JPS6346196Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention cleans and removes air bubbles generated and retained between the current-carrying pin and the wire electrode, and applies the wire electrode from which air bubbles have been removed to the workpiece. The present invention relates to wire cut electric discharge machining equipment to be supplied.

[Conventional technology]

2. Description of the Related Art Conventionally, there is a wire cut electric discharge machining apparatus as shown in FIG. 1, for example. In this wire-cut electric discharge machining apparatus, a wire electrode 2 is unwound from a reel provided in a column or the like of the apparatus main body (not shown) via a brake roller or the like, extends downward via a guide roller 11 of an arm 1, and extends downward through a guide roller 11 of an arm 1.
A guide roller, a take-up roller, a column, etc. of an arm (not shown) provided opposite to the main body lead to the take-up reel or collection container of the main body. Therefore, the wire electrode 2 located between the guide rollers
Electrical discharge machining is performed by applying intermittent voltage pulses from a machining power supply 15 between the machine and the workpiece 3. In this wire cut electrical discharge machining apparatus, an arm 1 disposed above has an L-shaped support in cross section so as to be substantially orthogonal to the arm 1 and can be vertically moved and positioned by a manual handle or a motor 12. The upper part of member 13 is attached. Support member 1
A wear-resistant, usually cylindrical, current-carrying pin 4 made of cemented carbide or the like is attached to the lower cross section of the wire electrode 2 to apply voltage pulses from the machining power source 15 in contact with the wire electrode 2. The pin 4 is in contact with the wire electrode 2 in a substantially straight portion between the guide roller 11 and the workpiece 3. Reference numeral 4A denotes a guide pin or roller which is insulated as required for wear resistance and is fixed to the support member 13 by a support means (not shown), and the wire electrode 2 is pressed against the energizing pin A by the guide roller 4A. This ensures sliding movement in which the wire electrode 2 and the current-carrying pin 4 move while being in contact with each other. A hollow cylindrical nozzle body 5 is provided at the lower end of the support member 13, and its upper end and other appropriate parts are fixed in such a way that the position can be minutely adjusted as necessary. Openings 51 and 52 are formed in the upper and lower end surfaces of the nozzle body 5, and these openings 51 and 52 are formed approximately at the center axis of the nozzle body 5, and the guide roller 11 and the workpiece 3 are connected to each other. The wire electrodes 2 are arranged in such a positional relationship that the wire electrodes 2 are coaxially inserted therebetween.
Further, a guide holder 6 of an upper positioning guide 61 is coaxially inserted into the nozzle body 5, and a nozzle 7 is coaxially fitted into the opening 52 of the lower end surface so as to be movable in the axial direction. It is set up. The guide holder 6 is a cylindrical body having a hole 6a, and a die-shaped positioning guide 61 is attached to the lower end thereof, and the wire electrode 2 is positioned above the workpiece 3 by this guide 61. . This guide holder 6 is fixed to the nozzle body 5 so that its position can be minutely adjusted as necessary. Also nozzle 7
is arranged at the lower part of the nozzle body 5, is pivotally supported by the opening 52 at the lower end of the nozzle body 5, and is movable up and down according to the pressure and flow rate of the supplied machining fluid, the distance from the workpiece 3, etc. They are mated. The nozzle 7 is a hollow cylindrical body having a desired axial length, inner diameter, and axial inner diameter restriction, and the outer diameter of the end 71 of the flange located inside the nozzle body 5 is the same as that of the lower end of the nozzle body 5. is formed approximately equal to the inner diameter of the opening 52 of the
By fitting and abutting the end portion 71 on the inner wall of the opening 52, the nozzle 7 is prevented from falling off from the nozzle body 5. In addition, a hose 5 for supplying machining fluid under pressure is provided at an appropriate position on the upper side of the nozzle body 5.
3 is attached, and the machining fluid flows from here to the nozzle body 5.
It cools the positioning guide 61 inside, and is ejected from the lower nozzle 7 to the processing part of the workpiece 3, and is ejected upward from the upper opening 51 to cool the energizing pin 4 and the wire. A machining fluid is also supplied between the wire electrode 2 and the current-carrying pin 4 to cool the wire electrode 2 and the current-carrying pin 4. The workpiece 3 is fixed to a processing table 31, and the processing table 31 is moved by motors 32 and 33 to a predetermined contour shape on a plane perpendicular to the axis of the wire electrode 2 under the control of a numerical controller. It is now possible to move freely along the

Note that many of the configurations and members described above are provided not only above the workpiece 3 but also below the workpiece 3.
The explanation will be omitted since it is the same as the above explanation except that each member is arranged so as to be substantially symmetrical in the upper and lower directions with respect to the center.

[Problem that the invention attempts to solve]

Therefore, it goes without saying that the vicinity of the machining gap formed between the workpiece 3 and the workpiece 3 is exposed to high temperatures.
The wire electrode 2 between the pair of upper and lower current-carrying pins 4 is easily heated by electricity and reaches a high temperature, and in particular, the current-carrying pin 4 and the wire electrode 2 are in a state of sliding contact and movement, and in this state, energization does not occur. Therefore, as mentioned above, cooling is performed by supplying machining fluid.

However, there is a wedge-shaped minute gap 2 between the current-carrying pin 4 and the wire electrode 2 as shown in FIGS.
Where A and 2B are formed, the machining fluid supplied to these minute gaps 2A and 2B tends to stay there due to its surface tension.

When either the positive or negative voltage of the machining power source 15 is applied to the wire electrode 2 through the energizing pin 4, hydrogen or oxygen bubbles are generated in the cleaning liquid in the minute gaps 2A and 2B due to electrolysis, and the wire electrode 2
Since the current is applied while the and the current-carrying pin 4 are in sliding contact,
In the sliding gap, it is heated by electricity, vaporizes into water vapor, etc., and often stays in the minute gaps 2A and 2B as air bubbles 16. Since the micro gaps 2A and 2B are wedge-shaped and narrow, the air bubbles 16 that have once accumulated are effectively affected by the surface tension of the machining fluid, and the opening 5
It is difficult to release the bubbles 16 even with the injection processing liquid from the wire electrode 2 and the current-carrying pin 4, which increases the contact or current resistance between the wire electrode 2 and the current-carrying pin 4, increasing the amount of heat generated, and the heat generated between the wire electrode 2 and the current-carrying pin 4. Cooling becomes impossible, and the generation of bubbles 16 increases due to heat generation or abnormal discharge in the relevant portion, and the wire electrode 2 becomes disconnected at the abutting current-carrying pin 4 portion. In addition, the bubbles 16 are attracted to the wire electrode 2 and sent to the workpiece 3, causing problems in pulse discharge in the machining gap between the wire electrode 2 and the workpiece 3.

[Means for solving problems]

The wire-cut electrical discharge machining apparatus of the present invention solves this problem, and the wire-cutting electrical discharge machining apparatus is formed by a current-carrying pin 4 and a wire electrode 2 in a nozzle in which a spray nozzle for cleaning liquid, which may be a machining liquid, is provided facing the wire electrode 2. A cleaning nozzle 10A is provided for spraying cleaning liquid at a high pressure of 1 kg/cm ² or more into the wedge-shaped minute gap 2B to clean and remove air bubbles 16 generated and retained between the energizing pin 4 and the wire electrode 2. The wire electrode 2 from which air bubbles have been removed and the adsorption of air bubbles removed is supplied to the workpiece 3.

〔Example〕

Hereinafter, embodiments of this invention will be described in detail based on the drawings.

2 to 4 are explanatory diagrams showing the schematic configuration and effect of the first embodiment of the present invention. 2 is a wire electrode, and a conductive pin or conductive roller 4 for applying a voltage pulse from a machining power source 15 to the wire electrode 2 is attached to a bracket 13A formed at the bottom of a support member 13.
The conductive pin or roller 4 in this embodiment has a semicircular groove 4a in the center, and is fixedly supported or rotatably mounted on a shaft 4C fixed to the shaft 4C. Reference numeral 9 denotes one output terminal of a machining power source 15 for wire-cut electric discharge machining which is connected and fixed to the shaft 4C.
Due to the positional relationship between the guide 61 and the pin 4A, the wire electrode 2 moves downward while being in contact with the groove 4a, and is then collected by being wound up on a reel (not shown) below.
is a cleaning nozzle which is provided at the end of a pipe connected to a cleaning unit (not shown) and sprays the machining fluid as cleaning fluid. This cleaning nozzle has a pair of nozzles 10A, 10A which face upward from below and are inclined from the left and right rear to face a wedge-shaped tiny gap 2B formed between the wire electrode 2 and the conductive pin or conductive roller 4.

It is known that the cleaning liquid stays in such a wedge-shaped minute gap 2B due to the surface tension of the supplied cleaning liquid. When one of the positive and negative voltages of the machining power source 15 is applied to the current-carrying pin 4 in this state, bubbles 16 of hydrogen, oxygen, etc. are generated in the retained cleaning liquid due to electrolysis. In addition, since the bubble 16 is energized while the wire electrode 2 and the current-carrying pin 4 are sliding while being in relative contact with each other, the cleaning liquid that is heated by electricity in the sliding gap is not likely to vaporize into water vapor or the like. It also occurs due to In this way, the air bubbles 16 that are generated due to various reasons and once accumulated are difficult to escape because the gap 2B is wedge-shaped and narrow, and the surface tension of the machining fluid is effectively acting on them. The particles remain adsorbed to the workpiece 2 and are sent to the workpiece 3, causing problems with pulsed discharge in the machining gap. Therefore, the pressure pump in the cleaning unit (not shown)
Kg/cm ² or more, the processing fluid pressurized to a high pressure of about 1 to 3 Kg/cm ² is sprayed as a cleaning fluid from the nozzle 10A toward the minute gap 2B to remove air bubbles 16. be.

Further, the other nozzle 10B connects the wire electrode 2 to the energizing pin or roller 4 from the front upward from below.
is arranged so as to spray the cleaning liquid so as to press it against the surface of the These cleaning liquid nozzles 10A,
Nozzles 10B form a pair approximately symmetrically around the wire electrode 2, and these nozzles 10A and 10B allow a jet of cleaning liquid to spread over almost the entire surface of the wire electrode 2, sufficiently wetting it and removing other deposits, etc. Also removes.

Figure 5 shows that the equipment shown in Figures 3 and 4 has a 0.2
It is a characteristic curve diagram showing the relationship between the disconnection current value (A) and the cleaning liquid ejection pressure (Kg/cm ² ) when a wire electrode 2 of mmφ is used. In this graph, it appears that when the cleaning jet pressure of the cleaning liquid exceeds 1 kg/cm ² , bubble removal and wetting action from the gap 2B becomes sufficient, and the cooling effect on the wire electrode 2 becomes remarkable. There seems to be a limit to the cooling effect when it exceeds 3 kg/cm ² , and even if the air bubble removal, wetting effect, and foreign matter removal are sufficient, at 3 kg/cm ² or more,
It seems that the cooling effect is not proportional to the ejection pressure, and the
In the embodiment shown in FIG. 4, a pressure of about 1 to 3 kg/cm ² seems to be suitable.

6 and 7, a plurality of cleaning rollers 8 are provided on the unprocessed wire electrode 2 that is supplied to the workpiece 3 separately from the current-carrying pin or the current-carrying roller 4 and the pressing roller 4A. Air bubbles and foreign matter adsorbed by the wire electrode 2 guided by the wire electrode 2 can be removed to clean the wire electrode 2.

That is, as shown in FIG. 7, a pair of pinch-type cleaning rollers 8 are rotatably mounted on brackets (not shown), sandwiching the wire electrode 2 from both sides. A pair of such cleaning rollers 8 are formed in three stages in the direction of the path of the wire electrode 2, and the directions of the shafts 82 of each stage are different from each other, such as crossing at right angles. In the upper cleaning roller 8 and the middle cleaning roller 8, a pair of cleaning liquid nozzles 10C are inclined from the upper side toward the wire electrode 2, and wedge-shaped gaps 2A, 2B are formed between the cleaning roller 8 and the wire electrode 2 in contact with each other. oriented towards. The number of nozzles 10C is increased as necessary to spray from the required direction, and the cleaning liquid is sprayed at high pressure from all directions to the wire electrode 2 by the three stages of cleaning nozzles 10C (top, middle, and bottom). It is possible to further improve the cleaning performance. Furthermore, if the rotation of each cleaning roller 8 is stopped so that it comes into sliding contact with the wire electrode 2, it is more effective to remove foreign substances such as burrs and improve wettability.

Note that any appropriate structure for attaching and holding the energizing pin 4 to the support member 13 and the internal structure of the pin 4 may be used;
You can refer to the one described in Publication No. 14014.

[Effect of idea]

According to this invention, before the moving wire electrode enters the processing part of the workpiece, it can be cleaned with a cleaning liquid such as processing fluid to remove the gas adsorbed on the wire electrode. It was possible to easily remove air bubbles generated in the cleaning fluid, such as machining fluid, which is supplied and stagnated in the wedge-shaped micro gap formed between the wire electrode and the wire electrode, making it possible to stabilize the machining current. This has the effect of improving processing ability because it can increase the disconnection current value.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the main parts of a conventional wire-cut electrical discharge machining device, Figs. 2 A and B are enlarged views of the upper energizing device, and Figs. 3 and 4 are explanatory views of an embodiment of the present invention. , a side view and a front view of the energizing pin or roller, the pressing pin, and the cleaning nozzle portion, FIG. 5 is a characteristic curve diagram showing the relationship between the disconnection current value and the cleaning liquid ejection pressure in the above embodiment, and FIG. 7 is a front view showing the cleaning pin or roller and the cleaning liquid nozzle attached to the cleaning pin or roller, and FIG. 7 is a plan view showing the cleaning pin or roller located in the center of FIG. 6. 2...Wire electrode, 10A, 10B, 10C...
...Washing nozzle, 4...Electricity pin.

Claims (1)

[Claims for Utility Model Registration] (1) The wire electrode is brought into contact with an energizing device disposed on one or both sides of the workpiece, and the wire electrode is updated and moved in the axial direction, and the wire electrode and the workpiece are connected. In a wire-cut electrical discharge machining device that performs electrical machining by applying intermittent voltage pulses during the process, a nozzle is installed so that a spray nozzle for pre-cleaning liquid, which may be machining liquid, faces the wire electrode 2. Inside, a wedge-shaped minute gap 2B formed between the current-carrying pin 4 and the wire electrode 2
A cleaning nozzle 10A is installed on the wedge-shaped minute gap 2B side to remove air bubbles generated and accumulated between the current-carrying pin 4 and the wire electrode 2 by spraying a cleaning liquid at a predetermined high pressure. , a wire-cut electrical discharge machining device that supplies a wire electrode 2 from which bubble adsorption has been removed to a workpiece 3. (2) The wire cut electrical discharge machining apparatus according to claim 1, wherein the predetermined high pressure is 1 Kg/cm ² or more.