JPS59134623A - Composite electrode wire for wire-cut electric discharge machining and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain the captioned composite electrode wire having a uniform thickness of covering and the stable electric discharge characteristic by covering the outer periphery of a core member made of steel wire, etc., with Zn-Be alloy containing a specific weight% Be. CONSTITUTION:The captioned composite electrode 2 has an outer covered layer 4 which is formed by covering the outer periphery of a core member 3 with other metal material. A copper wire or brass wire is used for the core member 3 similarly in the conventional, while Zn-Be alloy contaoning 0.003-0.3wt% Be is used for the outer covered layer 4. When said composite electrode wire 2 is prepared, the core member 3 is immersed into the Zn-Be alloy bath, and the outer periphery of the core member 3 is covered with Zn-Be, or afterwards said core member 3 is cold-elongated with a surface reduction rate of 5-90%. In another method, the outer periphery of the core member 3 having a wire diameter larger than the final desired wire diameter is hot-extrusion-covered with Zn- Be alloy and then cold-elongated with a surface reduction rate of 80% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a composite wire suitable as an electrode wire for wire cutting and eccentric processing, and a method for manufacturing the same.

(b) Background of the technology The wire-cut electrical discharge machining method involves creating electrical discharge between the workpiece and a linear machining electrode (hereinafter referred to as electrode wire).
This is a conventional method in which the electrode wire and the workpiece are moved relatively to cut the workpiece into a desired shape.

In this wire-cut electrical discharge machining method, a long wire with a diameter of usually 0.05 to 0.25 ruL* is prepared as the linear electrode wire, and new wires are sequentially supplied to the electrical discharge machining part. There is.

In the electric discharge machining method, the quality of the electrode wire used has a direct and significant effect on the machining speed, machining accuracy, and surface quality of the workpiece surface, so there is a strong demand for the use of suitable materials. ing.

In general, the requirements for this polarization line are: (1) Machining speed: Generally, the machining speed is not necessarily high in the wire cut electric discharge machining method, so it is possible to increase the machining speed even a little.

(2) Good dimensional accuracy and surface texture of the workpiece,
It can also be processed without causing surface roughness.

(3) Workability: If the electrode wire breaks during cutting work, workability will be significantly impaired, so the occurrence of breakage during this work should be low. Furthermore, when setting the wire in a processing machine, and especially when using an automatic wire feeding device, it is strongly desired that the wire has no curls and has straightness.

(4) Price: As mentioned above, the polarizing line is a consumable item, so it should be inexpensive.

etc. are listed.

Conventionally, copper wire, brass wire, tungsten wire, etc. have been used as polarizing wires that satisfy the above conditions.
However, recently, it has become unable to adequately meet the demands for increased processing speed and precision, as well as demands for automatic wire feeding. Therefore, recently, as disclosed in Japanese Patent Publication No. 57-5648, a composite electrode wire 2 has been proposed in which the surface of the core material 8 shown in FIG. Compared to conventional polarized wires, the electrical discharge machining speed can be increased. However, this composite line is not widely used due to various practical problems.

In the above-mentioned composite wire, the core material 8 is made of brass or steel, and the outer layer 4 is proposed to be Zn hot-dipped by electroplating or Zn by a fitting method. First of all, if the plating is performed using plating, the cost is high, especially since thin wires are required these days, making the cost extremely high and impractical. Next, in the case of the hot-dip plating method, thick plating is possible, but if the core material is brass, the molten bath
Since the temperature is around 50°C, the core material softens during passage.

Also, if the core material is steel, it has the advantage of high tensile strength, but Zn and F
Intermetallic compounds with E are formed, making wire drawing difficult, resulting in uneven thickness and unstable discharge characteristics. Further, in the third fitting method, it is difficult to fit a small diameter size, resulting in high cost, and there is a problem that even a large diameter size is difficult to process due to the difference in strength softening temperature between the core material and the outer layer material.

(c) Object of the Invention The object of the present invention is to solve the above-mentioned problems of the composite electrode wire and provide a composite electrode wire for wire-cut electric discharge machining that has a uniform coating thickness and stable discharge characteristics.

B) Disclosure of the Invention The feature of the present invention is that the core material is the same steel wire or brass wire as the conventional products, but the outer periphery of the core material is coated with Be in an amount of o, ooa to 0.3% by weight.
The reason is that it is a Zn-Be alloy containing Zn-Be. By containing this extremely small amount of Be, uniform hot-dip plating is possible, and extrusion coating also provides good extrudability, and subsequent cold drawability is also good, resulting in stable electrical discharge even when the wire is made into an extremely fine wire. It was found that it exhibits processing characteristics. Be is 0.003
If it is less than % by weight, there will be no effect of improving electrical discharge machining characteristics, and the above-mentioned effect of ease of manufacture will not be obtained. If Be exceeds 0.3% by weight, there is a risk of evaporation of Be during hot-dip plating, and the price becomes high, and the above-mentioned effects of property improvement, extrudability and wire drawability are saturated.

In the case of a hot-dip plating method, the composite wire of the present invention can be coated by dipping and passing a core steel wire or brass wire through a Zn-Be alloy bath having the above composition. Therefore, it has good plating properties and can be coated thinly and uniformly. Although it can be used as an electrode wire for wire-cut electrical discharge machining, it can be further cold drawn after coating to form a composite wire of desired dimensions. In this case, the area reduction rate is preferably 5 to 90%. If it is less than 5%, wire curls tend to remain, and if it is more than 90%, it is difficult to draw the wire, especially when the core material is a steel wire.

It can also be manufactured by extrusion coating.

In this case, Zn-
A Be alloy is hot extruded and coated, and then cold wire drawn with an area reduction of 80% or more. By setting the area reduction rate to 80% or more, the strength of the composite wire becomes 70 K9/ax or more, and it can be used with high tension applied during processing.

Since the present invention has the above-mentioned features, the hot-dip plating method allows coating by short-time dipping and is uniform without generating intermetallic compounds, resulting in stable discharge eco-performance.

Further, even in cold wire drawing to obtain dimensional accuracy and strength after plating, the surface of the Zn-Be alloy coating layer is smooth and has excellent workability.

Furthermore, since it contains Be, the electric discharge machining characteristics are stable,
This is superior to the case of simple Zn. Although the reason for this is not clear, it is thought that the thickness of the oxide layer on the surface of the Zn-Be layer has a subtle influence.

In addition, in the case of an extrusion coating method using brass as a core material, extrusion properties and cold drawability after composite are good, and the product is extremely easy to manufacture.

Next, a detailed explanation will be given using examples.

Example 12 0.6% carbon steel wire (outer diameter 0.25 #[+”) was heated in H2S
After electropolishing with an O4 solution, the steel wire was passed through a Zn-Be alloy bath containing 0.05% Be at a temperature of 450°C at high speed to form a Zn-Be layer on the outer peripheral surface of the steel wire.
．． 0 mX After closing, the outer diameter is 0.20 m by cold wire drawing.
*The composite line shown in Figure 2 was used. The Zn-Be layer 4 has a thickness of about 1
It is 7 μm.

Using this wire, the plate thickness was 4Qi by wire cut electrical discharge machining.
The results shown in Table 1 were obtained by cutting 5KD-11 material of x. In manufacturing this composite wire, it had excellent cold workability and was easy to manufacture.

The electrical discharge machining speed ratio in the table is the ratio when the conventional product (brass wire) is set to 1.0.

Example 2 A Cu-30% Zn alloy (brass) wire with an outer diameter of 8 mm was prepared, and the outer periphery was coated with Zn-Be alloy containing 0.08% Be by extrusion continuously at about 200°C. Outer diameter I Q m
After making an LN composite wire, it was cold drawn to 0.25r.
A composite electrode wire of uL was manufactured. Zn-B of this composite wire
The e-alloy layer had a thickness of 25 μm. Using this wire, a 5KD-11 material with a plate thickness of 20 bottles was cut into a wire cut group t, and the results shown in Table 2 were obtained. In the above production, extrudability and cold wire drawability were excellent and production was easy.

Table 2

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a conventional electrode wire, and FIG. 2 is an i-sectional view of a composite electrode wire of the present invention. 1: Single wire, 2: Composite wire, 3: Core material, 4.: Outer coating layer. Agent Patent Attorney Satoshi Tsukasa AI Figure 2

Claims (3)

[Claims] (1) In a composite wire in which the outer periphery of the core material is coated with another metal, the external use is a Zn-Be alloy containing o, ooa ~ 0.3% by weight of Be, and the core material is a steel wire or brass wire. A composite electrode wire for wire-cut electrical discharge machining, which is characterized by: (2) In a method for manufacturing a composite wire in which the outer periphery of the core material is coated with a fine metal, a steel wire or a brass wire is used as the core material, and this core material contains Z containing from o, ooa to 0.3% by weight of Be.
Zr is applied to the outer periphery of the core material by immersion in an n-Be alloy bath.
coated with r-Be or thereafter 5-90%
A method for producing a composite electrode wire for wire cut center-center processing, which is characterized by cold drawing at an area reduction rate of . (3) In a method for manufacturing a composite wire in which the outer periphery of the core material is coated with another metal, Be is contained in the outer periphery of a steel wire or brass wire with a wire diameter thicker than the final desired wire diameter in an amount of o, ooa to 0.3% by weight. After hot extrusion coating of ZnBe alloy, the area reduction rate was 80.
A method for producing a composite electrode wire for wire cut center-center processing, which is characterized by cold drawing of % or more.