JPH036973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal material suitable as a wire electrode material for a wire-cut electrical discharge machining device.

Wire-cut electric discharge machining equipment causes an electrical discharge phenomenon between a wire electrode and a workpiece, and cuts the workpiece using the heat and shock generated by the discharge. Suitable for machining large workpieces.

In general, wire cut electric discharge machining is required to have a good surface finish and dimensional accuracy of the workpiece, and to shorten the machining time. It is necessary to improve the machining efficiency due to the electric discharge that occurs between the material and the body. On the other hand, once the power supply type of the electrical discharge machining device, material of the workpiece, surface finish, dimensional accuracy, etc. are specified, the electrical discharge machining time etc. will depend on the material and wire diameter of the wire electrode used. It turns out.

Therefore, the wire electrode material should be easy to draw, have good conductivity, have a high processing speed when used as an electrode, preferably have a small consumption ratio, and have good heat resistance. The tensile strength does not deteriorate especially at high temperatures, and it is difficult to cut during use. It is also difficult to work harden and short circuit, and is suitable for two-dimensional processing, three-dimensional processing, and places where wire electrodes are wound or bent. In addition to this, the amount of deflection of the wire electrode during electrical discharge machining (the so-called tautness μ) is small, the hydrophilicity is good, and the contact resistance value, surface resistance, and barrier resistance are small. etc. properties are required.

For this reason, pure copper or copper alloys such as brass are generally used as electrode materials.
Copper alloys to which cuprous oxide is added have also been proposed.

Although copper electrodes have good values in terms of conductivity,
The wear ratio is around 60%, and it is also insufficient in terms of mechanical strength such as tensile strength and heat resistance, and brass wire is superior to copper wire in terms of mechanical strength such as tensile strength and processing speed. However, it is somewhat inferior in terms of conductivity and consumption ratio. Since it has tensile strength and hardness, that is, springiness, that exceeds that of hard copper, there is a residual curl, and it is difficult to achieve sufficient linearity unless the guides are moved with a sufficiently large tension between the guides. However, the problem of machining accuracy and wire breakage was contradictory.

On the other hand, an alloy wire made of pure copper mixed with 1-5% cuprous oxide Cu ₂ O has a conductivity that is not much different from that of pure copper and a low wear rate.
The processing speed is around 20-30%, and the processing speed is also excellent.
There is still a problem with difficulty in cutting.

On the other hand, there are wire electrodes made of tungsten, molybdenum, or their alloys drawn to a diameter of about 0.1 mm or less, but these were expensive and were only used for special purposes.

In addition, a wire cut electric discharge machining device generally moves a wire electrode from one reel to the other reel, and processes a desired shape by performing electric discharge machining by performing pulse discharge while supplying machining fluid. Therefore, the wire electrode is twisted and bent every time it passes between the brake roller and the pinch roller, between the capstan and the pinch roller, between the guide roller and the guide guide, etc., and as a result, the wire electrode undergoes work hardening. This may result in loss of linearity, or conversely, if processing is attempted at a strongly bent portion of the wire electrode, it may be impossible to obtain a small bending radius, resulting in overhang of the workpiece. For example,
There was a problem in that it was not possible to process the contours of the hollow part of the extrusion die, the cutting edge part of the trim die, etc.

The present invention has been made based on the above-mentioned viewpoints, and its objectives are to have good electrical conductivity and heat resistance, high tensile strength, break resistance, and extremely high processing speed. To provide an electrode material for wire-cut electric discharge machining that can be easily drawn, has a small amount of tension, can prevent short circuits, and has low contact resistance, surface resistance, and barrier resistance. It is in.

Therefore, the gist of the present invention is to mainly contain Cu, 5 to 50% by weight of Zn, and 0.05 to 50% Zn.
Consisting of 5% Pd and the remainder impurities and Cu,
A further object of the present invention is to obtain an electrode material for wire cut electric discharge machining that satisfies the above conditions and contains 0.05 to 7% by weight of a rare earth element in addition to the above.

As mentioned above, materials containing rare earth elements such as Y ₂ O ₃ or Mitsushi metal are known as electrode materials for wire cut electrical discharge machining.

For example, in Japanese Patent Application Laid-Open No. 53-49397, Cu or
JP-A-56-90943 discloses an electrode material containing one or more rare earth elements of 0.1 to 5% by weight in a Cu+Cu ₂ O alloy;
Contains Zn of
An alloy for wire-cut electrical discharge machining electrodes is described.

However, the addition of rare earth elements to these known electrode materials made of Cu-based alloys such as various brasses such as Cu and Cu-Zn not only improves the tensile strength and break resistance, but also improves the performance of electrical discharge machining, especially the discharge of rare earth elements. Although it is effective in increasing the machining speed, which is thought to be a result of contributing to the occurrence of electric discharge, the amount of deflection of the wire electrode during electrical discharge machining (the so-called flexure amount μ) is large, and it also prevents short circuits and increases contact resistance, surface resistance, and There was a problem that the barrier resistance could not be reduced.

According to various test studies conducted by the present inventor, Cu is the main component, and Zn with a weight percentage of 5-50% and 0.05-5%
% of Pd or further contains 0.05 to 7% of rare earth elements such as Mitsushimetal or Y ₂ O ₃ as an active ingredient to improve tensile strength and break resistance, and improve electric discharge machining performance and In addition to significantly increasing the processing speed, it was possible to reduce the amount of so-called tying, which had been a drawback, and furthermore, it was possible to prevent short circuits and reduce contact resistance, surface resistance, and barrier resistance.

The content of Zn is within the range of 5 to 50% by weight, but it is particularly desirable to keep it in the range of around 30%, while the content of Pd is within the range of 5 to 50% by weight.
It is within the range of 0.05 to 5%, but in particular, 0.1%
It is desirable to keep it within the range of 1%. Also,
In those containing rare earth elements as active ingredients, the content is within the range of 0.05 to 7%, but it is particularly recommended that the content be within the range of 0.1% to around 3%.

If the Zn content is less than 5%, mechanical strength such as tensile strength will decrease, and if it exceeds 50%, electrical conductivity will decrease, processing speed will also decrease, and problems such as easy bending will occur. .

Furthermore, if the content of Pd is less than 0.05%, the effect of reducing contact resistance, surface resistance and barrier resistance will be small, and if it exceeds 5%, problems such as an increase in the amount of coil and an increase in the frequency of occurrence of short circuits will occur.

Furthermore, when the content of rare earth elements is less than 0.05%, the contact resistance and
No particular effect was observed in terms of reducing surface resistance and barrier resistance, and if it exceeded 7%, a dashed line accident would occur.
This causes problems such as a decrease in heat resistance, an increase in the amount of coils, and an increase in the frequency of occurrence of short circuits.

In particular, mainly Cu and 30% Zn by weight percentage.
When electrical discharge machining was performed using a wire-cut electrical discharge machining electrode material containing 0.3% Pd, the machining speed was significantly increased compared to the conventional wire-cut electrical discharge machining electrode material, and the amount of stylus was reduced. At the same time, it was also possible to prevent short circuits. Also,
Contact resistance, surface resistance and barrier resistance could also be reduced.

In addition, Cu is the main component, and Zn is 30% by weight percentage.
Contains 0.3% Pd and 1.2% Pd as an active ingredient.
When electrical discharge machining was carried out using a wire-cut electrical discharge machining electrode material containing 50% of rare earth elements, substantially the same results as above were obtained.

Using the electrode material for wire-cut electric discharge machining according to the present invention, machining was performed under the following machining conditions.

Examples will be shown below in comparison with processing examples using conventionally known electrode materials.

<Machining conditions> No-load voltage 130V τ _ON 6 to 15μs τ _OFF 7μs I _M (Average machining current) 3.5A Machining fluid Specific resistance 30×10 ³ Ωcm pure water machining fluid Top nozzle discharge pressure 0.6Kg/cm ² Machining fluid Lower nozzle discharge pressure 1Kg/cm ² wire electrode feeding speed 1.5m/min Wire electrode diameter 0.2mmφ Workpiece thickness and material 25mm, S55C material example 1 Alloy composition of wire electrode Cu 69.7% Zn 30.0% Pd 0.3% When electrical discharge machining was performed using a wire electrode made of the wire-cut electrical discharge machining electrode material according to the present invention, machining could be performed at a machining speed of about 36 mm ² /min. In addition, the machined surface roughness at this time is
It was 11μRmax.

On the other hand, when using a wire electrode made of a conventional wire-cut electric discharge machining electrode material with an alloy composition of Zn 33% Cu 67%, the above average machining current I _M
When electrical discharge machining was performed under machining conditions of approximately 3.5 A, the machining speed was approximately 30 mm ² /min. Moreover, the machined surface roughness at that time was 11μRmax.

Further, electric discharge machining was performed using another conventionally known electrode material for wire cut electric discharge machining under the same machining conditions as described above.

Alloy composition of the wire electrode: Cu 4% Zn 20% Mg 1.5% Mn 0.5% Ti 0.5% Al 73.5% This result is approximately the same as when processing was performed using the conventionally known wire electrode made of Cu, Zn, and Al. The values were similar.

Example 2 Wire electrode alloy composition Cu 68.5% Zn 30.0% Pd 0.3% Rare earth element 1.2% Wire electrode made of a wire cut electrical discharge machining electrode material was used to perform electrical discharge machining under the same processing conditions as above. , machining can be performed at a machining speed of approximately 35 mm ² /min, and the roughness of the machined surface can be reduced.
It was possible to set it to 13μRmax.

Since the present invention is constructed as described above, the electrode material for wire-cut electric discharge machining according to the present invention can be easily wire-drawn, has good guidance rate and heat resistance, and has high tensile strength. Since the wire electrode has a high
It has a low consumption ratio, almost never breaks during use, can be processed at high current density, can greatly improve processing speed, can prevent short circuits, and Since contact resistance, surface resistance and barrier resistance can be reduced, work efficiency can be greatly increased.

Claims (1)

[Scope of Claims] 1. 5 to 50% Zn by weight percentage (the same applies hereinafter);
Wire cut electrode material for electrical discharge machining, consisting of 0.05-5% Pd, the remainder being impurities and Cu. 2 5-50% Zn, 0.05-5% by weight percentage
Pd, 0.05~7% rare earth elements, the rest is impurities
Electrode material for wire cut electrical discharge machining made of Cu. 3. The electrode material for wire cut electrical discharge _machining according to claim 2, wherein the rare earth element is _Y2O3 . 4. The electrode material for wire cut electric discharge machining according to claim 2, wherein the rare earth element is Mitsushi metal.