JPS6210029Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to the improvement of a wire-cut electrical discharge machine, and in particular, in a wire-cut electrical discharge machine, it prevents heating and disconnection of the conductive wire that is guided close to the workpiece and conducts the electrical discharge machining current. The present invention relates to an inexpensive wire breakage prevention device for preventing wire breakage.

Wire-cut electrical discharge machines use various types of conductive wire, such as copper wire, brass wire, tungsten wire, and steel wire, depending on the properties of the workpiece material and processing conditions. If the wire is high, it naturally has a high electrical resistance, and therefore it is heated by the large current for electric discharge machining supplied during electric discharge machining, and at the same time tension is applied, which often causes disconnection failures. Moreover, such a disconnection failure of the conductive wire can be avoided in the case of the conventionally used wire-cut electric discharge machine, in which the electric contact that transmits and supplies the electric discharge machining current to the conductive wire and the conductive wire are guided and guided toward the workpiece. In many cases, wire breakage occurs during the short time that the conductive wire moves between the wire guide element and the conductive wire, for example, even if the gap is as small as 2 mm, on the other hand, electrical discharge machining current flows through the conductive wire. No disconnection failure occurs in other parts, ie, between the workpiece and the wire guide element. The reason for this is that in the case of a wire-cut electrical discharge machine, machining fluid is injected from a machining fluid nozzle into the area where the workpiece and the conductive wire face each other, and this machining fluid simultaneously exerts a cooling effect on the conductive wire. heating of the conductive wire in the area is prevented;
Therefore, the occurrence of disconnection failures is prevented. Therefore, in order to prevent the conductive wire from breaking due to heating, it is effective to cool the conductive wire. A wire cut electric discharge machine is also provided in which a cooling water injection nozzle is provided separately from the machining nozzle, and the conductive wire is cooled by the water injection nozzle during electric discharge machining. However, in the case of a wire-cut electrical discharge machine equipped with such a cooling water injection nozzle, piping and water injection nozzle for a separate cooling water injection system that is not directly related to electrical discharge machining are required. The price is relatively high, and when the same water supply pump is used to supply both the machining fluid nozzle and the conductive wire cooling water injection nozzle at the same time, the water injection pressure on the machining fluid nozzle side is reduced. However, as a result, the electrical discharge machining ability may be reduced. Furthermore, if the capacity of the water supply pump is increased in order to avoid this decline in machining capacity, the price of the wire-cut electrical discharge machine will inevitably rise.

Therefore, the purpose of the present invention is to eliminate the drawbacks of the conventional wire-cut electric discharge machine as described above, and to proactively prevent disconnection failures of the conductive wire within a short distance between the electric contact and the wire guide element. An object of the present invention is to provide a wire breakage prevention device for a wire-cut electric discharge machine having a conventional structure. Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

Figure 1 shows one of the wire breakage prevention devices according to the present invention.
2 is a schematic front view showing essential parts of a wire-cut electric discharge machine equipped with an embodiment, and FIG. 2 is a front view and a side view showing important parts of the wire-cut electric discharge machine shown in FIG. 1 on a further enlarged scale.

In FIG. 1, reference numeral 10 denotes a conductive wire forming a wire electrode, which is unwound from a wire delivery reel 11, passes through an appropriate number of guide rollers 29, a brake device 33, wire guide elements 17a, 17b, etc., and is transferred to a workpiece 15. The conductive wire 10 is provided so as to be guided and guided close to the workpiece 15 and further wound around the winding roller 13 via the winding roller 31, and by applying an appropriate amount of tension to the conductive wire 10, the workpiece 15 is is configured to move through a predetermined minute gap. This conductive wire 10 is further in contact with an electric contact 19 at a position upstream of the wire guide element 17a, and this electric contact 19 is electrically connected to an electrical discharge machining power source 25 via a conductive wire 27. Therefore, the conductive wire 10 is the electrical contact 1
It is connected to this electrical discharge machining power supply 25 through the contact position with the electrical discharge machining device 9, and receives power supply for electrical discharge machining. On the other hand, the electric discharge machining power source 25 also has a conductive wire 27
It is electrically connected to the workpiece 15 via. As a result, machining liquid nozzles 21a and 2 are provided in the minute gap between the conductive wire 10 and the workpiece 15.
Electric discharge occurs using the machining fluid injected from 1b at a predetermined pressure as a discharge medium, and the workpiece 15 undergoes electric discharge machining. Note that 23a and 23b indicate piping that supplies machining fluid to the machining fluid nozzles 21a and 21b, respectively.

According to the present invention, in the wire cut electric discharge machine having the above-mentioned configuration, an electric contact 1 is further provided.
A wire breakage prevention device 35 is provided at an intermediate location between the conductive wire 10 and the wire guide element 17a, that is, at a distance where a breakage failure is most likely to occur with the conductive wire 10 guided and guided under a constant tension as described above. It is being As a specific embodiment of this wire breakage prevention device 35, as shown in FIG. is provided to face the conductive wire 10 with a small gap therebetween. Examples of the structure of the metal fitting member 35a are shown in FIGS. 3 and 4.
It is easiest to manufacture the surface of the metal fitting member 35a facing the conductive wire 10 as a flat surface as a liquid adhesion surface, but such a facing surface is not necessarily limited to a flat surface, and for example, as shown in FIG. It can also have a grooved surface as shown. By providing the metal fitting member 35a between the wire guide element 17a and the electric contact 19 in this way, a portion of the machining fluid injected from the machining fluid nozzle 21a into the discharge machining gap between the workpiece 15 and the conductive wire 10 is reduced. is received by the surface of the metal fitting member 35a, and the received machining liquid forms a water film 39 in the minute gap between the metal fitting member 35a and the conductive wire 10.
The conductive wire 10 running by the wire 9 is constantly cooled during electrical discharge machining. That is, the conductive wire 10 heated by the current from the electric discharge machining source 25 supplied via the electric contact 19 is cooled by the water film 39, thereby preventing wire breakage. It will become. Note that the above-mentioned metal fitting member 35a is connected to the conductive wire 1.
It is desirable that the wire can be replaced so that an appropriate micro-gap is formed between the conductive wire 10 and the conductive wire 10 to form a water film as the wire diameter changes. conductive wire 10
When using the metal fitting member 35a, attach it to the mounting plate 37.
It is also possible to form it integrally with. Of course, the object of the present invention can also be achieved by appropriately improving a part of the mounting plate 37, that is, the part between the electrical contact 19 and the wire guide element 17a, so that it can be used as a receiving part for the electrical discharge engineering fluid. can be achieved.
In addition, as another embodiment of the wire breakage prevention device 35, a liquid receiving member for electric discharge machining fluid made of a flexible and highly water-containing material such as felt material is attached to the mounting plate 37 in place of the above-mentioned metal member 35a. It is easy to understand that the same wire breakage prevention effect can be obtained even if the conductive wire 10 is configured to be guided while being in contact with the liquid receiving member.

As can be understood from the above explanation, according to the present invention, by using the machining fluid essential to wire-cut electric discharge machines, the machining fluid is guided to the distance between the electric contact and the wire guide. The wire breakage prevention device that actively cools the conductive wire can be constructed using extremely simple and inexpensive components, and there is no need to make any major modifications to the electrical discharge machine itself, making it possible to use conventional wire cut electrical discharge machining. It is possible to fully measure the problem solving in the machine.

[Brief explanation of the drawing]

Figure 1 shows one of the wire breakage prevention devices according to the present invention.
A schematic front view showing the main parts of a wire-cut electric discharge machine equipped with an embodiment, FIG. 2 is a front view and side view showing an enlarged view of the important parts of FIG. 1, and FIG. A perspective view, Figure 4 is a top view of Figure 3,
FIG. 5 is a top view similar to FIG. 4 showing another example of the metal fitting member. In addition, in the figure 10... conductive wire, 1
5...Workpiece, 17a, 17b...Wire guide element, 19...Electric contact, 21a, 21b...
... Machining fluid nozzle, 25... Electric discharge machining power supply.

Claims (1)

[Claims for Utility Model Registration] 1. Electrical discharge machining liquid discharged from a machining liquid nozzle between a guide element that guides a conductive wire of a wire-cut electric discharge machine and an electric contact that supplies electric discharge machining current to the conductive wire. A liquid-receiving member having a liquid-receiving surface that receives leakage is provided, and at this time, the liquid-receiving surface of the liquid-receiving member is opposed to the conductive wire with a small gap therebetween, and a water film is formed between the conductive wire and the liquid receiving surface. A wire-cut electrical discharge machine is provided at a close position where the conductive wire is immersed in the water film formed by the electrical discharge machining fluid, and the conductive wire is cooled by the water film of the electrical discharge machining fluid to prevent wire breakage. Wire breakage prevention device. 2. The wire breakage prevention device for a wire-cut electric discharge machine according to claim 1, wherein the liquid receiving member is a metal fitting member having a liquid receiving surface.