JP2000107943A - Wire electronic discharge machining electrode line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite electrode line inexpensive, and more excellent in electric discharge machining performance than a heavy metallic line such as a tungsten line and the like as a fine and accurate machining electrode line for wire discharge machining. SOLUTION: A piano wire made out of material containing more than 0.4 wt.% carbon by percentage, is made to be a core wire 1, copper (Cu) 2 and zinc (Zn) 3 both of which are substantially uniform in thickness, are sheathed in order over the outer circumference of the core wire 1 so as to be finished up to the outer diameter in cross section of less than 0.10 mm as an electrode line, and the covering thickness of Cu is more than the thickness enabling the covering of Zn 3 to be formed, but less than 5 μm wherein the covering thickness of Zn 3 shall be more than 0.5 μm, but less than 3.0 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode wire used as an electrode tool in wire electric discharge machining, and more particularly to an electrode wire used for fine and precision machining.

[0002]

2. Description of the Related Art Conventionally, electrode wires for wire electric discharge machining have a wire diameter of φ0.03 mm to φ0.35 mm.
There are already a wide variety of types, such as copper alloys, copper alloy-coated iron alloys, and heavy metal-based materials such as tungsten and molybdenum. It is not enough to just select and set the EDM condition. The wire diameter of the electrode wire is about 0.2mm of the standard wire diameter.
Therefore, it is necessary to use an electrode wire having a finer wire diameter of φ0.03 to 0.1 mm, specifically, for example, φ0.05 mm or φ0.07 mm.

However, when the wire diameter is reduced, the tension that can be applied to the electrode wire running between the pair of positioning guides is reduced. Therefore, a copper alloy electrode wire having a small tensile strength (tensile strength) is used. For this reason, heavy metal electrode wires such as tungsten and molybdenum having high tensile strength have been used. However, these electrode wires have problems not only in terms of their resources and production, but also are extremely expensive, and are not satisfactory in terms of electric discharge machining performance.

Recently, for example, Japanese Patent Publication No. 57-57211, Japanese Patent Publication No. 57-5648, and Japanese Patent Application Laid-Open No.
Various composite metal wires in which a steel wire of an iron-based alloy is coated with a copper-based alloy as disclosed in, for example, JP-A No. 1126 and JP-A-6-238523 have been developed.
mm wire wire has high tensile strength and stable electric discharge machining characteristics, and is much cheaper than the heavy metal-based electrode wires. In terms of not only the strength but also the machining speed combined with the electric discharge machining characteristics, especially in the region of small wire diameter, φ0.08 to φ0.07 mm or less,
For example, there is a problem that the above-mentioned tungsten wire is inferior.

[0005]

The prior art Japanese Patent Application Laid-Open No. 3-111126 discloses that a copper coating layer is formed on the surface of a metal wire such as a hard steel wire, a stainless steel wire, a brass wire, and the like. By forming a zinc coating layer on the coating layer, a coating layer having a two-layer structure with a total coating layer thickness of 0.2 to 20 μm is formed, and the average particle size is increased over one or both of the coating layers. Although there is a disclosure about an electrode wire in which graphite particles of 10 μm or less are dispersed, the electrode wire has a wire diameter of φ0.1 to
It seems that the target is 0.3 mm, and in the specific example, only a piano wire having a diameter of 0.17 mm before coating is used.
% Or less of the coating layer contains fine graphite particles in a dispersed manner, so that this technique can be applied to an electrode wire for fine and precision machining with a wire diameter of φ0.10 or less, or is effective when applied. It is not clear what it is.

Further, the above prior art is disclosed in Japanese Patent Application Laid-Open No. Hei 6-2385.
No. 23 discloses a composite wire in which a steel wire is coated with copper,
The area ratio of copper to steel on the surface is 25 to 75%, and the height from the bottom of the concave portion to the tip of the convex portion is 0. 0 over the entire boundary between copper and steel.
There is unevenness of 1 to 2 μm, and Zn of 1 μm or more
There is a description of a copper-coated steel wire for wire electric discharge machining provided with a layer, and a wire diameter φ0.05 to 0.3 mm as an electrode wire.
Although there is a suggestion that it is intended for those in the range of, in the specific example, the processing speed of the electrode wire finished by drawing the wire diameter to φ0.2 mm, the good heat conduction joining of the drawn steel and coated copper This technology relates to improved electrode wires, and this technology has a wire diameter of φ0.1
It is not clear whether a practically usable thin wire having a high tensile strength such as a tungsten wire or a molybdenum wire for fine and fine machining of 0 mm or less and having a moderate electric discharge machining performance can be obtained.

Accordingly, the present invention has a structure similar to that of the above-mentioned prior art in which a high-carbon piano wire is used as a core, copper is coated on the core, and zinc is further coated on the copper. However, the wire diameter is 0.10 mm or less, that is, φ
It has a high tensile strength that can be used in place of heavy metal wires such as the above-mentioned tungsten wire and molybdenum wire in the thin wire region of 0.03 to φ0.1 mm, and is equivalent in electric discharge machining performance such as machining speed. It is proposed because an electrode wire having the above-mentioned performance and being able to be used alternately at a significantly lower cost than the heavy metal wire is obtained.

[0008]

SUMMARY OF THE INVENTION The above-mentioned object of the present invention is as follows.
(1) A piano wire having a carbon content of 0.6% or more by weight as a core is used as a core wire, and copper (Cu) and then zinc (Zn) are sequentially coated on the outer periphery of the core wire with a substantially uniform thickness. An electrode wire having a cross-sectional outer diameter of φ0.10 mm or less, wherein a coating thickness of the copper (Cu) is not less than a thickness capable of forming a coating of the zinc (Zn) and not more than 5 μm; This is achieved by providing an electrode wire for wire electric discharge machining in which the coating thickness of the zinc (Zn) is 0.5 μm or more and 3.0 μm or less corresponding to machining conditions.

Another object of the present invention is to provide (2) a method in which the outer diameter of the cross section of the electrode wire is φ0.08 mm smaller than φ0.10 mm.
mm or less and φ0.03 mm or more, and the copper (C
The electrode wire for wire electric discharge machining according to (1), wherein the coating of u) and zinc (Zn) is formed by electroplating, and the lower limit of the coating thickness of the copper (Cu) is 1.0 μm or more. Is achieved by

The object of the present invention is as follows: (3) The core wire is a high-carbon piano wire having a carbon (C) content of 0.9% or more, and the electrode wire has a cross-sectional outer diameter of: Copper (Cu)
And zinc (Zn) are sequentially coated to a desired thickness and then drawn to a diameter of 0.03 mm to 0.08 mm, and the copper (Cu) coating thickness is 2 μm to 4 μm.
This is achieved by providing the electrode wire for wire electric discharge machining according to (1) or (2), wherein the coating thickness of the zinc (Zn) is 1 μm to 2.5 μm.

Another object of the present invention is to provide (4) heat-treating and drawing a high-carbon piano wire to obtain a high-strength steel wire having a diameter smaller than the outer diameter of a predetermined electrode wire. Electroplating of copper (Cu) and electroplating of zinc (Zn) are sequentially performed on the outer periphery to form respective coating layers, and the composite wire formed with the coating layers is formed of a predetermined electrode wire of φ0.10 mm or less. It is an ultrafine wire drawn to a diameter and subjected to a linear processing by hot tension, and the thickness of the copper (Cu) coating on the outer periphery of the steel wire is 5 μm.
m or less, and the thickness of the zinc (Zn) coating on the outer periphery of the copper coating is 0.5 μm or more and 3 μm or less, and the sectional diameter is φ0.10 mm or less. Better achieved.

Further, the object of the present invention is that (5) the diameter of the composite wire finished to the predetermined cross-sectional diameter is φ0.0
3 mm or more and φ0.08 mm or less, and the copper (C
u) The thickness of the coating is 2-4 μm and the zinc (Z
n) It is achieved by providing the electrode wire for wire electric discharge machining according to (4), wherein the coating has a thickness of 1 μm to 2.5 μm.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged sectional view for explaining an embodiment of a multiple composite electrode wire according to the present invention, wherein 1 is carbon (C).
Is at least 0.6% or more, preferably 0.9% or more.
% Of the high-carbon piano wire used as the core wire of the electrode wire of the present invention is twice the sum of the thicknesses of the copper (Cu) coating and the zinc (Zn) coating formed on the outer periphery thereof. Heat treatment and wire drawing are repeated from the desired piano wire to a small diameter corresponding to the diameter, thereby finishing the steel wire having the predetermined small diameter and high strength. As the carbon (C) content in the above-mentioned piano wire, it is desirable to use a wire having a large content such that a wire having a smaller diameter has a larger tensile strength per unit cross-sectional area, For example, as a wire material for an electrode wire having a wire diameter of φ0.08 to φ0.10 mm, a so-called 80-carbon piano wire (approximately 0.78 to 0.10 mm) is used.
83% C), and as a wire for an electrode wire having a wire diameter of φ0.07 mm or less, for example, φ0.03 mm, φ0.05 mm, or φ0.07 mm, a so-called 100 carbon piano wire (approximately 0.95 to 0.95 mm). 1.05% C).

2 is a copper (Cu) coating formed by electroplating or the like on a substantially uniform thickness of the outer periphery of a piano wire made of the high-strength steel wire as a core wire. Cu) is described in paragraphs [0005] and [0006] above.
As in the prior art described in
As a result, even if it may contribute to some extent, in the present invention, the wire diameter of the target electrode wire is a fine wire diameter of φ0.10 mm or less, and the condition of electric discharge machining is fine, precision finishing machining. Originally, the processing current flowing is not large, and the copper (Cu) coating is, in the present invention,
A kind of zinc (Zn) coating, which stably discharges and provides good discharge characteristics, can be formed on the surface of a steel wire with poor electric discharge machining characteristics in a state with good density, mechanical covering strength, etc. In view of the purpose of forming such a copper (Cu) coating, the copper (Cu) coating should not be thick in order not to reduce the tensile strength as an electrode wire. Therefore, the thickness of the copper (Cu) coating 2 is at most 5 μm, preferably 4 μm or less, and the lower limit is that if a direct coating of zinc (Zn) can be formed on a steel wire in principle, it is not possible. However, in order to enable easy formation of a good zinc (Zn) coating on the above-mentioned electric discharge machining, copper (Cu) having a thickness of 1 μm, preferably 2 μm or more which also contributes to an increase in energizing current is used. ) It is preferred to use a coating. The copper (Cu) coating is not limited to the above-described electroplating, but may be formed by electroless plating, physical vapor deposition (PVD), or chemical vapor deposition (CVD). In addition, as described above, this copper (Cu) coating mainly comprises zinc (Z
n) It is sufficient that the steel wire can be coated on the steel wire. From this viewpoint, it is easy to form a high-quality coating such as plating on the surface of the steel wire, and zinc (Zn) plating is performed on the coating. A highly conductive metal that can be easily removed, for example, nickel (Ni) or brass plated coating can be used instead.

3 is a copper (C) having a thickness of 5 μm or less formed substantially as an underlayer on the outer periphery of the high-strength steel wire.
u) Zinc (Z) formed on the coating by electroplating or the like
n) coating. By the way, the essence of the present invention has conductivity that can be used as an electrode wire for wire electric discharge machining, and has a high tensile strength, so that it can be used in place of a heavy metal electrode wire such as a tungsten wire or a molybdenum wire. In order to improve the electric discharge machining performance of the high carbon piano wire, a zinc (Zn) coating is provided on the outer periphery of the piano wire, and the zinc (Zn) coating is uniformly applied to the entire surface of the outer periphery of the piano wire, mechanically. A substantially desired uniform thickness on a copper (Cu) -coated substrate as described above such that the coating or bonding is high in strength and the coating is formed to a thickness that is sufficiently effective to improve EDM performance. The coating thickness is the minimum amount required under the processing conditions set according to the electrode wire diameter and the purpose of processing, specifically, the lower limit of the coating thickness. Is at least 0.5 μm or more, It is properly 1
μm or more is recommended, while the upper limit of the coating thickness is preferably 8 μm or less, at which the improvement in processing performance such as the processing speed is almost saturated and the decrease in the diameter of the core wire does not become larger than the outer diameter of the electrode wire. Is a coating having a thickness of 2 to 3.5 μm. The zinc (Zn) coating can be easily formed by electroplating or the like from the place where the above-mentioned copper (Cu) coating is provided, and can be formed by electroless plating or physical vapor deposition (P).
VD) and chemical vapor deposition (CVD) can also be used. In the present invention, the copper (Cu) coating and the zinc (Zn) coating are the same as those described above because of the relationship between the coating base and the coating. Thus, unlike the case where both are alloyed by heat treatment to form an electrode material brass, it is not necessary to form a coating with a thickness that takes into account the composition for producing a 6: 4 to 7: 3 brass alloy.

Next, a specific example of an electrode wire having an outer diameter of φ0.05 mm will be described. A piano wire of high carbon (0.8% C or more) has a diameter of 0.2 mm by repeating heat treatment and wire drawing.
After finishing to a 042 mm core wire, performing alkaline degreasing and pickling, copper (C) having a thickness of about 2.4 μm was electroplated with copper.
u) A coating was formed, followed by zinc electroplating to form a zinc (Zn) coating having a thickness of about 1.6 μm, which was finished to an outer diameter of 0.05 mm by wire drawing. According to the cross-section inspection, the core wire outer diameter φ0.042 mm (cross-sectional volume ratio of about 70
%), A copper (Cu) coating thickness of 2.4 μm (cross-sectional volume ratio of about 17%), and a zinc (Zn) coating thickness of 1.6 μm (cross-sectional volume ratio of about 13%). Is about 8% of the electrode wire diameter and the tensile strength is 2170 N / m
m ² .

Conventionally, copper (C)
u) The coating and the zinc (Zn) coating were heat-treated for alloy brass before the wire drawing treatment after the zinc (Zn) coating, but the present invention does not require such alloying.
Without conducting as described above, a wire finished to a predetermined outer diameter is heated to 350 to 400 ° C., and subjected to a straightening process for applying a tension of 20 to 40% of the tensile strength of the wire at normal temperature. Product. The following table shows the electrical discharge machining performance of the thus manufactured electrode wire of φ0.05 mm in comparison with the machining performance of a conventional electrode wire of the same kind.

[0018]

[Table 1]

In the above table, the upper column is a condition table of processing conditions used, and the lower column is a characteristic and processing performance table of various electrode wires.
The workpiece is SKD11 having a thickness of 5 mm, the processing fluid is mineral oil, the tension applied to the electrode wire is 100 g, and the running speed is 7 m / min. In the table, “with processing” of the tensile strength is the strength (g) after being used for processing, while “without processing” is the strength (g) of the unused one, and “A” is the processing speed. conditions"
Is the case of processing under the condition of C001 in the processing condition table [A],
The “highest speed” is the highest speed (m
m / min) and the processing conditions at that time (the processing conditions of the alphabets in []) are added, and the surface roughness is from the first cut of C001 to the finish processing of C911 in the order of the processing conditions [A]. It is the surface roughness after processing, the parallel direction is the surface roughness in the direction parallel to the processing feed of the electrode wire, and the vertical direction is the surface roughness in the same vertical direction, and if the value is small, At the same time, a small difference between the parallel direction and the vertical direction indicates that the processed surface roughness is uniform. And straightness means that the electrode wire before use is vertically
It indicates the degree of bending to the side when it is hung by mm, and the smaller the value, the higher the probability of automatic connection.

In the table of processing results, the "inventor's conventional alloy wire" is manufactured by brazing a copper (Cu) coating and a zinc (Zn) coating with a brass alloy, as mentioned in the above paragraph [0015]. This composite electrode wire was already considerably superior to the characteristics and processing performance of composite electrode wires such as other alloy wire 1 and alloy wire 2, but compared to commercially available tungsten wires. Then, especially in terms of processing speed etc., it was inexpensive, so it was simply cheap.
According to the electrode wire of the present invention, an unused electrode wire as a raw material is merely inferior in tensile strength, and all other characteristics and processing performance are equal to or more than that, and furthermore, such an electrode wire of the present invention is used. Is inexpensive as well as the conventional composite electrode wire, and I believe that it will be widely used in place of heavy metal wire such as tungsten wire.

[0021]

As described above in detail, according to the composite electrode wire of the present invention, when the wire diameter is less than φ0.10 mm,
Since it is intended for fine wires of about mm or more, it is not necessary to apply a large machining current by setting the machining conditions. Therefore, zinc (Zn) coating for improving the electric discharge machining performance for high carbon steel piano wires. The thickness of the copper (Cu) coating formed on the outer peripheral surface of the piano wire may be considered with a focus on the base necessary for good quality and good formation. The Zn) coating is an essential necessary amount (thickness) according to the processing conditions to be set and the purpose of the processing, and the thickness of the copper (Cu) coating can be up to 5 μm, and can be less than that. An electrode wire having a high tensile strength can be easily obtained, and the copper (Cu) coating and the zinc (Zn) coating are not subjected to the alloying treatment of brassization, and the discharge is performed with the zinc (Zn) coating as it is. Involve in gap discharge More discharge machining performance of more than heavy metal wire tungsten wire or the like can be obtained. Moreover from where it is inexpensive, wire electric discharge machining of the fine is large ones where contribute to precision machining.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view for explaining an embodiment of a multiple composite electrode wire according to the present invention.

[Description of Signs] 1: Core wire 2: Copper (Cu) coating 3: Zinc (Zn) coating

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideaki Shimoda 1-8-2 Marunouchi, Chiyoda-ku, Tokyo 1st Steel Building Suzuki Metal Industry Co., Ltd. F-term (reference) 3C059 AA01 AB05 DA06 DB03 DC01 4E096 EA02 EA13 KA09 5G307 BA07 BB04 BC03 BC07

Claims (5)

[Claims] 1. The method according to claim 1, wherein the carbon (C) content is 0.1% by weight.
An electrode having a core wire of 6% or more of a piano wire, and the outer periphery of the core wire is coated with copper (Cu) and then zinc (Zn) in a substantially uniform thickness in order to finish the outer diameter of the cross section to 0.10 mm or less. The coating thickness of the copper (Cu) is not less than a thickness at which the coating of the zinc (Zn) can be formed and not more than 5 μm, and the coating thickness of the zinc (Zn) depends on the processing conditions. Corresponding electrode wire for wire electric discharge machining having a size of 0.5 μm or more and 3.0 μm or less. 2. An outer diameter of a cross section of the electrode wire is φ0.10 mm.
Φ0.08 mm or less, φ0.03 mm or more, wherein the coating of copper (Cu) and zinc (Zn) is formed by electroplating, and the lower limit of the coating thickness of copper (Cu) is 1.0 μm or more. 2. The method according to claim 1, wherein
4. The electrode wire for wire electric discharge machining according to claim 1. 3. The core wire having a carbon (C) content of 0.9.
% Or more, wherein the outer diameter of the cross section of the electrode wire is φ0.03 mm to φ0.0 mm by drawing after coating copper (Cu) and zinc (Zn) in order to each desired thickness.
08 mm and the copper (Cu) coating thickness is 2
μm to 4 μm, and the coating thickness of the zinc (Zn) is 1 μm.
3. The electrode wire for wire electric discharge machining according to claim 1, wherein the electrode wire has a diameter of m to 2.5 μm. 4. 4. A high-carbon piano wire is subjected to heat treatment and wire drawing to obtain a high-strength steel wire having a diameter smaller than the outer diameter of a predetermined electrode wire, and electroplating copper (Cu) on the outer periphery of the steel wire. Zinc (Z
n) is sequentially performed to form each coating layer, and the composite wire on which the coating layer is formed is drawn to a diameter of a predetermined electrode wire of φ0.10 mm or less, and further straightened by hot tension. An ultra-fine wire that has been processed, and the copper (C
u) a wire having a cross-sectional diameter of 0.10 mm or less, wherein the thickness of the coating is 5 μm or less, and the thickness of the zinc (Zn) coating on the outer periphery of the copper (Cu) coating is 0.5 to 3 μm. Electrode wire for electric discharge machining. 5. The composite wire finished to a predetermined cross-sectional diameter has a diameter of not less than 0.03 mm and not more than 0.08 μm, and the thickness of the copper (Cu) coating is 2 μm to 4 μm.
And the thickness of the zinc (Zn) coating is 1 μm to 2.5 μm.
5. The electrode wire for wire electric discharge machining according to claim 4, wherein m is m.