JPH0647130B2 - Method for manufacturing electrode wire for wire cut electric discharge machining - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electrode wire used for wire-cut electric discharge machining, particularly a brass clad copper alloy electrode wire in which a Cu-Zn alloy is provided on the surface of a core material mainly composed of Cu. Manufacturing method.

(Prior art and its problems) Conventionally, as a method of manufacturing a brass clad copper alloy electrode wire for wire cut electric discharge machining, a method of press-fitting a core material into a brass pipe manufactured by extrusion in advance, and a brass and core material to be coated The method of simultaneously extruding, and the method of forming a brass coating layer on the surface of the core material by plating are widely used.

However, the above-mentioned press-fitting method has drawbacks in that a large-scale device utilizing hydraulic pressure is required for extrusion and press-fitting, the equipment cost is high, and a long product cannot be manufactured, resulting in poor production efficiency. In addition, the above-mentioned coextrusion method has a drawback that a large-sized hydraulic extrusion device must be used as compared with the above-mentioned press-fitting method, resulting in enormous equipment investment. On the other hand, in the above plating method, it is difficult to increase the thickness of the coating layer, and the plating process must be repeated many times to obtain the required thickness, resulting in a long manufacturing process and poor production efficiency, and preventing pollution. Therefore, it is necessary to treat the plating waste liquid, which results in high cost.

In view of the above situation, it is an object of the present invention to provide a method for producing a high-quality electrode wire having excellent electric discharge machinability with low cost and high production efficiency with simple equipment.

(Means for Solving the Problems) In order to achieve the above object, the method for manufacturing an electrode wire for wire-cut electric discharge machining according to the present invention is directed to a core wire having a diameter of 3 to 4 mm, which is mainly made of Cu and continuously runs. In addition, a strip material with a thickness of 0.6 to 0.8 mm made of Cu-Zn alloy is continuously supplied, this strip material is bent in the width direction by roll forming, and both side edges are abutted to form a core material inside. A pipe through which the wire is inserted is formed, and by a guide member provided in a stage preceding the roll forming portion, the core wire is eccentrically arranged in the pipe away from the abutting part, and the abutting part and the core wire are formed. A gap of 2 to 3.8 mm is formed between the pipes, the abutting parts of the pipes are welded, and the pipes after the welding are drawn at a normal temperature with a die to reduce the diameter, and the Cu-Zn alloy is adhered to the surface of the core wire. And adopted a configuration characterized by further wire drawing. It is.

Further, in the present invention, in the above-mentioned manufacturing method, the pipe cross section of the coating metal is an elliptical shape in which the abutting portion is located on one end side of the major axis before welding, and is corrected to a perfect circle at the front stage of the die after welding. Is the preferred embodiment.

(Operation) In the manufacturing method of the present invention, a Cu-Zn alloy is continuously supplied as a strip-shaped material along a core wire mainly composed of Cu which runs continuously, and the strip-shaped material is roll-formed on both sides thereof. The pipe is formed in a ring shape so that the edges are abutted together and the core wire is inserted inside, and then the abutting portions of the both side edges of this pipe are welded, but in the forming process because it is roll forming The band-shaped material is unlikely to be twisted and deformed, and the abutted side edges are always continuous as a straight line at a fixed position in the circumferential direction. In addition, since the core wire in the pipe is eccentrically arranged on the side away from the abutting portion and a gap is formed between the abutting portion, high heat during welding does not easily reach the core material, and the core due to the high heat does not It is possible to avoid deterioration and deterioration of the material, and to prevent welding heat from being dissipated due to heat conduction of the core material and causing welding failure.

Then, the coating metal used as the pipe adheres to the surface of the core wire due to the wire drawing shrinkage due to the die after welding, and is further completely integrated with the core material through wire drawing, and is drawn in this integrated state. Although the diameter of the wire is reduced to a covered electrode wire having a required wire diameter, since the wire drawing diameter reduction by the die is performed at room temperature, there is no change in the metal structure due to heat as in hot wire drawing, Moreover, since the coating metal is a Cu-Zn alloy, there is little difference in the malleability between the coating layer and the core material, and the adhesion between the two is good.

Therefore, the finally obtained electrode wire has extremely high suitability for electric discharge machining and has extremely high quality.

Incidentally, when the wire drawing diameter reduction by the die after welding is carried out hot, an intermetallic compound is formed and the structure becomes extremely brittle, so that the subsequent wire drawing step cannot be applied because it causes wire breakage.

Incidentally, if the abutting portion of the pipe cross section of the coating metal before welding is an elliptical shape with one end side of the major axis being located,
Since the twisting displacement of the pipe is reliably prevented in the process of moving the pipe together with the core wire from the roll forming portion to the welding position, it is possible to more completely avoid defective welding at the abutting portion. That is, when the cross section is a perfect circle, even if the pipe is sandwiched by forming rolls or guide rollers, it is easy to displace in the twisting direction due to pressure or vibration during forming, and due to this displacement, the abutting portion is welded. It will deviate from this and welding defects will occur. On the other hand, in the elliptical cross section, it becomes impossible to rotate in the circumferential direction at the sandwiched portion,
The butt portion is stably and continuously guided to the welding position. Then, by correcting the cross section into a perfect circle in the preceding stage of the die after welding, it is possible to prevent the deviation of the coating layer thickness when the coating metal is brought into close contact with the surface of the core material due to the wire drawing shrinkage by the die.

(Example) Hereinafter, the present invention will be specifically described based on illustrated examples.

FIG. 1 schematically shows the equipment for carrying out the method of the present invention. In the figure, 1 is a core wire mainly composed of Cu, and 2 is a strip material of Cu-Zn alloy, both of which are continuously fed out from a delivery device 3a to sequentially pass a degreasing tank 4, a cleaning tank 5, and a drying device 6. After that, it is guided to the roll forming device 7 via the guide roller 8.

FIG. 2 is a vertical sectional view showing an introduction portion to the roll forming apparatus, and FIG. 3 is a sectional view taken along line III-III in FIG. That is,
The strip-shaped material 2 is guided along the lower surface of the core wire 1 in front of the roll forming device 7, and in the roll forming device 7, a large number of pairs of forming rolls 7a, 7a arranged vertically and horizontally opposite to each other.
By being pressed between the two, the pipe 20 is bent in the width direction so as to wrap the core wire inward, and forms a pipe 20 with both edges abutting at the top. Then, as shown in FIG. 3, the pipe 20 is formed into an elliptical shape with the abutting portion 20a located at one end side of the long diameter so that it cannot rotate in the circumferential direction between the rolls 7a, 7a. The pipe 20 is pressed by the pressing pulley 9 arranged in front of the molding device 7.
It is arranged in the lower part of a, that is, on the other end side of the major axis in the above ellipse, and forms a gap t between the abutting portion 20a and the core wire 1.

The core wire 1 has a diameter of about 3 to 4 mm, the coating metal strip 2 has a thickness of about 0.6 to 0.8 mm, and the gap t in FIGS. A width of about 3.8 mm is used. Therefore, the area of the coating metal occupies about 60% of the whole metal of the cross section.

The pipe 20 exiting the roll forming device 7 is guided to the welding device 10 together with the core wire 1 inserted through the inside thereof as shown in FIG. 1, and the butt portion 20a is welded to form a complete pipe body. . This welding is preferably high frequency welding or arc welding, and it is recommended to perform it in a non-oxidizing atmosphere (inert gas or reducing gas atmosphere).

The pipe 20 after the welding is then narrowed between the forming rolls 11 and 11 so that the pipe 20 is corrected and formed to have a perfect circular cross section as shown in FIG. At the same time, the wire is drawn between the plurality of dies 12a, 12a ... These dies 12a are usually arranged in the order of 7 to 8, and in the first die, wire drawing with a cross-sectional reduction rate of 10% or less is made, whereby the Cu-Zn alloy 2a is adhered to the core material 1a as shown in FIG. The covered wire 21 is formed. The second die is
In order to mechanically improve the adhesion strength between the core material 1a and the Cu-Zn alloy 2a, the cross-sectional reduction rate is usually set to about 35 to 38%.
That is, when the cross-sectional reduction rate by the second die is too small, for example, about 25%, there is a possibility that so-called disconnection of the cylinder may occur in the subsequent drawing process due to insufficient adhesion strength. Therefore, after the third die, the cross-section reduction rate of 25% or less is sufficient as in the case of general wire drawing.

Next, the coated wire 21 that has passed through these dies 12a, 12a ... Is heat-treated through the annealing furnace 13a and then wound up by the winding device 14a. Then, the wound body of the wound coated wire 21 is removed from the winding device 14a and set in another feeding device 3b, and is subjected to wire drawing by the dies 12b, 12b ... And heat treatment in the annealing furnace 13b. The final wire drawing as an electrode wire is about 0.2 to 0.3 mm by repeating the same wire drawing and heat treatment. The wire drawing and heat treatment are usually 70-80
%, And the number of times is generally about 3 to 4 times until the final wire drawing diameter reduction.

In the above embodiment, the wire drawing / heat treatment from the second time onward is separated from the step following the first roll forming, but it may be a continuous step from the first time as long as it does not interfere with the equipment space or the like.

The electrode wire thus obtained has a tensile strength of 85 to 90 kgf / mm ² ,
The wire has a conductivity of 40-50%.

The material of the core material may be any material that is mainly composed of Cu.
In addition to alloys containing small amounts of other metals such as Sn and Ag, Cu alone may be used.

Next, the brass clad electrode wire obtained by the method of the present invention
Measurement of tensile strength, elongation, and electrical conductivity as physical characteristics of NO. 1 to 10 and brass clad electrode wires NO. 11 to 19 produced by the conventional coextrusion method of coating material and core material, respectively. did. The results are shown in Table 1 together with the composition of each electrode wire. Each electrode wire has a wire diameter of 0.3 mm and a coating material thickness of 60 μm (cross-sectional area ratio 64%).

From the above results, it is clear that the electrode wire obtained by the method of the present invention has physical properties equal to or higher than those of conventional products.

On the other hand, the electrode wires of No. 1 to No. 3 and No. 11 in Table 1 are used, and SKD-11, a 50 mm thick template (manufactured by Mitsubishi Electric Corporation) DWC90H) is used as a work material. When the cut electric discharge machining was performed, the machining speeds of the electrode wires No. 1 to 3 were about 1.3 times higher than those of the electrode wire No. 11. From this result, it is understood that the method of the present invention can provide a higher performance electrode wire for wire-cut electric discharge machining than the conventional method.

(Effects peculiar to the invention) According to the method of the present invention, Cu-Zn alloy is continuously supplied as a strip-shaped material along a core wire mainly composed of continuously running Cu, and the strip-shaped material is formed into a pipe shape. Since the core wire is inserted through the inside, and the butt portion of the pipe is drawn and reduced in diameter after welding, the equipment is very simple compared to the conventional equipment,
A long and high-quality electrode wire for wire cut electric discharge machining can be manufactured with high performance.

Moreover, in the method of the present invention, since the strip material of the Cu-Zn alloy is formed into a pipe shape by roll forming, twist deformation of the strip material is unlikely to occur in the forming process, and the abutting positions of the both side lines are always in the circumferential direction. Since it comes to the fixed position, the welded portion in the subsequent welding does not shift from the butted portion, and welding defects are prevented.

Furthermore, in the method of the present invention, since the core wire is arranged at a position apart from the abutting portion to be welded in the above-mentioned molded pipe, deterioration of the core material due to high heat of welding is avoided, and the core material It is also possible to prevent welding heat from escaping due to heat conduction and resulting in poor welding.Because the wire drawing diameter is reduced at normal temperature by the die after welding, a change in the metal structure occurs due to heat during hot wire drawing. In addition, since the coating metal and the core material are the same type of metal and the difference in malleability is small, the adhesion between the two is good, resulting in higher electrical discharge machinability than conventional ones. A good electrode wire can be obtained.

Further, in the above method, if the pipe formed from the band-shaped material has an abutting portion with an elliptical cross section located on one end side of the major axis, and a configuration is adopted in which the pipe is corrected into a perfect circle after welding,
Since it is possible to completely prevent the twisting displacement of the pipe in the process of moving from the forming portion to the welding portion, welding defects due to the displacement of the butted portion can be more completely prevented, and a stable and high-quality electrode wire can always be obtained.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing equipment for carrying out the method of the present invention, FIG. 2 is a vertical sectional side view of a roll forming introduction portion, and FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a front view in vertical section of the correction molding portion of the pipe, and FIG. 5 is a sectional view of the covered wire. 1 ... core wire, 1a ... core material, 2 ... band material, 2a ... Cu-
Zn alloy, 7 ... Roll forming device, 9 ... Pressing pulley (guide member), 10 ... Welding device, 12a, 12b ... Die, 20 ... Pipe, 20a ... Butt, t ... Gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Shinya 1 347, Teramae, Inadera, Amagasaki City, Hyogo Prefecture Daiichi Denko Co., Ltd. Engineering Department, Winding Division, Chief of Judgment Body Takato Tsutsumi Judge Hideo Shimizu Judge Hasebe Zentaro (56) Reference JP-A-47-42557 (JP, A) JP-A-56-36317 (JP, A) JP-A-53-147662 (JP, A)

Claims (2)

[Claims] 1. A strip material having a thickness of 0.6 to 0.8 mm made of Cu-Zn alloy is continuously supplied along a core wire having a diameter of 3 to 4 mm, which is mainly made of Cu, which runs continuously, and the strip material is rolled. By bending in the width direction by molding and abutting both side edges thereof, a pipe through which the core wire is inserted is formed, and the core member wire is formed by the guide member provided in the stage before the roll forming part. The pipe is welded at the butt portion of the pipe by eccentrically arranging in the pipe away from the butt portion to form a gap of 2 to 3.8 mm between the butt portion and the core wire, and the pipe after the welding A method for manufacturing an electrode wire for wire-cut electric discharge machining, comprising: drawing a wire at a normal temperature with a die to reduce the diameter of the wire, and closely adhering a Cu-Zn alloy to the surface of the core wire material; 2. The wire cut according to claim 1, wherein the cross section of the Cu-Zn alloy pipe is elliptical with the abutting portion located on one end side of the major axis before welding, and is modified into a perfect circle at the front stage of the die after welding. A method for manufacturing an electrode wire for electric discharge machining.