JPH09225748A - Manufacture of electrode wire for electrical discharge machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the traveling solution treatment while improving the machining speed and the machining characteristics. SOLUTION: A wire 7 of copper alloy containing Zr or Cr is heated while being traveled in a heating electric furnace 2 filled with the inert gas, and rapidly cooled in a cooling water tank 3 to achieve the traveling solution treatment. The powder coating containing Zn is performed on a surface of a solution- treated wire 15 in a powder coating container 16, and dried in a dryer 19 to form a surface layer. In addition, after the heat treatment in a heating electric furnace 20, the cold drawing is performed. The heat resistance (wire-breaking resistance) of an electrode wire is improved by the solution treatment, and the machining speed is improved by forming a surface layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electrode wire for electric discharge machining used in wire electric discharge machining, and more particularly to a method of manufacturing an electrode wire for electric discharge machining using a copper alloy.

[0002]

2. Description of the Related Art In wire electric discharge machining, a thin metal wire (electrode wire for electric discharge machining) serving as an electrode wire is wound up and three-dimensionally fed to a work piece so that a space between the metal wire and the work piece is increased. Since the workpiece is melted and blown to perform a sawtooth-type machining while discharging, a three-dimensional product can be created with high accuracy without using an electrode of a specific shape. Particularly, since a hard metal or the like that is difficult to machine can be machined with high precision, the practical range has been expanding in recent years.

As an electric discharge machining electrode wire which has been conventionally used, there is, for example, a Cu-35 wt% Zn brass electrode wire. Journal of Copper and Copper Technology, 26, (1987) P181
(Presenter: Orimo, Ishibashi, Okuno), it is known that the higher the Zn concentration in the composition, the higher the processing speed. However, the amount of Zn (zinc) is 40% by weight
If it exceeds, the β phase is formed, so that wire drawing cannot be performed in cold rolling. As described above, due to the problem of workability, in the electric discharge machining electrode wire containing Zn, Cu-35 wt% Z
n Brass wire is considered standard.

However, since an improvement in processing speed leads to an improvement in productivity, various proposals have been made to increase the processing speed while including Zn. For example, an electrode wire whose core material is coated with an alloy containing 50% or more of Zn (Japanese Patent Publication No.
-5648). Furthermore, as an electrode wire for forming a coating layer on the core material, for example, Zn (or Zn
Alloy wire) and a Zn-rich layer formed on the surface by immersion annealing (Japanese Patent Laid-Open No. 62-218026), and a composite electrode wire in which a steel wire is coated with a metal having good conductivity (Japanese Patent Publication No. 57-57).
No. 211), Cu-having a predetermined thickness on the surface of the copper alloy wire.
An electrode wire in which a Zn alloy layer is provided and a Zn layer having a predetermined thickness is further provided on the surface of the Cu—Zn alloy layer (JP-A-61-117021).
Publication). Also proposed is an electrode wire (Japanese Patent Publication No. 2-49849) in which an alloy layer is provided on the surface of a copper-coated steel wire so that the Zn concentration increases toward the outer surface.

Further, Cr, Zr, Fe, Be, Co, T
An alloy containing 0.03 to 5.0% by weight of any one of i and the like is used as a core material, and a metal containing 95% or more of Zn is hot-plated on the surface, and then cold working of 5% or more is performed. An electrode wire (Japanese Patent Laid-Open No. 59-134629) has also been proposed. By the way, in this proposal, a Cu—Zr alloy or a Cu—Cr alloy among the alloys constituting the core material is required to undergo solution treatment in order to obtain a desired tensile strength, but in general, a Cu—Zr alloy or a Cu—Zr alloy is required. The solution treatment of the -Cr alloy is usually performed at 950 ° C for a wire rod having a diameter of 8 to 13 mm,
It is performed by a method of quenching after heating for 3 hours.

[0006]

Therefore, as a conventional method for manufacturing an electrode wire for electric discharge machining, a Cu--Zr alloy or C alloy is used.
If the solution treatment of the u-Cr alloy is carried out under the condition of 950 ° C for 3 hours, it is inevitable that the cost will increase, and if the traveling solution treatment becomes possible, the cost for solution treatment will increase. Down is possible. Further, according to the conventional electrode wire for electric discharge machining, although a certain machining speed and machining characteristics can be obtained, further improvement in machining speed and breakage resistance are desired.

Therefore, an object of the present invention is to provide a method for manufacturing an electrode wire for electric discharge machining which enables a traveling solution while improving a machining speed and machining characteristics.

[0008]

In order to achieve the above-mentioned object, the present invention runs a wire made of a copper alloy containing Zr or Cr while heating in an inert gas atmosphere, and The passed wire rod is immediately water-cooled for solution treatment, and Zn is applied to the surface of the solution-treated wire rod.
A layer or a surface layer of a Cu—Zn layer is formed, and the wire rod having the surface layer is cold drawn.

According to this method, the traveling alloy solution treatment is performed by heating the copper alloy containing Zr or Cr while traveling in an inert gas atmosphere and cooling immediately after heating.
The copper alloy is solutionized. Further, a surface layer for improving the processing speed of Zn or Cu—Zn is formed on the solution-treated wire while the wire is running. As a result, the heat treatment of the electrode wire is improved in the solution treatment, and the processing speed is improved by forming the surface layer.

The surface layer can be formed by a method in which Zn powder, a resin anti-settling agent and a solvent are applied in a slurry form and then dried. According to this method, the material for forming the surface layer can be formed using the coating means and while the wire rod is running. Therefore, the equipment cost can be reduced. The surface layer can be formed by electroplating or hot dipping. This forming method can also be performed while the wire rod is running, and the device therefor can be simply configured.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing manufacturing equipment for achieving a method for manufacturing an electrode wire for electric discharge machining according to the present invention. The manufacturing equipment shown in FIG. 1 is composed of a traveling solution treatment line A and a powder coating line B. First, the configuration of the traveling solution treatment line A will be described. The traveling solution heat treatment line A has a configuration in which a payoff 1, a heating electric furnace 2, a cooling water tank 3, a constant speed winder 4, and an aligning winder 5 are sequentially arranged in series in the process flow direction. .

The payoff 1 is provided with two pulleys 6a and 6b, and is used for winding and guiding a wire rod 7 which becomes an electrode line for electric discharge machining after machining. The inside of the heating electric furnace 2 is heated by a heater (not shown), and openings (not shown) for inserting the wire rod 7 are provided at both ends. Then, inert to the inside to prevent such oxidation on the surface of the wire 7 is caused (N _2, Ar or the like) gas is supplied, the wire 7 (wire rod from payoff 1 in the inert gas atmosphere The configuration of 7 will be described later). The heating electric furnace 2 is provided with a gas supply port 8 and a gas discharge port 9 for circulating the inert gas.

The cooling water tank 3 is filled with a predetermined amount of cooling water 10, and a plurality of pulleys 11 for guiding are provided so that the wire rod 7 from the heating electric furnace 2 can pass through the cooling water 10.
a, 11b, 11c and 11d are installed. Furthermore,
The constant speed winder 4 has a plurality of pulleys 12a and 12b built therein,
It has a function of feeding the wire rod 7 from the cooling water tank 3 to the subsequent stage at a constant speed. The aligning winder 5 has a built-in pulley 13 that guides the wire rod 7 from the constant speed winder 4 and a pulley (or reel) 14 that winds up the wire rod 7.

Next, the structure of the powder coating line B will be described. The wire material 15 that has been subjected to the solution heat treatment in the traveling solution heat treatment line A is wound around the pulley 14. The wire rod 15 pulled out from the pulley 14 is the die 1
It is introduced into a powder coating container 16 equipped with 7,18. The die 17 is provided on the inlet side of the powder coating container 16, and the die 18 is provided on the outlet side. A dryer 19 is installed behind the powder coating container 16. The powder coating container 16 is made of Zn powder (or
Cu-Zn powder), a resin anti-settling agent, and a solvent are mixed to form a slurry having a viscosity of about 1000 cps.

Further, the heating electric furnace 2 is provided at the subsequent stage of the dryer 19.
0 is set. The heating electric furnace 20 includes a furnace body 20a having a hollow structure inside, and a heater 20b provided around the furnace body 20a for heating the inside of the furnace body. Furnace body 20a
Inert gas (N ₂ gas) is introduced into the inside. For this reason, the gas supply port 20c is provided at one end and the gas discharge port 20d is provided at the other end. This heating electric furnace 20
A surface oxide layer removing device 21 and a bobbin 22 are sequentially installed in the subsequent stage.

In the above structure, the wire rod 7 to be processed in the traveling solution heat treatment line A has, for example, 0.9 mm.
Φ Cu-0.16 wt% Zr (zirconium) is used. The reason why the Cu-Zr alloy wire is used is to prevent arc discharge from occurring in the electrode wire during electric discharge machining, which causes heat to be generated during electric discharge, which prevents breakage due to being unable to withstand the tension during machining. Is.

The wire rod 7 having the above-mentioned structure is pulled out from the pay-off 1 and 1 m in the inert gas atmosphere of the heating electric furnace 2.
700 ° C to 95 while traveling at a transportation speed of about 1 / min
Heat to 0 ° C. for solution. By this solution treatment,
Zr can be solid-dissolved, and the electrode wire can have heat resistance. Wire rod 7 heated in heating electric furnace 2
Is carried into the cooling water tank 3 immediately after leaving the heating electric furnace 2,
It is rapidly cooled with the cooling water 10 in the tank. Then, the cooled wire 7 is wound around the pulley 14 of the aligning winder 5 through the constant speed winder 4.

The Cu-Zr alloy wire is conventionally 8 to 13 mm.
Heat resistance is added to a copper wire of about φ by performing solution heat treatment at 950 ° C. for 3 hours and then rapidly cooling. But,
Such conventional heat treatment is expensive and time consuming,
The production cost of the electric discharge machining electrode wire cannot be reduced. Therefore, in the present invention, 700 to 950 ° in an intermediate size (for example, 0.9 mmφ) that can be solutionized at low cost.
After running heating of C, water cooling was performed so that heat resistance could be added by heat treatment in the line as described above.

Next, the processing of the powder coating line B will be described. The wire rod 15 (solution-treated Cu-Zr alloy wire) that has undergone the solution heat treatment in the traveling solution heat treatment line A is moved from the traveling solution heat treatment line A or rewound onto another bobbin or the like. Stuff) and drawn with a die 17. Then, in the process of passing through the powder coating container 16, the surface of the wire 15 is uniformly powder coated. Furthermore, dryer 1
Drying (hot air drying) of the powder coating is performed in the process of passing through 9. As a result, a surface layer containing Zn is formed on the surface of the Cu-Zr alloy wire.

Further, the wire rod 23 having the surface layer formed thereon is sent to the heating electric furnace 20 and subjected to heat treatment. The inside of the furnace body 20a of the heating electric furnace 20 is, for example, 8
It is heated to 00 ° C, and heat treatment is performed in an inert atmosphere while being conveyed in this furnace at a speed of 1 m / min. The wire rod 23 exiting the heating electric furnace 20 is naturally cooled in the air atmosphere while moving, and then the surface oxide layer removing device 21 mechanically removes the surface oxide layer of the wire rod 23. Then, the wire rod 23 is wound around the bobbin 22.
Further, the wire is sent to another line and cold drawn.

In the wire rod 23 which has passed through the powder coating line B as described above, 10 to 10 are formed on the surface of the Cu--Zr alloy wire.
A Cu- (30-40) wt% Zn alloy layer of about 20 μm was applied as a surface layer. Thus, Cu-Zn
By applying the alloy layer, the processing speed can be improved.

[0022]

EXAMPLES The inventors of the present invention made a prototype by the method of the present invention and evaluated the electrical discharge machinability. Thickness 4 as work piece
The breaking speed limit was measured using 0 mm SKD-11. The surface roughness of the work piece was also evaluated. As a result, a 0.02 mm wire rod was used, the discharge current was set to 36 A, the off time (current rest time) was kept constant (2.8 μs), and the on time (current application time) was varied to enable machining at a speed (wire Was measured. Further, for comparison with the present invention, 0.2 mm by the conventional method.
A φ-Cu-35 wt% Zn electrode wire (comparative example) was prepared.

When the on-time (current application time) was 0.8 μs, the processing speed of the Cu-35 wt% Zn electrode wire (comparative example) was 1.53 mm / min, while the electrode wire according to the present invention. Was 1.75 mm / min, and it was confirmed that the processing speed was improved. Further, if the current application time is lengthened, the processing speed is increased, but the electrode wire according to the present invention is 1.
The wire was broken at 2 μs. On the other hand, in the comparative example, 1.5 μs
The wire was broken at the current application time. From this, it was confirmed that the electrode wire according to the present invention has excellent resistance to disconnection.

Further, the surface roughness of the workpiece according to the comparative example was 1.35 μm, whereas the surface roughness of the electrode wire according to the present invention was 1.285 μm. Was confirmed to be excellent. Although the surface layer is formed by the powder coating method in FIG. 1 when forming the surface layer, the present invention is not limited to the powder coating method, and other electroplating methods,
A hot dip plating method or the like can be used.

Further, although a Cu-Zr alloy wire is used as the core material, a Cu-Cr alloy wire or Cu-Z having similar heat resistance is used.
It is also possible to use an r-Cr alloy wire or the like.

[0026]

As is apparent from the above, according to the present invention, a wire rod made of a copper alloy containing Zr or Cr is run while heating in an inert gas atmosphere, and the wire rod passing through the inert gas atmosphere is treated. Immediately water cooling and solution treatment,
Since a surface layer made of a Zn layer or a Cu-Zn layer is formed on the surface of this wire and further cold drawing is performed to produce an electrode wire for electric discharge machining, the heat treatment of the electrode wire is performed by solution treatment. It is possible to improve the cost and reduce the cost, and it is possible to improve the processing speed by forming the surface layer.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing manufacturing equipment for achieving a method for manufacturing an electrode wire for electric discharge machining according to the present invention.

[Explanation of symbols]

 1 Payoff 2 Heating Electric Furnace 3 Cooling Water Tank 4 Aligning Winding Machine 7 Wire Rod 10 Cooling Water 16 Powder Coating Container 17,18 Die 19 Dryer 20 Heating Electric Furnace 21 Surface Oxide Layer Removal Device

Claims (3)

[Claims] 1. A wire rod made of a copper alloy containing Zr or Cr is run while being heated in an inert gas atmosphere, and the wire rod that has passed through the inert gas atmosphere is immediately water-cooled to undergo solution treatment, Zn layer or Cu-on the surface of the treated wire
A method for producing an electrode wire for electric discharge machining, comprising forming a surface layer of a Zn layer, and cold drawing the wire having the surface layer. 2. The electrode wire for electrical discharge machining according to claim 1, wherein the surface layer is formed by applying Zn powder, a resin settling agent and a solvent in a slurry form and then drying the slurry. Production method. 3. The method for manufacturing an electrode wire for electric discharge machining according to claim 1, wherein the surface layer is formed by an electroplating method or a hot dipping method.