the wire electrode 1#U between the workpiece and the workpiece while continuously renewing feed in the axial direction of the wire electrode. The machining process is performed by intermittent electric discharge through the machining fluid, and the wire electrode must be used as straight as possible with a predetermined applied tension and with little vibration. However, when performing wire-cut electrical discharge machining, the axial renewal feed while the wire electrode is in contact with the guide, etc., and the pulsed discharge of electrical discharge machining may cause irregularities in the machining fluid jet or irregularities in the machining contour shape. Changes in routes such as corners, etc.
Vibration occurs in the wire electrode of the joint part between the pair of positioning guides as both guides act as fulcrums at both ends, resulting in liquid filling, overcutting of the machined part of the workpiece, that is, the width of the groove of the cutting machine. Taking into account the disadvantages of decreasing machining accuracy due to increase in size or partial change, this invention uses a graphite body to forcibly sandwich the wire electrode with the wire electrode at the center. At least one of the contacting bodies is a movable body, and is designed to prevent the generation of vibrations and to absorb or prevent the generated vibrations. be.

Next, an explanation will be given based on the diagram illustrating this case 8J1. FIG. 1 schematically shows a wire-cut electrical discharge machining device equipped with a vibration prevention device according to the present invention.
The column 102 provided in
A spatula (105i) which can be moved up and down is supported at the tip of the upper arm (+05), which extends toward the upper table side. A guide holder 106 is supported at the bottom of the head 105 so that it can be moved on a horizontal plane in X and Y directions perpendicular to each other by a numerical control device (not shown). The wire electrode 1, which can be wound around the storage drum 2a of the wire electrode 1, is interposed between a number of guide rollers 3a and 3bffi, and a brake is applied to drive the wire 711il in the axial direction to perform processing between the positioning kites. A pinch roller 4a that fully applies a predetermined tension to the wire electrode 1 and a brake roller 5a are provided with a clamp 1.
It is made to face the workpiece 7 through the pierced part and the 10,000-piece dock guide or die guide 6ai for positioning the processing part.

This workpiece 7 is mounted on a table 10f fixed to a table 107.
1 by a clamp plate 109.

This table 107 is supported by a bed 1o1, and is moved by a numerical control device (not shown) in XY directions perpendicular to each other on a horizontal plane parallel to the fine adjustment movement horizontal plane of the guide holder 106. There is. A machining voltage from a machining power source 8 is applied between the wire electrode 1 and the uncut machining body 7, and machining is performed under the injection of machining fluid 9.

The wire electrode 1 used for electrical discharge machining in the machining section between the guides is connected to the wire electrode 1 provided between the other dock or die guide 6b, the plurality of guide rollers 3d and 3e, and the guide rollers 3d and 38. The part sandwiched between the update drive pinch row 24b and the capstan 5b is passed through to take up the winding drum 2b.
It is wrapped around.

In FIG. 1, reference numeral 10 denotes a vibration prevention device according to the present invention, and FIG. 2 shows a cross-sectional view perpendicular to the wire electrode 1 in a main part configuration of one embodiment thereof.

In FIG. 2, reference numeral 11 denotes a main magnetic structure, and a bar-shaped movable iron piece 12 is inserted into a partially cut-out space so as to be movable in all axial directions, and is held in a predetermined position using a spring 13. The entire wire electrode 1 passes through between the movable contact body 14 and the fixed contact body 15 which are integrally attached to the movable iron piece 12. The magnetic structure 11 is fixed to a stand 18 by a pillar 17, and the stand 18, to which the inner rectangular contact body 15 is also attached, is attached to the guide holder 1.
06 or the tip of the lower arm 104.

In addition, the cage is an excitation wire ring, and B is applied to the wire electrode 1 of the processing section at both ends of the guides 6a and 6bi. The gold fixed contact body of the wire electrode 1 is energized by excitation, or alternatively by audible excitation with a pulse wave of a frequency (one integer multiple and one integer fraction) close to the resonant frequency of the wire electrode 1. 15 and the movable contact body 14 momentarily come into pinch-like contact during excitation, and the wire electrode 1 of the processing section
By changing the vibration fulcrums from the positions of both guides 6a and 6b to the position of at least one of the contact members 14 and 15, the generated vibrations are attenuated, stopped, or changed to vibrations of higher frequency and smaller amplitude, thereby substantially It limits vibration. As an example, IZO is usually used for the wire electrode 1, and 0U-Zn is used for the 2mmφCurl.

A tension of about 1 kg is applied between the guides 6a and 6b, and the length between the guides is, for example, about 100 mm, although it depends on the thickness of the workpiece 7.

What is illustrated in FIG. 3 is a longitudinal sectional view of another embodiment of the present invention, in which the frequency F of the wire electrode 1 is the vibration order, and n is the vibration order.
L is the length between the fulcrums (cm) + PU tension (Kg),
g i'Xft cuff 111 speed 981 crrI/s
”Iδ is determined by the unit length of the wire electrode (Kg/cm), so it is given by changing the above value by instantaneously touching the contact body 14 or 15 one or more times when vibration occurs, etc. Value (Normally, L is a fixed value as the length between the guides 6a and 6b.Ll is not a length but a different value.

This is intended to ensure that vibrations stop by allowing settings such as L2.

Therefore, in this embodiment, a pair of annular wire rings 19 and 20 are provided coaxially on a non-magnetic cylindrical support 21 at a predetermined distance apart in the axial direction of the entire wire electrode 1 so as to surround the wire electrode 1. , this support 21 is fixed to the stand 18. A pair in the groove 22 of the support body 21.

Alternatively, the wire electrode 1 is made of a magnetic material or a permanent magnet that is divided in the radial direction of the wire electrode 1 into a plurality of parts, such as three or four parts.
The contact bodies 25, 24 (cl) have a spring 27.2 fixed at one end in a hole 25.26 provided in the support body 21.
8 and is supported by the elasticity of tin rings 27 and 28.

In this case, the springs 27 and 28 may be simple wire-wound springs, but the springs 27 and 28 may be formed into an annular recess with the hole 25 and 26 opened on the inside, and a disk bellows-shaped spring is formed by dividing the contact body 25 and 24. It is preferable to have a fan-shaped bellows-shaped set divided in the radial direction depending on the number of parts, and the outer periphery is fixed to the bottoms of the annular recesses 25 and 26 of the support body 21. And these wire wheels 19. .

By energizing 20, the pair of contact bodies 25 and 24 are magnetized and attracted to each other with the wire electrode 1 as the axis,
The wire electrode 1 is contacted from at least a portion of the circumference so as to momentarily clamp the wire electrode 1.

That is, when the attractive force of the contact body 23.24 is lost by removing the excitation of the wire ring 19.20, the spring 27.28
The contact bodies 23 and 24 are pulled apart by the elasticity of the contact bodies 23 and 24, and contact with the wire electrode 1 is also stopped.

In this device, by switching the selection of the wire ring 19 or 20 to be excited, or by changing the strength and direction of the excitation applied to both f# wires 19, 20, for example, as shown in FIG. It can be moved to a predetermined position along the axial direction of the i-wire electrode 1 and brought into pinch-like contact with the wire electrode 1 at that position.

As a result, the entire length between the fulcrums of the wire electrode 1 can be changed according to the frequency of the vibration of the wire electrode 1, and the contact can be made in a pinched manner, so that the wire electrode 1 can be reliably contacted regardless of the vibration state of the wire electrode 1. It can be stopped. This wire electric @!
, 1 is illustrated in FIG. 5 as another example of a device configured to change the length between the supporting points of the wire electrode 1 according to the vibration state, vibration frequency, etc. of the wire electrode 1.

This device is the device shown in FIG. 1, in which a base 18 is slidably supported on a pair of guide rods 29 installed parallel to the wire electrode 1, and a screw 60 screwed into the base 18 is shown. The entire vibration prevention device can be moved by rotating it under numerical control using a servo motor.

Figures 6 and M7 are block circuit diagrams of an embodiment in which full excitation commands are given to the coils 19 and 20 in the embodiments shown in Figures 3 and 4, respectively, and Figures 1 and 4 respectively. 5. In the embodiment shown in FIG.
This is a block circuit diagram of an embodiment. In FIG. 6, reference numeral 61 denotes a clock signal source with an appropriate frequency, and the frequency is divided by a frequency dividing circuit 32 whose division ratio can be switched and control can be changed as necessary, for example, about 0. A signal pulse is output every IS to 3S, and the output is inputted to each digit element of the monostable element 53 and the ring counter 64. And in this example 6
Ring counter 34 (7) each with 2 and 4 digits
Outputs are provided for the digits 5 and 6, and the AND circuit 5 is provided, respectively.
-1.3-5-2.55-3. Each of the AND circuits 35-1.55-2.55-3
The other input terminal of the monostable element 6
The AND circuit 65-1 is input to the excitation command circuit 19' of the wire ring 19, the AND circuit 35-5 is input to the excitation command circuit 20' of the wire ring 2o, and the AND circuit 5
5-2 is configured to output an operation command signal based on a circular product to both the circuits 19' and 20'.

That is, in the circuit of this embodiment, depending on the frequency of the clock 51 and the division ratio of the frequency dividing circuit 620, the wire ring 19° and both wire wheels 19
and 20. The cycle 20 and again the cycle 19 are repeated, e.g. at intervals of about 0.98, the cycle 19.
20 is opened 71 times by about 0.058 degrees each time, and the contact bodies 23 and 24 are placed on the coil 19 side, at a position intermediate between the coils 19 and 20, on the coil 20 side, and again on the coil 19 side. contact the wire electrode 1 so as to clamp it for a moment, and the wire electrode 1
Attenuate or stop the vibration 21I+, or completely prevent the vibration that is occurring.

In this case, the contact f'Jd+ position of the contact bodies 25 and 24 and the wire electrode 1 in the support body 21 which is in the fixed position is sequentially displaced in the axial direction of the wire electrode 1 in the direction υζ. The long distance between the contact bodies 23, 24 of the anti-vibration device 10, i.e. the length of the wire electrode 1 in that part, or if the anti-vibration device 10 is provided only on one side, for example the upper boom 106 side. , by changing the length between the vibration prevention device 10 and the guide rod b of the other lower arm 104, that is, the length of the wire electrode 1 in that part.

Vibration of various vibration characteristics occurring or about to occur in the portion of the wire electrode 1 between the wire electrodes 6b can be completely damped 2 and completely prevented from occurring.

That is, assuming that the position of the pinched contact between the contact bodies 26 and 24 and the wire electrode 1 is always a constant position between the guides 6a and 6b, the contact position may vibrate depending on the generated vibration (high frequency vibration). There are cases where the contact body 23 is in contact with the nodes of the contact body 23 and attenuates or stops the vibrations. There are cases where the wire electrode 10 generation and imaging cannot be quickly and efficiently attenuated or stopped from a location where the wire electrode 10 and 24 are relatively close to the vibration fulcrum portion, that is, the guide 6a or 6b, but according to the present invention, Since the position of the pinched contact between the contact bodies 23 and 24 and the wire electrode 1 is constantly moved and changed in the opposing direction of the guides 6a and 6b, that is, in the axial direction of the wire electrode 1, the above-mentioned conventional drawbacks can be avoided. It is something that will be resolved.

In the above case, the order of excitation of the wire rings 19 and 20, the excitation switching speed, etc. depend on the purpose, the type and material of the wire electrode 1 used, the wire diameter, the length between the guides 6a and 6b, the thickness of the workpiece 7, etc. It is possible to change the settings as desired. Also 66
is an input terminal for a signal for changing the division rate of the frequency dividing circuit 620, such as increasing or decreasing the division rate, and a signal for detecting the quality of the electric discharge machining state in the machining gap, the frequency and amplitude of the vibration generated in the wire electrode 1, etc. The structure is such that the contact repetition frequency between the contact bodies 23 and 24 and the wire electrode 1 can be varied so that vibrations can be damped or stopped quickly and efficiently.

In FIG. 7, substantially the same thing or the same action is shown in the part with the same reference numerals as in FIG. The screw 60 of the example is moved by the MLA* circuit 30' to rotate a stepping motor (not shown) to rotate one or both of the vibration prevention devices 10? The guide 929 is used to cause the wire electrodes between the guides 6a and 6b to move up and down in the axial direction at a desired distance and at a desired relatively small time interval. It is something to do. 58 is an OR circuit which, in the case shown in the figure, sends a signal to the AND circuit 39 each time a signal enters each digit element of the second and fifth digits of the ring counter 34, and each time the monostable element 33' is triggered and the element is The output pulse of the pulse oscillator 57 which outputs a pulse of a desired frequency during the operation period of the AND circuit 69 is output.

401-j A polarity control circuit inverts the polarity of the output pulse of the pulse generation circuit 37 output from the AND circuit 69 - each time a signal enters the third and fifth digit elements of the e-ring counter 34 and sends it to the drive circuit 50'. This is what is output. Also 16'
Each time the element 35' is triggered, a signal is inputted after a desired set delay time via the delay circuit 41.
Although this is an excitation circuit for 6t-pulse excitation, the delay circuit 41 may be configured so that the Iha number is input from a desired digit 9m of the ring counter 54, and the vibration prevention device 10 is connected to the wire electrode 1. The upper and lower axial limits of I
The wire ring 16 is energized when the wire is in the I-position or during ascending or descending, so that the contact members 14 and 15 are brought into sandwiched contact with the wire electrode 1. In this case, the drive circuit 50
We have explained the case where the motor is a stepping motor whose rotation angle is determined by the number of pivot pulses, but the driven motor may be equipped with a rotary encoder for detection and control of the rotation angle or a rotary encoder for detection and control of the rotation speed as necessary. The attached DC motor and AC motor can be used as appropriate, and as in the case of Fig. 6, depending on the settings of the frequency dividing circuit and the input of the detection control signal from the terminal 6, etc. Alternatively, the time intervals for raising and lowering the vibration prevention device 10 can be varied in accordance with the combination of use of the column elements of the ring counter 34, and in the case of the embodiments shown in FIG. 3, FIG. 1M4, and FIG. 6. Similarly, it is clear that all vibrations of the wire electrode 1 between the guides 6a and 6b can be quickly and reliably damped or stopped.

Although the movable contact members 14 and 15, 23 and 24 have been described as magnetic materials such as permanent magnets and iron cores, the contact surface side with the wire electrode 1 may be made of graphite or the like as mentioned at the beginning. It is desirable to use a low-friction material with low contact friction, such as various composite materials or low-friction implants containing metal, or a felt-like pad.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of the main body portion thereof, Fig. 3 is a vertical cross-sectional view of another embodiment, Fig. 4 is an operating state diagram of Fig. 3, FIG. 5 is a cross-sectional view of the vibration prevention device shown in FIG. 2, which can be moved in a V direction along the wire electrode.
FIG. 6 is a block circuit diagram for driving the vibration prevention devices of the embodiments shown in FIGS. and M4 and the embodiments of FIGS. 2 and 5. FIG. In the figure, 1 is a wire electrode, 11 is a magnetic structure, 12 is a movable iron piece, 15 is a spring, and 14 is a movable contact body. 15 is a fixed contact body, 16 is an excitation wire ring, 19.21]I''
1 annular wire ring, 23.24 a contact body, 27.28 a spring. party 4 tuji 5 falcon 6 tu tun 7 district

Claims (4)

[Claims] (1) While a wire electrode is renewedly moved in the axial direction between a pair of positioning guides arranged at a distance, a force-receiving workpiece is made to face each other through a minute gap from a direction perpendicular to the axial direction of the wire electrode. In wire cut 11t machining, the wire electrode is forcibly pinched between at least one movable contact body and the opposing contact body between at least one wire electrode positioning guide and the workpiece. A vibration prevention device for a wire electrode in wire cut electrical discharge machining, which limits the vibration of the wire electrode by contacting the wire. (2) In the wire-cut electric discharge machining according to claim M1, wherein the movable contact body is a magnetic body or a permanent magnet, and the movable contact body is a magnetic body or a permanent magnet, and is brought into pinch-like contact with the wire'[pole] by coil excitation. Vibration prevention device for wire electrodes. (3) By sequentially selecting or combining excitation of a plurality of coils provided on both sides in the axial direction of the wire electrode with the movable contact body in between, the pinched contact position of the contact body with respect to the wire electrode is adjusted in the axial direction of the wire electrode. 2. A device for preventing vibration of a wire electrode in wire-cut electric discharge machining according to claim 1, wherein the device moves as follows. (4) A single-pole vibration prevention device for a wire in wire-cut electric discharge machining according to claim 1, wherein the holder of the movable contact body moves along the wire electrode by a moving device such as a screw. .