JPH0911047A - Manufacture of electrode wire for electric discharge machine - Google Patents

Abstract

PURPOSE: To manufacture an electrode wire, which is provided with high strength and is excellent in a drawing property and in economy, under an easily controlled manufacturing condition by strengthening Cu alloy with a draft of the specific value or more so as to add mechanical strength and applying Zn plating on its surface. CONSTITUTION: For improvement in purity of Cu in Cu-Nb alloy and in workability, heating at approximately 950 deg.C for 24 hours is carried out, and then, deposition is carried out. Subsequently, drawing is carried out so as to provide an outside diameter of approxiately 8mm, and cold drawing is carried out so as to provide an outside diameter of approximately 0.9mm (a draft is 99.99%). Finally, Zn plating is applied by an electrode plating method in a Zn aqueous solution for preventing decrease in strength due to heating (150kgf/ mm<2> or more), and cold drawing is carried out for providing a fiber type expanded structure, and consequently, an electrode wire, which is provided with an outside diameter of approximately 70μm (a draft is 99.99%), for electric discharge machining is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode wire for electric discharge machining, and more particularly, to an electrode wire for electric discharge machining which has high strength, excellent straightness and economical efficiency, and is easy to manage. The present invention relates to a method for manufacturing an electrode wire for electric discharge machining that can be manufactured under manufacturing conditions.

[0002]

2. Description of the Related Art Wire electric discharge machining is a method of causing an electric discharge phenomenon between a machining electrode and a work piece, and melting the work piece by the discharge energy to form a predetermined shape. It is used for processing complex and precise workpieces such as press dies.

Since heat and tension are applied to such an electrode wire for electric discharge machining, it is required that the electrode wire has high tensile strength at high temperatures and is hard to break. From these requirements, conventionally, tungsten wire, molybdenum wire, copper-coated steel wire or piano wire, etc.
A high-strength electrode wire is used, which is used alone or as a core material, and the outer surface of which is plated with Zn or brassed.

As a method of manufacturing this electrode wire for electric discharge machining,
For example, there is one disclosed in Japanese Patent Laid-Open No. 5-192821. According to this manufacturing method, a Zn layer is formed around copper or a copper alloy wire, and this is used as a β'- alloy of a binary alloy Cu-Zn.
Heat treatment is performed at a temperature lower than β transition temperature to form an outer layer consisting of a homogeneous β ′ phase, then pickling to remove oxides existing on the surface, and finally wire drawing with a workability of more than 100%. Then, the electrode wire for electric discharge machining is manufactured. According to this manufacturing method, it is possible to obtain an electrode wire for electric discharge machining having an outer layer of a Cu—Zn alloy of a homogeneous β ′ phase without an oxide.

[0005]

However, according to the conventional electrode wire for electric discharge machining using a tungsten wire, a molybdenum wire, a copper-coated steel wire or a piano wire, the high strength required for the electrode wire is dealt with. However, the cost is high and the strength is high, but the straightness is poor.

On the other hand, according to the method of manufacturing an electrode wire for electric discharge machining disclosed in Japanese Patent Laid-Open No. 5-192821, a homogeneous β ′ is obtained.
Because the outer layer of the Cu-Zn alloy of the phase is formed and the homogeneity and the hardness enhance the performance of the electrode wire,
There is a problem that it is difficult to control manufacturing conditions such as temperature.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric discharge machining electrode wire which has high strength, excellent straightness and is economically excellent, and which can be manufactured under easily controlled manufacturing conditions. It is to provide a manufacturing method of an electrode wire for processing.

[0008]

In order to achieve the above object, the present invention provides a copper alloy containing an element that is difficult or insoluble in copper, and the copper alloy is 99.99%.
For electrical discharge machining, characterized by subjecting the surface of the copper alloy subjected to the strong working to Zn plating by electroplating by subjecting the strong working to the mechanical strength of 150 kgf / mm ² or more with the above working degree A method for manufacturing an electrode wire is provided. In this case, the copper alloy is a Cu-Nb copper alloy,
It is preferably a Cu-Cr copper alloy or a Cu-Fe copper alloy.

In order to achieve the above object, the present invention provides a copper alloy wire made of Cu-Nb or Cu-Cr, which has been brassiZed by Zn plating or a subsequent heat treatment, in an amount of 99.99% or more. It is intended to provide a method for manufacturing an electrode wire for electric discharge machining, which is characterized by being subjected to strong machining.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Copper alloy or Cu-N that has been brass-plated by Zn plating in advance or by subsequent heat treatment.
By processing 99.99% or more of b, Cu-Cr, and Cu-Fe alloy wires, the two phases of the copper phase and the additive metal phase that does not form a solid solution become a structure in which the copper wire extends fibrously in the longitudinal direction. A high-strength electrode wire for electric discharge machining having a strength of 150 kgf / mm ² or more and excellent straightness can be achieved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing an electrode wire for electric discharge machining according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1 First, Cu-21% by volume Nb
A (20 wt% Nb) cast material (outer diameter 30 mm) is prepared, and this is chamfered to prepare a sample with an outer diameter of 25 mm. Next, this sample is wire-drawn in a draw bench to be molded into an outer diameter of 20 mm.

Next, in order to increase the purity of Cu in the Cu-Nb alloy and improve the workability, heating is performed at 950 ° C. for 24 hours to perform a precipitation treatment. After heating for 24 hours, wire drawing is carried out to an outer diameter of 8 mm, and cold wire drawing is carried out to an outer diameter of 0.9 mm (working degree 99.99%). 99.
The workability of 99% means that when the workability is 99.99% or less, the strength as an electrode wire is insufficient, and the added metal phase does not become sufficiently fibrous in the longitudinal direction and is stretched as an electrode wire. This is because the straightness is not sufficiently achieved.

Finally, in order to prevent the decrease in strength due to heating, Zn plating is performed by an electroplating method in a Zn aqueous solution, and cold drawing is carried out to form a fibrous elongated structure having an outer diameter of 70 μm. The electrode wire for electric discharge machining was (working degree 99.999%).

This Cu-21% by volume Nb (20% by weight Nb
b) The work hardening curve of the copper alloy wire is shown by the chain line A in FIG. As shown in the figure, the strength of the electric discharge machining electrode wire having an outer diameter of 70 μm is 170 kgf / m.
It was m ² and it was confirmed that it exhibits good strength and is excellent in straightness. Also, the outer diameter is about 190 μm
(Processing degree 99.993%) From below, 150k
It was confirmed that a strength of gf / mm ² or more was obtained.

The solid line B in FIG.
It is a work hardening curve of a brass-covered Cu-21 volume% Nb (20 wt% Nb) alloy wire of m. This work hardening curve is also Cu
Similar to the -21% by volume Nb (20% by weight Nb) copper alloy wire, 150 kgf / from an electric discharge machining electrode wire having an outer diameter of about 0.19 mm (working degree 99.993%) or less.
It was confirmed that a strength of mm ² or more was obtained.

Example 2 By the same method as in Example 1, the outer diameter of Cu-15% by volume Cr (20% by weight Cr) was 70 μm.
When the electrode wire for electric discharge machining of m was prepared and measured, it was confirmed that the strength was 160 kgf / mm ² and the wire had good straightness.

In addition to the above, Cu-F is used as the copper alloy.
Similar results were obtained using the e-alloy wire.

Thus, as the copper alloy, Cu--Nb,
By using Cu-Cr and Cu-Fe, it is possible to supply an electrode wire for electric discharge machining having a strength of 150 kgf / mm ^{2 or} more, which is required as a high strength electrode wire. In addition, since these alloy wires are made of elements that are difficult or insoluble in copper, a wire structure produces a fibrous structure, and electrode wires for electrical discharge machining that are also excellent in straightness Can be supplied. Furthermore, compared with tungsten wire, molybdenum wire, etc., the cost of these alloy wires is about 1/2 or less, so that it is possible to supply an economically excellent electrode wire for electric discharge machining.

[0020]

As described above, according to the method for manufacturing an electric discharge machining electrode wire of the present invention, it is possible to manage an electric discharge machining electrode wire which is high in strength but excellent in straightness and economically excellent. It is possible to provide a method for manufacturing an electrode wire for electric discharge machining, which can be manufactured under easy manufacturing conditions.

[Brief description of the drawings]

FIG. 1 is a diagram showing work hardening characteristics of Cu-21% by volume Nb (20% by weight Nb) copper alloy wire.

[Explanation of symbols]

A Cu-21% by volume Nb (20% by weight Nb) work hardening curve of a copper alloy wire B Brass Cu-21% by volume Nb (20% by weight Nb)
Work hardening curve of alloy wire

Front page continuation (72) Inventor Osamu Nakamura 4-10-1 Kawajiri-cho, Hitachi-shi, Ibaraki Hitachi Cable Ltd. Toyoura factory

Claims (3)

[Claims] 1. An element which is difficult or insoluble in copper
Is prepared, and the copper alloy is subjected to strong working at a working degree of 99.99% or more.
150 kgf / mm ^TwoThe above mechanical strength is given, and the surface of the copper alloy subjected to the strong processing is electroplated.
Therefore, an electrode for electric discharge machining characterized by being plated with Zn
Wire manufacturing method. 2. The copper alloy is Cu-Nb copper alloy, Cu-
The method for producing an electrode wire for electric discharge machining according to claim 1, wherein the electrode wire is a Cr copper alloy or a Cu-Fe copper alloy. 3. An electric discharge machine characterized by subjecting a copper alloy wire made of Cu—Nb, Cu—Cr, which has been brass-plated by Zn plating or a subsequent heat treatment, to a strong working of 99.99% or more. Method for manufacturing electrode wire.