JPH0335048B2 - - Google Patents

Description

[Detailed Description of the Invention] A wire cut electric discharge machining device using a wire electrode winds the wire electrode while pulling it from one reel to the other reel, and then winds the wire electrode from a direction approximately perpendicular to the axis of the wire electrode, which is updated and moved in the axial direction. A method of forming a discharge machining gap by placing the workpieces facing each other, supplying a machining fluid such as water or oil to this gap, and repeatedly supplying intermittent voltage pulses to generate a discharge pulse, and repeating this discharge. The workpiece is machined by the wire electrode or the workpiece, and cutting and punching of various shapes can be performed by applying machining feed such as a relatively predetermined contour shape to the wire electrode or the workpiece on the plane in the perpendicular direction. It is possible. The wire electrode used usually has a wire diameter of 0.05~
A thin wire of approximately 0.5 mmφ is used, and in addition to applying sufficient tension in the axial direction, it is moved in the axial direction while facing the workpiece with a minute gap, so the applied part is a narrow slit and is constantly kept in a minute position. will be maintained.

On the other hand, the machining liquid supplied to this machining part is usually poured from a nozzle provided on the side of the machining part wire electrode toward the machining part, so that sufficient liquid is supplied to the gap. There was a fear that it would not be possible to supply the The action of this machining fluid is to act as a medium for electrical discharge, as well as to cool and clean the machining part, and to remove machining debris from the outside.If this fluid is sufficiently supplied to the gap and does not flow, the machining fluid will close to the gap. Because it is filled with gaseous media such as decomposed gas, steam, and air, it is easy to cause discharge in the gas and cause arc discharge, and short circuits may occur, making it impossible to perform stable discharge machining and machining current cannot be increased. As a result, an increase in machining speed and an improvement in machining accuracy cannot be expected.

For this reason, the machining fluid jetting nozzle may be of a coaxial machining fluid jetting nozzle type that surrounds a wire electrode and sprays machining fluid coaxially, as described in JP-A-50-54538, for example. For example, a nozzle system as described in Japanese Utility Model Application Publication No. 54-167496, in which the coaxial nozzle is a narrow nozzle for high-velocity jetting, and a low-speed jetting nozzle is provided coaxially with the nozzle to prevent gas from being sucked into the surrounding area. Various methods have been proposed, such as the method described in JP-A-47-20797, in which the object to be processed, and therefore the processing part, is immersed in a processing liquid and further sprayed from a nozzle. However, the reality is that there is still nothing that is completely satisfying.

However, when considering the cause of this problem, in general, when the workpiece is relatively thin (less than a few tens of millimeters thick), or when the workpiece is moderately thick, the setting of the machining current (discharge repetition frequency ) and maintaining machining accuracy, high efficiency machining is possible with almost no problems with machining performance such as machining speed, but when the thickness of the workpiece exceeds several tens of mm, various problems arise. Various slightly different machining conditions occur depending on the machining condition settings, and conventional machining liquid jet nozzles such as those mentioned above cannot adequately handle the situation. In addition, there are problems in terms of machining accuracy, and machining accuracy tends to deteriorate due to abnormal discharge such as arc discharge, as well as As shown in Figure 3, the contour shape of the machined surface in the machining feed direction is circular and convex, making it difficult to achieve machining accuracy, especially at corners and corners with a small radius of curvature.
Furthermore, when attempting to improve the processing speed, problems such as an increase in wire electrode breakage accidents occurred.

In view of the above-mentioned problems, the present invention enables high precision and high speed machining by supplying sufficient machining liquid to the machining gap, and in particular prevents the contour shape of the machining surface from becoming circular convex. The machining fluid spouting nozzle device for wire cut electric discharge machining of the present invention was invented with the aim of enabling highly accurate machining. a nozzle having an elongated ejection opening opening in a uniaxial direction and configured such that the elongated ejection opening is movable in position on the plane; and a relative relationship between the wire electrode and the workpiece. a detection device for detecting a machining feed advancing direction; The present invention is characterized by comprising a control device that controls the movement of the elongated ejection opening based on the output signal of the detection device so that it is always located at the leading edge side end in the feeding direction. A detailed explanation will be given below based on the drawings.

FIG. 1 is a front explanatory view showing a schematic configuration of the mechanical parts of a conventional wire-cut electrical discharge machining device, in which 1 is a bed, 2 is an X-Y cross slider placed on the bed 1, and 3 and 4 are cross sliders. 2 is a drive motor for each of the axially movable sliders 2A and 2B; 5 is a machining fluid receiver; 6 is a supporting machining table for a workpiece 7 which is connected to the cross slider 2; 8 is one end on the bed 1; A column set up on the side of the department,
9 and 10 are upper and lower arms that are vertically spaced apart and extend parallel to each other in the horizontal direction from the column 8 so that their tips correspond to the processing table 6; A processing head 12 and 13 is provided so as to be movable up and down relative to the upper arm 9, and wire electrode guides 14 are provided vertically opposite to each other in the processing head 11 of the upper arm 9 and the lower arm 10. A storage drum for the wire electrode 15, 16 a winding drum for the wire electrode,
Reference numeral 17 denotes a pull-out device equipped with a cab stan and a pinch roller for pulling out and running the wire electrode 15;
Reference numeral 8 denotes a tension applying device consisting of a brake drum and a pinch roller that applies a brake to the drawing out of the wire electrode 15 and applies tension; 19 and 20 refer to guides 12 and 20 provided on the processing head 11 and the lower arm 10; 13, as shown in the figure, the same or different diameters are provided on the processing head 11 and the lower arm 10 so as to enclose the guides 12 and 13, respectively, and to penetrate coaxially with the wire electrode 15. The machining fluid injection nozzles 21 and 22 are supplied with the same or different predetermined flow rates from a machining fluid supply device (not shown) to the nozzles 19 and 20, respectively.
Processing fluid pipe supplying pressure processing fluid, arrow 23
is the machining feed direction of the workpiece 7 with respect to the wire electrode 15, 7A is one cut surface of the machining groove of the workpiece 7 corresponding to the machining feed direction 23, and 7B is the contour of the machining surface in the machining feed direction 23. This is what is shown.

The elongated ejection openings 19A and 20A of the machining liquid injection nozzles 19 and 20 are circular, as shown in the front view in FIG. It is injected along the line of the wire electrode 15 into the machining gap with the workpiece 7 and into the already machined groove which is usually on the opposite side of the machining gap.

Note that there are various cases in which one or both of the machining liquid injection nozzles 19 and 20 are provided, and when both are provided, the respective machining liquid injection pressures may be the same or different (usually the nozzle 20 side is high pressure).

Therefore, the tension applied to the wire electrode 15,
It also changes depending on the machining feed rate set in accordance with the electric discharge machining voltage pulse conditions, but if the machining feed rate is not set to a value sufficiently slower than the machining speed due to a special purpose etc., the workpiece 7 The plate thickness is several 10
When the thickness becomes thicker than mm, as shown in FIGS. 1 and 3, the cross-sectional contour line 7B of the machining surface or machining gap surface of the workpiece 7 has a convex circular arc shape in the direction of machining feed. The portion of the wire electrode 15 corresponding to this is also renewedly moved in a curved state due to machining gap pressure such as discharge pressure.

Depending on the condition of the processed parts, the elongated ejection openings 19A and 2 of the nozzles 19 and 20
The machining fluid spouted coaxially from 0A along the wire electrode 15 is also influenced by the contour 7B of the machining gap, and within the machining fluid groove, as shown by arrows 19B and 20B, the machining fluid has already been machined on the opposite side of the machining gap. Therefore, in the case shown in the figure, the jet flow is directed towards the direction of the machined groove, and therefore, in the case shown in the figure, the jet flow from the upper nozzle 19 and the lower nozzle 20 is approximately 1/2 of the thickness of the workpiece 7, and normally the jet flow from the upper nozzle 19 and the lower nozzle 20 is In the machining gap and the machining groove of the body 7, stagnation may occur in the flow of the machining fluid before and after the collision and equilibrium portion, but cavitation occurs, and the machining fluid is not sufficiently supplied or refreshed. In any case, the machining action at the front and back portions (in the axial direction of the wire electrode 15) of the portion where the cavitation action etc. occurs is not smooth and is obstructed, and accidents such as disconnection of the wire electrode may also occur due to the occurrence of aerial discharge, etc. It becomes like this. Furthermore, since the profile of the machined surface in the processing feed direction becomes an arcuate convex shape, the processing accuracy deteriorates particularly at corners and curved portions with a small radius of curvature. The occurrence and effects of such phenomena could not be prevented by the conventional machining liquid spray nozzle as described above.

4A, B, C, D and E show different embodiments of the elongated ejection openings 19A and 20A of the machining liquid injection nozzles 19 and 20 according to the present invention; FIG. Square spout opening 19A (20
When A) is configured in the form of a slit or an elongated ellipse, Figure B shows the ejection opening 19A (20A)
In the figure, the opening area of the jet opening is gradually decreased from the coaxial circular jet opening 19a (20a) around the wire electrode 15 with respect to the relative machining feed direction 23A between the wire electrode 15 and the workpiece 7. In the case where a narrow slit-shaped injection port 19c (20c) is provided continuously to a coaxial circular injection port 19a (20a) around a continuous throttle injection port 19b (20b), Fig. D shows the coaxial circular injection port 19b (20b). Injection port 19a (2
When the nozzle injection ports 19d (20d) whose opening diameters become smaller in sequence are arranged in the above-mentioned direction integrally in 0a), and in Fig. E, the nozzle injection ports 19d (20d) in Fig. D are arranged in the coaxial circular shape. Injection port 19
This figure shows a configuration in which the nozzles 19e (20e) are formed as independent nozzle injection ports 19e (20e) separately from the nozzles 19a (20a).

Such a long ejection opening 19A (20A)
According to the machining liquid injection nozzles 19 and 20 having the following, the longitudinal axis of the elongated ejection opening 19A (20A) is made to coincide with the machining feed direction 23A,
In addition, the penetrating portion of the wire electrode 15 is located on one end side in the longitudinal direction, and the one end side is located on the tip side of the processing feed, that is, the wire electrode 1
5 is always located at the front edge side end of the elongated ejection opening 19A (20A) in the processing feed direction, so that the ejection port 1 around the wire electrode 15
Nozzle ports 19b (20b) and 19C that are narrower or have a smaller diameter than 9a (20a)
(20C), 19d (20d), and 19e (20e)
is opposed to the already machined groove portion of the workpiece 7, and the machining fluid supply source for all the injection ports is the same or the supplied processing fluid is appropriately branched and supplied to each injection port. Then, the injection port 19a (20a)
The injection port 19b (20
b), 19C (20C), 19d (20d), 19e
(20e), especially injection ports 19d (20d) and 19
e (20e), the injection flow velocity is high, and the injection openings 19b (20b) and 19C (20C) also have aperture widths that allow the injection to smoothly flow into the machined groove and lose energy. Also, in the case of the configurations shown in figures A, B, and C, the injection ports 19a (20a) around the wire electrode 15 and the injection ports 19b (20b), 19C in other parts can be made stronger.
(20C) and the injection port 19b by providing a partition wall etc. as appropriate.
(20b), 19C (20C) side can be increased, and preferably, the flow rate or pressure on the side of injection port 19b (20b), 19C (20C) can be configured to be appropriately narrowed into a slit shape. ,19
When the machining fluid jet flow 19X (20X) from d (20d), 19e (20e), etc. flows into the already machined machining groove 7A effectively as shown in FIG. 5, the machining around the wire electrode 15 is completed. Liquid jet flow 19a
(20a) is difficult to escape to the already machined groove 7A side, and the wire electrode 15 is pressed against the machined surface, and the wire electrode 15 either maintains a straight line in the direction in which tension is applied or is forced to become straight. As a result, the phenomenon in which the contour shape of the machined surface in the machining feed direction becomes circularly convex is eliminated or reduced, and the contour shape of the machined surface becomes linear. Deterioration of processing accuracy can be prevented.

Such operation by the nozzle equipped with the elongated ejection opening 19A (20A) is performed by the nozzle 19.
and 20 are provided, or when both nozzles 19 and 20 are provided and the machining liquid injection pressures of both nozzles are different, for example, the injection machining liquid from the lower nozzle 20 is applied to the wire electrode including the machining gap. 15 and in the processed groove 7A, the workpiece 7
The situation is substantially the same even when the air is blown up close to the upper surface of the workpiece 7 and the upper nozzle 19 is injecting enough to prevent the airflow from reaching the upper surface of the workpiece 7. The linearity of the wire electrode 15 in the processing portion opposite to the wire electrode 7 is improved, the processing accuracy is easily increased, and disconnection accidents of the wire electrode 15 can be suppressed to a minimum.

FIG. 6 shows, for example, that a machining liquid jet nozzle 19 having a configuration as shown in FIG. This is an explanatory cross-sectional view of a portion of an embodiment of the present invention in which the operation is performed by rotating the nozzle 19 itself, and the lower nozzle 20 is omitted. In the figure, 24 connects the nozzle 19 to the head 11.
12A is an upper electrode guide, which in this case is a die guide, and the axis of the die guide hole in the nozzle 19 is aligned with the rotation axis of the nozzle 19. Although the guide 12A is attached to a fixed portion such as the head 11, the guide 12A may be attached to a fixed portion such as the head 11. 19L is a machining liquid reservoir pocket connected to the machining liquid spout ports 19a and 19C of the nozzle, and a predetermined machining liquid is supplied through the machining liquid supply hole 19M and the flexible pipe 25 at a predetermined liquid pressure and flow rate. 19N is a rotating gear provided on the outer periphery of the nozzle 19, 26 is a spur gear attached to the head 11 by a rotating shaft 27 and meshes with the gear 19N, 28 is a pulley attached to the shaft 27, and 29 is a rotating gear. A servo motor, 30 is a pulley attached to its rotating shaft, 31 is a belt connecting the pulley 30 to the pulley 28, 32 is a rotary encoder, 32A is a code plate, 3
2B is a code reading head; 33 is a feedback circuit that returns the read signal to the numerical control device 34 to control rotational operation; and 35 is the axis (X) supplied from the numerical control device 34 to the processing table motors 3 and 4. , Y) direction and detects the feed command signal output of a predetermined contour shape in the machining feed direction 2.
3 (23A), the nozzle 19 is rotated by the motor 29, and the ejection opening shape of the nozzle 19 is rotated in the long axis direction and the progress direction 23 of the machining feed.
(23A) is an arithmetic detection device that matches 3
6 is a servo amplifier for the motor 29.

FIG. 7 shows another embodiment in which the elongated ejection orifice is moved, and the nozzle ejection orifice 19 around the wire electrode 15 is moved.
The injection ports 19d of D or E in FIG.
(20d) or 19e (20e) in total, usually fixed in one piece, that is, the nozzle 19 itself is not rotated as in the embodiment shown in FIG. 6, but the eight nozzles are provided. 19 _o-1 , 19 _o-2 ...
..., 19 _o-8 each on and off solenoid valve 37 _-1 ,
_37-2 ... _37-8 to move the elongated ejection opening substantially in the same manner as when the nozzle 19 in FIG. 6 is rotated. 35A is a switching control device that switches the valves _37-1 , _37-2 , ... _37-8 on and off based on the calculation result of the calculation detection device 35; 37 is the injection port 1;
A valve 9a (20a) controls the supply of machining liquid to the nozzle, and P is a machining liquid supply pump. According to the embodiment shown in FIG. 7, the elongated ejection opening moves in increments of 45 degrees, but if necessary, the nozzle _19o can be divided into a larger number of equal parts, such as _19oo . Not only can the angle be 30 degrees, 22.5 degrees, or even 15 degrees, but the entire angle can be within a predetermined angle range of 360 degrees or less around the axis of the wire electrode 15, for example, 360 degrees can be 720 degrees, 1080 degrees, or 2000 more
It is possible to perform control movement divided into a large number of parts, so as to perform more finely adaptive switching control.

Further, in the embodiment shown in FIG. 6, a case has been described in which the rotation control of the nozzle 19 is performed by detecting the contour machining feed control signal outputted from the numerical control device 34, but the numerical control device 34 The control may be configured to be controlled by the recording tape recording signal at 34 or the reading signal of the MDI input storage signal, or the feedback of the input signals of the motors 3 and 4 and the operation results of the motors 3 and 4 to the numerical control device 34. It can also be configured to detect and control based on signals X', Y', etc.

In carrying out the present invention as described above, the wire electrode 1
If there is a possibility that the surrounding air may be drawn in as bubbles and mixed in with the injection of machining liquid into the machining groove, or even into the processed groove, adjust the aperture, formation, arrangement, etc. of each nozzle injection opening. Therefore, if necessary, it is preferable to prevent this by forming and positioning the elongated ejection opening of the present invention in a machining liquid injection nozzle opening with a large opening diameter, or by immersing the ejection opening in the machining liquid. It is possible to apply it or make various changes.

As described above, according to the machining fluid jetting nozzle of the present invention, sufficient machining fluid is supplied to the machining gap.
It not only improves the machining accuracy of wire cut electric discharge machining, but also improves the machining speed and reduces wire electrode breakage accidents. Since it is possible to prevent the shape from becoming an arcuate convex shape, it has an excellent effect of improving the machining accuracy particularly at corners and curved parts.

[Brief explanation of drawings]

Fig. 1 is a front view showing the schematic configuration of the mechanical part of a conventional wire-cut electric discharge machine, Fig. 2 is a front view of the same machining fluid injection nozzle, and Fig. 3 is a side cross-sectional explanatory view of the machining section in the machining feed direction. , Fig. 4 A, B, C, D, and E are front views of different embodiments of the injection opening of the processing liquid injection nozzle of the present invention, and Fig. 5 shows the machining feed direction of the processing part when the same processing liquid injection nozzle is used. Side cross-sectional diagram,
FIG. 6 is an enlarged cross-sectional configuration diagram for explaining a portion of a device equipped with a machining liquid spray nozzle according to an embodiment of the present invention, and FIG. 7 is a diagram for explaining another embodiment of the nozzle spray opening and nozzle rotation control. 15 is a wire electrode, 19 and 20 are machining fluid injection nozzles, and 23 and 23A are machining feed directions.

Claims (1)

[Scope of Claims] 1. While a wire electrode is renewedly moved in the axial direction between a pair of guides arranged at a distance, the workpiece is opposed to each other through a minute gap from a direction perpendicular to the axial direction of the wire electrode. and applying intermittent voltage pulses between the wire electrode and the workpiece while jetting and supplying machining fluid from a machining fluid jet nozzle disposed coaxially with the wire electrode into the gap, and repeatedly generating electric discharge; In wire cut electrical discharge machining in which machining is performed by applying a relative machining feed between the wire electrode and the workpiece on a plane perpendicular to the direction, an opening is formed on a plane perpendicular to the axial direction of the wire electrode. a nozzle having an elongated ejection opening in a uniaxial direction and configured such that the position of the elongated ejection opening on the plane is movable; and a sensor for detecting the advancing direction of the machining feed. The device is configured such that the longitudinal direction of the elongated ejection opening always substantially coincides with the processing feed advancing direction, and the wire electrode is always located at the leading edge side end of the elongated ejection opening in the processing feed advancing direction. A machining fluid spouting nozzle device for wire cut electric discharge machining, comprising a control device that controls movement of the elongated spouting opening according to an output signal of the detection device so that the elongated spouting opening is positioned. 2. Claim 1, wherein the elongated ejection opening is formed by an elliptical or slit-shaped opening, and the movement of the elongated ejection opening is performed by rotational movement of the nozzle itself. The machining fluid jetting nozzle device for wire cut electric discharge machining described above. 3. The elongated ejection opening is formed by a plurality of circular openings arranged in parallel in one axial direction, and the movement of the elongated ejection opening is performed by rotational movement of the nozzle itself. A machining fluid jetting nozzle device for wire cut electric discharge machining according to claim 1. 4. The elongated ejection opening is formed by a plurality of circular openings that are arranged in parallel in a uniaxial direction, and the nozzle connects the plurality of elongated ejection openings to each end of the circular opening. The elongated ejection openings are commonly used and are arranged radially in the same shape. A machining fluid spouting nozzle device for wire cut electrical discharge machining according to claim 1, which is performed by switching.