JP2003136341A - Electrode wire for wire discharge work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode wire for wire discharge work capable of achieving high speed compared to conventional wires for suppressing processing cost low. SOLUTION: Copper alloy or copper-coated steel wire is used as a center core material 2, a high zinc density copper - zinc alloy layer 3 with 45-65 wt.% zinc density is formed in 10-20% thickness of finished outer diameter, and a surface layer on its outer circumference is ground. A zinc plating layer 4 is further provided with 0.5-3% thickness of total finished outer diameter to provide this electrode wire 1 for wire discharge work. After the high zinc density alloy layer is formed, a rough part in the surface layer is shaved by a shaving die or the like only for a part where adhesion of electroplating is kept, so that a void layer 5' as in conventional devices is eliminated. Peeling of plating is thus eliminated, and the high zinc density layer which affects processing speed can be left to the utmost. High speed processing can thus be achieved.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode wire used in a wire electric discharge machine, and more particularly to a machining speed for shaving a cut object in order to keep machining costs low. The present invention relates to an electrode wire 1 for wire electric discharge machining, which can be made faster and faster than a conventional wire. 2. Description of the Related Art At present, various types of electrode wires for wire electric discharge machining are on the market for the purpose of high-speed machining. Electrode wires having a composite structure in which a high copper-zinc alloy layer is formed on the electrode wire surface have become mainstream. When copper alloy and zinc are interdiffused in a high temperature atmosphere in the process of manufacturing such a conventional composite structure electrode wire, as shown in FIG. 2, a void layer 5 composed of an aggregate of cavities is formed on the surface of the electrode wire. 'Are generated frequently and the surface becomes rough. In the case where the outermost layer is coated with zinc or the like, since the roughness of the surface layer significantly reduces the adhesion of the plating, the surface is polished by electrolytic pickling as a pretreatment for plating to improve the adhesion of the plating. . However, a zinc plating layer is formed on a surface layer of a copper-zinc alloy, and interdiffusion is performed by heat treatment in an oxidizing atmosphere to obtain a high zinc concentration of 45 to 65%. When an alloy layer is formed, there is a large difference between the diffusion rate of zinc in copper and the diffusion rate of copper in zinc, so that interdiffusion starts densely from the interface between the copper-zinc alloy and the zinc plating layer, In addition, since a cavity is formed in the surface layer, a smooth surface state cannot be obtained. To further form a galvanized layer on the electrode wire having the high zinc concentration alloy layer,
It is necessary to smooth the surface, and there is a method of shaving the surface layer by pickling as a method, but there is a disadvantage that zinc concentration in the surface layer is reduced by dezincification, which hinders the improvement of wire electric discharge machining speed. there were. More specifically, a wire coated with zinc by electroplating on a surface layer of a copper-zinc alloy having a zinc concentration of 20 to 40 wt% is allowed to stay in a high-temperature atmosphere of 400 to 900 ° C. Form a layer. Although it depends on the zinc concentration of the central core material, in the case of a copper-zinc alloy having a zinc concentration of 20%, a void layer 5 'consisting of a collection of cavities is generated in the surface layer with a thickness of about several tens of micrometers, and the surface becomes rough. . If zinc is coated by electroplating in this state, the cavity is not plated, and a void layer 5 'composed of a hollow aggregate is formed at the interface between the high zinc alloy layer and the zinc plating layer. In this state, the product outer diameter of the electrode wire for wire electric discharge machining is 0.1.
There is also a drawback that when the wire is drawn to 0.3 mm, the zinc in the surface layer swells and the plating peels off. In addition, if the surface is polished by electrolytic pickling as a technique for improving the finished state of zinc plating, a layer in which the zinc concentration is drastically reduced due to the dezincing phenomenon is formed, which causes a reduction in the processing speed. There were drawbacks. According to the present invention, as a result of diligent studies to solve these problems, a copper alloy or a copper-coated steel wire is used as the center core material 2 and the surface of the center core material 2 Zinc concentration 4
A copper-zinc alloy layer 3 of high zinc of 5 to 65 wt% is formed with a thickness of 10 to 20% of the finished outer diameter, and the outer peripheral surface layer is polished and shaved off.
Is an electrode wire 1 for wire electric discharge machining provided with a thickness of 0.5 to 3% of the total finished outer diameter. After forming the high zinc alloy layer, the rough portion of the surface layer is subjected to electroplating adhesion with a shaving die or the like. By shaving off only the portion where is maintained, the high zinc concentration layer which affects the processing speed can be left as much as possible. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrode wire 1 for electric discharge machining according to the present invention will be described.
The embodiment will be described. FIG. 1 is a cross-sectional view of an electrode wire 1 for wire electric discharge machining according to the present invention, and a description will be given taking a case where a typical copper-zinc alloy is used as a copper alloy as an example. A copper-zinc alloy or a copper-coated steel wire having a zinc concentration of 20 to 40% is used as the center core 2, and the surface of the center core 2 has a zinc concentration of 4%.
A copper-zinc alloy layer 3 of high zinc of 5 to 65 wt% is formed with a thickness of 10 to 20% of the finished outer diameter, and the outer peripheral surface layer is polished and shaved off.
Is an electrode wire 1 for wire electric discharge machining provided with a thickness of 0.5 to 3% of the total finished outer diameter. Here, the copper-coated steel wire refers to a steel wire, an alloy steel wire, and an iron whose outer periphery is coated with copper. This electrode wire 1 for electric discharge machining is formed by plating zinc on a surface layer of a copper-zinc alloy serving as a central core material having an outer diameter of 0.9 mm by electro-galvanization to a thickness of 20 to 30 μm, and at 400 to 900 ° C.
And a high zinc alloy layer is formed by mutual diffusion. At this time, the aggregate of the cavities in the surface layer having a thickness of about several tens of μm was scraped off by a shaving die or the like, and the outermost layer was subjected to electrogalvanization. A structure that leaves a high zinc concentration layer that affects the processing speed by shaving off the rough part of the surface layer after shaping with a shaving die etc. only the part where the electroplating adhesion is maintained. It was made. As a method of polishing and shaving, a typical shaving die was used, but the method is not limited to this. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The results of evaluation using the electrode wire for electric discharge machining 1 of the present invention in an actual electric discharge machine are shown below. The electrode wire used in this embodiment was obtained by shaving the center wire of the electrode wire shown in FIG. 1 with an electrode wire using a copper-zinc alloy having a zinc concentration of 20%, and an electrolytic pickling as a comparative electrode wire. And two types of electrode wires. Using a wire diameter of 0.30 mm, workpiece material SKD-11, workpiece thickness 60 mm, and the maximum conditions for rough machining using an electric discharge machine SX-10, raise the machining conditions until wire breakage occurs as shown in Table 1 below. The maximum processing speed of each wire was compared. [Table 1] Next, the results are shown in Table 2 below, wherein the processing speed is expressed as a ratio when the maximum processing speed of the electrode wire subjected to the electrolytic pickling is set to 1. Table 2 below shows the results of the evaluation of the processing speed for shaving a cut object with respect to the electrode wire of the present invention, the conventional electrode wire prepared by the conventional manufacturing method, and the comparative electrode wire. [Table 2] The following results are obtained from the evaluation results in Table 2 above. 1. Processing speed is improved by pre-processing with a shaving die or the like. 2. The pre-treatment with a shaving die or the like can improve the disconnection resistance. Until now, a copper-zinc alloy has been described as a typical example of a copper alloy, but the present invention is not limited to this, and copper-tin, copper-magnesium, copper-silver, copper-chromium alloy, etc. may be used. It goes without saying that it is within the scope of the present invention. As described above, according to the present invention, when a high zinc alloy layer is formed by interdiffusion, a void layer 5 'formed of an aggregate of surface cavities of about tens of μm is generated. Is scraped off with a shaving die or the like, and the outermost layer is subjected to a pretreatment so that electrogalvanizing with high adhesion strength can be easily applied, so that the conventional void layer 5 'is removed. Since the high zinc concentration layer which affects the processing speed can be left as much as possible, it is possible to achieve an excellent effect that the speed can be increased, so that its industrial value is extremely large.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an electrode wire 1 for wire electric discharge machining of the present invention. FIG. 2 is a sectional view of a conventional wire electrode for wire electric discharge machining 1 '. DESCRIPTION OF SYMBOLS 1 Electrode wire for wire electric discharge machining of the present invention 2 Center core material (copper alloy or copper-coated steel wire) 3 High zinc copper-zinc alloy layer (zinc concentration 45 to 65)
% Copper-zinc alloy) 4 galvanized layer 1 'conventional electrode wire for wire electric discharge machining 2' center core material (copper alloy) 3 'high-zinc copper-zinc alloy layer 4' galvanized layer 5 'aggregate of cavities Void layer consisting of

Continuation of front page    (72) Inventor Masakazu Yoshimoto             2-12 Shimoodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             No. 8 Oki Electric Wire Co., Ltd. (72) Inventor Yoichiro Kimoto             2-12 Shimoodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             No. 8 Oki Electric Wire Co., Ltd. F term (reference) 3C059 AA01 AB05 DA06 DB03 DC02                 4K024 AA01 AA05 AB02 BA09 BB09                       BC03 DA10 DB01 DB07 GA01

Claims (1)

Claims: 1. A copper alloy or a copper-coated steel wire is used as a core material 2 and a high-zinc copper-zinc alloy layer 3 having a zinc concentration of 45 to 65 wt% is formed on the surface of the core material 2. Outer diameter 10-20
%, And the outer peripheral surface layer is polished and shaved off, and the outer periphery is further provided with a galvanized layer 4 having a thickness of 0.5 to 3% of the total finished outer diameter. Electrode wire 1 for electric discharge machining.