JPS60232829A - Method and device for wire-cut electric discharge machining - Google Patents

Abstract

PURPOSE:To insert a wire electrode into an electrode inserting fine hole securely and efficiently by arranging in such a way that the insertion of said wire electrode into said fine hole is somultaneously carried out with the operation of forming said fine hole, in a wire-cut electric discharge machining means. CONSTITUTION:After the process of forming an electrode inserting fine hole for inserting a wire electrode 2 into a workpiece 34 and, after the fine hole has been formed, the electrode 2 is made arrive at, and engaged with, a take-off device and, after that, the workpiece 34 undergoes wire-cut electric discharge machining. When the electrode inserting fine hole is being formed, a brake-and-capstan 29 is operated as a capstan, to insert the electrode 2 into the hole 1a of a fine tube type electrode 1. Thus, since an electrode inserting fine hole forming operation can be simultaneously carried out with the insertion of the wire electrode, the wire electrode can be inserted into the inserting fine hole securely and efficiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a wire cutter H't3 processing method that can automatically form a machine start hole in a workpiece and insert a wire electrode therethrough, and the method thereof. Regarding equipment.

[Conventional technology]

Wire-cut electrical discharge machining equipment does not require the production of electrodes corresponding to the machining shape each time it is machined, unlike regular electrical discharge machining equipment, and with the development of numerical control equipment (NC equipment), long-term unmanned operation is possible. Due to certain reasons, it is now widely used.

When contouring a cutting die or the like using a wire-cut electrical discharge machining device, first a hole for passing the wire electrode through the workpiece is formed, and the wire electrode is inserted into the hole for passing the electrode. At the same time, the wire electrode is usually stretched in a straight line with an appropriate tension between a pair of electrode guides provided at the ends of two arms, and during processing, the wire electrode is stretched between the wire electrode and the workpiece. While supplying the liquid, intermittent voltage pulses are applied between the two to generate an electric discharge, and the wire electrode or the workpiece is fed by a numerical control device, thereby cutting and sampling the desired contour shape. It performs processing such as

However, it is extremely difficult to form a straight and uncurved hole for electrode insertion in a thick workpiece, and the machining process is performed using a drilling machine or jig such as Polar, which is separate from the wire-cut electrical discharge machining equipment. If the drilling is performed using a mechanical drilling device or a drilling device using electric discharge or electrolytic machining, it is necessary to position the workpiece twice, once during drilling and once during wire-cut electrical discharge machining, which requires a lot of skill. There was a problem in that it was not only necessary but also time consuming.

Furthermore, the wire electrode has a diameter of 11111 or less,
It is an extremely thin wire that usually lasts about 0.05 to 0.3 days.
There is also the problem that it is extremely difficult to accurately insert this electrode into the electrode insertion hole formed in the workpiece before starting processing, and to also stretch it in a straight line between a pair of guides. Ta.

In order to solve this problem, for example, patent application No. 58-2
In the wire-cut electrical discharge machining apparatus described in No. 39822, a tubular electrode is attached to a chuck that can be raised and lowered, a wire electrode is inserted into the thin tubular electrode, and a clamp provided on a member that supports the chuck is used. A wire electrode is held so that it is processed and fed in the axial direction together with the thin tubular electrode, and then the tip of the wire electrode is cut so as to be substantially flush with the tip of the thin tubular electrode. A machining liquid is supplied to the center hole of the electrode, and a voltage pulse is applied while the tips of the thin tubular electrode and the wire electrode are opposed to the workpiece, and the fine hole for electrode insertion is opened while the thin tubular electrode is processed and fed. After processing and forming and penetrating the electrode insertion hole is completed, power supply to the capillary electrode is stopped, the grip on the wire electrode is released, and the wire electrode is sent to a wire electrode take-up device. An apparatus has been developed which is configured to pull out the tubular electrode from the electrode insertion hole and start wire force/throat electric discharge machining.

Therefore, the above device is configured so that the wire electrode is inserted into the electrode insertion hole substantially simultaneously with the processing and formation of the electrode insertion hole. It became possible to reliably insert the material into the pores.

[Problems to be solved by the present invention]

However, the above-mentioned device requires
When the thin tubular electrode penetrates the workpiece, machining fluid may leak from the micropores that are initially created, or there may be unprocessed parts of the workpiece, which may cause machining problems during the so-called extraction process. For example, an air discharge may occur between the electrode and the workpiece, which may interrupt machining, or damage may occur to the capillary electrode, especially its tip or the workpiece, which may cause the capillary to be damaged even after the penetrating process has been completed. There was a problem in that the wire electrode could not be fed out from the tip of the shaped electrode, and the success rate of automatic insertion and setting of the wire electrode would be significantly lowered.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to process even thick workpieces, hardened workpieces, cemented carbide, etc. , the electrode insertion hole can be processed safely and reliably, and the wire electrode can be inserted into the formed electrode insertion hole substantially simultaneously with the loe formation (of the electrode insertion hole). By configuring the wire electrode so that it can be inserted through the electrode, it is possible to carefully, reliably and efficiently insert the wire electrode into the electrode. Even if it is a guide, the wire electrode can be inserted reliably, and the wire electrode can be stretched in a straight line using a pair of guides, allowing highly accurate automatic processing, and furthermore, the work is labor-intensive and time-consuming. It is an object of the present invention to provide a wire-cut electric discharge machining method and an apparatus thereof, which can make the entire apparatus compact.

[Means to solve problems]

The above object is to provide a wire-cut electric discharge machining apparatus that automatically inserts a wire electrode into the electrode insertion hole to start electric discharge machining at the same time as forming a hole for the electrode insertion in the workpiece. Then, a thin tubular electrode is attached to a chuck that is rotatable and movable up and down, a wire electrode is inserted into the thin tubular electrode, a workpiece is attached to a predetermined position, and the center hole of the thin tubular electrode is machined. The liquid is supplied, and the processing part 6 is provided while rotating the capillary electrode, while the wire electrode is appropriately fed or held so that the tip of the wire electrode is always located at a desired position near the open end of the capillary electrode. , a voltage pulse is applied between the thin tubular electrode and the wire electrode, and the workpiece to process the electrode insertion hole, and the workpiece is opened just before the electrode insertion hole is drilled in the workpiece. Machining is carried out while spouting and supplying machining fluid to the workpiece from a position facing the thin tubular electrode through the medium, and once machining of the electrode insertion hole is completed, the machining fluid is being supplied. At least the ejection supply of the latter is stopped, the rotation and power supply of the capillary electrode is stopped, and the tip of the wire electrode is sent out from the tip b' of the capillary electrode to the wire electrode take-up device, and then the This is achieved by pulling out and retracting the tubular electrode from the electrode insertion hole.

[Effect]

As mentioned above, when processing the electrode insertion hole, when the electrode insertion hole opens, sufficient processing liquid is supplied to the processing part, and the remaining part can be processed well, so it is possible to process thick workpieces. Even if the workpiece is hardened or made of cemented carbide, the occurrence of air discharge etc. is prevented when the electrode insertion hole is opened. Damage to the workpiece can be prevented, a hole for electrode insertion can be formed safely, reliably, and quickly, and a wire electrode can be inserted reliably at the same time as the hole is penetrated through the formed hole for electrode insertion. This allows processing to proceed smoothly.

〔Example〕

Hereinafter, details of the present invention will be specifically explained with reference to embodiments of the drawings.

FIG. 1 is an explanatory diagram showing a state in which a wire-cut electrical discharge machining apparatus according to the present invention is machining an electrode insertion hole for inserting a wide electrode into a workpiece, and FIG.
An explanatory diagram showing the state in which the electrode insertion hole has been machined and a wire electrode has been inserted, FIG. 3 is an explanatory diagram showing the state when wire cut electrical discharge machining has started, and FIG. FIG. 5, an enlarged sectional view of the machining liquid nozzle unit, is a fourth example showing another embodiment of the wire electrode control and feeding mechanism.

In FIGS. 1, 2, 3, and 4, 1 has a wire electrode 2 of about 0.05 to 0.4 φ inserted therein;
A thin tube-shaped electrode having a predetermined length and having a hole 1a through which the machining fluid can be passed and sprayed, 3.4 is an open/close type machining fluid nozzle unit, 3a and 4a are split nozzles, and 3b and 4b are Seal member, 4C is machining fluid supply hole, 5.
6 is a cutter operated by a solenoid (not shown); 7
8 is a V-shaped electrode guide, 9 is a spring, 10 and 11 are the opening/closing type machining liquid nozzle unit 3.
．． 4 is a hydraulic cylinder that opens and closes, 12 is a nozzle device attached to the lower arm 13, and 14 is a machining fluid supply hole 14.
15 is a nozzle, 16 is a bag nand, 17 is a die guide, 17a is its guy 1; holder;
Reference numerals 18 and 19 refer to power feeding pins that can move forward and backward, 20 refers to a spring provided as necessary, 21 refers to a rubber valve, and 22 refers to a stem holder that holds a chuck 25 for attaching a capillary electrode consisting of a stem 23 and a tightening nut 24. 22a is a machining fluid supply hole formed in the stem holder 22, 26 is a bearing, and 27 is an upper arm 2 of the wire-cut electric discharge machining apparatus.
A hydraulic cylinder is fixed to 8 and moves the stem holder 22 up and down with respect to a table (not shown) for mounting the workpiece, and 29 acts as a brake roller when the motor is stopped or rotating at a predetermined speed. 3o is a pinch roller, and 31 is a cap for taking up wire electrodes and applying tension. 32 is a pinch roller, 33 is a rubber valve, 34 is a workpiece, 35 is an energizing shoe for supplying power to the capillary electrode 1, 36 is an O ring, 37 is attached to the stem holder 22, and its shirt) 37a is a motor in which a gear 38 attached to the shaft meshes with a gear 39 attached to the stem.

Thus, the capillary electrode 1 has a stem 23 and a tightening nut 24.
It is detachably attached to a chuck 25 for attaching a capillary electrode, and when the capillary electrode 1 is worn out due to the machining of the electrode insertion hole,
By loosening the capillary tube, the worn out tubular electrode 1 can be reattached or replaced with a new tubular electrode 1.
Preferably, the device is configured to be an automatic electrode exchange type device.

The stem 23 has a hair ring 26 inside the stem holder 22.
The stem holder 22 is rotatably held through the stem holder 22, and is configured to rotate about its axis by the rotation of a motor 37 attached to the stem holder 22. Therefore, as the motor 37 rotates, the thin tubular electrode 1 is rotated around the axis, and the workpiece (not shown) is mounted on the table by the action of the hydraulic cylinder 27 that supports the stem holder 22. It is configured so that it can be moved up and down with respect to the attached workpiece 34.

The opening/closing type machining fluid nozzle unit 3.4 includes split nozzles 3a, 4a, seal members 3b, 4b, and machining fluid supply holes 4.
0, etc., and is configured to be opened and closed in the diametrical direction by the action of hydraulic cylinders 10 and 11. Further, an electrode retainer 7 configured to be acted on by the elastic force of a spring 9 is placed in the central portion of the interior of the nozzle unit 3, and an electrode retainer 7 configured to act on the electrode retainer 7 of the other nozzle unit 4 is provided with an An electrode guide 8 having a V-shaped cross section is attached to determine the position of the wire electrode 2 above the workpiece 34 during wire cut electrical discharge machining, and to hold the wire electrode 1 in a straight line.

A mounting flange 14a and a machining fluid supply hole 14b are formed in the nozzle body 14, a guide boulder 17a is accommodated in the nozzle body 14, and the nozzle 15 is slidably movable in the axial direction of the wire electrode 2. The spring 20 and the cap nut 16 are then fitted in this order. Thereafter, this nozzle device 12 is attached to the flange 14a, and attachments not shown are attached to the lower arm 13 with bolts or the like.

In the wire-cut electrical discharge machining apparatus according to the present invention, the step of forming the electrode insertion hole for inserting the wire electrode 2 into the workpiece 34 and the step of forming the wire electrode 2 after forming the electrode insertion hole. The process from reaching and engaging the take-off device to applying wire-cut electrical discharge machining to the workpiece 34 will be described.

As shown in FIG. 1, when forming the electrode insertion hole through which the wire electrode 2 is inserted into the workpiece 34, the pre-kissing roller and capstan 29 acts as a capstan, and the hole in the thin tubular electrode 1 is A wire electrode 2 is inserted into 1a.

The wire electrode 2 passes through the hole la of the capillary electrode 1,
When its tip protrudes a predetermined length from the tip of the capillary electrode 1, the brake roller/capstan 29
The supply of the wire electrode 2 is temporarily stopped.

At this time, if there is a discrepancy such as the tip of the thin tubular electrode 1 being above the position of the cutters 5 and 6, the hydraulic cylinder 27 is operated to adjust the positions of the cutters 5 and 6 so that they match, and then the cutter 5 is
and 6 are operated by a solenoid (not shown), and the wire electrode 2 is cut so as to be substantially flush with the tip of the tubular electrode 1.

In the above description, when the capillary electrode 1 is replaced due to wear or the like or is newly attached to the capillary electrode mounting chuck 25, the operation starts from a state where the tip of the wire electrode 2 has not reached the base position of the capillary electrode 1. When starting, when replacing the thin tubular electrode 1, etc., the wire electrode 2 is replaced with this electrode 1.
It is also possible to manually insert the capillary electrode 1 into the tube and then attach the capillary electrode 1 to the chuck 25 for attaching the capillary electrode. In addition, in many cases, when the previous wire-cut electrical discharge machining is completed, the wire electrode 2 is cut at the tip of the thin tubular electrode 1 on the supply side by the cutters 5 and 6 before the next machining is performed. Since the device is in a kind of standby state for operation, in such a case it can be said that the operation and process of inserting the wire electrode 2 into the thin tubular electrode 1 has been completed.

Voltage pulses for electric discharge machining are supplied to the capillary electrode 1 from a power supply circuit (not shown) via the current shoe 35, and at the same time, the capillary electrode 1 is subjected to rotational movement by the motor 37 and hydraulic pressure. The downward moving motion by the cylinder 27 is applied via the stem holder 22 and the stem arm, and the brake roller/capstan 29 is moved in synchronization with the downward moving speed by the hydraulic cylinder 27.
operates as a capstan, feeding out the wire electrode 2, and at the same time, the same machining fluid as for normal wire cut electric discharge machining is supplied from the hole 1a of the capillary electrode 1 to the machining part of the workpiece 34, and the wire electrode 2 is fed out. Processing of the insertion hole is performed.

When drilling a hole for electrode insertion, rotational movement is applied to the thin tubular electrode 1 as described above, and the pre-kissing roller/capstan 29 moves the wire electrode in synchronization with the downward movement speed of the hydraulic cylinder 27. Since the wire electrode 2 is fed out, the free end of the wire electrode 2 is always kept substantially flush with the tip of the thin tubular electrode 1 during processing.

Further, from just before the electrode insertion hole is formed in the workpiece 34, the nozzle 1 of the nozzle body 14, which is provided at a position opposite to the capillary electrode 1 through the workpiece 34,
The machining fluid supplied from 5 through the machining fluid supply path 14b is approximately equal to the fluid pressure of the machining fluid supplied and ejected from the capillary electrode 1, which will be described later, to the hole-machined portion for electrode insertion of the workpiece 34. The machining fluid is supplied under pressure at or below the equilibrium pressure.

Machining of a hole for electrode insertion into the workpiece 34 using the capillary electrode 1 requires that the wire electrode 2 is inserted into the hole 1a of the capillary electrode 1, and that the capillary electrode 1 is given a rotational motion. The machining liquid is applied to the part of the workpiece 34 that faces the thin tubular electrode 1 of the electrode insertion hole formed by the thin tubular electrode 1 in the workpiece 34 from just before the completion of the electrode insertion hole machining. Except that the machining fluid supply hole 22a is supplied under pressure, the machining fluid supply hole 22a is at least 10~
Processing fluid is supplied under pressure at 20 kg/cJ or more, and although not shown, preferably a capillary electrode 1
As described in the above-mentioned publication, processing is performed while applying ultrasonic vibration and constant speed or servo feed by the hydraulic cylinder 27, and in this way, the part of the workpiece 34 where the electrode insertion hole is formed. By jetting high-pressure machining fluid from both sides of the workpiece, rotating the thin tubular electrode 1, and applying ultrasonic vibrations, machining of floor-assembled holes, which conventionally could not be performed smoothly, is now possible with hardened steel and ultra-high-pressure machining. This process can be carried out smoothly and at high speed even on hard metals, etc., and even in the case of a thick workpiece 34, a straight and uncurved electrode insertion hole can be formed at high speed.

As the machining progresses and a pore for electrode insertion opens on the lower surface of the workpiece 34, the machining fluid usually leaks from the opening and the machining fluid pressure in the machining gap drops rapidly. However, machining fluid is no longer supplied to a part of the machining area, and the remaining machining area moves or deforms, causing a short circuit.
It causes air discharge, short circuit, abnormal discharge, etc.
In the device of the present invention, the machining fluid is supplied from below at a considerable pressure, so even if an opening occurs, the machining fluid will not leak out, and the remaining machining area will not be moved or deformed. It is possible to process 100 rounds by completely machining a part, so even if the workpiece is thick, hardened or made of cemented carbide, it is safe and especially This allows the electrode insertion hole to be formed reliably and quickly without causing any damage to the tip of the tubular electrode 1 that would make it difficult or impossible to send out the wire electrode 2.

In addition, when processing this electrode insertion hole, the wire electrode 2
Of course, when some electrical discharge machining power source is connected to the wire electrode 2, even if no power source is connected, the tip of the wire electrode 2 may wear out due to being in some kind of contact with the thin tubular electrode 1. Therefore, if the wear and retraction length of the tip of the wire electrode 2 with respect to the tip of the capillary electrode 1 reaches, for example, around several plates or more, the wire electrode 2 should be fed out more often by the brake roller/cab cushion 29. However, it is better to correct the tip so that it is near the tip of the tubular electrode 1, so that the wire electrode 2 for future guides etc.
This is desirable because it ensures the insertion and setting of the parts.

When the electrode insertion hole for inserting the wire electrode 2 is formed in the workpiece 34, the electrode insertion hole is located near the tip of the thin tubular electrode 1, and the electrode insertion hole is already inserted along with the tip of the thin tubular electrode 1. The tip of the wire electrode 2 is sent out toward the nozzle device 2 by the capstan action of the brake roller/capstan 29, is inserted into the die guide 17, is captured, passes through the guide holder 17a, and is inserted into the rubber valve. 21, and when the pinch roller 32 reaches and engages the wire electrode pulling device consisting of the capstan 31 and others, it is detected by an appropriate means to complete the pulling engagement, and the wire The electrode 2 is forcibly taken off from the tip and collected in a wire electrode collection box (not shown) provided on the bed or the like of the main body of the wire-cut electrical discharge machining apparatus.

When the wire electrode 2 is taken up by the taking-off device as described above, the rotation of the motor 37 is stopped to stop the rotational movement of the tubular electrode 1, and the hydraulic cylinder 27 is operated to remove the stem holder 22. is moved upward to raise the thin tubular electrode l upward, and as a result, the open/close type machining liquid nozzle unit 3.4 is connected to the hydraulic cylinders 10 and 1.
1, and the wire electrode 2 is connected to the electrode presser 7 and V inside the opening/closing type machining fluid nozzle unit 3.4.
It is movably pressed down by the letter-shaped electrode guide 8.

Then, a voltage pulse for electrical discharge machining is supplied from the power supply pins 18 and 19 that are in contact with the wire electrode 2 in the nozzle body 14, and a machining fluid is supplied from the machining fluid supply hole 4c of the opening/closing type machining fluid nozzle unit 4. The machining fluid is supplied from the machining fluid supply hole 14b of the nozzle body 14, and wire cut electrical discharge machining is performed while the machining fluid is supplied under pressure from the nozzle 15 to the machining portion of the workpiece 34.

In addition, if the thin tubular electrode 1 is worn out and its length becomes equal to or less than the thickness of the workpiece 34 to be processed, 1. The wire electrode 2 is replaced by cutting it at the tip of the capillary electrode 1, but when replacing the capillary electrode 1 manually, the wire extending from the tip of the capillary electrode attachment chunk 25 is 4. Insert the electrode 2 into the hole 1a of the new capillary electrode 1.
However, if the thin tubular electrode 1 is replaced automatically, it is extremely difficult to do so, so in such a case, the wire electrode 2 that is being stretched should be replaced by reversing the capstan 29 and attaching it to the stem. A method is adopted in which the wire electrode 2 is returned to near the base, a new capillary electrode 1 is attached, and the wire electrode 2 is sent out by rotating the capstan 29 in the forward direction, and the wire electrode 2 is passed through to the tip of the capillary electrode 1.

At the point where the wire electrode 2 is inserted, the die guide 1
7, coupling pin 18.19, rubber valve 21, capstan 3
1 and the pinch roller 32, or the electrode pulling device further ahead, if insertion or centage fails, for example, the thin tube-shaped electrode 1 is once pulled up to the position shown in FIG. 3, and the wire electrode 2 is removed from the thin tube. The wire electrode 1 is cut at the tip position, and then the cut wire electrode 2 inserted into the workpiece 34 is extracted manually or with a robot hand and discarded, and the thin tube electrode 1 is sent down by the hydraulic cylinder 27. The feeding of the wire electrode 2 by the capstan 29 is controlled and synchronized so that the tip of the wire electrode 2 does not protrude from the tip of the tubular electrode 1, and preferably, the tip of the wire electrode 2 shown in FIG. Until the process of inserting into the die guide 17, the machining fluid does not need to be applied at a high pressure from the machining fluid supply hole 22a as during the drilling of the workpiece 34, but the machining fluid is spouted from the tip of the thin tubular electrode 1. After the downward feeding of the capillary electrode 1 is stopped, the tip of the wire electrode 2 is projected from the tip of the capillary electrode 1 and sent out, and the insertion of the wire electrode 2 is attempted again.

Further, in the above embodiment, the brake roller and capstan 29 is operated as a brake roller and a capstan, and other explanations are added, but in the configuration of the illustrated embodiment, the brake roller and capstan 29
Although it can suitably function as a brake roller, it is not necessarily sufficient as a capstan for sending out the wire electrode 2 for automatic insertion and setting of the wire electrode 2, and the brake roller and the pinch roller serve as the brake roller/capstan 29. is simply a guide roller, and a brake roller is provided as an open/close type on the wire electrode supply side of the preceding stage of this guide roller, or an open/close type brake roller and a pinch roller are provided on the supply side of the wire electrode 2 of the open/close type nozzle unit 4. can be provided.

In addition, the brake roller/capstan 29 and the pinch roller 30 are simply a guide roller at the upper part that holds and guides the wire electrode 20 portion before and after the processing part in a substantially straight line between the capstan 31 and the pinch roller 32 at the lower part. In this case, this guide roller and the stem holder 2
2, there is a control feeding mechanism 4 for the wire electrode 2 which is set at least when the wire electrode 2 is automatically inserted and set.
0 is set.

FIG. 5 is an explanatory diagram showing an example of the control feeding mechanism 40, in which 40a is a capstan, 40b is a pinch roller, and is rotatably attached to link arms 40C and 40d, each of which has one end pivotally supported. 40C and 40d
By operating the other end with a hydraulic cylinder 40e, the wire electrode 2 can be clamped and released, making it possible to approach and separate it. The capstan 40a sends out the wire electrode 2 while its rotation is controlled by a motor 40h having a rotary encoder 40'f for detecting a rotational angle or position and a rotational speed detector 40g.

When drilling holes for electrode insertion in the workpiece 34 using the capillary electrode 1, depending on the dimensions such as the inner diameter or outer diameter of the capillary electrode 1, the wire electrode 2 may be set at the same potential as the capillary electrode 1, or a separate power source may be used. are connected to form a hole in the workpiece 34 for insertion of an electrode. It should be noted that the wire electrode 2 may be worn out during the machining of the fine hole for electrode insertion, or the wire electrode 2 may be
Since this may cause welding near the tip of the electrode or inside the tube, when drilling a hole for electrode insertion using the thin tubular electrode 1, the feeding by the capstan 40a and the pinch roller 40b should be adjusted back and forth at a frequency of around several fiz. It is recommended that you proceed as you progress. That is, the capstan 40a is rotated, for example, at a ratio of 0.5 to 0.9 in reverse to 1 in normal rotation (with a maximum length of about 5 mm for retraction, and 0.1 to 0.9 for continuous rotation).
By feeding the wire electrodes 2 and 11 in combination, it is possible to prevent welding of the wire electrode 2 and the tubular electrode 1.

Moreover, since the tubular electrode 1 is rotating, the risk of welding with the tip of the wire electrode 2 is somewhat low, but if welding occurs, there is a possibility of an accident that is difficult to recover from, so it is more reliable. A means to prevent welding is necessary. Furthermore, if the tip of the wire electrode 2 is positioned at a position sufficiently retreated from the tip of the thin tubular electrode 1, the risk of welding will be reduced, but the risk of welding will be reduced. If you want to involve the machining of the hole for electrode insertion, etc., or if you connect a separate power source, you may need to separately apply vibration to the tubular electrode 1, or repeat the minute back and forth movement as described above. This type of feeding method is effective for inserting the tip of the wire electrode 2 into the die guide 17 by feeding the wire electrode after completing the drilling process of the electrode insertion hole. Of course dice guide 1
The above-mentioned vibratory feeding method may be adopted only when the wire electrode 2 is inserted into the wire electrode 7.

In any case, it is natural that it is necessary to accurately know the tip position of the thin tubular electrode 1 when drilling the hole for electrode insertion and inserting the wire electrode 2, but it is also necessary to accurately know the tip position of the wire electrode 2. For this reason, a rotary encoder 40f and a rotation speed detector 40g are used to detect the feed length and feed speed and feed it back to a sequence controller, NC control device, etc.
etc. are attached.

As described above, just before the drilling of the electrode insertion hole progresses and the workpiece is penetrated, the hole is opened from the nozzle 15 to the workpiece 34.
Since the machining liquid is sprayed and supplied to the part where the electrode insertion hole is machined, a straight and uncurved electrode insertion hole is formed without causing any damage such as damage to the tip of the tubular electrode 1. It is.

In addition, the tip of the thin tubular electrode 1 had suffered some damage due to the drilling of the electrode insertion hole in the workpiece 34 by electric discharge machining, and we had to take the time to machine the electrode insertion hole. Even if the wire electrode 2 is removed from the tip of the capillary electrode 1,
It is impossible to send out the electrode, or the sending out condition is not good, for example, the tube-like electrode 1 is sent out with a deviation from the coaxial axis direction to the direction of the surrounding area, or the electrode is sent out while vibrating intermittently due to a catch, etc. There may be cases where it is impossible to insert, feed, or center the tip of the wire electrode 2 into the die guide 17 or a portion beyond it.

Therefore, if such a situation is assumed, the opening drilling process of the present invention described above is completed just before the electrode insertion hole is opened in the workpiece by electrical discharge machining using the thin tubular electrode 1. Until then, the machining conditions under which machining liquid is supplied to the workpiece from a position opposite to the thin tubular electrode 1 through the workpiece to perform electrical discharge machining, particularly the electrical machining conditions for each discharge, i.e. By changing the voltage pulse and discharge pulse conditions to machining conditions that cause more electrode wear on the thin tubular electrode 1, the thin tubular electrode 1 is The tip of the electrode 1 is damaged or damaged, that is, the thin tube-shaped electrode 1 of the wire electrode 2 described above.
It is recommended to wear out and remove the tip that makes it impossible or malfunctioning to be delivered.

In order to increase the amount of electrode wear of the capillary electrode 1 made of ordinary steel or copper alloy, the electrical discharge drilling of the electrode insertion hole using the capillary electrode 1 is performed using Tsufu water or a water-based machining fluid. From the viewpoint of
The polarity of the workpiece 34 is changed from the positive polarity to the reverse polarity, and the machining wear due to electric discharge machining is applied to the tubular electrode 1 (or even the wire electrode 2) (in general, the amount of wear of the electrode 1 is greater when the polarity is reversed).
By adding wear and tear due to electrolytic processing to
This is preferable because it is possible to make the tip of the tubular electrode 1 almost free from damage or damage, rather than simply having a length that causes a large amount of wear.

Of course, in addition to switching the applied polarity of the machining voltage pulse as described above, or together with the polarity switching, the current amplitude 1p of the discharge pulse is increased and/or the discharge pulse width To++ is decreased and miniaturized. Alternatively, in many cases, the above-mentioned thin tube-shaped electrode 1 is
It is possible to increase the wear and tear of the capillary electrode 1 and to perform a kind of cleaning or adjustment of the tip of the capillary electrode 1 due to the wear. As is already clear, when the machining fluid is water or an aqueous machining fluid, the thin tubular electrode of the wire electrode 2 is If feeding is attempted from the tip of the thin tubular electrode 1, and feeding is not possible or fails, either the tip of the thin tubular electrode 1 is retracted a predetermined amount without protruding forward from the electrode insertion hole of the workpiece 34, or the tip of the thin tubular electrode 1 is The electrode 1 and the nozzle 15 for machining liquid are temporarily retracted so that only a predetermined length of the tip that is thought to be damaged or damaged is inserted into the electrode insertion hole. While continuing the jet supply from both or either one, switch the voltage polarity between the capillary electrode 1 (or even the wire electrode 2) and the workpiece 34, and preferably reduce the voltage (2) to a low value and reduce the voltage pulse width. T
Increase of ON and decrease of current amplitude (p) or any one or more of them, or direct current, electrolytically process the capillary electrode 1 as a positive electrode to remove the damaged or damaged portion at the tip of the capillary electrode 1. It is also possible to perform a type of cleaning or adjustment of the tip portion of the capillary electrode 1 in a separate process so as to remove it (usually together with the wire electrode in that portion).

The control for starting and stopping the jetting of the machining liquid from the nozzle 15 to the part of the workpiece 34 facing the thin tubular electrode 1 includes the automatic drilling of the electrode insertion hole and the automatic wire electrode A series of programs and sequence control G for the insertion set can be integrated and controlled, or can be set and controlled independently. Assuming that the voltage and discharge pulse conditions for electrical discharge machining have been selected and set, if the material of the workpiece 34, especially the plate thickness signal is inputted, the time when drilling of the workpiece 34 with the thin tubular electrode 1 starts. When the drilling time or the drilling depth reaches a predetermined value based on the position or position, a valve (not shown) provided in the machining fluid supply path 14b is opened, and from that point or position, the drilling process is continued for a further predetermined time or a predetermined time. This can be implemented in various ways so that the valve can be controlled to close when the processing feed length is reached.

After finishing the electrode insertion hole machining, in the automatic insertion set by feeding the wire electrode 2 to the part after the die guide 17, a detection electrode should be provided at an appropriate position or the nozzle 15 , the guide boulder 17a, the current-carrying pins 18, 19, the rubber valve 21, the capstan 3 which is a device for taking up the wire electrode 2, and a part or all of the pinch roller 32, or the sensing electrode. A detection voltage is applied between the wire electrode 2 and the wire electrode 2. For example, when the tip of the wire electrode 2 contacts or engages with the capstan 31 or pinch roller 32 of the take-up device, the wire electrode 2 is fed out a predetermined length from that point, and then the motor 40h is stopped and the capstan 31 is The wire electrode 2 is driven to be pinched between the pinch roller 32 and the wire electrode 2 is started to be pulled up, and then the thin tube-shaped electrode 1 is pulled up, the feeding control mechanism is released, and the machining liquid nozzle uni-nod is pulled up. A transition to the preparation process for wire cut electric discharge machining such as 3.4 occlusion is performed.

〔Effect of the invention〕

Since the present invention is constructed as described above, when the wire cut electric discharge machining method and apparatus according to the present invention are used,
Even if the workpiece is thick or hardened, the wire electrode can be easily passed through the straight electrode insertion hole, which can be quickly and safely created without damaging the tip of the tubular electrode. In addition, since the wire electrode is already inserted at the same time as the electrode insertion hole is processed and formed, subsequent guides, electrode pulling devices, etc. It is sufficient to operate the tip of the wire electrode to position and insert it, so the probability of success in automatic insertion of the wire electrode is extremely high. Even if there is, the wire electrode can be inserted with high probability. Furthermore, since the wire electrode can be stretched in a straight line using a pair of guides, highly accurate automatic machining is possible, and the entire wire force/nod electric discharge machining device can be configured compactly. .

Note that the present invention is not limited to the embodiments described above. That is, for example, in this embodiment, the above-mentioned water is supplied from the nozzle 15 to the workpiece 34 via the machining fluid supply path 14'b of the nozzle body 14 just before the electrode insertion hole is formed in the workpiece. Although the machining fluid is supplied to the portion under pressure, one or more machining fluid spraying devices may be provided near the nozzle 15.

Further, in the above-mentioned embodiment, the structure is such that the thin tube-like electrode 1 and the wire electrode 2 are fed separately when forming a hole for electrode insertion.
As described in 3J+, the wire electrode 2 is inserted into the capillary electrode 1 so that the tips are almost aligned, and in this state, the wire electrode 2 is locked and fixed to the capillary electrode 1, and the capillary electrode 1 is processed and fed. The wire electrode 2 may be pulled out as a single unit as the wire electrode 2 is fed, and the feeding mechanism for the wire electrode 2 may include a device other than the capstan and the pinch roller, for example, the wire electrode 2. Various mechanisms can be used, such as a mechanism that combines a material handling mechanism that grips and releases the wire electrode with a feeding mechanism, and feeds out the wire electrode little by little through repeated operations.

Furthermore, although the tubular electrode 1 is configured to be moved up and down by the hydraulic cylinder 27 via the stem holder 22, it may be configured to be moved up and down by a motor via a gear. A known power supply method can also be used for supplying power to the device. Furthermore, if the thin tubular electrode is machined while applying ultrasonic vibrations during the machining of the fine hole for electrode insertion, the time required for machining the fine hole for electrode insertion can be further shortened and the process can be carried out reliably.

In addition, machining fluid is supplied to the open/close type machining fluid nozzle unit during wire-cut electrical discharge machining by sandwiching and sealing the tip of the capillary electrode 1 with seal members 3b and 4b without using the hole 4c. Alternatively, the power supply pin or power supply roller for supplying power to the wire electrode 2 may be provided on the upper side of the workpiece.

Furthermore, it is also recommended that the guide 8.17, power supply bottle 18.19, etc. be provided outside the nozzle unit or the nozzle body to facilitate opening/closing, forward/backward movement, etc. In addition, as the guide 8.17, it is not only possible to use a composite guide whose guide hole can be enlarged/reduced or opened/closed, as described in, for example, Japanese Patent Application No. 58-181234, No. 5B-194952, or No. 58-210374. , as a machining fluid injection nozzle, for example, Japanese Patent Application Nos. 58-40949 and 58-4095.
Various configurations described in No. 0 or No. 58-70506 can be used. Furthermore, when processing a fine hole for electrode insertion as a crab start hole using a capillary electrode,
Various modifications are possible, such as providing a guide for positioning and guiding the thin tubular electrode on or near the top surface of the workpiece so that it can move forward and backward, and preventing bending of the pores formed in the thick workpiece. Furthermore, the present invention can also be applied to a wire-cut electrical discharge machining apparatus of a type in which the wire electrodes of the illustrated embodiment are fed upside down for renewal. In addition, the position and method of mounting the die, the method of supplying machining fluid, the method of rotating the capillary electrode, the method of collecting the wire electrode, etc. can be freely changed within the scope of the purpose of the present invention. Therefore, the present invention encompasses all of them.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state in which a wire-cut electric discharge machining apparatus according to the present invention is machining a hole for inserting an electrode into a workpiece, and FIG. An explanatory diagram showing the state in which the insertion hole has been machined and the wire electrode has been inserted. Fig. 3 is an explanatory diagram showing the state when wire cut electric discharge machining has started. Fig. 4 is an explanatory diagram showing the state when the wire electrode is inserted. Fig. 4 shows the machining fluid for opening and closing. FIG. 5, an enlarged sectional view of the nozzle unit portion, is an explanatory diagram showing another embodiment of the wire electrode control and feeding mechanism. 1------------ One capillary tubular electrode 1 a-
−−−−−−−−−−−−−−−−−1 hole 2−−−−−−
=−−−−−−−−−−−−Wire electrode 3.4−−−
------------One-open/close type machining liquid nozzle unit 3a, 4a------------- One-split nozzle 3b, 4b---- ---Seal member 4
cm-----------------------One machining liquid supply hole 5.6-----------------One force, 7
7-------------1--Electrode holding 8
−−−−−−−−−−−−−−−−−−− V-shaped electrode guide 9.20−−−−−−−−−−−−−−−Spring 10.11−−−−− ------------ Hydraulic cylinder 12-------------------- Nozzle device 13----- --- Lower arm 14 --- To --- Nozzle body 15 --- Nozzle 16 --- −1・−−−−1−−−−−−−−−−−
Bag, 1, 17-------------To 1---Dice guide 17 a-'----------
------ Guide holder 17 b ---------
---・--1--Processing fluid supply path 18.19-----
−−−−・−Power supply pin 21.33−−−−−−−−−
-----Rubber valve 25------------・----
-Chank 27 for attaching a capillary electrode
--------One hydraulic cylinder 28---------
-----------Upper arm 29----1---------
−−−−−−−−〜−Brake roller and cab scun 3
0.32------------Pinch roller 31-
−−'−−−−−−−−−−−−−−Capstan 34
−−−−−−−−−−−−−−1・−−1−−Workpiece 35−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−= −−−−−−−1・−−−
−−0 ring 37−−−−−−−−−−−−−−−
-Motor 37 a --------------1--Shaft 38.39---------------------
--Gear 40 f -, ------------
- Rotary encoder 40 g ----------
-----One rotation speed detector 40 h -----------
---Electric motor patent applicant Inoue Japax Co., Ltd. Agent (7524) Shotabe Mogami

Claims (1)

[Claims] 1) Consisting of the steps described in items a) to g) below, a wire electrode is automatically inserted into the electrode insertion hole at the same time as a hole for electrode insertion is formed in the workpiece. A wire cut electric discharge machining method characterized in that electric discharge machining is started by a) A step of attaching a thin tubular electrode to a chuck that is rotatable and movable up and down. b) A step of inserting a wire electrode into the capillary electrode. C) A step of attaching the workpiece to a predetermined position. d) Supplying machining liquid to the hole of the capillary electrode and applying machining feed while rotating the capillary electrode, holding or holding the wire electrode such that the tip of the wire electrode is always located near the open end of the capillary electrode. A process of machining a pore for electrode insertion by applying voltage pulses between a tubular electrode and a workpiece while maintaining a controlled state. e) From just before the electrode insertion hole is opened in the workpiece until the opening is completed, machining fluid is jetted and supplied to the workpiece from a position facing the capillary electrode through the workpiece. The process of doing. f) After completing the machining of the electrode insertion hole, ゛Stop the jet supply of the machining fluid, stop the rotation and power supply of the capillary electrode, and send the wire electrode to the wire electrode take-up device. Process. g) A step of pulling out and retracting the tubular electrode from the electrode insertion hole. 2) A wire-cut electrical discharge machining device characterized by comprising the components described in items h) to 1) below. h) A thin tube-shaped electrode that has a central hole for passing a wire electrode and a machining liquid therein, and is rotatably and detachably attached to the machining head. i) A wire electrode is inserted into the center hole of the capillary electrode, and rotation is applied to the capillary electrode during processing of the hole for electrode insertion, and the wire 4 and the tip of the electrode ψ are always connected to the open end of the capillary electrode. A device capable of delivering a wire electrode so that it is located near the j) When machining a small hole for electrode insertion, supply a voltage pulse for electrical discharge machining at least between the capillary electrode and the workpiece, and during wire cut electrical discharge machining, supply a voltage pulse for electrical discharge machining between the wire electrode and the workpiece. power circuit. k) A device provided at a position opposite to the capillary electrode via the workpiece, and configured to spray and supply machining fluid to the workpiece. l) A device that is provided at a position opposite to the capillary electrode through the workpiece and takes the wire electrode sent out from the tip of the capillary electrode to the processing part along a desired path. −”