JP2001162447A - Method of manufacturing electrode tube for discharge machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrode tube for discharge machining capable of manufacturing, at a low cost, an electrode tube for discharge machining having a uniform metallographic structure through the entire length of the tube and a uniform discharge characteristics. SOLUTION: In this method of manufacturing an electrode tube for discharge machining from a copper line or a copper alloy line 1, the copper line or the copper alloy line 1 is bent in lateral direction, both end parts thereof are butted against each other in lateral direction, and a butted part 2a is welded so as to form a tube material 5. An area reduction machining of 50% or higher in an area reduction is applied to the tube material 5, and an annealing treatment at the recrystallization temperature of copper or copper alloy is applied to the tube material 8 after the area reduction machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing an electrode tube for electric discharge machining, and more particularly to a method of manufacturing an electrode tube for electric discharge machining using a welding tube forming method.

[0002]

2. Description of the Related Art Since the processing accuracy required in the manufacture of a die is extremely high, as typified by the manufacture of a press die for an LSI lead frame having a large number of pins, cutting and shape processing of a die material and the like are required. An electric discharge machine or a wire cut electric discharge machine capable of precision machining is used.

An electrode tube for electric discharge machining used for pre-processing (cutting of a hole for starting electric discharge machining) and counterboring of wire cut electric discharge machining is performed by spraying pure water or oil onto a discharge portion.
In addition, machining is performed while rotating the electrode tube, and a machining liquid is caused to flow from the tip of the electrode tube during machining to discharge machining chips entering the inside of the electrode tube. The discharge characteristics of the electrode tube for electric discharge machining are important in improving the machining accuracy of the mold.

Usually, copper or copper alloy having excellent workability and discharge property is used as a constituent material of the electrode tube for electric discharge machining, and its outer diameter is about 0.1 to 5.0 mm.

[0005] Further, as a method of manufacturing an electrode tube for electric discharge machining, there are an extrusion method using an extruder, and a welded tube in which copper or copper alloy strips are butted at both ends in the width direction and the butted portions are welded. Law.

The method of manufacturing an electrode tube for electric discharge machining using the extrusion method has a feature that an electrode tube having a uniform metal structure can be obtained. In addition, the method of manufacturing an electrode tube for electric discharge machining using the welding pipe forming method has a feature that relatively small-scale facilities are sufficient and continuous manufacturing is possible.

[0007]

However, the method of manufacturing an electrode tube for electric discharge machining using the extrusion method requires a large-scale facility, and is not suitable for manufacturing a long material. Had.

In the method of manufacturing an electrode tube for electric discharge machining using the welding pipe forming method, heat due to welding is applied to a butt portion, so that a copper alloy additive sublimates in a welded portion or a metal structure in a welded portion is not good. Become uniform. The uneven metallographic structure
In the drawing process in the subsequent step, it causes cracks and tube breakage, and the sublimation of the copper alloy additive causes deterioration in performance as a discharge electrode for which uniform discharge characteristics are desired.

Accordingly, the present invention solves the above-mentioned problems, and provides an inexpensive electrode tube for electric discharge machining capable of producing an electrode tube for electric discharge machining having a uniform metal structure of the entire tube and uniform discharge characteristics. It is to provide a manufacturing method of.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing an electrode tube for electric discharge machining from a copper strip or a copper alloy strip, wherein the copper strip or the copper alloy strip has a width. Bend in the direction and butting both ends in the width direction,
After the butt portion is welded to form a tube material, the tube material is subjected to a surface reduction process with a surface reduction rate of 50% or more, and the reduced surface temperature of the tube material is equal to or higher than the recrystallization temperature of copper or a copper alloy. Is performed.

According to the above method, the metal structure of the entire pipe can be made uniform. In the case of an electrode tube for electric discharge machining comprising a copper alloy strip, sublimation of the copper alloy additive can be suppressed.

According to a second aspect of the present invention, a copper strip or a copper alloy strip is curved in the width direction and the both ends in the width direction are butted, and the butt portion is welded to form a pipe material, and then the pipe material is reduced in surface area. The surface reduction is performed at a rate of 50% or more, and the pipe material after the surface reduction is subjected to an annealing treatment at a temperature equal to or higher than the recrystallization temperature of copper or a copper alloy.

[0013] The invention of claim 3 is that the copper alloy strip is made of Cu-
The electrode tube for electric discharge machining according to claim 2, comprising 35 wt% Zn.

According to the above configuration, it is possible to obtain an electrode tube for electric discharge machining in which the metal structure of the entire tube is uniform and the discharge characteristics are uniform.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of a method for manufacturing an electrode tube for electric discharge machining according to the present invention. 1 (a) is a cross-sectional view of the tubular member 2, FIG. 1 (b) is a cross-sectional view of the tube 5 after welding, and FIG. 1 (c) is a cross-sectional view of the processed tube 8 after surface reduction processing. Figure 1
(D) is a cross-sectional view of the electrode tube for electrical discharge machining 10 after the annealing treatment.

First, a copper alloy strip 1 continuously supplied from a delivery device or the like is curved in the width direction by roll forming and the both ends in the width direction are joined to form a tubular member 2 shown in FIG.

Next, the butted portion (edge end surface) 2a of the tubular material (skelp) 2 is locally heated by high-frequency current and welded by pressing, and as shown in FIG. A tube material 5 having a welded portion 3 and a welded portion 4 including an edge end face and a portion in the vicinity thereof is formed.

Thereafter, the tube 5 is subjected to a surface reduction process with a surface reduction rate of 50% or more to form a processed tube 8 shown in FIG. 1 (c). An annealing treatment is performed at a temperature higher than the recrystallization temperature of the alloy, and FIG.
The electrode tube 10 for electric discharge machining of the present invention shown in FIG.

The method of roll forming is not particularly limited, and examples thereof include an edge forming method, a center forming method, a circular forming method, and a combination of these methods.

The local heating by the high-frequency current is performed by induction or direct energization via an induction heating coil or a contact.

Examples of the surface reduction processing include all general surface reduction processing, such as drawing using a die.

Here, a Cu-35wt% Zn alloy widely used as an electrode wire for wire-cut electric discharge machining is a copper alloy strip 1
When the electrode tube 10 for electric discharge machining is manufactured from the copper alloy strip 1, Zn is applied from the surface of the electrode tube 10 during electric discharge machining.
Sublimates (vaporizes).

For this reason, the electrode tube for electric discharge machining made of a Cu-35 wt% Zn alloy has the features that it has good cutting workability and that it can remove machining chips accompanying cutting. However, Cu-35wt% Zn alloy has higher hardness than copper, so the workability in surface reduction is inferior to copper,
Further, there is a problem that Zn in the Cu-35 wt% Zn alloy is sublimated (vaporized) by heat during the annealing process.

According to the present invention, after the tube 5 is formed from the copper alloy strip 1 such as a Cu-35 wt% Zn alloy, the tube 5 is subjected to a surface reduction process with a surface reduction rate of 50% or more. Thus, the recrystallization temperature of the copper alloy can be lowered, and a copper alloy additive (for example, Zn in the case of a Cu-Zn alloy)
(Sublimation (evaporation), etc.) can be reduced.

Further, by subjecting the processed pipe 8 after the surface reduction processing to an annealing treatment at a temperature equal to or higher than the recrystallization temperature of the copper alloy, the metal structure of the entire pipe becomes uniform, There is no risk of cracking or disconnection.

Further, by this annealing treatment, the welding portion 4
Electrode tube for electric discharge machining suitable for precision machining because the copper alloy additive which has been unevenly segregated near the welded portion diffuses and the concentration of the copper alloy additive in the entire tube becomes uniform, resulting in uniform discharge characteristics. It becomes 10.

In the description of the present invention, copper alloy strip 1
Although the case where the electrode tube 10 for electric discharge machining is manufactured using the above is described, it is needless to say that the electrode tube for electric discharge machining may be manufactured using a copper strip.

[0029]

First, four copper alloy strips made of Cu-35 wt% Zn are prepared.

Next, the copper alloy strips are bent in the width direction, and both ends in the width direction are butted, and the butted portions are welded to form a pipe material. Annealing processing is performed on the tube material after machining to produce four types of electrode tubes for electric discharge machining (1-1, 1-2, 1-3, 1-4).

Here, the electrode tube for electric discharge machining of 1-1 has a reduction in area of 50% and the annealing treatment has been performed at 400 ° C. for 1 hour. Was set to 50% and the annealing treatment was performed at 450 ° C. × 1 hour. The electrode tube for electric discharge machining of 1-3 had a surface reduction rate of 90% and the annealing treatment was performed at 400 ° C. × 1 hour.
The electrode tube for electrical discharge machining, which was 1 hour, had an area reduction rate of 90% and an annealing treatment at 450 ° C. × 1 hour.

The metal structure in the welded portion of each of the electrode tubes for electric discharge machining was examined, and the effects of the area reduction and the annealing treatment on the recrystallization of the metal structure were evaluated. Table 1 shows the evaluation results.

[0033]

[Table 1]

As shown in Table 1, the metallographic structure of the welded portions of the electrode tubes for electric discharge machining of 1-1, 1-2 and 1-3 was an incomplete recrystallized structure. In contrast, 1-
The metal structure in the welded portion of the electrode tube for electric discharge machining of No. 4 was a completely recrystallized structure.

That is, in the electrode tube for electric discharge machining 1-4 in which the area reduction rate is 90%, the recrystallization temperature is lower than the annealing temperature of 450 ° C. The metal structure in the weld was able to be recrystallized by the annealing treatment.

On the other hand, in the electrode tube for electrical discharge machining of 1-3 which has been subjected to a surface reduction process with a surface reduction rate of 90%, the recrystallization temperature is higher than the annealing temperature of 400 ° C.
It was not possible to recrystallize the metal structure in the welded portion by annealing for one hour.

Also, in the electrode tube for electric discharge machining of 1-1 or 1-2 which has been subjected to surface reduction with a surface reduction rate of 50%, the recrystallization temperature is higher than the annealing temperature of 400 ° C. or 450 ° C. At 400 ° C. × 1 hour or 450 ° C. × 1 hour, it was not possible to recrystallize the metal structure in the welded portion.

This indicates that the recrystallization temperature can be lowered by increasing the area reduction rate of the area reduction processing.

As described above, the embodiments of the present invention are not limited to the above-described embodiments, and it is needless to say that various other embodiments are also conceivable.

[0040]

In summary, according to the present invention, after a pipe material is formed from a copper strip or a copper alloy strip, the pipe material is subjected to a surface reduction process with a surface reduction rate of 50% or more. By performing an annealing treatment at a temperature equal to or higher than the recrystallization temperature of copper or a copper alloy, an excellent effect that the metal structure of the entire pipe becomes uniform is exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a method for producing an electrode tube for electric discharge machining according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper alloy strip (copper strip or copper alloy strip) 2a Edge end surface (butting part) 5 Tube material 8 Machining tube material (tube material 8 after surface reduction processing) 10 Electrode tube for electric discharge machining

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // C22F 1/00 691 C22F 1/00 691B 694 694A (72) Inventor Hiroaki Numata Kawajiri-cho, Hitachi City, Ibaraki Prefecture 4-10-1 Hitachi Cable Co., Ltd. Toyoura Plant (72) Inventor Masato Watanabe 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture Hitachi Cable Co., Ltd. Power System Research Laboratory (72) Inventor Takeshi Sato Ibaraki Prefecture 4-10-1, Kawajiri-cho, Hitachi City Hitachi Cable Co., Ltd. Toyoura Plant (72) Inventor Toshiyuki Horikoshi 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture F-term in Power Systems Research Laboratory, Hitachi Cable, Ltd. (Reference) 3C059 AA01 AB01 DA03 DA08 DB07 DC02

Claims (3)

[Claims] 1. A method for manufacturing an electrode tube for electric discharge machining from a copper strip or a copper alloy strip, wherein the copper strip or the copper alloy strip is curved in the width direction and both ends in the width direction are abutted. After welding to form a tube material, the tube material is subjected to a surface reduction process with a surface reduction rate of 50% or more, and the tube material after the surface reduction process is subjected to an annealing treatment at a temperature equal to or higher than the recrystallization temperature of copper or a copper alloy. A method for producing an electrode tube for electrical discharge machining, characterized by the following. 2. A copper strip or a copper alloy strip is bent in the width direction and the both ends in the width direction are butted, and the butted portion is welded to form a pipe material. An electrode tube for electrical discharge machining, characterized in that the surface reduction processing is performed, and the tube material after the surface reduction processing is subjected to an annealing treatment at a temperature equal to or higher than the recrystallization temperature of copper or a copper alloy. 3. The electrode tube for electrical discharge machining according to claim 2, wherein said copper alloy strip is made of Cu-35 wt% Zn.