JPS5931857A - Manufacture of electrode wire for electric spark machining for wire cutting - Google Patents

Abstract

PURPOSE:To manufacture an electrode wire for electric spark machining for wire cutting, by coating a core material having higher strength and a higher m.p. than a shell material with a Zn alloy contg. a specified amount or more of Zn as the shell material by extrusion in a solid-liq. mixed state. CONSTITUTION:A metallic wire having higher strength and a higher m.p. than a shell material, e.g., a steel wire or a brass wire is used as a core material. The core material is coated with a Zn alloy contg. >=70% Zn, e.g., a Zn-Sn alloy contg. >=70% Zn and <30% Sn by extrusion in a half-melted state after heating to 200-350 deg.C. The coated wire may be further coated by extrusion. The wire is then drawn at <=90% reduction rate of area.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method of manufacturing an electrode wire for wire-cut electrical discharge machining.

(Background Art) Wire-cut electric discharge machining (hereinafter simply referred to as electric discharge machining) is a method in which electric discharge is caused between a workpiece and a linear machining electrode (hereinafter referred to as an electrode wire). This is a conventional method in which the workpiece is cut into a desired shape by relatively moving the workpiece and the workpiece.

In this electrical discharge machining method, a long wire having a diameter of 0.05 to 0.2 mm is usually prepared as a linear electrode wire, and new wires are sequentially supplied to the electrical discharge machining area.

Conventionally, copper wire, brass wire, etc. have been used as electrode wires for electrical discharge machining. However, copper wire does not have very high strength and breaks easily, and is generally inferior to brass wire in terms of processing speed. In addition, although the machining speed of brass has been improved over that of copper wire, it is still insufficient.Recently, composite wires such as steel wires and copper wires fully coated with zinc or zinc alloy (hereinafter simply referred to as zinc) have been tested. = i-sa-not-t. It is said that the presence of zinc stabilizes the electrical discharge during electrical discharge machining and increases the machining speed.

Traditionally, metal wires were coated with zinc using a plating method, but
In the case of plating at the final size, with bath dipping it is difficult to produce a thick enough plating to stabilize the mature chicken during electrical discharge machining, and with electroplating it takes a long time to achieve thick plating, which is not economical. Furthermore, when plating a thick intermediate size and drawing it to the final size, hot-dip plating cannot achieve the desired thickness, and electroplating takes a long time to achieve thick plating, making it uneconomical.

Another option is to use a cladding method such as an extrusion method to coat zinc with gold, but in the case of extrusion of general wire composite wires, even if the deformation resistance of the sheath metal is small, the pressure that causes it to adhere tightly to the core material is high. If extruded with
Therefore, it is difficult to industrially combine the final size or its vicinity (thin wire).Also, it is difficult to coat and reduce the area with a wire that is too thick compared to the final size, such as zinc and steel wire. As in the case of high tensile strength 5-layer materials, the strengths and softening temperatures are too different, so there are drawbacks such as difficulty in surface reduction processing.

(Disclosure of the Invention) The present invention was created to solve all of the above-mentioned problems, and by extruding Zn@gold in a semi-molten state, the extrusion pressure is reduced and composite wires are formed in fine wires. In addition, the high-tensile core material improves linearity, and the coating is thick.
It is an object of the present invention to provide a method for manufacturing an electrode wire that stabilizes the discharge during electrical discharge machining, increases the machining speed, and improves the dimensional accuracy after machining.

In the present invention, on the outer periphery of the core material, which has higher strength and higher melting point than the outer covering material,
This is a method of manufacturing an electrode wire for wire-cut electrical discharge machining, which is characterized in that a Zn base metal outer covering material containing 70% or more of Zn is coated by extrusion processing in a solid-liquid mixed state.

The extrusion device used in the present invention is not particularly limited, and may be any of, for example, a billet extruder, a continuous extruder, a single friction drive type extrusion device, and the like.

In addition, Zn base metal containing 70% or more of Zn (hereinafter simply referred to as Zn alloy) includes, for example, Zn-5%Ag alloy, Zn
-10% Sn alloy, Zn-596Ag -196Cu
A 3% Sn alloy or the like is used. If the Zn content is less than 70%, the effects of stabilizing discharge in wire cutter and discharge electric machining and improving machining speed will be reduced.

The core material is a wire having higher strength and melting point than the above-mentioned jacket material, such as steel wire, copper wire, copper alloy wire, tungsten wire, etc.

The extrusion temperature is selected appropriately depending on the composition of the outer shell L0.

For example, in a Zn-5n alloy containing less than 30% of 5n, 2
00-350°C is good.

Hereinafter, the present invention will be explained by examples using all the drawings. FIG. 1 shows a cross-sectional blade for explaining an embodiment of the method of the present invention. In the figure, 1 is a container, 2 is a ram, and a heater 3 for heating is provided around the container 1. A hollow mandrel 5 for inserting a core material is provided on the opposite side of the extrusion die 4.

The container of such an extruder is charged with Zn@gold 7 as a billet using the IK outer jacket and heated with a heater 3 to semi-melt the Zn alloy 7 into a solid-liquid mixed state, and then the hollow mandrel 5
When the core material 6 is inserted and pressure is applied to the ram 2, the composite wire 8 is extruded from the extrusion die 4. FIG. 2 is a cross-sectional view showing an example of a composite wire coated by extrusion in this manner, where 6 is a core material and 7 is Zn@gold.

In this case, the core material 6 is a Zn alloy 7. Kf) Due to its high strength and high melting point, the Zn base metal does not melt even in a semi-molten state and maintains high strength, so the core material 6 does not deform and its linearity is not compromised. Since it is extruded with small deformation stress, it can be extremely easily composited even if the core material is thin and the Zn@gold layer is thick.

The composite wire 8 may be used as it is, or it may be coated with a thicker size near the final size for the purpose of improving dimensional accuracy, etc., and then elongated with an area reduction rate of 90% or less. ! ? You can also apply it.

(Example) All extrusion devices shown in 1st [W are used, and O and I are used as the core material 6.
7mmpy 0.89e)C steel wire, Zn alloy 7 as Z
Using n-1096Sn base metal, Zn-8n alloy 240
Extruded in solid-liquid mixed state at °C, Zn@gold thickness 0.02
After obtaining all 8 composite wires of 0.21 m, 1 L, and 9 f mm, electrode wires of o.2 oimy were prepared by skin bath wire drawing.

Similarly, 0.18m! 71U' Cu 3096
The outer periphery of the Zn brass wire was coated with Zn-5%Sn alloy by extrusion at 220℃ to a thickness of 0.015 #Jf to form a composite wire with an excitation limit of 0.2I, and then the wire was drawn in a skin bath to 0.20A. The final electrode wire was created.

In either case, the extrusion pressure was low, the productivity was excellent, and composite wires were obtained.

For comparison, a 020πIJr O copper wire, a brass wire, and an electrogalvanized steel wire with a plating thickness of 5 μm were used as electrode wires, and a steel plate with a thickness of 50 μm (SKD -11 material) under the electrical discharge machining conditions shown in Table IVC and the wire tension shown in Table 2, the wire cutting process became acoustic.

The dimensional accuracy and processing speed ratio after wire cutting are shown in Table 2. Note that this speed ratio is based on copper wire (flat 3) il, o
It is expressed as .

Table 1 From Table 1, it can be seen that the material according to the present invention has a faster machining speed and better dimensional accuracy after machining than the comparative example.

(Effects of the Invention) The method for manufacturing an electrode wire for wire-cut electric discharge machining according to the present invention having an fLR constructed as described above has the following effects.

(b) Z
Since the Zn alloy jacket material containing N170% or more is extruded and coated in a solid-liquid mixed state, the jacket material is in a semi-molten state, so the extrusion deformation stress is small and extrusion coating is possible, so it can be used for applications such as electrode wires. However, even if the core material is thin, it can be used very easily.

Furthermore, extrusion coating with a size close to the final size and skin bath wire drawing is easier than conventional coating with a thick size.

(b) As mentioned above, the core material is the outer covering material, l: high strength,
Since it has a high melting point and the extrusion pressure during extrusion coating is low, it does not deform, does not impair linearity, and can be coated with a thick Zn base metal, so the electrical discharge during electrical discharge machining becomes stable and the machining speed increases. Since electrical discharge machining can be performed under high tension, dimensional accuracy after machining can be improved. The above-mentioned skin bath wire drawing can further improve dimensional accuracy.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining an embodiment of the method of the present invention. FIG. 2 is a sectional view showing an example of a composite wire obtained by an embodiment of the method of the present invention. 1... Conte f-12... Ram, 3... Heater,
4... Extrusion die, 5... Hollow manodrel, 6...
・Core material, 7...Zn base metal, 8...composite wire.

Claims (1)

[Claims] (+) On the outer periphery of the core material, which has higher strength and higher melting point than the outer covering material,
A method for producing an electrode wire for wire-cut electrical discharge machining, which comprises extruding and coating a Zn alloy jacket material containing 70% or more of Zn in a solid-liquid mixed state. (2) A method for producing an electrode wire for wire-cut electric discharge machining according to claim 1, wherein the core material is a steel wire or a brass wire. (3) The outer sheath material is Zn-5 containing Sr+30% or less.
3. The method for producing an electrode wire for wire-cut electrical discharge machining according to claim 1 or 2, wherein the electrode wire is made of metal and the extrusion coating is carried out in a solid-liquid mixed state at 200 to 350°C. (4) A method for producing a polar wire for wire-cut electric discharge machining according to claim 1, 2, or 3, wherein after extrusion coating, the wire is drawn with an area reduction of 9096 or less.