JPH0480768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a wire cut electrical discharge machining apparatus which automatically forms a processing start hole in a workpiece and inserts a wire electrode therethrough to start processing. The present invention relates to a method and an apparatus thereof.

Wire-cut electrical discharge machining equipment does not need to manufacture 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), it is possible to operate unattended for long periods of time. For these reasons, it is now widely used.

When performing contour processing such as cutting dies using a wire cut electric 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, there is no tension between the wire electrode and the workpiece. A machine that supplies machining fluid and applies intermittent voltage pulses between the two to generate electrical discharge, and then applies machining feed to the wire electrode or workpiece using a numerical control device, thereby machining the desired contour. It is.

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 machine such as a drill press or jig borer that is separate from the wire cut electric discharge machining equipment. If this is done using a target drilling device or a drilling device using electric discharge or electrolytic machining, it is necessary to perform positioning operations for the workpiece twice, once during drilling and once during wire cut electrical discharge machining. The problem was that it was not long enough to require skill and was time consuming. Furthermore, the wire electrode is an extremely thin wire with a diameter of 1 mm or less, usually about 0.05 to 0.3 mm, and is inserted accurately into the electrode insertion hole formed in the workpiece before processing starts. At the same time, there was also the problem that it was extremely difficult to stretch the wire in a straight line between a pair of guides.

In order to solve the above problems, the hole for inserting the wire electrode is drilled by machining or electrical machining while the workpiece is positioned and attached to a wire cut electric discharge machining device (for example,
Methods have been proposed in Japanese Unexamined Patent Publication No. 48-33493, Japanese Utility Model Application No. 51-31195, etc.).

That is, before starting machining, a drill tool or a thin tubular electrode for electric machining is movably attached to the machining head of a wire-cut electric discharge machining device, or in the axial direction of a perforation machining head that is provided in the head so as to be retractable and removable. Drilling a hole for inserting a wire electrode into the workpiece using a drill tool or a capillary electrode for electric machining, and then retracting the tool or the rod-shaped hollow capillary electrode from the processing part. ,
Next, the wire electrode supply head is guided to the processing part, and the wire electrode is fed out, and the wire electrode is inserted and penetrated into the electrode insertion hole machined in the workpiece, and the tip of the penetrated wire electrode is engaged with a recovery device so that it can be recovered. When the wire electrode is stretched in a straight line by a pair of guides on both sides of the workpiece, a relative machining feed is applied to the wire electrode and the workpiece to start electrical discharge machining. A wire cut electric discharge machining apparatus equipped with an automatic wire electrode insertion device has been developed.

In the above case, it is preferable that the pair of guides provided on both sides of the workpiece be provided at positions close to the workpiece, so that the wire electrode does not pass through the electrode insertion hole of the workpiece. As for the guide on the side that comes out, it is desirable to use a conventional die guide or the like as is, or in the case of a V-groove sliding contact guide, the guide should be retracted slightly or be configured so that it can be opened and closed. .

Furthermore, the V-groove sliding contact guide can be used as long as the holding piece against the V-groove can be retracted, but the guide on the electrode supply side can be used with a tool that drills the electrode insertion hole. When using a thin tube-like electrode, the retraction distance of the die guide, V-groove guide, its holding piece, etc. must be large. However, if the opening/closing degree of the V-groove guide or composite die guide is configured to be large, even if positioning is performed with a fairly high degree of precision, the wire electrode may curve,
In addition to the curls and the shape of the cut end, when the wire electrode is sent out with its tip free, it may come into contact with the guide, the inner circumferential wall of the electrode insertion hole, the contact energizing pin, and other inclusions by rollers, etc. Since the automatic wire electrode insertion device described above not only requires complicated work for insertion, but also requires the operation of inserting the wire electrode into the electrode insertion hole or the operation of inserting the wire electrode through the guide. There was a problem that it was not always carried out well.

That is, in the above device, the formation of the electrode insertion hole and the insertion of the wire electrode into the electrode insertion hole are divided into two steps. Even if the processing of the inner peripheral wall surface of the inner peripheral wall surface is performed well because the roughness of the processed surface is small, the diameter of the above-mentioned insertion hole is at most 1.
If the wire electrode is small, around mmφ or less, and the thickness of the workpiece is several tens of mm or more, it is not easy to insert the wire electrode, and even if the electrode insertion hole is successfully drilled, the It has been quite difficult to insert the wire electrode inside and reliably insert or position the tip of the wire electrode into a small guide die or other guide.

In addition, since the above-mentioned drill tool and device for moving the thin tube electrode up and down are attached to the upper arm or the machining head, there is a problem that the entire upper structure of the wire cut electric discharge machining apparatus becomes large. It was hot.

In order to solve this problem, in a wire-cut electrical discharge machining device, a thin tube-shaped electrode was attached to a chuck that could be raised and lowered, a wire electrode was inserted into the thin tube-shaped electrode, and a wire electrode was attached to a member that supported the chuck. The wire electrode is held by a clamp 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, and the A machining liquid is supplied to the center hole of the capillary electrode, the tips of the capillary electrode and the wire electrode are opposed to the workpiece, and a voltage pulse is applied to feed the capillary electrode while processing the electrode insertion hole. After forming the hole and completing the penetrating process of the electrode insertion hole, the power supply to the capillary electrode is stopped, the grip on the wire electrode is released, and the wire electrode is transferred to the wire electrode pulling device. An apparatus has been developed which is configured to send out a wire and stretch it, then pull out the tubular electrode from the electrode insertion hole and start wire cut electrical 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 pore.

However, when forming a hole for electrode insertion, the above device inserts a wire electrode into a thin tubular electrode, grips the wire electrode with a clamp so that it is processed and fed in the axial direction together with the thin tubular electrode, and then After cutting the tip of the wire electrode so that it is approximately flush with the tip of the tubular electrode, the hole for electrode insertion must be machined, and once the hole for electrode insertion is finished, For example, while releasing the grip on the wire electrode by the clamp,
The wire electrode has to be sent to a wire electrode take-up device and stretched, which is a complicated work, and there are problems in that the work is time-consuming and labor-intensive.

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 workpieces, etc. In addition, the wire electrode can be inserted into the formed electrode insertion hole at the same time as the formation of the electrode insertion hole. By configuring the wire electrode so that it can be inserted into the electrode insertion hole reliably, the wire electrode can be reliably inserted into the electrode insertion hole, and the guide on the other side of the workpiece can be The wire electrode is a guide that allows the wire electrode to be inserted securely, and the wire electrode is stretched in a straight line using a pair of guides, allowing highly accurate automatic processing, and furthermore, it saves time and effort. However, the present invention aims to provide a wire cut electric discharge machining method and an apparatus thereof, which can make the entire apparatus compact.

The above object is to provide a wire cut electric discharge machining method in which a fine hole for electrode insertion is formed in a workpiece and at the same time a wire electrode is automatically inserted into the fine hole for electrode insertion to start electric discharge machining. (a) below
The steps described in paragraphs to (f), that is, (a) the wire electrode to be stretched linearly in the processing area during processing is rotatable around the tension axis and along the tension axis; (b) inserting a wire electrode into a hole parallel to the axis of the capillary electrode, and inserting the tip of the wire electrode into a hole parallel to the axis of the capillary electrode; (c) attaching the workpiece to a predetermined position across the advance/retreat path of the capillary electrode; (d) aligning the hole of the capillary electrode with the opening end of the tip of the capillary electrode; supplying machining fluid to the tube-like electrode, giving a machining feed toward the workpiece while rotating the thin-tubular electrode, and feeding out the wire electrode so that the tip of the wire electrode is always located near the open end of the thin-tubular electrode. A step of applying a voltage pulse between the capillary electrode and the workpiece to form a pore for electrode insertion in the workpiece, and (e) after completing the processing of the pore for electrode insertion, and (f) pulling out and retracting the tubular electrode from the electrode insertion hole. It can be achieved.

Further, the above-mentioned wire cut electric discharge machining method is performed using a wire cut electric discharge machining apparatus having the components described in the following items (g) to 1, that is, (g) a wire to be stretched in a straight line in a machining area during machining. (h) a chuck provided so that the electrode can rotate around the tension axis and move up and down toward the workpiece along the tension axis; has a hole parallel to the axis for
(i) a capillary electrode attached to the chuck so that its hole axis is parallel to the tension axis of the wire electrode; (j) a cutter capable of cutting the wire electrode extending from the tip of the electrode at the tip position of the capillary electrode; (j) inserting the wire electrode into the hole of the capillary electrode;
(k) a wire electrode feeding device capable of feeding out the wire electrode according to the moving speed of the capillary electrode during processing of a fine hole for electrode insertion; (l) A power supply circuit that supplies electric discharge machining voltage pulses to the wire cut electric discharge machining, and (l) a power supply circuit that supplies electric discharge machining voltage pulses between the wire electrode and the workpiece during wire cut electric discharge machining; A wire electrode pulling device is provided at a position where the wire electrode is pulled out along a desired path, and the wire electrode is sent out from the tip of the thin tubular electrode that has passed through the electrode insertion hole drilled in the workpiece. This can be carried out using a wire cut electrical discharge machining apparatus characterized by the following.

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 a hole for inserting an electrode into a workpiece, and FIG. An explanatory diagram showing a state in which a general pore has been machined and a wire electrode has been inserted, Fig. 3 is an explanatory diagram showing a state when wire cut electric discharge machining has started, and Fig. 4 is an explanatory diagram showing a state in which a wire cut electric discharge machining is started. FIG. 5, an enlarged sectional view of the part, is an explanatory diagram of a modified embodiment of the part of the present invention.

In Figs. 1, 2, 3, and 4, 1 has a wire electrode 2 with a diameter of about 0.05 to 0.4 mm inside.
A thin tubular electrode having a predetermined length and a hole 1a through which the machining fluid can be inserted and passed through and can be flow-injected, 3 and 4 are open/close type machining fluid nozzle units, 3a and 4b are split nozzles, and 3b , 4b is a sealing member, 4c is a machining fluid supply hole, 5 and 6 are cutters operated by a solenoid (not shown), 7 is an electrode holder, 8 is a V-shaped electrode guide, 9 is a spring, 10 and 11 are the above opening/closing holes 12 is a nozzle device attached to the lower arm, 14 is a nozzle body, 15 is a nozzle, 16 is a cap nut, 17
17a is a die guide, 17a is a guide holder, 18 and 19 are movable power supply pins, 20 is a spring provided as necessary, 21 is a rubber valve, and 22 is a thin tube-shaped electrode consisting of a stem 23 and a tightening nut 24. A stem holder for holding the mounting chuck 25, 22a is a machining fluid supply hole formed in the stem holder 22, 26 is a bearing, 27 is fixed to the upper arm 28 of the wire cut electrical discharge machining device,
A hydraulic cylinder 29 that moves the stem holder 22 up and down with respect to a workpiece mounting table (not shown) acts as a brake roller when the motor is stopped or rotating at a predetermined speed, and when the motor is under sequence control. 30 is a pinch roller, 31 is a capstan for taking up the wire electrode and applying tension, 32 is a pinch roller, and 33 is a capstan. A rubber valve, 34 is a workpiece, 35 is an energizing shoe for supplying power to the thin tubular electrode 1, 36 is an O-ring, 37 is attached to the stem holder 22, and a gear 38 attached to the shaft 37a is connected to the stem 23.
This is a motor that meshes with a gear 39 attached to the motor.

The chuck 25 for attaching the capillary electrode 1 is composed of a stem 23 and a tightening nut 24, and as explained below, the chuck 25 is used to attach a wire electrode stretched in a straight line in the processing area during processing. 2
It is configured to be able to rotate around the tensioning shaft, and to be able to move up and down toward the workpiece 34 along the tensioning shaft.

Further, the thin tubular electrode 1 is detachably attached to the stem 23 of the chuck 25 so that its central axis coincides with or parallel to the tension axis of the wire electrode, and is suitable for machining a pore for electrode insertion. Therefore, when the thin tubular electrode 1 is worn out, the tightening nut 24
Preferably, the device is configured to be an automatic electrode exchange type so that a worn out tubular electrode 1 can be reattached or replaced with a new tubular electrode 1 by loosening the electrode.

The stem 23 has its central axis aligned with the wire electrode 2.
It is rotatably held relative to the stem holder 22 by a bearing 26 in a state aligned with the tension axis of the stem holder 22, and is rotated by the rotation of a motor 37 attached to the stem holder 22 via gears 38 and 39. It is configured to rotate around an axis. Therefore, the capillary electrode 1 attached to the stem 23
The wire electrode 2 is also rotated around the tension axis of the wire electrode 2 as the motor 37 rotates, and is rotated along the tension axis of the wire electrode 2 by the action of the hydraulic cylinder 27 that supports the stem holder 22. It is configured to move in the vertical direction and to move forward and backward relative to a workpiece 34 attached to a workpiece mounting table (not shown).

The opening/closing machining fluid nozzle units 3 and 4 are formed with split nozzles 3a and 4a, seal members 3b and 4b, and machining fluid supply holes 4c, etc., and are diametrically controlled by the action of hydraulic cylinders 10 and 11. It is configured so that it can be opened and closed. Further, an electrode retainer 7 configured to act on the elastic force of a spring 9 is arranged in the central part of the interior of the nozzle unit 3, and a transverse An electrode guide 8 having a V-shaped surface is attached, and determines and positions the wire electrode 2 above the workpiece 34 during wire cut electrical discharge machining.
hold in a straight line.

The nozzle body 14 has a mounting flange 14a, a liquid reservoir chamber 14b, and a machining fluid supply hole 14c, and a nozzle 15 is fitted into the nozzle body 14 so as to be able to slide freely in the axial direction of the wire electrode.
0 and the cap nut 16 are installed in sequence. Thereafter, this nozzle device 12 is attached to the mounting flange 14a.
It is attached to the lower arm 13 with a mounting bolt or the like (not shown).

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 of reaching and engaging the pulling device and then performing wire cut electric discharge machining on the workpiece 34 by wire cut electric discharge machining will be described.

As shown in FIG. 1, when forming an electrode insertion hole through which the wire electrode 2 is inserted into the workpiece 34, the brake roller/capstan 29 acts as a capstan, and inside the hole 1a of the thin tubular electrode 1. A wire electrode 2 is inserted therethrough.

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

Note that at this time, the tip of the capillary electrode 1 is connected to the cutter 5.
If there is a discrepancy, such as above the positions of the wire electrodes 5 and 6, the hydraulic cylinder 27 is operated to make the adjustments consistent, and then the cutters 5 and 6 are operated by solenoids (not shown), and the wire electrodes are 2 is cut so as to be substantially flush with the tip portion of the capillary electrode 1.

That is, the cutters 5 and 6 are attached to positions facing the advancing and retreating path of the thin tubular electrode 1, for example, in the illustrated embodiment, the upper ends of the machining fluid nozzle units 3 and 4, and are attached to the wires extending from the tips of the thin tubular electrodes. The electrode can be cut at the tip of the tubular electrode.

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 attachment chuck 25, the operation starts from the state where the tip of the wire electrode 2 does not reach the base position of the capillary electrode 1. When starting, and when replacing the capillary electrode 1, the wire electrode 2 is manually inserted into the electrode 1, and then the capillary electrode 1 is inserted into the capillary electrode mounting chuck. 25 can also be operated. In addition, in many cases, when the previous wire cut electric discharge machining is completed, the wire electrode 2 is cut at the tip of the capillary electrode 1 on the supply side by the cutters 5 and 6, and then the next machining operation is performed. In this case, the operation and process of inserting the wire electrode 2 into the thin tubular electrode 1 has been completed.

Voltage pulses for electrical discharge machining are supplied to the capillary electrode 1 from a power supply circuit (not shown) via the current supply shoe 35, and at the same time, the capillary electrode 1 is subjected to rotational movement by the motor 37 and hydraulic pressure. A downward movement movement by the cylinder 27 is applied via the stem holder 22 and the stem 23, and
The brake roller/capstan 2 is moved in synchronization with the downward movement speed of the hydraulic cylinder 27.
9 acts as a capstan, the wire electrode 2 is fed out, and at the same time, the same machining fluid as for normal wire cut electric discharge machining is applied to the hole 1 of the thin tubular electrode 1.
While being supplied to the processing portion of the workpiece 34 from a, the electrode insertion hole is processed.

When drilling a hole for electrode insertion, as described above, rotational motion is applied to the thin tubular electrode 1, and the brake roller/capstan 29 moves the wire electrode 2 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 tube electrode 1 during processing.

Machining of a hole for electrode insertion into the workpiece 34 using the capillary electrode 1 requires that the wire electrode 2 is inserted through the capillary electrode 1 and that the capillary electrode 1 is given rotational motion. Other than what is mentioned above, the machining is performed by high-speed machining by electric discharge machining of deep holes as described in detail in, for example, Japanese Patent Application Laid-open No. 56-69033, and at least 10 to 20 kg/cm ² from the machining fluid supply hole 22a. or above, the machining fluid is supplied under pressure, and preferably, although not shown, constant speed or servo feed is applied by the hydraulic cylinder 27 while applying ultrasonic vibration to the thin tubular electrode 1 as described in the above-mentioned publication. In this way, the injection of high-pressure machining fluid, the rotation of the thin tubular electrode 1, and the application of ultrasonic vibrations enable machining of deep holes, which previously could not be performed smoothly, on hardened steel or other materials. This process can be carried out smoothly and at high speed even on cemented carbide, etc., and even in a thick workpiece 34, a straight and uncurved electrode insertion hole can be formed in a short time.

Note that when machining this electrode insertion hole, the wire electrode 2 can be formed into a thin tubular shape, not only when the wire electrode 2 is connected to some kind of electric discharge machining power source, but even when the power source is not connected. Since the tip of the wire electrode 2 may be worn out due to being in some kind of contact state with the electrode 1, the length of wear and retreat of the tip of the wire electrode 2 relative to the tip of the capillary electrode 1 may reach, for example, approximately several mm or more. In this case, it is better to increase the amount of wire electrode 2 sent out by the brake roller/capstan 29 and correct it so that its tip is near the tip of the thin tube electrode 1, so that the wire electrode 2 can be inserted into the guide etc. later on. This is desirable because it ensures that

When the electrode insertion hole for passing the wire electrode 2 through the workpiece 34 is formed, the thin tubular electrode 1
The tip of the wire electrode 2, which is near the tip of the electrode 1 and has already been inserted through the electrode insertion hole along with the tip of the electrode 1, is sent out toward the nozzle device 12 by the capstan action of the brake roller/capstan 29. After being inserted and captured by the die guide 17, it passes through the hole 17b of the guide holder 17a, passes through the rubber valve 21, and is engaged after reaching the wire electrode pulling device consisting of the capstan 31 and others, which the pinch roller 32 approaches and separates. Then, by detecting it by an appropriate means, etc., the pulling engagement is completed, and the wire electrode 2 is forcibly pulled out from the tip of the wire electrode 2. The wire electrodes are collected in a wire electrode collection box (not shown) or the like.

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 thin tubular electrode 1, and the hydraulic cylinder 27 is operated to hold the stem. The body 22 is moved upward to raise the thin tubular electrode 1, and accordingly, the opening/closing machining liquid nozzle units 3, 4 are closed by the action of the hydraulic cylinders 10 and 11, and the wire electrode 2 is moved upward by the opening/closing operation. Electrode presser 7 inside the machining liquid nozzle unit 3, 4
and a V-shaped electrode guide 8 to move freely. Then, voltage pulses for electrical discharge machining are supplied from the power supply pins 18 and 19 that are in contact with the wire electrode 2 in the nozzle body 14, and machining fluid is supplied from the machining fluid supply hole 4c of the opening/closing type machining fluid nozzle unit 4. Wire cut electrical discharge machining is performed while the liquid is supplied to the machining portion of the workpiece 34.

Note that during normal machining, the current-carrying pins, guides, etc. reach a considerable temperature due to electrical discharge machining current, friction, and the like. However, in the wire cut electrical discharge machining apparatus according to the present invention, the power supply pins 18, 19, the die guide 17, etc. in the nozzle body 14 are sufficiently cooled by the machining fluid passing through the liquid reservoir chamber 14b. Therefore, it can withstand long-term driving.

In addition, when the thin tubular electrode 1 is worn out and its length becomes equal to or less than the workpiece 34 to be processed, the wire electrode 2 is cut at the tip of the thin tubular electrode 1 and replaced. However, when replacing the capillary electrode 1 manually, it is sufficient to pass the wire electrode 2 extending from the tip of the capillary electrode attachment chuck 25 through the hole 1a of the new capillary electrode 1. This is extremely difficult if the shaped electrode 1 is replaced automatically, so in such a case, the extending wire electrode 2 is
A method is adopted in which the wire electrode 2 is reversed and returned to near the base of the stem 23, and then a new capillary electrode 1 is attached, and the wire electrode 2 is sent out by straightening the capstan 29, and is inserted up to the tip of the capillary electrode 1. It will be done.

In the wire electrode 2 insertion set, the die guide 17, the coupling pins 18, 19, the rubber valve 21,
If the insertion or setting fails at the capstan 32, the pinch roller 38, or the electrode pulling device further ahead, for example, the thin tubular electrode 1 is temporarily pulled up to the position shown in FIG. 3, and the wire electrode 2 is removed. The thin tubular 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 tubular electrode 1 is lowered by the hydraulic cylinder 27. The feeding and sending out of the wire electrode 2 by the capstan 29 are controlled and synchronized so that the tip of the wire electrode 2 does not protrude from the tip of the capillary 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 sent out to protrude from the tip of the capillary electrode 1, and the insertion and setting of the wire electrode 2 is attempted again.

Further, in the embodiment described above, 29 operates as a brake roller and capstan and other explanations are added, but in the configuration of the embodiment shown above, although 29 can suitably function as a brake roller, It is not necessarily sufficient as a capstan to send out the wire electrode 2 for insertion set,
In addition, the brake roller and pinch roller 29 are simply guide rollers, and the guide roller 2
A brake roller can be provided on the front wire electrode supply side of the opening/closing nozzle unit 4 as an open/close type brake roller, or an open/close type brake roller and a pinch roller can be provided on the wire electrode 2 supply side of the open/close type nozzle unit 4. Furthermore, when 29 and 30 are simply upper guide rollers that hold and guide the wire electrode 2 portions before and after the processing section in a substantially straight line between the lower capstan 31 and the pinch roller 32,
Between the guide rollers 29, 30 and the stem holder 22, there is provided a mechanism 40 for controlling and feeding out the wire electrode 2, which is set at least when the wire electrode 2 is automatically inserted and set.

FIG. 5 is an explanatory diagram showing an example of the control sending 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.
The other ends of arms 40c and 40d are connected to hydraulic cylinder 4.
The capstan 40a is configured to be able to be attached and detached by clamping and releasing the wire electrode 2 by operating the capstan 40a, and the capstan 40a is also used as a rotary encoder 40f for detecting rotation angle or position. The wire electrode 2 is fed out while its rotation is controlled by an electric motor 40h having a rotational speed detector 40g which may be a finger speed generator or the like.

When drilling the start hole in the workpiece 34 using the thin tubular electrode 1, depending on the dimensions such as the inner diameter or outer diameter of the thin tubular electrode 1, the wire electrode 2 may be set at the same potential as the thin tubular electrode 1, or a separate power supply may be applied. The wire electrode 2 may be connected and involved in machining the start hole of the workpiece 34, or the wire electrode 2 may be consumed due to the above-mentioned structure, or it may be placed near the tip of the thin tubular electrode 1 or at an appropriate position within the tube. To avoid this, when the capstan 40a and the pinch roller 40b are fed back and forth at a frequency of around several Hz, when the capstan 40a and the pinch roller 40b are being fed back and forth at a frequency of around several Hz, the capstan 40a is When the forward rotation is 1 and the reverse rotation is 0.5 to 0.9 (the length is about 5 mm at most in the backward rotation, usually 0.1 to 1 mm)
By feeding the wire electrode 2 and the tubular electrode 1 in combination, it is possible to prevent welding of the wire electrode 2 and the tubular electrode 1. Moreover, although the risk of welding from the rotating part of the thin tubular electrode 1 to the tip of the wire electrode 2 is somewhat low, 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; however, if the wire electrode 2 is to be involved in machining the start hole, Or, if a separate power supply is connected, it is necessary to separately apply vibration to the thin tubular electrode 1 or to send it out by repeating the minute forward and backward movement as described above.
Such a feeding method is effective for inserting the tip end of the wire electrode 2 into the die guide 17 by feeding the wire electrode after completing the drilling of the start hole. Of course, the above-mentioned vibratory feeding method may be employed only when the wire electrode 2 is inserted into the die guide 17. In any case, it is natural that it is necessary to accurately know the tip position of the tubular electrode 1 when drilling the start hole and inserting the wire electrode 2, but the tip position of the wire electrode 2 can also be accurately detected and controlled. Therefore, it must be equipped with a rotary encoder 40f and a rotation speed detector 40g, etc., which detect the feed length and feed speed and provide feedback to the sequence controller, NC control device, etc. , In the automatic insertion set by feeding the wire electrode 2 to the part after the die guide 17 of the wire electrode 2 after finishing the start hole machining, a detection electrode is provided at an appropriate position, or the nozzle 15, guide holder 17a , energizing pins 18, 19, rubber valve 2
1 and the wire electrode 2, a part or all of the capstan 31 and the pinch roller 32, which are the pulling devices, are provided with a detection electrode that serves as a detection electrode, and a detection voltage is applied between the capstan 31 and the wire electrode 2. For example, when the tip of the wire electrode 2 contacts or engages with the capstan 31 or the pinch roller 32 of the take-up device, the wire electrode 2 is fed out a predetermined length from that point, the motor 40h is stopped, and the pinch roller 32 is driven. and pinch the wire electrode 2 with the pinch roller 3.
1 and starts the pulling operation of the wire electrode 2, and further pulls up the thin tubular electrode 1, releases the feeding control mechanism, and operates the machining fluid nozzle units 3 and 4.
A transition to a preparatory process for wire cut electrical discharge machining, such as occluding the wire, can be performed.

Since the present invention is configured as described above, when the wire cut electric discharge machining method and apparatus according to the present invention are used, a wire electrode can be easily passed through even a thick workpiece or a hardened workpiece. It is possible to process and form a straight electrode insertion hole in a short time, and the wire electrode can be inserted into the electrode insertion hole at the same time as the electrode insertion hole is formed. Therefore, it is only necessary to position and insert the tip of the wire electrode into the guide or electrode pulling device, etc., so the success rate of automatic insertion of the wire electrode is extremely high. Even if the guide on the other side of the workpiece is a small guide die or the like, the wire electrode can be inserted with high probability. Furthermore, since the wire electrode can be stretched in a straight line by the pair of guides, highly accurate automatic processing is possible, and the entire apparatus can be constructed compactly.

Note that the present invention is not limited to the embodiments described above. That is, for example, in this embodiment, the tubular electrode was configured to be moved up and down by a hydraulic cylinder via a stem holder, but it may also be configured to be moved up and down by a motor via a gear. Furthermore, a known power supply method can be used to supply power to the capillary electrode and the wire electrode.
Furthermore, if the structure is such that ultrasonic vibration is applied to the tubular electrode while machining the fine hole for electrode insertion, the time required for machining the fine hole for electrode insertion can be further shortened.
And it can be done reliably. In addition, machining fluid can be supplied to the open/close type machining fluid nozzle unit during wire cut electric discharge machining by clamping 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, guide 8,1
7, power supply pins 18, 19, etc. can be provided on the outside of the nozzle unit or nozzle body to make it easy to open/close, move forward/backward, etc.; -194952 or 58-210374, etc., the guide hole can be enlarged/reduced or opened/closed, and can also be used as a machining fluid injection nozzle, for example, in Japanese Patent Application No. 58-40949, No. 58-40950 or No. 58-70506
It is possible to use various configurations described in the No. 1, etc. Furthermore, a guide for positioning and guiding the tubular electrode at or near the top surface of the workpiece is provided so that it can move forward and backward when machining a thin hole for electrode insertion as a processing start hole using the thin tubular electrode. Various modifications are possible, such as preventing bending of the pores formed in the pores.Furthermore, the present invention allows wire electrodes to be sent from bottom to top for renewal, as in the illustrated embodiment, which is upside down. It can also be applied to a supply type wire cut electric discharge machining apparatus. Other dice installation positions and installation methods,
The method of supplying the 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, and the present invention encompasses all of them. It is.

[Brief explanation of the drawing]

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 a hole for inserting an electrode into a workpiece, and FIG. An explanatory diagram showing a state in which a general pore has been machined and a wire electrode has been inserted, Fig. 3 is an explanatory diagram showing a state when wire cut electric discharge machining has started, and Fig. 4 shows a machining fluid nozzle unit for opening and closing. FIG. 5, an enlarged sectional view of the part, is an explanatory diagram of a modified embodiment of the part of the present invention. DESCRIPTION OF SYMBOLS 1... Capillary electrode, 1a... Hole, 2... Wire electrode, 3, 4... Open/close type machining fluid nozzle unit, 3a, 4a... Split nozzle, 3b, 4b...
Seal member, 4c... Machining fluid supply hole, 5, 6...
Katsu, 7... Electrode holding, 8... V-shaped electrode guide, 9, 20... Spring, 10, 11...
Hydraulic cylinder, 12... Nozzle device, 13... Lower arm, 14... Nozzle body, 15... Nozzle, 16... Cap nut, 17... Dice guide,
18, 19... Power supply pin, 21, 33... Rubber valve, 25... Capillary electrode mounting chuck, 27...
...Hydraulic cylinder, 28... Upper arm, 29...
Brake roller and capstan, 30, 32...
Pinch roller, 31... Capstan, 34...
Workpiece, 35...Electricity shoe, 36...O ring, 37...Motor, 37a...Shaft, 3
8,39...Gear.

Claims (1)

[Claims] 1 Consisting of the steps described in the following items (a) to (f), 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 by inserting the wire and starting electric discharge machining. (a) A wire electrode to be stretched in a straight line in the processing area during processing is provided so that it can rotate around the tension axis and can move up and down toward the workpiece along the tension axis. The process of attaching a capillary electrode to the chuck. (b) A step of inserting a wire electrode into a hole parallel to the axis of the capillary electrode, and aligning the tip of the wire electrode with the open end of the tip of the capillary electrode. (c) A step of attaching the workpiece to a predetermined position across the forward and backward movement path of the capillary electrode. (d) supplying a machining fluid to the hole of the capillary electrode;
While rotating the capillary electrode, a machining feed is applied toward the workpiece, and while the wire electrode is fed out so that the tip of the wire electrode is always located near the open end of the capillary electrode, the capillary electrode and the workpiece are A process in which a voltage pulse is applied during the process to create a pore for electrode insertion in the workpiece. (e) After completing the machining of the electrode insertion hole, stopping the rotation and power supply of the tubular electrode, and feeding the wire electrode toward the wire electrode take-up device. (f) A step of pulling out and retracting the tubular electrode from the electrode insertion pore. 2. A wire-cut electrical discharge machining device characterized by comprising the components described in items (g) to (l) below. (g) The wire electrode to be stretched linearly in the processing area during processing is provided so that it can rotate around the tension axis and move up and down toward the workpiece along the tension axis. Checked. (h) A thin tubular electrode having a hole therein parallel to the axis for passing the wire electrode and the machining fluid, and attached to the chuck so that the axis of the hole is parallel to the tension axis of the wire electrode. (i) A cutter that is provided at a position facing the forward and backward movement path of the capillary electrode attached to the chuck and is capable of cutting the wire electrode extending from the tip of the capillary electrode at the tip position of the capillary electrode. (j) A wire electrode feeding device capable of inserting a wire electrode into the hole of the capillary electrode and feeding out the wire electrode according to the moving speed of the capillary electrode when processing a hole for electrode insertion. (k) 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. (l) A wire electrode is provided at a position opposite to the above-mentioned capillary electrode through the workpiece, and is fed out from the tip of the capillary electrode that has passed through a pore for electrode insertion made in the workpiece to the desired position. Wire electrode pulling device that pulls along the path.