JPH01274927A - Wire electrode automatic feeding method in wire cut electric discharge machining device - Google Patents

Abstract

PURPOSE:To increase the success probability of wire electrode insertion by repeating a plurality of times of cycle operation for detecting a failure and re-starting an automatic wire feed until the engagement of the wire electrode with a wire electrode recovery part. CONSTITUTION:A wire electrode 2 fed from an upper guide 20 on the turn of a pinch roller pair is fed to a space between the belt 47 of a wire recovery device running at a speed higher than the pinch roller, and a lower roller 48 via a machining start hole 77, a lower die guide 40 and a power feeding die 41, thereby being pulled. In this case, when it is judged from the output of an encoder for detecting a wire feed velocity that the high load failure where the tip of the wire electrode 2 comes in contact with the guide 40 and the passage failure where the wire electrode 2 is de scribed from the guide 40, are taking place, automatic feed is again made. If the wire electrode 2 is not yet engaged with the recovery device and re-feed operation is made by N-times, the wire electrode 2 is cut and the process is repeated until the engagement of the wire electrode 2 with the recovery device. According to the afore said construction, the success probability of wire electrode insertion can be made higher.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for supplying wire T41 in a wire-cut electric discharge machining device, by detecting a supply failure due to a trouble during automatic wire supply.

This will probably be related to how to make automatic wire supply a little more successful, and first of all, Figure 1 shows the conventional wire 1! The configuration of the extremely automatic feeding system will be explained.

In the figure, (1) is a wire supply reel, which is connected to a torque motor (not shown), and is configured to apply reverse torque to obtain enough braking force to prevent the wire electrode (2) from slackening. (3) is a brake roller, which is connected to a mold can brake (not shown); and (4) is a presser roller, which is pressed against the brake roller (3) by a spring force. The wire electrode (2) is sandwiched between the brake roller (3) and the presser roller (4) 1171, and a constant tension is applied thereto without slipping. (5) is a direction conversion roller, and 16) is a positioning die, the inner diameter of which is slightly larger than the diameter of the wire electrode (2). (7) is a pinch roller for wire feeding;
(8) is a wire feeding press roller. The above roller (
7) is only available during automatic wire supply.

The pinch roller motor (
Rotated by 1G. Further, the roller (8) is pressed against the roller (7) by a spring force, and during automatic wire feeding, the wire' electrode (2) is pressed against the roller (7),
18) and is designed to be fed downward in the figure without slipping, the wire fit % 12) is fixed to the roller fil, +
It never deviates from the 81 range.

The elevating and lowering of the elevating plate 19) was coupled to an elevating motor in and a coupling 1z. A pole nut for converting the rotation of the ball screw 03 into vertical linear movement is attached to the back side iQl in the figure of the elevating plate 19) which is caused by the rotation of the ball screw a3.

This ball screw port j is supported by the motor mounting part 0!9 attached to the lifting guide 4, and the other end is connected to the shaft 9.
It is supported by +TE and has a 9-end support system.

In addition, since the elevating plate (9) is supported in elevating and lowering by the elevating guide α bottle, accurate vertical linear movement is possible.

Further, a pipe guide 0η is fixed to the elevating plate +91 via a guide fixing plate Os. This pipe guide t
i9 moves up and down as the lifting plate (9) moves up and down.

It is supported by a bearing to prevent shaking. Furthermore, a die guide (a) for supporting the wire electrode f2) is attached to the tip of the pipe guide αη. In addition, bearing full, Q! 1. The lifting guide +14 is attached to the fixed plate 12Il. Next is the cutting motor, 171 is the arm rotation motor, and both are fixed to the box (2). 9 is the wire cutting part. , ~ is a cutting arm, @ is a tray for discarding wire chips after cutting the wire, and the cutting device I'74 and the tray @ are attached to the fixed plate +29.In addition, the cutting device (2) The pipe guide 1171 and wire cutting function will be described in detail later.
During processing, the plate 1 is pressed against the reference V-groove plate 1 and is fixed. This reference V-groove plate is received by the V-groove surface so that the above-mentioned pipe guide ^D fits therein, and its position is determined. Note that the reference V-groove plate is always fixed to the nine boxes 4, and one range is attached to the fixed plate 121+. Further, a nozzle (toward) for jetting and supplying the machining liquid r311 to the machining section c3'3 is attached to the ninth hole.

In addition, the pipe guide 0η has three notches as shown in Figure 9, and during the construction of ηa, the power supply bin ~, (to)
There is a 3-point contact with the wire terminal * +21.

The power supply bottle (2) from which power is supplied is fixed to the movable plate (to), and when the pipe guide fin moves up and down, it moves to the right in Figure 9 to avoid contact.

Similarly, the @@pin ring is fixed to the movable plate (B), and the push button 9 degrees to the left in the figure moves together with the plate 1. (7) is the workpiece, and @ is the table.

Next, L41 is the lower die guide, 40 is the lower power supply die, and both are set to 1 box + 46.
Seven boxes (43) attached to the lower arm include nozzles (2) for supplying machining liquid aV to the machining equipment.
8) is attached, and four guide nozzles (4 nozzles) are attached to guide the wire electrode (2).

The wire electrode (2) passing through the guide nozzle C4 is transferred to the belt roller 49. (Lower belt G1η stretched on 4[9
and the lower roller (c), and are guided to the trumpet pipe. After that, the wire electrode (2) passes through the 9 collection pipe (to) and +ol collection roller (51
>, the wire is sandwiched between the collection belt (53) stretched over (52) and the collection roller (54), and is led to the collection box (55) 9, where the wire overlaps f2) as shown in Figure 1. are discarded in a circle. The feeding speed of the wire electrode (2) is variable by the rotation of a motor with a reduction gear attached to the back of the first collection roller (54) in the figure.

Furthermore, the collection roller (54) and the lower roller scoop are belt-transmitted on the back side. Moreover, both rollers f41. (54) have the same diameter, so the wire polarization (2) is prevented from slipping due to the frictional force caused by the lower roller (4 turrets) and that by the recovery roller (54). Being pulled.

It is collected into a collection box (55).

Next wire';1! I (56) is a cutter for cutting the wire Ml pole (2). and is fixed to the movable rod (5 days) with a screw (57).A wire [
A support rod (
59) is fixed, and rubber (60) is adhered to the contact portion to prevent slippage.

Also, (61) is the cutting plate, which is secured by screws (62).

It is fixed to the cutting arm. The above cutting plate (61)
Rubber (64) is glued to prevent slipping. When cutting the wire electric f (21), between the cutting receiving plate (61) and the cutter (56).

The movement I movement 1 (58) moves to the left in the figure.

It is cut and simultaneously supported between rubber (60) and (64). There is a screw cut into the right end of the moving rod (5th) in the figure, and after inserting the compression spring (65), tighten the locking nut (
66) is screwed in and fixed. The horizontal movement of the moving rod (5th) is performed by the half-rotation operation of the eccentric cam (67). Figure 7 shows the case where the eccentric cam (67) is at the rightmost end, and the S moving rod (58) is also moved by the compression spring ( 65) is on the far right due to the restoring force. On the other hand, when cutting the wire electrode, the eccentric cam (67) rotates half a turn to the left end position, so the movable rod (5th) and stopper (56) are located at the left end, and the cutter (56) and the cutting plate (61).

Next, the rotation of the cutting arm will be explained.

When the arm rotation motor attached to the box Q4 rotates, the gear (70) is rotated by the gear (69) attached to its shaft. The gear (70) is fixed to the arm rotating rod (7I), and the cutting arm 1 is further connected thereto. The arm rotating rod (71) is a bearing (72) w
(73) is supported by. However, as the arm rotation motor G rotates approximately half a turn, the cutting arm rotates 180° in the opposite direction in Figure 9 and stops.
The position 180° opposite to the position shown in the figure is detected by a limit switch, etc.

It is now possible to decide.

Next, the rotation of the eccentric cam (67) will be explained.

An eccentric cam rotating rod (74) is inserted into the center of the arm rotating rod (71), as can be seen in the interrupted section in Figure 1, and is rotatable once. An eccentric cam (67) is fixed to the lower end of the eccentric cam rotating rod (74), and a bearing (75)
This allows for smoother rotation.

Further, the upper end is connected to a cutting motor via a coupling (76). Therefore, I cut the cutting arm 1
The arm rotation motor is rotated to position it on the opposite side by 80 degrees, and at the same time, the cutting motor is activated and rotated by 180 degrees. As a result, the eccentric cam (
Since the relationship between the cutter (56) and the locking nut (66) remains the same, the wire '1lt4ij (2) is located between the cutter (56) and the cutting plate (61). After that, by rotating only the cutting motor an additional 1800 times,! I @ Y (5th) moves in the direction of the cutting plate (6 I) and can cut the wire electrode (2) as described above. After that, leave the cutting motor in the open position. , return the arm rotation motor to the position shown in Figure 9 by rotating it 180°. Then, by rotating the cutting motor G 1800 times in the opposite direction, the state shown in Fig. 1 can be returned.

Next, we will explain the operation of cutting the wire electrode (2) in Fig. 3. First, Fig. 3 (1) shows a state in which the wire electrode f21 passes through the machining start hole (77) of the workpiece (to). Initialize.

This will be the case when entering the cutting operation, that is, the initial setting state is shown in FIG. First, in order for the pipe guide aD to rise in the direction of the arrow in the center of the figure, the power supply bottle is moved.

(to) is attached to the moving plate (7), @ and 's
@ When the plate (to) is attached, plate 1 moves in the direction of the arrow in Figure I.

Note that when the pipe guide η rises to a certain predetermined position and stops, the wire feed pinch roller (7) and the wire feed roller (8) move together with the pipe guide 1η, as described in Section 11. As it rises and stops as one.

It rotates around as shown by the arrow in the figure.

**V-groove plate 1 is always fixed and pipe guide a
When the pipe guide 71 moves up and down, it rubs.The nozzle is always fixed.When the pipe guide 0η rises, the die guide 1 is the wire? The lower end position It of the die guide holder shown in the figure, which has a clearance sufficient to scrape the lj pole (2), will be referred to as the cutting position.

Next, in Figure 3 (1)), the cutting arm (A) is rotated 180 degrees and brought to the cutting position. ) has been positioned, the operation of the arm rotation motor of the cutting motor is as described in Figure 2.The wire feed pinch roller (7) and wire feed roller 18) are It is stopped at this time.

Furthermore, a one-way clutch (not shown) is attached to prevent the pinch roller (7) VcFi from rotating in the direction opposite to the direction of the arrow in FIG. 3j, FIG. 1a). 2) shows the state after actually cutting. That is, as described in the second layer, after cutting, the cutting arm holder rotates 180 degrees and returns to its original position. And the wire after cutting? The lower part of lj f 12+ detects that the cutting motor has further rotated by 180° as described in Fig. 2, and the collection roller (54) shown in Fig. 55). Next, FIG. 3(d) shows the state in which the wire electrode (2) has actually been completely cut. In other words, Figure 3 (
After the state of C) is completed, the pipe guide surface descends until it reaches the state of Fig. 3(d). This state is the initial state of Fig. 3(9) with the movable plates ~, and the sub-plates still moving. It is a state.

Now, the position of the pipe guide (In will be the same as in Fig. 1, and the lower end of the die guide )
is sandwiched between the wire feed pinch roller (7) and the wire feed roller (8), and since the pinch roller (7) is equipped with a one-way clutch and does not reverse, the die guide (2) It will not come out from the tip and come out upwards. Cutting is completed in the state shown in Figure 3 1dl. During the cutting operation shown in Figure 3 ft) to (d), the The braking force of the magnetic brake connected to brake roller "3" is extremely weakened.

Next, referring to FIG. 4, the insertion operation of passing the wire electrode (2) through the processing start hole and the lower die guide will be described.

Here, the process of starting the process, passing the wire electrode through the lower die guide, and sending it to the collection box (55) in Figure 1 will be referred to as the insertion operation of the wire electrode (2). (The state of al is the initial state of the wire insertion operation. This is the same state as the final state of the cutting operation in Fig. 3. In other words, the upper die guide ■ and the machining start hole (
77) and the lower die guide f4Q are aligned in the vertical direction.

Next, as shown in Fig. 4 ft)l, lower the pipe guide D and pass it through the machining start hole (77).
This means that the lower die guide +41 is opposed to the upper die guide (3). The lower gs of the upper die guide ① in this state will be referred to as the lower part. This position is determined by the rotational force of the wire feed pinch roller (7) and the wire feed roller (8), as shown in Fig. 4(c). The wire electrode (2) sandwiched between them begins to advance. FIG. 4(C) shows the wire electrode (2) passing through the lower die guide (41).

Thereafter, the wire electrode (2) passes through the feeding die C49 and the guide nozzle (44) as seen in FIG.

It is guided to the lower belt @n. In addition, lower roller G4
11 and the collection roller (54) start rotating at the same time as the pinch roller (7) and the press roller (8) rotate at the fourth (g).The lower roller thread and the collection roller (54) are synchronized by belt transmission. Therefore, the wire electrode 12) is connected to the lower belt 6η.

The feed I40 and the collection box (55) are drawn in and guided between the two as they advance to the entrance of the lower roller ridge, and are collected into the collection box (55) as shown in Figure 1.
), the wire electrode (
2) has been led to the collection box (55). After the touch is detected in this way, the image shown in Figure 4 ft.
) As shown in the figure, the pipe guide an rises to the fixed position and settles, and then the top, rib plate (to), (support), and pressing plate move in the direction of the arrow in the figure to fix the vibe guide η. At the same time, the power supply bin (to).

(To) makes it possible to supply power to the wire electrode 121.

This makes it possible to start the ηloe, and at the same time the state shown in Fig. 4(d) is the completion of the insertion operation.In the same way as during the cutting operation shown in Fig. 3, during the insertion operation shown in Fig. 4, the state shown in Fig. 1 The braking force of its brake connected to the brake roller (3) is extremely weakened.

As described above, the conventional automatic wire feeding method performs a cutting operation every time the machining start hole changes, and then performs an insertion operation to automatically bring the wire into a ready state for machining. We will discuss the drawbacks during the insertion operation in the automatic feeding method.

First of all, 1*man operation refers to the period from (phantom to fd) in Figure 4. There are various problems that can occur during insertion operation, but Figures 5 and 6 show that the insertion operation cannot be continued. Let me explain the possible troubles. Figure 5 (1
1)、! Let us consider a case where the distance between the lower surface of the workpiece (to) and the upper end surface of the lower nozzle (7th) is large, as in 1)). 1 or 4 (cl), the pipe guide 0η is at the lower limit position seconds after entering the machining start hole (77).The lower die guide holder is shown in cross section. Embedded in the center are diamonds, sapphires, and other jewelry dice (79).

5 axis), the wire 14 pole (2) is connected to the die (
79) and instead enters the gap between the lower die guide 14G and the lower nozzle (7th). This is due to internal strain (or curling) in the initial state of the wire electrode (2).On the other hand, in the case of Fig. 5(b), the lower nozzle (78) In both cases, the wire'electrode 12) is connected to the die (79).
Since it does not pass through the wire electrode (
The electrification in 2) will fail, and it will be impossible to continue the process because the subsequent strip machining will not be possible.Next, as shown in Figure 6, the workpiece (to) Let us consider a case in which the problem of a large distance between the lower nozzle (7o) and the upper end surface is resolved.

Other situation settings are the same as in FIG.

In the case of this Fig. 6 (!I), Fig. 6 shows the lower die guide 1 It can be said that it is easy to guide the wire 1! to the position where the wire 2) is placed.

However, if the wire electrode (2) bends at a nearly right angle to the introduction taper of the lower die guide (4C1) as shown in Fig. 6 1b), the wire electrode (2) will get caught and cannot be bent any further. As shown in Fig. 6 fc, the processed chips generated by N radiation machining may accumulate on the introduction taper part of the lower die guide over a long period of time. The material is constantly immersed in the machining fluid (the dry state is returned to the dry state after a period of time, so it becomes hard (irregular deposits (80)).
In this case, compared to FIG. 6 tb), a stuck state occurs more often than not, and the wire electrode +21 is prevented from advancing as in FIG. 6 fb). In this way, in the case of Figure 6 (bl, tc+), wire electrode (2)
Not only will the progress of the wire be blocked, but if you try to move it in the direction of the arrow with a stronger force, it will cause a large bend or break, and as in Figure 5, the insertion of the 14-pole wire f2) will fail, making it impossible to continue. Become.

Therefore, in view of one or more of the drawbacks, the present invention attempts to significantly improve the probability of a successful wire electrode insertion operation by detecting failure and restarting the insertion operation to ultimately succeed.

First, it is time to classify failures during the insertion operation and explain the principle behind emitting each failure.

There are two types of failures as shown below.
A case like the one shown in Figure J6 can be mentioned.

This can be said to be a case where a high load occurs on the advancing ability of the wire electrode, so it is not limited to Fig. 6 (also,
It includes anything that impedes progress.

12+ Cases in which the wire insertion operation is not completed Mainly as shown in FIG. 5, unlike in case 1 above, the progress of the wire electrode is not hindered, but the wire electrode advances outside the insertion path area. .

First, regarding [111/1m] among the above failures, the detection principle in that case will be described.

FIG. 7 (T) corresponds to the state of No. 4!9 (cl).

That is, the wire feeding pinch roller (7) is driven.

And wire '11! The pole A2) is sandwiched between the presser rollers 18)K during wire feeding and moves in the direction of the arrow in the figure.The wire wire 1f2) has a slight clearance with the die (81) and slides. That's why.

In addition, the wire feed roller: 8) is fixed on the fixed plate (82
) due to the force of the spring (83) on the wire? tE pole (
2) is pressed against the first wire feed pinch roller (7), and the wire electrode (2) is turned on at this point, and the 6 parts are as follows. (Normal force N due to spring (83) force from the spear.

If the friction coefficient between the rollers (71, !81 and the wire 1 pull 2) is μ, then the frictional force that tries to move the roller (force, (8) force, wire force + 21) is μ. Also, the wire electrodes (
For 2).

A tensile force TO is acting on the supply reel fi+ in Fig. 1 (due to the braking force and the brake roller (3)), but during the insertion operation, In order to reduce To, the braking force of the brake roller (3) is weakened to a low level. Therefore, the force that advances the wire electric J4 (2+) is μN-TQ from the figure. Naturally, μ
It goes without saying that N>T(l).
Figure ft) l is wire electric F! 11(2) where there is an obstacle (84) on the path of travel. However, in reality,
This refers to the high load mentioned in Figure 6, but for the sake of simplicity, it will be treated as an obstacle in Figures 1 and onwards.

Figure 71 (1) l shows that the wire 'Ft' (2) is an obstacle (
84), the pipe guide 0'
It is in a state where it is deformed by the bending force inside rI.

Therefore, since the elastic deformation is against the bending rigidity, the reaction force that returns the deformation to its original state moves as shown by F in Figure 9. Therefore, the pinch roller for wire feed -ζ7) moves in the direction of the arrow. The rotation continues due to the rotatable one-way clutch, but the wire 111. As a result, slipping occurred between the wire and the pole 121, and the press roller (8) during wire feeding stopped rotating once.
What does it mean to stop? This means that -1-TQ=μN.

To explain in more detail, as shown in section 71c), the inner pipe guide 4 (85) and the wire electrode C2
) is μm, and the normal force pushing against the inside -1 (ss) is n, then the force that tries to put the wire electrode (2) into the pipe guide (for the range shown in the figure) Due to -To, the wire electrode (2) undergoes deformation, and as shown in the figure, the wire electrode (2) is deformed by the inner Q (85) at multiple points, generating a frictional force of μmn at each point. ＠[2] works like a spring inside 'Q(85), and as the contact progresses at multiple points, the wire ′; As the deformation progresses, the resultant force y of the reaction force of the bending deformation increases.The final form is shown in Fig. 7 (1), and ? =μN−'ro, that is, in this state of 71g(b), the wire?
The progress of I%(2) would have been completely stopped. Therefore, the inventor of the present invention conducted various experiments to confirm the results shown in Fig. 7, and found that the wire [ i
+21 may stop completely.

It was found that interruptions in the progress occurred. This will be explained using Figure 8.16) in Figure 8 shows that the wire electrode (2) is still an obstacle (84) K.
This is the case when the target is not reached. In addition, (86) is a wire magnetic pole (
2) tip position, (87) is the position of the die part. Even in this case, the die part is connected to the wire i [4 sets 2]
This is probably due to the frictional force fQ that occurs when .
The wire Mli +21 is being pulled in the direction of 88). Next, when the wire Mli +21 contacts the obstacle (84), fo increases to fl (>fo) However, since μN −'ro>fj, the arrows (8th day) are still in the same direction.

Next, Icl and Idl are -1fi (8
5) Inside.

The bending deformation of the wire '*l fit +21 is increasing, and the reaction forces f2 and f5 are increasing, but aN-To > F2. fs, the direction of the arrow (8th) does not change, and then the bending of the wire electrode (2) progresses until the point in Figure 8 to+ (then it increases to 4 due to 9 reaction forces, and μN-TQ = f4
7 +'W(b), and the advance of the wire electrode (2) stops +h.And ideally, the wire feeding pinch roller (7) should be the same as the wire electrode (7).
2) It seems like it rotates while sliding on the surface.However, in reality, there is a play in the one-way clutch attached to the pinch roller (7) and the effective transmission gear, and a change in the concentricity of the pinch roller (7). Due to changes in the surface properties of the outer circumference of the pinch roller (7), the reverse rotation of the pinch roller (7) and the change in μN cause 1 reaction force f as shown in (f).
4 and almost returns to F4-Δf.

In other words, in (f), the direction of the arrow (8 days) changes and the wire tlIi (2) returns, causing the 9 reaction force drop Δf to be considered to be equivalent to the decrease in μN. The direction of the arrow (88) changes as shown in No. 81'3Qfgl, and the wire electric '! Six i 12+ are sent in, and the cycle of Figure 8 ts+ → Figure 8 (f) → ar91g) is repeated, and the wire? The W pole r2) performs a cutting motion (including a reverse movement), and the holding roller (8) performs intermittent rotation during wire feeding.

The so-called 81st Cabinet Ce1. ff1. Depending on the length of the wire electrode (2) fed into the range L in fg), spring movement occurs with a change in reaction force f4 (Δf). This movement! L in g
This continues as long as the wire in the range 1 does not buckle.

Also, at this time, the direction changing pulley (5) shown in Fig. 1 similarly stops or moves intermittently (rotates), so by detecting this, the progress of the wire electrode 12) is obstructed. It is possible to determine whether there is a high load or a high load. This type of detection) tl will be named ``detection of high load during wire evacuation.'' Next, regarding the failure mentioned above, tll15
I will explain the principle.

The 91st side is the upper die guide ■ and the lower die guide f
4 [! This is the case when the wire is being inserted and the humiliation is far away. In this case, the wire mandrel (2) starts to advance after the pipe guide 0n and the object to be eroded are brought into contact (they are electrically connected through the die guide). 1 drop of board of subject η Loe object C@ is Hm=lK of hanging sky
In addition, the lengths shown in the diagram are specific to one machine and can be determined arbitrarily.

First, the wire 'lt pole (21) indicated by a solid line is a case where the insertion is successful, and the wire 71 i F21 fed from the upper die guide ■ is inserted into the machining start hole (77
), the nozzle (78), and the lower die guide l (1
, power supply dice +411. It passes through the guide nozzle (44 and 1) and is fed between the belt roller T49 and the lower belt (4n and the lower roller (c), and is then pulled by the lower roller device. This is the regular wire insertion path. Therefore, the time and distance required for this are determined almost uniquely.The wire 1!2+ shown by the broken line is an example of a failure in insertion, and the wire is deviated from the 1* wire path. The inventor has developed a 41m wire feeding pinch roller 1.
71 and the speed at which the wire electrode advances and the lower roller 1
Since the speed at which the wire 'beak pole is pulled by 41 and advances is different, the failure method of ejection may have been overlooked. In other words, the carrying speed by the lower rollers f and l11 is the same as the speed during the late qt/Io work. Similarly, the one using the wire feeding pinch roller 17) is slow because it passes through a small clearance like the die guide +4+).

Next, the detection principle will be explained using Figure 1019).
QIII of Ib) is the speed v of the wire electrode f2)
So? ”2 is due to the lower roller, vl
is due to the wire feeding pinch roller (7), and on the horizontal axis, S is the length along the wire insertion path from the 919th die guide C1, and T is the wire feeding pinch roller + 7). '? Dan! 1=1), which is the light failure time from the beginning of 2), is a graph of V and S, where (89) is a successful insertion, and (90) is a failed insertion.

As you can see from this graph, llfl human route Hm9
After x+L Kouchi Jun, if successful, vl to v2
The speed increases to Vl, and in case of failure, it remains at e vl.The reason why the speed does not increase immediately from vl to v2 at position L is due to the deviation due to the drawing λ time to the lower belt. .

Next, as you can see from the graph of tO1mTol, the first
Figure 0 (time T for speed increase from phantom vl to v2
L is uniquely determined. Therefore, when the wire electrode (2) advances to the wire feeding pinch roller 17) and the advancing speed does not increase from vl to v2 after TL has elapsed even though the ignition has elapsed, it is determined that the wire has deviated from the wire insertion path. It can be treated as a failure.

Like this, the wire? lj By emitting changes in the speed of progress after the stationary and temple use from the first time the field +21 progresses,
You can gush about your failures. This type of detection 1tl will be referred to as detection of wire polarization f21 being removed from the wire insertion path.

Next, we will describe the real ellipse + I/lJ of the circuit that actually detects failure. First, the high load b8 when advancing the wire electrode (2)! Ifls how many routes will be explained.

First, as explained in the 8th section, in order to provide an intermittent movement of the movement of the wire pole 12), the rotation of the direction changing pulley (5) in the 11th direction is replaced with an intermittent movement. , the 111th side would be a detection device for that purpose, on the direction changing pulley 15) in Figure 11 (!I).

An encoder (9I) is attached. wire t1
When the electrode (2) performs an intermittent forward motion, the direction change pulley (5) rotates intermittently. Also, Kyu 11 +g
fbl explains how to use the encoder (9I).

P5 (+5V) external power supply is shared by the diode side and the transistor 4111. R is a resistor that limits the jet flowing to the diode. Output 11!11 A,
B i is connected to the detection circuit.

Next, the ejection circuit will be explained using FIG. 12. Note that the A and B input terminals correspond to those in Figure 11,
The Bi law is the Diotler law (in Figure 7112, the encoder output is AC in the range of 0 to 5V, so first the DC component is cut by the capacitor C1e and the resistor R1, leaving only the AC component. Next, the OP amplifier (9
2) performs amplification by a factor of R3/R2, and then clamps in the range of a to 5v using diodes DI and D2.

The waveform of Wl after passing through the inverter is converted into a pulse in the range of 0 to 5V, which is the waveform-shaped alternating current of Wl.> (95) is a high load test t! The output pulse has a width of Tc1.

Relay coil L1 is for high load detection, and D5 is a protection diode. In addition, (94) is a one-shot for failure to eject outside the path of 61, which will be described later, and the output pulse has a width of TQ2.

Relay coil L2 is for detection outside the insertion path.

D4 is the diode under protection, ``1 e'' in Figure 12! * Using the waveform of ``S'', a schematic timing chart will be shown in the 13th section to explain the high load detection method.

Wl in FIG. 13 (!I) is the output waveform of the encoder. This is the rotation of the direction changing roller by the wire feeding pinch roller, and is the case when the wire is inserted. At this time, the waveform of Wl is a square wave pulse with period T1, and the waveform of W3 is a one-shot pulse generated at the rising edge of the pulse of Wl, so v Tt
< Tc1, the voltage is always at a high level of 5V while the wire is inserted, so the relay coil L1 in FIG. 12 is ON.

It turns out that the situation is. This state is a state where no high load is occurring.

Next, (θ) off) in Fig. 8, ! Under the situation g), the waveform of Wl is shown in FIG. 13(b). That is,
Is the normal pulse width with a short period T1 and a short pulse width (with a long pause period T2)?This is because the pulse is output even if the encoder is reversed.

If (2) is returned by the spring force when inserting the wire as shown in Fig. 8 (b), the reverse lo1 rolling force acts instantly, and as shown in Fig. 13 rb.
), the pause at T1 is short (and the pulse at T2 is also short. On the other hand, in the case of zS diagram fg), the rotation of the pinch roller for wire feeding starts to rotate forward, so the rise of the appetizer is short. 9. Because it takes a long time between vfs. Kimi 13+
1:+) T2, the body becomes long (this means that when the detection circuit is actually observed with a synchroscope etc., a waveform corresponding to +b) Wl can be confirmed. The waveforms of y, W, and Tfl are 1@
At this time, the relay coil L1 shown in FIG. 12 becomes OFF'. In this way, the occurrence of intermittent rotational movement of the direction conversion pulley can be detected by the relay coil L1 changing state from ON to oyy.

Next, we will explain the failure detection circuit outside the insertion path and the timing chart; T52.

Regarding the inspection a3rF5U path, Fig. 14, which is probably similar to Fig. 12, is a timing chart at the time of wire insertion, and the 1-day section seen in wl of f4FsQ(a) is shown in Fig. 13 (!l). ), and is caused by the rotation of the wire feeding pinch roller (7). The subsequent high gastric wave number appears to be drawn into the lower belt θη in FIG. 9 and fly in a state where the advancing speed of wire 1 wound 2) is increased, so t T1 appears at 141b+
The section 1 is the ■ period T1, and after that it changes to 'rm' between stations. At this time, the waveform of T4 has a one-shot width of T(T2 (Ti > Tc2 > Tm)
Therefore, the pulse width is Tc2 in the section of vT8, and is at a high level thereafter. Therefore, 1 day corresponds to the time when the insertion was successful, so 9For example, '
I's (TD) After the time TD, the state of T4 is always at a high level. In other words, the relay coil L2 in Fig. 12 is always ON after the wire feed pinch roller (7) starts rotating. If the wire electrode (2) advances outside the wire insertion path, the waveform of T2 will continue to be a pulse with a period of T1, as shown in Fig. 14+1)). The waveform of is continuous with a pulse width TQ2. Therefore, T D (
TD) TB) After.

By looking at the waveform of T4, it can be seen that there is a pause called 'rf2.

At this time, the 121st relay coil L2 is in the OFF state. In this way, if the wire ', iE 4iji+21 deviates from the human path (ψ) during insertion of the wire electrode (2), it can be detected by determining the state of relay coil L2 from ON to OFF or OFF after TD. I can do it.

Next, a failure ejection signal is generated from the state of the relay coil L1 e L2, and the rage check circuit is set to the first one.
This will be explained using Figure 5.

Timer relay RT1, RT2, relay f1,
The f2 coil operates at T24 (+24V).

9M2G is a relay for a wire insertion command which is given by a computer or the like or manually, and WW1' is a relay which is turned on while the wire feeding pinch roller is rotating.

First, in the case of a high load failure, the wire insertion starts, the relay 6wy is turned on, and the timer RT1 is set. Relay IRTl turns ON after 2 seconds.

Since the back mA of relay IRA is open during normal operation and closes when there is a failure, resulting in a short circuit, failure detection relay lf1 is connected to C1.
The relay mark RT1 held as 1VC'Ik has a function on the detection element to prevent false detection at the rising edge of the wire electrode (2) progression. A timer RT2 is set from the start of wire insertion. The relay signal R'l'2 will turn ON after TD.The relay signal RA will be short-circuited in the event of a failure, similar to the failure of a high load.

Failure ejection relay anger f2 is turned on and held 6
Therefore, if both parties fail, the relay will
Or f2 turns ON. Therefore, T5 (+5V
), if relay #'11 f2 is connected in parallel, the 7 outputs will change to high level in response to either failure, and the F signal can be sent to a computer or the like.

next? When a signal is processed using a computer, the processing method used will be explained using the flowchart in FIG. 16.

First, by flow start, an insertion command is issued to perform an insertion operation.

Unless a failure is detected (the IP flaw signal is at a high level), the insertion will be completed. If a failure is detected, it is determined whether the number of failures has reached N times.

If the number of times has reached N, it is assumed that there is an abnormality in the mechanical device and the function is stopped. If the number of times has not reached N, a cutting command is issued to cause the cutting operation to be performed.

The cutting and insertion mentioned here mean the series of operations shown in Fig. 31 and Fig. 4.

However, in the cutting operation, the wire power required to fail [12]
is removed and inserted using the cutting device shown in Figure 3.

Use a new wire fi 1 iji +21.

After the cutting is completed, the insertion command is issued again and the insertion operation is repeated. In this way, the 16th flow is repeated until the number of successful and unsuccessful insertions reaches N times.

Here, the reason why Tffiff of failure is counted will be explained.

If the probability of failure when inserting the wire fi pole 12) is also assumed, the probability of failure N times in a row is: IN
Therefore, the probability that wire insertion is successful on the mth time is P
will be as follows P jm) = 1- In the case of 30%, m = 3 times P (31 = 97% m = 4 times P (4) = ss% As you can see in the above example, the success rate of one divine ceremony is 50% (X
= 50%), the success rate can be increased to 99% by detecting failure and re-inserting.
If the success rate of riJ is 70% (X=30%), it increases to 99% by reinserting it four times. In this way, even if the probability of successful insertion in one attempt is low, the success rate increases by repeating the insertion several times.In other words, it can be said that the reliability of insertion has been greatly improved.

To summarize, the present invention detects failure during wire electrode insertion and leads to success by re-inserting the wire electrode, and provides a highly reliable wire electrode automatic feeding method. It goes without saying that the scope of the present invention includes any method that automatically redoes the insertion by using other means for detecting failure.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional wire electrode feeding system; Fig. 2 is a block diagram of a conventional cutting device; Fig. Figures showing the polarization insertion operation, @Figure 5, Figure 6 are diagrams showing the conventional drawbacks, Figures 1~
Figure 10 is a diagram explaining the reason for the drawback and the ripple effect.
Figures 11 and 12 are embodiment diagrams of the detection means and circuit for implementing the present invention, Figures 13 and 14 are timing charts of the detection circuit and diagrams showing the detection principle, and Figure 15 is an insertion failure. 16 is a flowchart for implementing the present invention by computer. In the figure, 12) is a wire electrode, and 15) is a direction changing pulley. (9?) is the engineer/coder, and (92) is the op amp. (93) and (94) are one-shots.

Claims (2)

[Claims] (1) Wire-cut electric discharge machining in which the wire electrode is automatically fed so as to pass the wire electrode from the wire electrode supply section to the machining start hole of the workpiece and engage with the wire electrode collection section. In the wire automatic feeding method in the device, the cyclic operation of feeding the wire electrode from the wire electrode supplying section, detecting a failure, and restarting the automatic wire feeding again leads to the wire electrode engaging with the wire electrode collecting section. A method for automatically supplying a wire electrode in a wire-cut electrical discharge machining device, characterized in that the wire electrode is repeatedly manipulated several times. (2) The cycle operation for restarting automatic wire supply is as follows:
2. The automatic wire electrode feeding method in a wire-cut electrical discharge machining apparatus according to claim 1, wherein the method is terminated by detecting that the wire electrode has engaged with the wire electrode collecting section.