KR20070075516A - Manufacturing method and structure of electrode line for electric discharge machining - Google Patents

Abstract

It is an object of the present invention to provide an electrode wire for electric discharge machining and a method of manufacturing the same, wherein the diffusion layer has a thickness greater than or equal to a predetermined thickness to improve the processing speed.

In order to achieve the above object, a method of manufacturing the electrode wire for electric discharge machining according to the present invention includes one of copper wire, copper alloy wire, or copper strip steel wire having a first diameter, and the core wire is plated with a first metal having a lower vaporization temperature than copper. The first process to do,

A heat treatment second step of applying heat to form a copper alloy layer by the first metal plated and the copper mutual diffusion reaction;

A third step of drawing the plated wire material having the copper alloy layer formed in the second step into a plated wire material having a second diameter;

A fourth process of heat treating the plated wire of the second diameter to recrystallize and soften the cross-diffusion reaction;

A fifth step of plating the plated wire rod of the fourth step with a second metal having a lower vaporization than the same to form a second metal layer on the plated wire rod of the fourth step;

A sixth step of drawing the plated wire rod in the fifth step in which the second metal layer is formed to have a cross section of a final dimension;

And a seventh step of stabilizing and heat treating the product of the sixth step having the final dimensions.

Description

Method for manufacturing electrode wire for electric discharge machining and its structure {WIRE ELECTRODE FOR ELECTRO DISCHARGE MACHINING AND THE SAME METHODE}

1 is a view for explaining a general discharge processing method,

Fig. 2 is a diagram showing a cross section of a main portion of the electrode line for electrical discharge machining according to the first embodiment of the present invention.

3 is a view showing a cross section of a main portion of the electrode line for electrical discharge machining according to the second embodiment of the present invention.

The present invention relates to a method for manufacturing an electrode wire for electric discharge machining and its structure, and more particularly, to a method for manufacturing an electrode wire for electric discharge machining having an improved processing speed and a structure thereof.

A general discharge processing method will be described with reference to FIG. 1.

In the electric discharge machining method, the electrode wire 2 is inserted into a starting hole 7 drilled into the workpiece 1 in advance, and the electrode wire 2 is moved in the insertion direction while the electrode wire 2 is driven. By applying a high frequency voltage between the inner wall surfaces of the workpiece, an arc is generated between the workpieces, and the workpiece 1 is melted and processed into a predetermined shape. According to the principle of electric discharge machining, the electric discharge machine is provided with a power supply device, an electrode wire feeder, a workpiece feeder, and a processing liquid circulation device.

The workpiece conveyance apparatus is moved in the direction orthogonal to the electrode wire 2 as shown by the arrow, and the electrode wire 2 is continuously sent out from the supply reel 3, and the guide rollers 5 at both ends of the workpiece 5 ') is wound around the reel 4.

At this time, a high frequency voltage is applied between the workpiece 1 and the electrode line 2 to perform cutting, and deionized pure water is supplied to the processing portion as a processing liquid in order to remove heat generated during processing.

The efficiency of discharge machining, in particular the processing speed, depends on the feed rate of the processing liquid, the current level, and parameters such as the discharge shape and frequency. However, this discharge machining speed can be optimized to the limit depending on the material constituting the electrode and the workpiece by adjusting these parameters.

Conventionally, pure copper has been widely used because of its good conductivity, good elongation, and ease of thin wire processing. However, the electrode wire made of pure copper has many drawbacks such as low tensile strength, which is easily disconnected, and its vibration cannot be suppressed during electrical discharge machining, resulting in poor machining and slow processing speed.

US Patent No. 4,287,404 discloses an electrode wire coated with zinc on a copper wire and a brass wire. That is, the core wire is made of a material having a relatively high tensile strength or electrical conductivity, such as copper, brass, or iron, and the material having a lower vaporization temperature, such as zinc, cadmium, tin, lead, antimony bismuth, and alloys thereof, is transferred to the core layer. A plated electrode wire and a method of manufacturing the same are disclosed. U.S. Patent 4,287,404 is responsible for the mechanical strength and energization required for the electrode wire, and the processing speed is increased by improving the cooling rate and flushability by the material having low vaporization temperature plated on the core wire.

 In other words, since the zinc plated layer on the core wire is easily vaporized by heat during processing, it also serves to protect the core wire from thermal shock. As described above, the method of manufacturing a galvanized electrode wire may provide zinc plating by an electroplating method to the final drawn fine wire, and may also draw the final fine wire after electroplating zinc on a wire having a suitable diameter. .

Therefore, electrode wires made of brass, an alloy of copper and zinc, are now widely used for general processing.

However, the higher the zinc content in the brass alloy is expected to increase the processing speed, but when the zinc content exceeds 40%, weak ß phase is formed, so drawing is not easy when thinning.

Another method of improving the processing speed is disclosed in US Pat. No. 4,977,303. According to this method, the metal core is plated with zinc, cadmium or its alloy capable of forming a mixed alloy layer through diffusion reaction with the core wire after heat treatment, and the plated core wire is heat-treated at least 700 ° C. in an oxidizing atmosphere. Forming a mixed alloy layer, for example, a copper-zinc alloy layer by generating diffusion between the core wire metal and the plated metal, and a fine wire step involving work hardening of the heat-treated plated wire. At this time, the structure of the electrode wire is composed of a core layer and a mixed alloy layer surrounding the core and the outermost oxide layer. At this time, the oxide layer serves to improve the short circuit between the electrode line and the workpiece during discharge processing.

In addition, US Patent 4,686,153 discloses a copper-clad steel wire coated with zinc alloy. The steel wire in the core wire increases the mechanical strength to provide excellent processing accuracy, and the coated copper can be used to provide excellent electrical conductivity. Zinc is electroplated or hot-dipped on the copper-clad steel wire to form a copper-zinc alloy layer through a heat treatment step. In particular, when the zinc content is 40-50% by weight, an improved processing speed is obtained compared to the zinc-plated copper wire. The zinc-plated copper-clad steel wire, the copper-coated core wire, and a copper zinc alloy layer, wherein the zinc content is in the range of 10-50% by weight, preferably 40-50% by weight. The electrode wire manufacturing method includes the steps of providing a core wire of a copper-clad steel wire, electroplating zinc on the core wire, drawing the galvanized core wire into fine wires, and heating the zinc-plated layer to a copper-zinc alloy. Converting to a layer, the zinc concentration is in the range of 10-50% by weight, preferably 40-50% by weight, and includes a heat treatment step of gradually increasing the zinc concentration in the circumferential direction from the core wire.

When the brass wire passes through the plating bath in which the zinc is molten and the zinc is coated on the surface of the brass wire, while the brass wire passes through the plating bath in which the zinc is molten, the zinc attached to the copper atoms of the brass wire and the surface of the brass wire The mutual diffusion reaction causes copper atoms of the brass wire to diffuse toward the zinc layer attached to the surface, and zinc atoms attached to the surface of the brass wire diffuse toward the inside of the brass wire. The manufacturing method and the zinc-coated electrode wire and its manufacturing method were developed by this inventor.

The conventional electrode wire developed by the present inventors improves the processing speed by increasing the contact area with the processing liquid by increasing the surface area of the national wire due to the porosity caused by the alloy layer and the crack, thereby increasing the cooling rate even more.

However, the prior art invented by the present invention is difficult to obtain a coating layer of a certain thickness as it passes through the hot tub of more than 420 ℃ by plating the core wire of 0.9mm copper or copper alloy in the molten zinc bath as well as product It is difficult to ensure uniformity of

In other words, when the immersion time is increased or the temperature is increased to increase the thickness of the diffusion layer by a predetermined thickness or more, the core wire is stretched when passing through the galvanizing bath, thereby making it difficult to secure the uniformity of the product.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrode line for electric discharge machining, and a method of manufacturing the same, which improves the processing speed by making the thickness of the diffusion layer more than a predetermined thickness.

Another object of the present invention is to provide an electrode wire for electric discharge machining and a method for manufacturing the same, wherein the thickness of the diffusion layer is greater than or equal to a predetermined thickness and the processing speed of securing uniformity of the product is improved.

Another object of the present invention is to provide an electrode wire for electric discharge machining and a method of manufacturing the same, which have a thickness of the diffusion layer greater than or equal to a certain thickness, ensure product uniformity, and improve processing precision and processing speed.

In order to achieve the above object, the present invention provides a core wire of one of copper wire, copper alloy wire or copper strip steel having a first diameter, and the core wire is plated with a first metal having a lower vaporization temperature than copper;

A heat treatment second step of applying heat to form a copper alloy layer by the first metal plated and the copper mutual diffusion reaction;

A third step of drawing the plated wire material having the copper alloy layer formed in the second step into a plated wire material having a second diameter;

A fourth process of heat treating the plated wire of the second diameter to recrystallize and soften the cross-diffusion reaction;

A fifth process of plating the plated wire rod of the fourth step with a second metal having a lower vaporization temperature to form a second metal layer on the plated wire rod of the fourth step;

A sixth step of drawing the plated wire rod in the fifth step in which the second metal layer is formed to have a cross section of a final dimension;

The seventh step of stabilizing and heat treatment of the product of the sixth step having the final dimensions.

In order to achieve the above object, the present invention uses one of copper wire, copper alloy wire, or copper wire having a first diameter as a core wire, and the core wire is melt-plated with a first metal having a lower vaporization temperature than copper. A first step of forming a copper alloy layer by the first metal and the copper mutual diffusion reaction;

A second step of drawing the plated wire rod having the copper alloy layer formed therein in the first step to form a plated wire rod having a second diameter;

A third process of heat treating the plated wire of the second diameter to recrystallize and soften the cross-diffusion reaction;

A fourth step of forming a second metal layer on the plated wire material of the third step by plating the plated wire material of the third step with a second metal having a lower vaporization than the copper;

A fifth step of drawing the plated wire rod in the fourth step in which the second metal layer is formed to have a cross section of a final dimension;

The sixth step of stabilizing and heat-treating the product of the fifth step having a final dimension is passed.

That is, the electrode wire for electric discharge machining of the present invention is plated with a first metal on a core wire made of copper wire, copper alloy wire or copper-clad steel wire, and subjected to primary heat treatment to form a diffusion alloy layer. And plating and spreading a second metal on the second heat-treated plated wire, and performing a stabilization heat treatment process after the second fresh plating of the second metal plated wire to a predetermined thickness.

In particular, as the heat treatment method of the coating electrode line, it is very effective to perform the electrical resistance heat treatment method or the induction and radiation heat treatment method of the recrystallization heat treatment method or stabilization heat treatment method.

The reason for selecting electric resistance heat treatment method or induction and radiation heat treatment method is heat treatment method which can instantaneously heat-treat the plated wire which is carrying out the fast moving process in a short time in a short time. This is because it has the advantage of being adjustable.

In addition, the reason for selecting the electrical resistance heat treatment method or induction and radiation heat treatment method is the cost reduction and productivity because the two processes can be performed at the same time at high speed by integrating the wire drawing process and the recrystallization heat treatment or stabilization heat treatment process in one production facility. This can have a big effect on improvement.

In the present invention, as the first and second metals, one metal selected from zinc, aluminum, magnesium, selenium, zirconium, tin, or an alloy including these metals may be used.

Hereinafter, the technical configuration of the present invention will be described in detail.

Example 1

First, a brass wire having a diameter of 2-4 mm and preferably 3 mm is plated with zinc (first step).

The zinc-plated wire is heated to a temperature of 100-900 ℃, and the copper atoms of the brass wire and the zinc attached to the surface of the brass wire cross-diffusion reaction, and the copper atoms of the brass wire diffuse into the zinc layer attached to the surface. Atoms of zinc adhering to the surface of the metal are allowed to diffuse toward the inside of the brass wire (second step).

In the second step, the zinc-plated brass wire is drawn to a diameter of 0.9 mm to 1.2 mm (third step).

In the third process, wire rods of 0.9 mm to 1.2 mm in diameter are heat treated to be recrystallized and softened. At this time, since the recrystallization heat treatment temperature is high, the copper atoms of the brass wire and the zinc adhered to the surface of the brass wire are actively diffused, and the copper atoms of the brass wire diffuse to the zinc layer attached to the surface and adhere to the surface of the brass wire. Atoms of zinc that are diffused further toward the inside of the brass wire (fourth process).

The wire rod in the fourth step is plated with zinc again (the fifth step).

The wire rod in the fifth step is drawn to a diameter of 0.2 mm to 0.3 mm, the final dimension (sixth step).

Stabilize the wire with final dimensions by heat treatment (Step 7).

Example 1 can solve the problem caused by stretching the core wire when passing through the galvanizing bath by the above process.

Further, in the second process, the zinc deposited on the outer surface diffuses at a high temperature to form a diffusion layer, and when the heat treatment is performed to recrystallize in the fourth process, the diffusion reaction continues to obtain a diffusion layer having a thicker diffusion layer.

In addition, according to the present invention, the zinc is plated on the outside of the diffusion layer and left in the fifth process to ensure the precision during discharge processing.

Example 2

In the case of using the hot-dip plating method, heat is automatically applied when the wire passes through the plating bath in which zinc is molten, so that the present invention can be carried out by the following process.

First, a brass wire having a diameter of 2-4 mm, preferably 3 mm, is passed through a plating bath in which zinc is melted at 420-800 ° C. When the brass wire passes through the zinc-plated molten bath, the copper atoms of the brass wire and the zinc attached to the surface of the brass wire cross-diffusion reaction, and the copper atoms of the brass wire diffuse into the zinc layer attached to the surface, and the surface of the brass wire Atoms of zinc attached to the metal diffuse toward the inside of the brass wire (first process).

In the first step, the brass wire passing through the plating bath in which zinc is molten is drawn to have a diameter of 0.9 mm to 1.2 mm (second step).

In the second process, wire rods of 0.9 mm to 1.2 mm in diameter are heat treated to be recrystallized and softened. At this time, since the recrystallization heat treatment temperature is high, the copper atoms of the brass wire and the zinc adhered to the surface of the brass wire are actively diffused, and the copper atoms of the brass wire diffuse to the zinc layer attached to the surface and adhere to the surface of the brass wire. Atoms of zinc that are diffused further toward the inside of the brass wire (third process).

The wire rod in the third step is again plated by passing through a plating bath in which zinc is melted at a temperature of 420-800 ° C.

At this time, if necessary, the wire rod passed through the plating bath may be plated or quenched at a low temperature in the above temperature so that the zinc layer may be left on the outside without further diffusion. If necessary, plating may be performed at a high temperature and gradually cooled to sustain the diffusion reaction, thereby making the thickness of the diffusion layer thicker.

The wire rod in the fourth step is drawn to a diameter of 0.2 mm to 0.3 mm, which is the final dimension (fifth step).

The final size wire is stabilized by heat treatment (sixth step).

Example 2 solves the problem that the core wire is stretched when passing through the galvanizing bath by passing the galvanizing bath with a large diameter wire.

Furthermore, in the first process, a diffusion reaction occurs through the zinc bath in which the wire having a large diameter passes through the zinc bath, and a diffusion layer is formed. In the third process, the diffusion reaction is continued and the thickness of the diffusion layer becomes thicker. In addition, by passing the plating bath in which zinc is melted again in the fourth step, the diffusion layer has a thicker diffusion layer.

In addition, by passing through the plating bath in which zinc is molten again in the fourth step, a zinc layer or a diffusion layer having a high zinc concentration remains on the outer surface of the diffusion layer, thereby ensuring accuracy during discharge processing.

As described above, plating a first metal on a core wire of one of copper wire, copper alloy wire, or copper-clad steel wire and forming a diffusion alloy layer by performing a first heat treatment, followed by a first fresh drawing to a predetermined thickness and a second heat treatment. The electrode wire for electrical discharge machining according to the present invention, which is subjected to a stable heat treatment after plating the second metal on the secondary heat-treated plated wire and secondarily freshing the plated wire on which the second metal is plated to a predetermined thickness, passes through a zinc plating bath. When the core wire is drawn, the problem can be solved, and the effect of increasing the thickness of the diffusion layer can be obtained.

In particular, the zinc can be obtained by replating the outer surface of the diffusion layer to ensure precision during discharge processing.

In the conventional technology, since an alloy plating layer of about 3 microns to 10 microns or less is formed, the core wire is exposed immediately when the thin plating layer is vaporized during processing, thereby improving the processing speed, but the thickness of the copper diffusion layer of the present invention is about 10. As it can be formed from micron to 100 micron, the evaporation of the thick copper diffusion layer is continued during the processing and the cooling effect is continued, so the processing speed is improved and the core wire is kept until the electrode wire is completely passed through the lower part of the workpiece while discharging processing. As it is protected, the dimensional accuracy of electric discharge machining is improved, and when discharging thick workpieces, a thick copper diffusion layer can obtain a better effect in terms of processing speed and machining precision.

Claims (11)

A first step of plating a first metal having a vaporization temperature lower than copper by using one of copper wire, copper alloy wire, or copper wire steel wire having a first diameter as a core wire; A heat treatment second step of applying heat to form a copper alloy layer by the first metal plated and the copper mutual diffusion reaction; A third step of drawing the plated wire material having the copper alloy layer formed in the second step into a plated wire material having a second diameter; A fourth process of heat treating the plated wire of the second diameter to recrystallize and soften the cross-diffusion reaction; A fifth process of plating the plated wire rod of the fourth step with a second metal having a lower vaporization temperature to form a second metal layer on the plated wire rod of the fourth step; A sixth step of drawing the plated wire rod in the fifth step in which the second metal layer is formed to have a cross section of a final dimension; A seventh process for stabilizing heat treatment of the product of the sixth step having the final dimensions, the electrode line manufacturing method for electrical discharge machining. The method of claim 1, The first and second metals are zinc, aluminum, magnesium, selenium, zirconium, tin selected from one of the metals or alloys containing these metals, characterized in that the electrode line manufacturing method for electric discharge machining. The method of claim 1, The first diameter is 2-4mm, the second diameter is 0.9mm-1.2mm manufacturing method of the electrode line for electrical discharge machining, characterized in that consisting of. The method of claim 1, And wherein the recrystallization heat treatment method or stabilization heat treatment method is an electric resistance heat treatment method or an induction and radiation heat treatment method. One of copper wire, copper alloy wire or copper wire having a first diameter is used as a core wire, and the core wire is hot-plated with a first metal having a lower vaporization temperature than copper, and the first metal and the copper cross-diffusion reaction on the core wire A first step of forming a copper alloy layer by A second step of drawing the plated wire rod having the copper alloy layer formed therein in the first step to form a plated wire rod having a second diameter; A third process of heat treating the plated wire of the second diameter to recrystallize and soften the cross-diffusion reaction; A fourth step of plating the plated wire rod of the third step with a second metal having a lower vaporization temperature to form a second metal layer on the plated wire rod of the third step; A fifth step of drawing the plated wire rod in the fourth step in which the second metal layer is formed to have a cross section of a final dimension; A sixth step of stabilizing heat treatment of the product of the fifth step having the final dimensions, the electrode line manufacturing method for electrical discharge machining. The method of claim 5, The first and second metals are zinc, aluminum, magnesium, selenium, zirconium, tin selected from one of the metals or alloys containing these metals, characterized in that the electrode line manufacturing method for electric discharge machining. The method of claim 5, The first diameter is 2-4mm, the second diameter is 0.9mm-1.2mm manufacturing method of the electrode line for electrical discharge machining, characterized in that consisting of. The method of claim 5, And wherein the recrystallization heat treatment method or stabilization heat treatment method is an electric resistance heat treatment method or an induction and radiation heat treatment method. Plating a first metal on a core wire made of one of copper wire, copper alloy wire, or copper-clad steel wire and forming a diffusion alloy layer by primary heat treatment, followed by primary freshness and secondary heat treatment to a predetermined thickness, and the secondary heat-treated plating. The electrode wire for electrical discharge machining, characterized in that the plated diffusion of the second metal on the wire rod and the secondary wire is plated with the second metal to a predetermined thickness and then subjected to a stable ring heat treatment process. The method of claim 9, The first and second metals, the electrode wire for electric discharge machining, characterized in that made of one metal selected from zinc, aluminum, magnesium, selenium, zirconium, tin or an alloy containing these metals. The method of claim 9, The first diameter is 2-4mm, the second diameter is the electrode line for electrical discharge machining, characterized in that consisting of 0.9mm-1.2mm.

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