JPH0520211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire-cut electric discharge machining apparatus, and more particularly to a novel wire-cut electric discharge machining apparatus configured to perform machining by reciprocating a wire electrode to a machining area.

[Prior Art] Unlike normal machining, which performs machining by applying mechanical force directly to the workpiece, electrical discharge machining equipment uses a machine that places the workpiece and electrode facing each other with a small gap between them. This is a non-contact machining process in which a machining fluid is interposed in the gap, a voltage pulse is applied between the two, and machining is performed using the discharge erosion phenomenon that occurs at that time.

Therefore, as long as the workpiece is a conductive material, any complex or minute shape can be machined, regardless of its hardness, and the force applied to the workpiece and electrode is lower than in machining. Since it is extremely small, it can be easily processed into thin plates, tubes, and thin wires.

In particular, wire-cut electrical discharge machining equipment, which uses a wire electrode to cut or punch a workpiece by electrical discharge machining, does not require a specific shaped electrode compared to die-sinking electrical discharge machining equipment, and also uses machining fluid. Since deionized water is used as the water, there is no risk of fire, and furthermore, with the development of NC equipment, arbitrary machining feed between the workpiece and the wire electrode can be performed unattended for long periods of time, reducing production costs. It is widely used today for the purpose of processing through-type dies, such as punching dies and extrusion dies, because it can shorten the manufacturing period.

In the conventionally known wire-cut electric discharge machining apparatus, a single wire electrode is drawn out from a wire electrode supply drum and guided to a machining section through various guide rollers, etc. A guide for dies, etc. for positioning a pair of electrodes while maintaining a predetermined machining gap with the workpiece (usually installed within the tips of a pair of arms extending from a column toward the workpiece). The electrodes are stretched in a straight line under a predetermined tension, and the used electrodes that have passed through the processing section are wound up on an electrode collection drum or disposed of in a collection box. For this reason, in the processing portion facing the workpiece, a single wire electrode is simply stretched in a straight line and allowed to run slowly.

[Problem that the invention seeks to solve]

As mentioned above, in the conventionally known wire-cut electric discharge machining equipment, only one wire electrode exists in the machining part, and machining is performed using this one wire electrode, which improves machining efficiency. is not necessarily sufficient, and the wire electrode is bent in an arcuate manner in the direction opposite to the machining progress direction due to the discharge pressure, resulting in reduced machining accuracy at corners of the machining contour shape, small radius arc parts, etc. It was hot. Furthermore, at the start of machining, it is necessary to route the wire electrode between various guide rollers and insert it into an electrode positioning die, but this work may occur if the wire electrode breaks during machining or if the wire electrode is continuously When cutting out multiple parts, it is necessary to redo the process each time, which is very troublesome.

Furthermore, if there is only one wire electrode, the machining wave cannot be sufficiently supplied into the machining gap formed between the wire electrode and the workpiece, resulting in a decrease in machining accuracy and insufficient cooling effect. There was a problem in that efficient machining could not be performed due to the large current. In addition, the outer peripheral surface of the wire electrode passing through the machining part is gradually worn away by electric discharge and becomes serrated, making it difficult to perform good finishing when the workpiece is thick. There were also problems.

The present invention was made to solve many of these problems, and its purpose is to:
It is an object of the present invention to provide a novel wire-cut electrical discharge machining device that improves machining efficiency and accuracy, allows wire electrode routing work to be carried out automatically and easily, and furthermore provides a good finished surface.

[Means for Solving the Problems] In order to achieve the above object, the wire cut electric discharge machining apparatus according to the present invention includes a first arm or a machining head equipped with a wire electrode supply and recovery device, and a a second arm or processing head that is equipped with an electrode return device that folds back the wire electrodes supplied from the arm or processing head, contacts each other, runs in the opposite direction, and sends them back to the recovery device provided in the first arm or processing head; an electrode transport device for stretching and suspending the wire electrode from the first arm or processing head to the electrode return device of the second arm or processing head; a device for holding the workpiece; and the above first and second
a processing feed device that brings the wire electrodes that reciprocate between the arm or the processing head close to each other and face each other, a power supply device and a power supply mechanism that apply a discharge voltage pulse between the workpiece and the wire electrode, and the workpiece and a device for supplying machining liquid to a machining gap formed by a body and a wire electrode that are closely opposed to each other.

[Effect]

With the above configuration, the wire electrode led out from the first arm or the processing head passes through the processing portion facing the workpiece, and then passes through the electrode provided on the second arm or processing head. The wire is hung over the return device, turned back here, passed through the processing position again, and then sent back by the first arm or processing head, so the two reciprocating wire electrodes run in parallel in the processing section. You will be forced to do so. When this happens, the machining fluid is 2
Since the machining liquid flows through a relatively wide machining gap formed between the main wire electrode and the workpiece, the machining fluid flows well, improving machining efficiency, and the two wire electrodes are kept sufficiently close or in contact with each other. If the wire electrode is made to travel with the wire, the overall strength of the wire electrode increases, the bending of the electrode due to the discharge pressure is eliminated, and highly accurate machining becomes possible. Furthermore, among the two wire electrodes that are folded back and brought into contact with each other and run in opposite directions as described above, a wire with a damaged surface is returning from the second arm or processing head to the first arm or processing head. A good surface finish can be obtained by performing the initial rough machining with the electrode and finishing with the new wire electrode from the first arm or machining head to the second arm or machining head. Also, when pulling the wire electrode around at the start of processing, etc., the middle part of the wire electrode that has already been connected from the electrode supply device to the recovery device in the first arm or processing head is held by the electrode transport device. Since the work of tensioning the electrode on the processing part is completed by simply hooking it to the second arm or the electrode return device of the processing head, the work can be done automatically and easily. be.

〔Example〕

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

FIGS. 1 to 3 are explanatory diagrams showing step-by-step the wire electrode tensioning process in an embodiment of the wire cut electric discharge machining apparatus according to the present invention, and FIGS. 4 to 6 show the wire electrode tensioning process step by step. FIGS. 7 and 8 are explanatory diagrams of one embodiment showing stepwise the process of transferring the electrode by the electrode transport device provided on the second arm or processing head to the electrode return device provided on the second arm or processing head, and FIGS. 7 and 8 illustrate the present invention. FIG. 4 is an explanatory diagram showing different machining situations by the wire cut electrical discharge machining apparatus.

1 to 3, 101 is a column, and 102 is a first arm or a first arm provided to be movable in the vertical direction in the drawings with respect to the column 101 and to extend toward the processing position. Processing head, 1
03 is a second arm or processing head that is provided to be movable in the vertical direction in the figure with respect to the column 101 and extend toward the processing position; 104 is a wire electrode; 105 is a wire electrode supply drum;
06 to 112 are guide rollers for supplying wire electrodes, 113 is a brake roller provided so as to be able to approach and separate from the guide roller 111, 114 is an electrode folding roller, 115 and 116 are energizing rollers, and 117 and 118 are electrode positioning rollers. A guide such as a die or a boat shape 119 holds the electrode folding roller 114 on the second arm side and holds the wire electrode 1.
120 and 121 are presser rollers, 122 is a capstan, 123 is a pinch roller that is movable toward and away from the capstan 122, and 124 to 126 are A guide roller for collecting the wire electrode, 127 is an electrode winding drum,
128 is an electrode transport device that can be expanded and contracted in a nested manner;
Reference numeral 29 denotes a split type machining liquid spouting nozzle, 130 a machining tank, 131 a stage provided in the machining tank, 132 a moving table 133 in the X-axis direction, and a Y-axis moving table 133;
A cross slide table consisting of an axial movement table 134 and its drive motors 135 and 136, 137 is a bed, 138 is a stage 13
Workpiece fixed with a clamp etc. on 1, 139
is a power supply device that applies voltage pulses for electrical discharge machining between the wire electrode 104 and the workpiece 138 via the energizing roller 115.

FIG. 1 shows the tensioned state of the wire electrode 104 before the start of processing, and at this time,
The wire electrode 104 pulled out from the wire electrode supply drum 105 passes through guide rollers 106 to 111 for supplying the wire electrode, and is then guided directly to the capstan 122 and pinch roller 123, and then to the guide roller 12 for recovering the electrode.
4 to 126, and are connected to the electrode winding drum 127 so as to be collected.

At this time, the guide rollers 107, 109 and the brake roller 113 are all separated from the corresponding guide rollers 105, 108, 111, and the presser roller 121 is also separated from the guide roller 111.
2, the energizing rollers 115 and 116 also move away from each other, and the presser roller 120 is also displaced to the right in the figure from its position during processing as shown in FIG. In addition, as the guides 117 and 118 for electrode positioning, for example, Japanese Patent Application No. 194952/1989,
The guides 117 and 118, such as dies and boat-types that can be opened and closed by approaching and separating or rotating, as described in No. 210374, etc., are operated to open and close or are retracted to the left side in the figure, and the split-type machining fluid spouting nozzle 129 is also opened. in a state. Furthermore, the folding roller 114, which is moved to and held by the electrode return device 119 during processing, is also attached to the tip of the electrode transport device 128 in the state shown in FIG.

When starting processing, the telescopic electrode conveying device 128, which expands and contracts using hydraulic pressure, a motor, or the like as a power source, is gradually extended as shown in FIG. In such a case, the wire electrode 104 stretched between the guide roller 111 and the capstan 121 is hooked onto the electrode 114 by an electrode folding roller attached to the tip of the electrode conveying device 128, and is moved downward in the figure. is stretched to. At this time, since the guide rollers 107, 109, brake roller 113, etc. are separated from the corresponding guide rollers 105, 108, 111, the wire electrode 104 is freely released from the supply drum 105 as the electrode conveying device 128 is extended. drawn out.
A groove is formed on the outer periphery of the folding roller 114 to hold and guide the wire electrode so that it does not fall off.

When the electrode transport device 128 extends and its tip reaches the second arm or the electrode return device 119 provided inside the processing head 103, the folding roller 114 is separated from the tip of the electrode transfer device and returns to the electrode return device. 119. The situation during that time,
This will be explained with reference to the embodiments shown in FIGS. 4 to 6.

These figures show an example of the structure of the electrode return device 119 and an example of the structure of the tip portion of the electrode transfer device 128. Rod, 12
8b is an electromagnet holder attached to the tip of the rod, 128c is the iron core of the electromagnet, 128d is a coil, and 128e, 128e (only one of them is shown in the figure) has one end connected to the iron core 128c.
A recess 1 is fixed to the magnetic pole of the electrode and has a recess 1 at the other end for adsorbing the shaft 114a of the electrode folding roller 114.
28' is a roller suction element formed with
In the electrode return device 119, 119a is a casing;
119b is a frame rotatably supported on the casing, 119c is a gear fixed to the rotation shaft of the frame so as to rotate together with the frame;
9d is an intermediate gear, 119e is a worm gear fixed to the rotating shaft of the motor 119f and meshed with the intermediate gear 119d, 119g is an electromagnet, and 119h, 119h (only one of which is shown in the figure) is one end thereof. is the above electromagnet 119g
A recess 1 is fixed to the magnetic pole of the electrode and has a recess 1 at the other end for adsorbing the shaft 114a of the electrode folding roller 114.
A roller suction plate 19h' is formed, 119i is an electromagnet attached to the inner side wall of the casing 119a, and 119j is an iron material that is attracted to the electromagnet 119i and prevents the frame from opening when the frame 119b is closed.

Thus, as shown in FIG. 4, the wire electrode 104
The folding roller 114, which is wrapped around the
In the process of approaching the electrode return device 119 while being attracted to electrodes 8e and 128e, the return roller 1
Electrode return device 119 so as not to obstruct the progress of 14
The frame body 119b is lifted upward and left open. The electrode conveying device 128 is further extended, and the shaft 114a of the folding roller 114 is moved as shown in FIG.
is received in the recess 119h' at the tip of the roller suction plate 119h of the electrode return device 119, the electromagnetic coil 128d attached to the electrode transport device
The energization is cut off, and the electromagnet 119g on the electrode return device 119 side is energized instead, so that the shaft 114a of the folding roller 114 is attracted to the roller suction plates 119h, 119h of the electromagnet 119g. Therefore, if the electrode transport device 128 is contracted at this point, the return roller 114 will be detached from the roller suction elements 128e, 128e of the transport device 128, and will remain attracted to the roller suction plate 119h on the electrode return device 119 side. It will be done. Next, the motor 119f is operated to close the frame 119b as shown in FIG. 6, and the electromagnet 119i is energized to attract the iron material 119j provided on the frame. In this case, even if tension is applied to the wire electrode 104, the frame body 119b remains closed, thereby holding the folding roller 114 on the electrode return device 119 side.

As described above, when the folding roller 114 is moved to and held by the electrode return device 119 provided on the second arm or processing head 103, the wire electrode 104 is transferred to the first arm or processing head 103.
2 and the second arm or machining head 103, it is stretched in a U-shape.

Thereafter, as shown in FIG. 3, the nested electrode conveying device 128 is completely retracted, and the presser rollers 120 and 121 are moved to the left in the figure to move the electrode between the first and second arms or processing heads. At the same time, the wire electrodes that are reciprocatingly stretched are brought close to and in contact with each other, and the guide rollers 107, 109 and the brake roller 113 are moved to the guide roller 10, respectively.
5, 108, 111, energized roller 1
16 to the left side and connect the other energizing roller 1.
15, and furthermore, the electrode positioning dies 117 and 118 are displaced to the right in the figure to hold the wire electrode in a fixed position, and the capstan 122 is rotated to slowly move the wire electrode. Next, the divided machining fluid jet nozzle 129 is closed to start supplying the machining fluid, and the power supply device 139 is activated to apply a voltage pulse between the wire electrode 104 and the workpiece 138, and the workpiece is ready for machining. , cross slide table 1
32 motors 135 and 136 are driven based on commands from a numerical control device (not shown) to feed the workpiece while maintaining a predetermined gap between the wire electrode 104 and the workpiece 138, the workpiece can be fed as desired. Electric discharge machining of the shape is performed.

In the series of operations for tensioning the wire electrodes as described above, the movements of the guide rollers 107, 109 and the brake roller 113, the presser roller 12, etc.
0,121, the movement of the energizing roller 116, the movement of the electrode positioning guides 117, 118, and their opening/closing operations,
The opening and closing operations of the divided machining fluid jet nozzle 129, the operations of the electrode transport device 128 and the electrode return device 119, etc. are controlled to be performed in a predetermined order according to a program built into the numerical control device. be.

In the above explanation, the wire electrode 104 before starting processing is transferred from the electrode supply drum 105 to the guide rollers 106 to 111 as shown in FIG.
It is assumed that the wire electrode is stretched so that it is immediately collected from now on to the electrode winding drum 127 via the capstan 121 and guide rollers 124 to 126. In such a case, the guide roller 111 and brake roller 11
If one end of the cut wire electrode remaining on the downstream side of point 3 is held by an appropriate electrode capturing mechanism and guided between the capstan 121 and the pinch roller 123, the wire electrode will return to the first point. Since the wire electrode is stretched as shown in the figure, the electrode conveying device 128 and the like are operated in the same manner as described above to reciprocate the wire electrode between the first arm and the second arm. It can be strung up.

Thus, the wire electrode 1 is stretched in a manner that it reciprocates between the first and second arms or processing heads.
04 will be described with reference to FIG. 7. The figure shows a wire electrode 104a (outgoing electrode) that is made to run from the first arm or processing head to the second arm or processing head. , the wire electrode 10 is folded back at the second arm or processing head and returned to the first arm or processing head.
4b (return side electrode) are shown in a state in which the workpiece 138 is being machined in a state where they are sufficiently close to or in contact with each other. In this case, processing is carried out so that the wire electrode 104b returning from the second arm or processing head to the first arm or processing head is on the front side in the direction of processing progress. In such a case, wire electrode 1
Since a relatively wide machining gap 140, 140 is formed between 04a and 104b and the workpiece 138, the machining fluid flows smoothly through this gap, thereby enhancing the cooling effect and passing a large current to the wire electrode. Therefore, processing can be performed more efficiently. Furthermore, the surface of the wire electrode becomes rough as it passes through the machining part twice, but as mentioned above, the wire returns from the second arm or machining head to the first arm or machining head. electrode 104
If machining is performed with the wire electrode 104b facing forward in the direction of machining progress, the initial rough machining is performed using the wire electrode 104b with a rough surface, and then the wire electrode 104a with a non-rough surface performs the machining. As a result, finishing machining is performed, and machining with a good finish can be efficiently performed.

Furthermore, as shown in FIG. 8, for example, if the reciprocating wire electrodes 104a and 104b are arranged substantially perpendicular to the machining progress direction, a relatively wide machining gap 141 can be created in the front of the machining progress direction. is formed, so the cooling effect is increased in this case as well, and efficient processing can be performed using a large current.

〔Effect of the invention〕

Since the present invention is configured as described above, in accordance with the present invention, the machining fluid flows through a relatively wide machining gap formed between the two wire electrodes and the workpiece, so that the flow of the machining fluid is prevented. This improves the cooling effect and improves machining efficiency.If the two wire electrodes are run sufficiently close to each other or in contact with each other, the overall strength of the wire electrodes increases and the discharge pressure is reduced. Deflection of the electrode is also eliminated, allowing high-precision machining. Further, by appropriately setting the arrangement of the two reciprocating wire electrodes with respect to the direction of machining progress, rough machining and finishing machining can be performed simultaneously and efficiently. Furthermore, when the wire electrode is routed at the start of machining or when cutting the wire electrode, the first
The middle part of the wire electrode, which has already been connected from the electrode supply device to the recovery device in the arm or processing head, is grasped by the electrode transfer device and hooked onto the electrode return device of the second arm, and the wire electrode is transferred to the processing section. Since the work of stretching the electrodes is completed, the work can be done automatically and easily.

Note that the configuration of the present invention is not limited to the above-mentioned embodiments. That is, for example, the electrode transport device 12
8 does not necessarily have to be of a telescoping type, and may be one that simply raises and lowers a single rod. It is recommended that the machining fluid jetting nozzle 129 is also attached not only to the first arm or machining head but also to the second arm or machining head. The electrode return device 119 may have any form as long as it is configured so that the wire electrode 104 can be folded back on the second arm or processing head side and returned to the first arm or processing head side. . For example, the electrode folding roller 114
is fixed to the electrode return device 119 from beginning to end, and the most advanced rod 12 of the electrode transfer device 128 is
The wire electrode hooked to 8a or the rod 12
The wire electrode 8a can be configured to be a long and thin pipe and the wire electrode that is folded back into and out of the pipe is hooked on the fixed folding roller 114, and the guides 117 and 118 are boat-shaped or open-close type that can be opened and closed in close proximity. It may be a dice-shaped guide. Furthermore, in the above embodiment, used wire electrodes are collected in the electrode winding drum 127, but they may be disposed of directly in a collection box.
Accordingly, the present invention encompasses all modifications that may readily occur to those skilled in the art from the above description.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing step-by-step the wire electrode tensioning process in an embodiment of the wire cut electric discharge machining apparatus according to the present invention, and FIGS. 4 to 6 show the wire electrode tensioning process step by step. FIGS. 7 and 8 are explanatory diagrams of one embodiment showing stepwise the process of transferring the electrode by the electrode transport device provided on the second arm or processing head to the electrode return device provided on the second arm or processing head, and FIGS. 7 and 8 illustrate the present invention. FIG. 4 is an explanatory diagram showing different machining situations by the wire cut electrical discharge machining apparatus. 101...column, 102...first arm,
103...Second arm, 104...Wire electrode, 105...Wire electrode supply drum, 106-
112... Guide roller, 113... Brake roller, 114... Electrode folding roller, 115,1
16... Current roller, 117, 118... Electrode positioning guide, 119... Electrode return device, 119a
...Casing, 119b...Frame, 119c...
...Gear, 119d...Intermediate gear, 119e...Worm gear, 119f...Motor, 119g...
Electromagnet, 119h, 119h...roller suction plate,
119i...Electromagnet, 119j...Iron material, 12
0,121...Press roller, 122...Capstan, 123...Pinch roller, 124-126
... Guide roller, 127 ... Electrode winding drum, 128 ... Electrode transport device, 128a ... Cutting edge rod, 128b ... Electromagnet holder, 128c
...Electromagnet iron core, 128d...Electromagnet coil, 1
28e, 128e...Roller suction element, 129...
Divided machining fluid ejection nozzle, 130... Processing tank, 131... Stage, 132... Cross slide table, 137... Bed, 138... Workpiece, 139... Power supply device, 140, 141...
Machining gap.

Claims (1)

[Claims] 1. A first arm or processing head equipped with a wire electrode supply and recovery device and a wire electrode supplied from the first arm or processing head are folded back, and the two reciprocating wire electrodes are brought into contact with each other and moved in opposite directions. a second arm or processing head that is equipped with an electrode return device for running and returning the wire electrode to a recovery device provided in the first arm or processing head;
an electrode transport device that extends and hangs the electrode to the electrode return device of the arm or processing head; a device that holds the workpiece; and a device that reciprocates between the workpiece and the first and second arms or the processing head. a processing feed device that causes the wire electrodes to approach each other in close opposition to each other; a power supply device and a power feeding mechanism that apply voltage pulses for electrical discharge machining between the workpiece and the wire electrode; A wire cut electric discharge machining apparatus characterized in that it is equipped with a device for supplying machining fluid to a machining gap formed by the process.