JPS61236429A - Wire cut electric discharge machine - Google Patents

Abstract

PURPOSE:To perform stable machining with no generation of a wire break or the like while a wire is in machining, by performing the machining with two forward and return wire electrodes respectively being given optimum tension. CONSTITUTION:A wire electrode 4, being fed from a wire electrode supply drum 5 via a brake roller 9 and a power feed roller 10 and turned back by a guide roller 15 thereafter passing through a capstan 11 and a pinch roller 12, is collected to a wire electrode collecting drum 13. A speed of rotation of the guide roller 15 can be adequately controlled, and an electric discharge machine, further applying friction force in accordance with a turning motion of the guide roller 15 to the wire electrode 4 in a forward path during machining in addition to the tension applied by the brake roller 9 and the capstan 11, provides strong tension in said electrode 4 in the forward path, but the machine reduces tension, applied to the wire electrode 4 in a return path after the electrode 4 passes through a part of the guide roller 15, to be damped by the friction force given by the turning motion of the guide roller 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an improvement in a wire-cut electric discharge machining device that processes a single wire electrode by folding it back and using two wire electrodes.

[Conventional technology]

A first arm or processing head on the side that supplies and collects the wire electrode, and a wire electrode automatic folding device that guides the wire electrode supplied from the first arm or processing head side to the guide groove of the guide roller and folds it back. a second arm or a processing head provided with a guide roller; and a wire electrode is conveyed from the side of the first arm or processing head to the wire electrode automatic folding guide roller of the second arm or processing head and then hung there; an electrode conveyance device, a device for holding the workpiece, a processing feed device that causes the wire electrodes that reciprocate between the workpiece and the first and second arms or the processing heads to face each other adjacent to each other; A power supply device and a power supply device that apply voltage pulses for electrical discharge machining between the workpiece and the wire electrode, and a device that supplies machining fluid to a machining gap in which the workpiece and the wire electrode are closely opposed to each other, A wire-cut electric discharge machining apparatus has been proposed that performs machining using a wire electrode that reciprocates between first and second arms or a machining head.

In the above-mentioned wire-cut electric discharge machining apparatus, one wire electrode is folded back by the guide roller to form two wire electrodes, and machining is performed using these two wire electrodes. The machining gap formed by the workpiece is widened, and therefore a sufficient amount of machining liquid can be supplied to the machining gap, and the machining feed direction of the two wire electrodes can be changed. By controlling in relation to the direction of , it is possible to create a machining state in which finish machining is performed with the one of the two folded wire electrodes that has not been damaged by electric discharge, so a good finished surface can be obtained. It becomes like this.

Furthermore, when using the above-mentioned device, it is possible to perform not only normal machining where the cut end is perpendicular to the main plane of the workpiece, but also machining with a constant distance between two reciprocating wire electrodes, or machining of the workpiece. Since the two reciprocating wire electrodes can be made to intersect at a certain point, even complex cross-sectional shapes can be processed relatively easily and in a short time.

However, the wire electrode has the property that it becomes soft due to discharge and its tensile strength also decreases. Although this hardness is recovered by the plastic working that the wire electrode undergoes when it is folded back by each roller, the tensile strength tends to further decrease.

Therefore, even in the wire-cut electric discharge machining apparatus that performs machining using the two reciprocating wire electrodes, it is necessary to apply high tension to the wire electrodes and stretch the wire electrodes in a straight line. Tension was applied by a common tensioning device on the return trip, but the wire electrode on the return trip not only had many scratches due to discharge, but also the material had deteriorated, and the wire was folded back by the guide roller. As a result, the overall strength has decreased and the wire has become brittle, which may cause wire breakage on the return trip, so it is necessary to interrupt processing each time and feed the wire electrode along a predetermined electrode supply path. There was a problem. Therefore, when moving and feeding the wire electrode, it is necessary to change the tension applied to the wire electrode during the forward and return trips.

[Problems to be solved by the present invention]

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to fold back one wire electrode to make two reciprocating wires, and to perform wire cut discharge for machining using these two wire electrodes. In the processing equipment, processing is performed while applying the optimum tension to each of the two reciprocating wire electrodes, independently of the other wire electrode, and stable processing is performed over a long period of time without the occurrence of processing interruption lines, etc. The present invention is intended to provide a wire-cut electrical discharge machining apparatus that can obtain the desired results.

[Means for solving problems]

The above purpose is to fold back one wire electrode to make two reciprocating wires, and in a wire-cut electrical discharge machining device that performs machining using these two wire electrodes, to This is achieved by providing a device capable of applying an optimum tension to each of the wire electrodes independently of the other.

[For production]

With the above configuration, processing can be performed while applying the optimum tension to each of the two reciprocating wire electrodes, independently of the other wire electrode, so that processing interruption lines, etc., do not occur. It is possible to perform stable processing over a long period of time.

〔Example〕

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

FIG. 1 is an explanatory diagram showing one embodiment of a wire-cut electric discharge machining apparatus according to the present invention, and FIG. 2 is an enlarged explanatory diagram of a wire electrode return device portion of the apparatus having a capstan function.

In FIGS. 1 and 2, 1 is a part of the wire-cut electric discharge machining apparatus according to the present invention, in which one wire electrode is folded back to form two reciprocating wires, and machining is performed using these two wire electrodes. 3 is a first arm or processing head, and 3 is a second arm or processing head, which are attached to a column or the like erected on the main body (bed) of the processing machine or on the side thereof. 4
is a wire electrode, 5 is the first arm or processing 7 do 2
Wire electrode supply drum provided on the side, 6.6 and 7 are guide rollers, 8 is a pinch roller, 9 is a brake roller, 10 is a power supply roller, 11 is a capstan, 12 is a pinch roller, 13 is a wire electrode recovery drum , 14 is a wire electrode automatic folding guide roller with a tension adjustment function, which is composed of a guide roller 15 and a motor 16 that rotates the guide roller 15, 15a is a wire electrode guide groove of the guide roller 15, and 15b is the wire electrode. a spiral wire electrode introduction groove connected to the electrode guide groove 152; 15c is a cylindrical portion of the guide roller 15; 15d is a tip end of the guide roller 15;
16a is a shaft of the motor 16; 17 is a slide table for moving the motor 16 in a direction perpendicular to the wire electrode 4; 18 is a base on which the slide table 17 is mounted; 19 is a slide table mounted on the slide table 17; 20 is a motor for moving the slide table 17; 20a is a shaft of the motor 20; 21 is a feed screw; 22 is an extrusion bar; Reference numeral 23a denotes a pore for a machining start hole formed in advance in the path of the workpiece.

Note that the guide roller 6.6 and the power supply roller 1 facing each other
0 and the guide rollers 7 facing each other can move in the left and right directions in the figure, and can maintain a certain distance between the two wire electrodes 4 that have been folded back. 4 can be held in close contact with each other.

The first arm or processing head 2 side of the wire-cut electric discharge machining apparatus 1 includes a wire electrode supply drum 5, a pinch roller 8, a brake roller 9, a power supply roller 10, a guide roller 7, a capstan 11, and a pinch roller. A roller 12, a wire electrode collection drum 13, etc. are built-in, and
A guide roller 6 is provided on the second arm or processing head 3 side.
．． 6 and a wire electrode automatic folding guide roller 14 equipped with a tension adjustment function.

The extrusion bar 22 is supported so as to be movable in the vertical direction, and the portion of the extrusion bar 22 that contacts the wire electrode 4 is formed in a semicircular shape.

Thus, before the start of processing, the extrusion bar 22 is pulled upward, and the extrusion bar 22 can pass between the guide roller 7 and the power supply roller 10 and between the guide rollers 6 and 6, respectively. A certain distance is maintained. The pinch roller 8 is also spaced apart from the brake roller 9 by a certain distance.

When the wire electrode 4 pulled out from the wire electrode supply drum 5 is wound around the wire electrode collection drum 13 from the brake roller 9 through the capstan 11 and the pinch roller 12, the extrusion bar 22 moves downward. The wire electrode 4 is pushed down to the position of the guide roller 15 of the wire electrode automatic folding guide roller 14 equipped with a tension joint function.

That is, the extrusion bar 22 extends from between the guide roller 7 and the power supply roller 10 to the processing start hole 23a of the workpiece path.
The wire electrode 4 passes between the guide rollers 6 and 6.
It pushes down downward.

Thus, the semicircular portion of the extrusion bar 22 is
When reaching the position opposite to the outer peripheral surface of the cylindrical portion 15c of the guide roller 15, the downward movement of the extrusion bar 22 is stopped, and then the extrusion bar 22 is slightly pulled upward, and the extrusion bar 22 is pulled up slightly. A ring of wire electrode 4 is formed at the tip of 22 .

At the same time, slide table 1 equipped with motor 16
7 begins to move toward the extrusion bar 22, and at the same time, the motor 16 rotates and the guide roller 15 begins to rotate.

The guide roller 15 is a cylindrical portion 15 in which a wire electrode guide groove 15a is provided along the intersection line between the outer peripheral surface and one plane perpendicular to the axis.
C, and the cylindrical portion 15C is integrally provided adjacent to the cylindrical portion 15C, and the wire electrode guide groove 15a is formed from the top on the outer peripheral surface of the cylindrical portion 15C.
It is formed of a conical part and a tip part 15d provided with a spiral wire electrode introduction groove 15b that continues into the conical part.

Thus, the tip portion 15d of the guide roller 15 enters the ring of the wire electrode 4 formed at the tip portion of the extrusion bar 22, and the wire electrode 4 is inserted into the loop of the wire electrode 4 formed at the tip portion of the extrusion bar 22.
As the guide roller 15 moves in two directions and rotates, the wire electrode guide groove 15b is formed in the guide roller 15, and further passes through the wire electrode guide groove 15b to the wire electrode guide groove 15a. be guided.

The wire electrode 4 is connected to the wire electrode guide groove 15 of the guide roller 15
When wrapped around a, the extrusion bar n is pulled upward, and the lifting operation of the extrusion bar 22 is completed.

In the case of normal processing, the guide roller 7, the power supply roller 1O, and the guide roller 6.6 each move toward the wire electrode 4, and the wire electrode 4, which is folded back into two by the guide roller 15, is moved toward the wire electrode 4. are placed close to each other or in close contact with each other at a predetermined minute interval. That is, the wire electrode 4 passes from the wire electrode supply drum 5 through the guide roller 7 and the power supply roller 10, passes from the workpiece arm through the guide roller 6 provided on the second arm or the processing head 3 side, and then passes through the guide roller 15. After being folded back and wrapped around the guide groove 15a, it passes from the guide roller 6 through the workpiece guide, the guide roller 7, the capstan 11, and the pinch roller 12, and is installed on the first arm or processing head 2 side. The collected wire electrodes are collected in the collecting drum 13.

In this kind of conventional wire-cut electrical discharge machining apparatus, the wire electrode 4, which is made up of two reciprocating wires, is moved and fed at a constant speed, and the power supply roller 10 is powered from a power supply device (not shown). A machining voltage pulse is applied to the wire electrode 4 and the workpiece through the wire electrode 4 to perform wire cut electric discharge machining.

Of the two wire electrodes 4 that are reciprocating, the wire electrode 4 on the outward path becomes less hard due to electric discharge, and the guide roller 1
5, the hardness increases. On the other hand, the surface of the wire electrode 4 on the return trip is damaged by the discharge during the return trip, and the hardness decreases due to the discharge again on the return trip, making the wire electrode 4 as a whole brittle. Therefore, it is necessary to apply appropriate tension to each of the wire electrode 4 on the outbound trip and the wire electrode 4 on the return trip.

However, in the conventional device, the guide roller 15 during processing
Since the wire electrode 4 was not specially driven and could be rotated lightly, a constant tension was always applied to the wire electrode 4 as a whole by the brake roller 9 and the capstan 11, and in this state. The wire electrode 4 was moved and fed. Therefore, depending on the shape of the wire to be processed, the wire electrode 4 often breaks during processing.

On the other hand, in the wire cant electrical discharge machining apparatus according to the present invention, during machining, the wire electrode 4 is moved and fed while applying different tensions to the wire electrode 4 in the forward and backward passes, thereby performing wire cut electrical discharge machining. In order to do this, the rotation of the guide roller 15 is appropriately controlled to increase the tension of the wire electrode 4 on the outward journey and to lower the tension on the wire electrode 4 on the return journey.

Therefore, during processing, the wire electrode 4 on the forward path is subjected to strong tension due to the frictional force caused by the rotation of the guide roller 15 being added to the tension applied by the brake roller 9 and capstan 11. The tension applied to the wire electrode 4 on the return path after passing through the section is reduced by the amount of frictional force exerted by the rotation of the guide roller 15.

Looking at it from another perspective, stronger tension is applied to the wire electrode 4 on the outward journey by the pinch roller 8, brake roller 9, and guide roller 15, and a slightly weaker tension is applied to the wire electrode 4 on the return journey by the guide roller 15, capstan 11, and pinch roller 12. It provides tension.

〔Effect of the invention〕

Since the present invention is constructed as described above, processing can be performed while applying the optimum tension to the two reciprocating wire electrodes, independently of that of the other, and the wire electrodes do not break during processing. Therefore, stable normal machining and finishing machining can be performed at the same time over a long period of time.

Note that the present invention is not limited to the embodiments described above. That is, for example, in this embodiment, one wire electrode automatic folding guide roller equipped with a tension adjustment function is provided, but a tension adjustment function consisting of a plurality of guide rollers with guide grooves of different diameters and a motor is provided. a wire electrode automatic folding guide roller is attached to a rotary plate, and the rotary plate is rotated by a motor to select a desired guide roller;
Alternatively, a pinch roller may be further provided to press the wire electrode against the wire electrode automatic folding guide roller. Further, other known methods can be used to apply tension to the wire electrode. Further, although the guide roller 7, the power supply roller 10, and the guide roller 6.6 are used to guide the wire electrode, a known guide die, a boat-shaped guide, or the like may be used in place of these. In addition, the shape of the guide roller, the control method of each part, etc. can be freely changed within the scope of the purpose of the present invention, and the present invention encompasses all of them.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing one embodiment of a wire cant electric discharge machining apparatus according to the present invention, and FIG. 2 is an enlarged explanatory view of a portion of the wire electrode return device having a capsun function of the apparatus. 1------------1----
1------First arm or processing hand 3-
・-----・-----
-11--------Wire electrode 5--------
−・−・・−−−1−−−Wire electrode supply drum 6.6
．． 7--------・--Guide roller 8.12-
・・−・・−１−−・・−〜−−Pinch roller 9−・−
---1.------・−−−−−1−−−・−・・Capstan 13−−−−−−・−−1−−−−−・−−
1-----Wire electrode collection drum 14, 1.----1--Wire automatic folding guide roller with tension adjustment function

Claims (1)

[Claims] A first arm or processing head on the side that supplies and collects the wire electrode, and a wire electrode supplied from the first arm or processing head side that guides the wire electrode to the guide groove of the guide roller. a second arm or processing head having a wire electrode automatic folding guide roller for folding the wire electrode, and a wire electrode automatic folding guide roller of the second arm or processing head for folding the wire electrode from the side of the first arm or processing head; A process in which an electrode transport device that transports and hangs the workpiece, a device that holds the workpiece, and a wire electrode that reciprocates between the workpiece and the first and second arms or processing heads are placed adjacent to each other and face each other. A feeding device, a power supply device and a power supply device that apply voltage pulses for electrical discharge machining between the workpiece and the wire electrode, and supplying machining fluid to a machining gap in which the workpiece and the wire electrode are closely opposed to each other. In a wire-cut electric discharge machining device that performs machining using a wire electrode that reciprocates between a first and second arm or a machining head, the two reciprocating wire electrodes are connected to each other. The wire-cut electric discharge machining apparatus described above is characterized in that it is provided with a device that can apply tension independently.