JPS63237818A - Wire cut electric discharge machining device - Google Patents

Abstract

PURPOSE:To ensure the better discharge of machining chips and the like and enable the application of a substantial current supply and a stable and high-speed wire cut process by inserting a high pressure injection nozzle in a low pressure injection nozzle so formed as to enclose a wire electrode, a guide and the like. CONSTITUTION:Within a space enclosing the wire electrode 1 of a low pressure injection nozzle 5, a high pressure injection nozzle 6 is provided at a micro distance from the electrode 1. And thereby a high pressure jet is available easily, a high pressure machining fluid is injected and concentrated upon a micro space between the electrode 1 and a workpiece 3 without any hindrance and a large quantity of the fluid can move efficiently in the machining gap. Also, the nozzle 5 encloses and cools the electrode 1, a guide 2 and a conducting element 4, and a large amount of electric currents can be supplied from the element 4 to the electrode 1, thereby alleviating friction between the electrode 1 and the guide 2 and ensuring the stable guide of the electrode 1. Then, the high pressure fluid from the nozzle 6 is controlled for reduction during stable machining and adaptable control can be made to raise a fluid pressure upon the occurrence of unstable machining. And automatic control can be made in such a way as to enable machining in a machining feed direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement of a wire-cut electric discharge machining apparatus using a wire electrode, particularly a machining fluid jet nozzle.

[Prior art and problems]

In wire-cut electrical discharge machining equipment, it is necessary to supply a sufficient amount of machining fluid to the machining gap, and for this purpose various improvements have been made to the machining fluid supply nozzle. Conventionally, the nozzle commonly used is a single nozzle with a nozzle diameter of about 4 to 8IIφ installed coaxially with the wire electrode, and the machining fluid is supplied in jet form from the entire circumference of the wire electrode, so it is sufficient to fill the machining gap. It was difficult to supply a suitable machining fluid.

If the supply of machining fluid is insufficient, machining debris and gas generated in the machining gap will not be sufficiently discharged, causing arc discharge and short circuits, and insufficient cooling effect, resulting in wire electrode breakage and
This causes a decrease in machining speed, worsening of machined surface roughness, etc., resulting in a decrease in machining performance. In order to increase the flow layer of machining fluid in the machining gap, it is possible to increase the jet pressure from the nozzle, but in this case, most of the jet fluid stays on the workpiece and bounces back into droplets, spreading around the workpiece. This has the drawback of making machining work difficult and corroding the sliding surfaces of machines. In addition, since surrounding air is drawn in by the force of the jet liquid, air bubbles are supplied to the machining gap, making the discharge unstable and reducing the cooling effect.

Conventionally, in order to improve the above-mentioned points, a dual nozzle in which a high pressure nozzle and a low pressure nozzle are coaxially formed around the wire electrode has been proposed. In this case, the high-pressure nozzle is installed inside and the low-pressure nozzle is installed outside, so the working fluid from the high-pressure nozzle is used to cool the guide, etc., making it difficult to seal the liquid and making it impossible to apply sufficient high pressure. In addition, since the high-pressure nozzle is provided coaxially with the wire electrode, the nozzle jet diameter cannot be narrowed down to a small size, and there is a drawback that it is not possible to effectively supply a jet of machining fluid to a narrow machining gap.

[Means for solving problems]

The present invention was invented to improve the above points,
A machining fluid jet nozzle is provided, which includes a low-pressure jet nozzle surrounding a wire electrode, a guide, etc., and a high-pressure high-pressure jet nozzle inserted into the low-pressure nozzle.

〔Example〕

The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, a wire electrode 1 is normally supplied from a reel (not shown) and is driven to run between upper and lower guides (dice) 2 with a predetermined tension and speed. Note that a drive control take-off device and brake device are not shown.

3 is a workpiece to be machined facing the wire electrode between the guides 2; 4 is an electric current that supplies electricity to the electrode 1, which is provided outside the upper and lower guides and is connected to one terminal of a processing power source (not shown); , the other is directly connected to the workpiece and applies pulses to the gap. 5 is a wire electrode 1, a guide 2 and a conductor 4
A low-pressure jet nozzle surrounds the nozzle and has a tip 51 facing the machining gap between the wire electrode and the workpiece, and machining fluid (water) at a low pressure of about 0.1 to 10 kt/cm2 is supplied from the supply port 52. This nozzle 5 is vertically symmetrically provided with the workpiece 3 in between, and supplies a jet of machining liquid from above and below. 6 is a high-pressure jet nozzle inserted into the low-pressure nozzle 5.
The tip is provided so as to be parallel to the wire electrode 1, the nozzle diameter is formed to be as small as the wire diameter of the wire electrode 1, and a high-pressure machining fluid with a fluid pressure of about 5 to 100 ki/cm2 is supplied to this nozzle.

FIG. 2 is a cross-sectional view of the wire electrode 1 and the tips of the nozzles 5 and 6, clearly showing the structure in which the high-pressure jet nozzle 6 is provided at a small distance from the wire electrode 1 inside the wire electrode 141 of the low-pressure jet nozzle 5. It is something.

Normally, the tip diameter of the low-pressure jet nozzle 5 is about 1 to 2 mφ,
The diameter of the high-pressure jet nozzle is approximately 0.3 to 0.5u+φ, and the distance from the wire electrode is set to The electrode should be set at about 0.3 to 1111B so that the electrode does not vibrate and touch.

The wire diameter of the wire electrode 1 is normally selected in the range of about 0.05 to 0.5 IIφ, but especially when performing high-speed processing, the wire diameter is selected in the range of about 0.3 to 0.5
The high-pressure jet nozzle 6 is installed parallel to the wire electrode 1, so it can be easily formed into a thin one with a diameter of about 0.3 to 0.5II11φ. The jet flow is made easier, and the high-pressure machining fluid can be sprayed and driven into the minute gap between the wire electrode 1 and the workpiece 3 in a concentrated manner without any obstacles, allowing a large amount of machining fluid to flow efficiently into the machining gap. be able to. Also, since the low-pressure jet nozzle 5 surrounds and cools the wire electrode 1, guide 2, and conductor 4, a large current can flow from the conductor 4 to the wire electrode 1, reducing friction between the wire electrode 1 and the guide 2. This allows for stable guidance. Since the machining fluid in this low-pressure jet nozzle 5 is controlled to a sufficiently low pressure, even if the seal between the nozzle 5 and the moving wire 1 is not sufficient, the machining fluid leaks to the surroundings and is safe. Further, the jet liquid from the tip opening 51 of the low-pressure jet nozzle forms a liquid flow around the machining gap, but since the jet pressure is low, there is little scattering of droplets, and the high-pressure jet nozzle 6 is in this liquid flow.
The machining fluid is injected from the machine, preventing the high-pressure fluid from scattering, and preventing air from being entrained in the high-pressure jet fluid, making it possible to have a stable flow of the high-pressure jet fluid into the machining gap. do.

The pressure of the machining fluid jetted from the high-pressure jet nozzle is not limited to a constant pressure, but is adaptively controlled to reduce the pressure during stable machining and increase the pressure when machining becomes unstable, depending on the discharge state of the machining gap. It is also possible to automatically control the high-pressure jet nozzle to perform processing while directing the high-pressure jet nozzle in the processing feed direction using a processing feed signal or the like.

〔Effect of the invention〕

As described above, the present invention provides a wire-cut electrical discharge machining device in which a machining fluid jet nozzle is provided with a low-pressure jet nozzle surrounding a wire electrode, a guide, etc., and a high-pressure jet nozzle is inserted into the low-pressure jet nozzle. As a result, the diameter of the tip of the high-pressure jet nozzle is made sufficiently small to facilitate high-pressure jetting of machining fluid, and a large amount of machining fluid can be efficiently jetted into the machining gap, thereby reducing the removal of machining debris. It is possible to carry out a large current and perform stable, high-speed wire cutting.

Furthermore, since the low-pressure jet nozzle efficiently cools the wire electrode, guide, conductor, etc., it is possible to stably supply a large current, thereby preventing wire electrode breakage and increasing the processing speed.

In addition, since the liquid pressure inside the low-pressure jet nozzle is low, there is little leakage of the cooling liquid, and the machining liquid jetted from the tip opening is at low pressure, so it is less likely to scatter to the surroundings. As a result, the curtain effect of the low-pressure liquid prevents the high-pressure liquid from scattering to the surrounding area, and also prevents air from being drawn into the jet liquid from the surroundings, thereby creating a stable jet of machining liquid in the machining gap. This enables stable, high-speed, and highly efficient wire-cut electrical discharge machining.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of the present invention, and FIG. 2 is a sectional view of a part thereof. 1...Wire electrode 2...Guide 3...Workpiece 4...Electronic current 5.・・・・・・・・・Low pressure jet nozzle 6・・・・・・・Iris pressure jet nozzle Patent applicant Kiyoshi Inoue, Representative of Inoue Japax Laboratory Co., Ltd.

Claims (2)

[Claims] (1) In a wire-cut electric discharge machining device that processes a wire electrode between guides facing a workpiece, a nozzle that supplies machining fluid to the opposing gap is provided surrounding the wire electrode, guide, etc. A wire-cut electric discharge machining device comprising: a low-pressure jet nozzle; and a high-pressure jet nozzle inserted into the low-pressure nozzle. (2) The wire-cut electric discharge machining apparatus according to claim 1, which is provided with a high-pressure jet nozzle whose jet aperture is approximately the same as the wire diameter of the wire electrode.