Electrode wire for electric spark discharge machining and its manufacturing method

Abstract

The present invention provides an electrode wire for electric spark discharge machining and a manufacturing method thereof, the electrode wire comprising a core material (1), an intermediate layer (2) located outside the core material (1), and a surface layer (3) located outside the intermediate layer (2), the core material (1) being a metal or alloy, the intermediate layer (2) being a copper-zinc alloy, pits (20) being formed on the surface of the intermediate layer (2), micropits (200) being formed on the surfaces of the pits (20), the dimensions of the micropits (200) being smaller than the dimensions of the pits (20) in which they are located, and the surface layer (3) intermittently covering the outside of the intermediate layer (2) so as to fill the pits (20) and micropits (200). During the manufacturing process, the copper-zinc alloy is formed inside the electrode wire by electroplating, heat treatment, and drawing processes, and is then pressed against the surface of the intermediate layer (2) to form the pits (20) and micropits (200).

Description

[Technical Field]

[0001] The present invention relates to the field of electric spark wire-cut electrical discharge machining, and more particularly to an electrode wire for electric spark wire-cut electrical discharge machining and a method for manufacturing the same. [Background technology]

[0002] The basic operating principle of Wirecut Electrical Discharge Machining (WEDM) is to use a continuously moving thin metal wire (called an electrode wire) as an electrode to apply pulsed spark discharge to the workpiece to erode, cut, and shape the metal.

[0003] Electric spark wire EDM uses the principle of electric spark discharge to machine a workpiece. Before machining, the workpiece is connected to the positive pole of a pulsed power supply, and the electrode wire is connected to the negative pole of a high-frequency pulsed power supply as the tool electrode. The workpiece is then cut by spark discharge. The pulsed power supply provides the machining energy, and a dedicated wire cutting working fluid is used during the machining process to remove the debris generated during machining. A strong electric field causes the cathode and anode surfaces to be bombarded by electron and ion flows, respectively, creating an instantaneous high-temperature heat source in the electrode gap, melting and vaporizing the local metal, forming corrosion pits on the electrode wire and workpiece. The vaporized working fluid and workpiece material instantly expand, and the combined effects of this thermal expansion and the washing of the working fluid expel the molten and vaporized workpiece material from the discharge channel, completing one spark discharge cycle. When the next pulse arrives, the above spark discharge process is repeated, cutting and shaping the workpiece.

[0004] The cutting speed, cutting accuracy and surface roughness of the workpiece after machining are the evaluation indexes of the quality of the electric spark wire cut EDM process, and each of the above indexes is closely related to the performance of the electrode wire used.

[0005] In order to achieve a high cutting speed, in the prior art, a high zinc alloy layer having a high zinc content is plated on the surface of the electrode wire, and by taking advantage of the low sublimation temperature of zinc, a high discharge pressure is reached in the machining process, which further improves the cutting EDM speed.

[0006] To improve the speed of electric discharge machining, conventional techniques involve forming cracks on the surface of the wire electrode through processes such as tensioning. This increases the contact area between the wire electrode surface and the working fluid, improving the efficiency of cleaning the wire electrode with the working fluid and the cooling effect of the wire electrode. This shortens the time required for a single spark discharge, thereby increasing the number of spark discharges per unit time and improving the speed of electric discharge machining. Furthermore, tips can be formed at the edges of the cracks, which make the tips more likely to discharge, thereby improving the speed of electric discharge machining.

[0007] However, as the electric spark wire cutting EDM process progresses, the surface of the electrode wire is gradually consumed, the high-zinc alloy layer on the surface and the crack structure on the surface gradually disappear, the metal vaporization and cracking effects of the high-zinc surface are reduced, and the cutting speed is reduced. Summary of the Invention

[0008] The present invention provides an electrode wire for electric spark discharge machining and a method for manufacturing the same, in order to solve the problem of the reduction in cutting speed due to wear of the electrode wire in the prior art.

[0009] The present invention employs the following technical means: an electrode wire for electric spark discharge machining includes a core material, an intermediate layer located outside the core material, and a surface layer located outside the intermediate layer, the core material being a metal or alloy, the intermediate layer being a copper-zinc alloy, pits being formed on the surface of the intermediate layer, micropits being formed on the surfaces of the pits, the dimensions of the micropits being smaller than the dimensions of the pits in which they are located, and the surface layer intermittently covering the outside of the intermediate layer so as to fill the pits and the micropits.

[0010] The present invention has the following beneficial effects:

[0011] 1. When using this electrode wire for electric spark wire cutting electrical discharge machining, the surface layer of the electrode wire is worn away by electrical discharge corrosion as the machining process progresses, exposing the middle layer of the electrode wire. The surface of the middle layer has pits, and the surfaces of the pits have micro-pits. After the surface layer is first worn away by electrical discharge corrosion during the machining process, the exposed surface area of ​​the middle layer increases. Therefore, when the electrode wire is washed and cooled with working fluid, the contact area between the surface of the electrode wire and the working fluid is greatly increased, further improving the efficiency of washing and cooling the electrode wire by the working fluid and shortening the time for one spark discharge. Thus, the number of spark discharges per unit time can be increased and the speed of electric spark wire cutting can be improved.

[0012] 2. Tips are formed at the opening edges of pits and micro-pits, which make it easier for the tips to discharge. This shortens the reaction time for the electrode wire to generate an electric spark during electric discharge machining, thereby improving the speed of electric spark wire cutting.

[0013] 3. The surface layer intermittently covers the outside of the intermediate layer, forming a tip at the break in the surface layer. This makes it easier for the tip to discharge, shortening the reaction time for the electrode wire to generate an electric spark during electric discharge machining, and improving the speed of electric spark wire cutting.

[0014] Preferably, the intermediate layer has a thickness of 1 to 50 μm, and the surface layer has a thickness of 0.1 to 20 μm. The thicknesses of the surface layer and intermediate layer finally formed in the manufacturing process are related to the thickness of the galvanized layer; if the galvanized layer is too thin, it will not function as a functional layer, and if the galvanized layer is too thick, the outermost galvanized layer will not be able to participate in the alloying reaction. The thickness ranges of the surface layer and intermediate layer manufactured using galvanized layers of appropriate thickness are as described above.

[0015] Preferably, the thickness of the intermediate layer is 5 to 40 μm, and the thickness of the surface layer is 0.1 to 15 μm. Specifically, the thickness of the intermediate layer may be 5 to 30 μm, 10 to 40 μm, 10 to 30 μm, or 20 to 30 μm, and the thickness of the surface layer may be 0.1 to 10 μm, 1 to 15 μm, 1 to 10 μm, 5 to 15 μm, or 5 to 10 μm.

[0016] Preferably, the pits have a depth of 0.1 to 20 μm and the micropits have a depth of 0.05 to 10 μm along the radial direction of the wire electrode. The pits and micropits having the above dimensions can ensure a sufficiently large contact area between the wire electrode and the working fluid when the pit and micropit structures are exposed, and can also ensure that the tips formed on the edges of the pits and micropits have a good tip discharge effect, thereby improving the speed of electric spark wire-cut EDM.

[0017] Preferably, the pits have a depth of 0.1 to 10 μm and the micropits have a depth of 0.05 to 5 μm along the radial direction of the electrode wire. Specifically, the pits may have a depth of 0.5 to 10 μm, 1 to 10 μm, 0.5 to 5 μm, or 1 to 5 μm along the radial direction of the electrode wire, and the micropits may have a depth of 0.05 to 3 μm, 0.05 to 2 μm, 0.05 to 1 μm, 0.1 to 5 μm, 0.1 to 3 μm, 0.1 to 2 μm, or 0.1 to 1 μm.

[0018] Preferably, the surface layer contains carbon and zinc, which ensures that the surface layer has a good vapor flushing effect and improves the cutting electric discharge machining speed, while the presence of carbon improves the conductivity of the electrode wire, which improves the cutting electric discharge machining speed, and also improves the hardness of the surface layer, which is beneficial to the formation of pit and micro-pit structures on the surface of the intermediate layer.

[0019] Preferably, the content of carbon element in the surface layer is ≧0.5% by mass, and the content of zinc element is ≧60% by mass, which ensures that there are sufficient zinc element and carbon element in the surface layer, and is advantageous for the related components to function well.

[0020] Preferably, the intermediate layer further has cracks. As described above, since tips are formed at the cracks, and the tips are more likely to discharge, the reaction time for the electrode wire to generate an electric spark during electric discharge machining can be shortened, thereby improving the speed of electric spark wire cutting. Furthermore, the cracks can also have a similar effect to the pits to some extent, increasing the contact area between the electrode wire and the working fluid, thereby improving the cutting speed. Therefore, after the entire surface layer is consumed, the pit, micropit, and crack structure of the intermediate layer can further improve the cutting speed.

[0021] Preferably, the intermediate layer and / or the core material are exposed at the discontinuities in the surface layer. The exposed intermediate layer or core material can improve the electrical conductivity of the surface layer, improve the transmission of discharge energy, and further increase the cutting speed. Furthermore, the exposure of the intermediate layer or core material can form discontinuities in the surface layer, which, as described above, can increase the cutting speed.

[0022] Preferably, the core material is copper or a copper alloy.

[0023] In order to solve the above technical problems, the present invention further employs the following technical means: A method for manufacturing an electrode wire for electric spark discharge machining, comprising: Step S100 of providing a tough pitch copper bus bar or a copper alloy bus bar; Step S101: plating a surface of a bus bar with zinc using an electroplating solution containing an additive made of a saccharide organic compound to form a zinc plating layer on the surface of the bus bar, and manufacturing a first wire blank; and 2 Step S101: Step S102: heat-treating the first wire blank, during which copper elements in the bus bar and zinc elements in the galvanized layer diffuse into each other to form an intermediate layer, thereby producing a second wire blank having a core material, an intermediate layer, and a surface layer in this order from the inside to the outside; and step S103 of subjecting the second wire blank to tensile and stress annealing to manufacture a finished electrode wire. By applying the above-described manufacturing method provided by the present invention, the addition of a sugar organic compound to the electroplating solution causes the sugar organic compound to adsorb to the crystalline surface of the bus bar and the zinc plating layer, slowing down the reduction reaction of zinc ions, slowing down the crystallization rate of the zinc plating layer, and miniaturizing the crystal grains of the zinc plating layer, resulting in the formed zinc plating layer being hard and brittle. Furthermore, in this manufacturing method, the current density during electroplating is set to a range of 5 to 150 A / dm 2 Within this current density range, the crystal grains of the zinc-coated layer become finer, and more sugar organic compounds are adsorbed onto the crystal surfaces of the zinc-coated layer. Thus, the sugar organic compounds effectively slow down the reduction reaction of zinc ions, resulting in a denser, harder, and more brittle zinc-coated layer. In a subsequent heat treatment process, an alloying reaction occurs between the zinc-coated layer and the busbar, during which the sugar organic compounds and copper and zinc elements between the crystal grains form a harder mixture containing elements such as copper, zinc, and carbon, and their oxides. Structurally, the surface layer converted from the zinc-coated layer has irregular microparticles distributed on the surface facing the intermediate layer. After stretching using a mold, cracks occur in the surface layer, forming a block or sheet-like structure that is distributed outside the intermediate layer. The hard and brittle mixture and its oxide are pressed into the intermediate layer in a block or sheet-like form, forming pits, and the irregular microparticles are pressed against the inner surfaces of the pits, forming micropits. In this way, the intermediate layer in the finished electrode wire has pits and micro-pits that can increase its surface area, resulting in better cleaning effect. In addition, tips are formed at the opening edges of the pits and micro-pits, which are easy to discharge, thereby improving the cutting efficiency in the electric spark wire-cut EDM process.

[0024] Preferably, in step S102, the heat treatment temperature is 300 to 500°C, the heat treatment time is 1 to 50 hours, and the formed intermediate layer is made of a β-phase copper-zinc alloy and / or a β-phase copper-zinc alloy. ’ β-phase copper-zinc alloy or β-phase copper-zinc alloy ’ The copper-zinc alloy has high electrical conductivity, which can improve the discharge efficiency and further increase the cutting speed.

[0025] In order to solve the above technical problems, the present invention further employs the following technical means: A method for manufacturing an electrode wire for electric spark discharge machining, comprising: Step S200 of providing a tough pitch copper bus bar or a copper alloy bus bar; Step S201: plating a surface of a bus bar with zinc using an electroplating solution containing an additive made of a sugar organic compound to form a zinc plating layer on the surface of the bus bar, and manufacturing a first wire blank; and 2 Step S201: Step S202: heat-treating the first wire blank, during which copper elements in the bus bar and zinc elements in the zinc plating layer diffuse to form a copper-zinc alloy layer, thereby producing a second wire blank having, from the inside to the outside, a core material, a copper-zinc alloy layer, and a surface layer; Step S203: drawing the second wire blank to produce a third wire blank; Step S204: heat treating the third wire blank to manufacture a fourth wire blank having a core, an intermediate layer, and a surface layer in this order from the inside to the outside; and step S205 of performing tension and stress annealing on the fourth wire blank to manufacture a finished electrode wire.

[0026] As above, the unique electroplating process allows the middle layer of the final electrode wire to have pits and micropits, improving cutting speed.

[0027] Preferably, in step S202, the heat treatment temperature is 100 to 250°C, the heat treatment time is 3 to 20 hours, and the formed copper-zinc alloy layer contains a gamma-phase copper-zinc alloy. After plating, the copper-zinc alloy is alloyed at a relatively low heat treatment temperature to produce a gamma-phase copper-zinc alloy. Because the gamma-phase copper-zinc alloy is hard, it fractures and cracks during the subsequent tensile process. The electric field formed between the electrode wire and the workpiece also has localized strength differences, and the electric field is stronger where cracks form. Therefore, discharges occur preferentially at the edges of the cracks. Compared to when cracks are not present in the intermediate layer, using an electrode wire with cracks in the intermediate layer shortens the reaction time for the electrode wire to generate an electric spark and improves the speed of wire cutting due to electric sparks. Furthermore, similar to the pits and micropits, cracks can also have a certain effect of increasing the contact area between the intermediate layer and the working fluid.

[0028] Preferably, in step S204, the heat treatment temperature is 300 to 550°C, the heat treatment time is 1 to 50 hours, and the formed intermediate layer is a β-phase copper-zinc alloy and / or a β'-phase copper-zinc alloy. ’ By converting it into a β-phase copper-zinc alloy, the final intermediate layer is formed. ’ In addition to pits, β-phase Cu-Zn alloys have cracks. ’ The γ-phase copper-zinc alloy has a higher conductive effect than the γ-phase copper-zinc alloy, and can further improve the cutting speed.

[0029] In order to solve the above technical problems, the present invention further employs the following technical means: A method for manufacturing an electrode wire for electric spark discharge machining, comprising: Step S300 of providing a tough pitch copper bus bar or a copper alloy bus bar; Step S301: plating a surface of a bus bar with zinc using an electroplating solution containing an additive made of a sugar organic compound to form a zinc plating layer on the surface of the bus bar, and manufacturing a first wire blank; and 2Step S301: Step S302: drawing the first wire blank to produce a second wire blank; Step S303: heat-treating the second wire blank, during which copper elements in the bus bar and zinc elements in the galvanized layer diffuse into each other to form an intermediate layer, thereby producing a third wire blank having a core material, an intermediate layer, and a surface layer in this order from the inside to the outside; and step S304 of performing tension and stress annealing on the third wire blank to manufacture a finished electrode wire.

[0030] Similarly, due to the unique electroplating process, the intermediate layer of the final electrode wire product has pits and micropits, which improves the cutting speed. Furthermore, since tension is performed after electroplating, the dense, hard, and brittle zinc plating layer is prone to fracture, and the internal bus bars are prone to extrusion from the zinc plating layer, so the core material and intermediate layer of the final electrode wire are prone to extrusion from the surface layer, which gives the core material and intermediate layer better electrical conductivity, improving discharge efficiency and increasing the cutting speed.

[0031] In step S303, the heat treatment temperature is 200-500°C, the heat treatment time is 1-50 hours, and the formed intermediate layer is a β-phase Cu-Zn alloy and / or a β'-phase Cu-Zn alloy and / or a γ-phase Cu-Zn alloy. The heat treatment in step S303 uses different process parameters, and the intermediate layer of the finally produced electrode wire exhibits different phases, including a β-phase Cu-Zn alloy and a β ’ The γ-phase Cu-Zn alloy is softer and easier to be pressed in the subsequent pulling process to form pits and micro-pits, thus improving the cleaning effect more significantly, while also having better electrical conductivity, improving discharge efficiency and cutting speed. The γ-phase Cu-Zn alloy is relatively hard, while the β-phase Cu-Zn alloy and β-phase Cu-Zn alloy are relatively hard. ’Compared to copper-zinc alloys, the pits and micropits formed by pressing are shallower, so the cleaning effect is less improved, but the zinc content is high, so the vaporization effect during electric spark wire cutting is significant, and wire cutting speed can also be improved.

[0032] Preferably, the concentration of the additive in the electroplating solution is 8 to 25 g / L.

[0033] Preferably, the sugar organic compound is one of maltose, lactose, dextrin and sucrose or a mixture thereof.

[0034] Additional aspects and advantages of the invention will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a partial cross-sectional schematic view of an electrode wire manufactured by the manufacturing method provided by the present invention. [Figure 2] 1 is an electron microscope image of the surface of the electrode wire of Example 1 before corrosion. [Figure 3] 1 is an electron microscope image of the surface of the electrode wire of Example 1 after corrosion. [Figure 4] 10 is a partial cross-sectional schematic view of another electrode wire manufactured by the manufacturing method provided by the present invention. [Figure 5] 1 is an electron microscope image of the surface of the electrode wire of Example 4 before corrosion. [Figure 6] 10 is an electron microscope image of the surface of the electrode wire of Example 4 after corrosion. [Figure 7] 10 is a partial cross-sectional schematic view of another electrode wire manufactured by the manufacturing method provided by the present invention. [Figure 8] 10 is an electron microscope image of the surface of the electrode wire of Example 7 before corrosion. [Figure 9] 10 is an electron microscope image of the surface of the electrode wire of Example 7 after corrosion. [Figure 10]10 is a partial cross-sectional schematic view of another electrode wire manufactured by the manufacturing method provided by the present invention. [Figure 11] 10 is an electron microscope image of the surface of the electrode wire of Example 10 before corrosion. [Figure 12] 10 is an electron microscope image of the surface of the electrode wire of Example 10 after corrosion. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, the embodiments of the present invention will be described in detail, and examples of the embodiments are shown in the drawings, and the same or similar reference numerals throughout indicate the same or similar parts or parts having the same or similar functions. The embodiments described below with reference to the drawings are illustrative and are intended to interpret the present invention, but should not be understood as limiting the present invention.

[0037] Before describing specific embodiments, the structural features of the electrode wire for electric spark discharge machining provided by the present invention and the principle of the manufacturing method thereof will be described.

[0038] When manufacturing bus bars, brass bus bars are generally used, specifically CuZn37 brass or CuZn40 brass. Bus bars may also be manufactured using tough pitch copper (i.e., pure copper) or copper alloys other than brass.

[0039] Since the electroplating solution contains an organic sugar compound, the organic sugar compound is adsorbed to the crystalline surface of the bus bar and the zinc plating layer, slowing down the reduction reaction of zinc ions, slowing down the crystallization rate of the zinc plating layer, and minimizing the crystal grains of the zinc plating layer, resulting in a hard and brittle zinc plating layer. In addition, in this manufacturing method, the current density during electroplating is set to a range of 5 to 150 A / dm 2Within this current density range, the crystal grains of the zinc-coated layer become finer, and more sugar organic compounds are adsorbed onto the crystal surfaces of the zinc-coated layer. This allows the sugar organic compounds to more effectively slow the reduction reaction of zinc ions, resulting in a denser, harder, and more brittle zinc-coated layer. Furthermore, during a subsequent heat treatment process, an alloying reaction occurs between the zinc-coated layer and the busbar, during which the sugar organic compounds and copper and zinc elements between the crystal grains form a harder mixture containing elements such as copper, zinc, and carbon, and their oxides. Structurally, the surface layer converted from the zinc-coated layer has irregular microparticles distributed on the surface facing the intermediate layer. After stretching using a mold, cracks form in the surface layer, forming a block or sheet-like structure that is distributed outside the intermediate layer. The hard and brittle mixture and its oxide are pressed into the intermediate layer in a block or sheet-like form, forming pits, and the irregular microparticles are pressed against the inner surfaces of the pits, forming micropits. The current density range plays an important role in the manufacturing process: if the current density is too low, it will not promote the refinement of the crystal grains in the zinc-plated layer, and if the current density is too high, it will affect the zinc-plating effect and cause the zinc-plated layer to become blackened. Furthermore, the micropits are formed when irregular microparticles on the surface layer facing the intermediate layer are pressed against the inner surfaces of the pits, and the irregular microparticles in the surface layer may not be regular and smooth, but may have certain depressions. Therefore, when the pits and micropits are formed after drawing using a mold, the structures between adjacent micropits may be relatively flat, or may have certain protrusions.

[0040] In actual production and processing, there is a possibility that some gaps may exist between the surface layer and the pits or micropits due to the volatilization of some components, wear loss, etc. In this embodiment, the above-mentioned filling includes both the case where the pits and micropits are completely filled and the case where the surface layer does not completely fill the pits and micropits, leaving gaps. In the same electrode wire, there is a possibility that the above-mentioned cases of complete filling and incomplete filling may exist simultaneously.

[0041] During the heat treatment stage of the manufacturing process, the zinc element in the galvanized layer and the copper element in the core material diffuse together to form a copper-zinc alloy (i.e., alloying process). Depending on the heat treatment process parameters, the copper-zinc alloy can be in β phase, γ phase, or β phase + γ phase. The β phase can be β ’ For convenience of explanation, the β phase is used in the following examples. That is, the β phase hereinafter may be used in combination with the β phase and the β ’ represents one or both of the phases.

[0042] From a position perspective, pits are formed at the interface between the intermediate layer and the surface layer, and micropits are formed on the surface of the pits. From a dimensional perspective, the pit depth is 0.1 to 20 μm, and the micropit depth is 0.05 to 10 μm. The pit depth and micropit depth refer to data obtained by crossing the electrode wire and measuring the radial dimensions of the pits and micropits at different positions on the cross section, and the dimensions of the pits and micropits at different positions are within the above range. Both the pits and micropits exhibit an irregular distribution. Under certain process conditions, the intermediate layer inside the electrode wire exhibits cracks, and the cracks, pits, and micropits exhibit significant morphological differences: the cracks are elongated slit-like, while the pits and micropits are open pit-like. Due to the differences in their structural morphology, the pits and micropits play a significant role in increasing the contact area between the intermediate layer and the working fluid. The cracks are formed when the copper-zinc alloy layer breaks during the tension process, and the pits and micropits are formed when the intermediate layer is pressed by the surface layer during the tension process.

[0043] In actual manufacturing, the wire diameter specification of the selected bus bar is generally 0.5 to 1.2 mm, and the thickness of the intermediate layer of the finished electrode wire is 1 to 50 μm, and the thickness of the surface layer is 0.1 to 20 μm. Note that the thickness of the intermediate layer and the surface layer refer to data obtained by cross-sectionally measuring the radial dimensions of the intermediate layer and the surface layer at different positions on the electrode wire, and the dimensions of the intermediate layer and the surface layer at different positions are within the above ranges.

[0044] In terms of mass percentage, the electrode wire manufactured in this example has a carbon element content of ≧0.5% and a zinc element content of ≧60% in the surface layer.

[0045] The present invention provides three types of manufacturing methods. Examples 1 to 3 below use a first type of manufacturing method. The cross section of the finished electrode wire produced is as shown in Figure 1, and surface electron microscope images of the electrode wire before and after corrosion are as shown in Figures 2 and 3. Examples 4 to 6 below use a second type of manufacturing method. The cross section of the finished electrode wire produced is as shown in Figure 4, and surface electron microscope images of the electrode wire before and after corrosion are as shown in Figures 5 and 6. Examples 7 to 12 below use a third type of manufacturing method. The cross section of the finished electrode wire produced in Examples 7 to 9 is as shown in Figure 7, and surface electron microscope images of the electrode wire before and after corrosion are as shown in Figures 8 and 9. Examples 10 to 12 use a cross section of the finished electrode wire produced in Figure 10, and surface electron microscope images of the electrode wire before and after corrosion are as shown in Figures 11 and 12. In the present invention, the surface layer of the electrode wire is corroded by chemical corrosion, and then the electrode wire is observed using an electron microscope to obtain an electron microscope image of the corroded electrode wire. Specifically, the electrode wire product is cut and a portion is placed in dilute hydrochloric acid (mass fraction 10% to 20%) for 30 to 120 seconds to corrode the surface layer and expose the intermediate layer.

[0046] Example 1 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S100 provides a CuZn37 brass bus bar having a wire diameter of 1.2 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 20 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 150 A / dm 2 Step S101, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 12 g / L; Step S102: heat-treating the first wire blank at a heat treatment temperature of 420°C for 10 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy intermediate layer, and a surface layer; and step S103, in which the second wire blank is subjected to tension and stress annealing to produce a finished electrode wire having a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 1. In step S103, the surface layer 3 breaks during the tensioning process to form cracks, and the intermediate layer 2 is pushed out through the cracks during the tensioning process, so that the final electrode wire appears with the surface layer 3 intermittently covering the outside of the intermediate layer 2. Note that the surface layer 3 is pressed into the intermediate layer 2 during the tensioning process to form pits 20 in the intermediate layer 2, and micro-pits 200 are formed within the pits 20.

[0047] Example 2 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S100 provides a CuZn40 brass bus bar having a wire diameter of 1 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 12 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 100 A / dm 2Step S101, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 8 g / L; Step S102: heat-treating the first wire blank at a heat treatment temperature of 500°C for 1 hour, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy intermediate layer, and a surface layer; and step S103, in which the second wire blank is subjected to tension and stress annealing to produce a finished electrode wire having a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 1. In step S103, the surface layer 3 breaks during the tensioning process to form cracks, and the intermediate layer 2 is pushed out through the cracks during the tensioning process, so that the final electrode wire appears with the surface layer 3 intermittently covering the outside of the intermediate layer 2. Note that the surface layer 3 is pressed into the intermediate layer 2 during the tensioning process to form pits 20 in the intermediate layer 2, and micro-pits 200 are formed within the pits 20.

[0048] Example 3 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S100 provides a CuZn37 brass bus bar having a wire diameter of 0.5 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 3 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 5 A / dm 2 Step S101, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 25 g / L; Step S102: heat-treating the first wire blank at a heat treatment temperature of 300°C for 50 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy intermediate layer, and a surface layer; and step S103, in which the second wire blank is subjected to tension and stress annealing to produce a finished electrode wire having a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 1. In step S103, the surface layer 3 breaks during the tensioning process to form cracks, and the intermediate layer 2 is pushed out through the cracks during the tensioning process, so that the final electrode wire appears with the surface layer 3 intermittently covering the outside of the intermediate layer 2. Note that the surface layer 3 is pressed into the intermediate layer 2 during the tensioning process to form pits 20 in the intermediate layer 2, and micro-pits 200 are formed within the pits 20.

[0049] By applying the manufacturing methods provided in Examples 1 to 3 above, the inner surface of the intermediate layer 2 of the finished electrode wire can be enhanced with pits 20 and micropits 200, which can increase its surface area and improve cutting efficiency during the electric spark wire cutting EDM process. As shown in Figures 2 and 3, cracks appear in the surface layer 3 of the initial electrode wire, exposing the inner intermediate layer 2 (which is a β-phase copper-zinc alloy 22 for the electrode wire). As the electric spark wire cutting EDM process progresses, the surface layer 3 is consumed by electrical discharge corrosion, exposing the intermediate layer 2 located below the surface layer 3, revealing the pits 20 and micropits 200 located on the surface of the intermediate layer 2. Furthermore, because the surface layer intermittently covers the outer surface of the intermediate layer, a tip is formed where the surface layer is broken. Because the tip is more susceptible to electrical discharge, the reaction time for the electrode wire to generate an electric spark during electric spark wire cutting EDM can be shortened, improving the speed of electric spark wire cutting.

[0050] Example 4 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S200 provides a CuZn40 brass bus bar having a wire diameter of 0.8 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 8 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 70 A / dm 2 Step S201, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 25 g / L; Step S202: heat-treating the first wire blank at a heat treatment temperature of 130°C for 20 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a γ-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a γ-phase copper-zinc alloy, and a surface layer; Step S203: pulling the second wire blank to produce a third wire blank with a wire diameter of 0.3 mm, and the surface layer and the gamma-phase copper-zinc alloy are both fractured during the pulling process, causing cracks in the surface layer and cracks in the gamma-phase copper-zinc alloy; Step S204: heat-treating the third wire blank, the heat treatment temperature is 300°C, and the heat treatment time is 50h to produce a fourth wire blank, and convert the γ-phase Cu-Zn alloy into an intermediate layer of β-phase Cu-Zn alloy; and step S205 of performing tension and stress annealing on the fourth wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 4. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0051] Example 5 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S200 provides a CuZn40 brass bus bar having a wire diameter of 1.2 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 15 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 120 A / dm 2 Step S201, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 8 g / L; Step S202: heat-treating the first wire blank at a heat treatment temperature of 250°C for 3 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a γ-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a γ-phase copper-zinc alloy, and a surface layer; Step S203: pulling the second wire blank to produce a third wire blank with a wire diameter of 0.5 mm, and the surface layer and the gamma-phase copper-zinc alloy are both fractured during the pulling process, causing cracks in the surface layer and cracks in the gamma-phase copper-zinc alloy; Step S204: heat treating the third wire blank, the heat treatment temperature is 550°C, the heat treatment time is 1 hour, to produce a fourth wire blank, and convert the γ-phase Cu-Zn alloy into a β-phase Cu-Zn alloy; and step S205 of performing tension and stress annealing on the fourth wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 4. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0052] Example 6 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S200 provides a CuZn37 brass bus bar having a wire diameter of 0.95 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 11 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 90 A / dm 2 Step S201, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 16 g / L; Step S202: heat-treating the first wire blank at a heat treatment temperature of 180°C for 20 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a γ-phase copper-zinc alloy, thereby producing a second wire blank having, from the inside to the outside, a core material, a γ-phase copper-zinc alloy, and a surface layer; Step S203: pulling the second wire blank to produce a third wire blank with a wire diameter of 0.55 mm, and the surface layer and the gamma-phase copper-zinc alloy are both fractured during the pulling process, causing cracks in the surface layer and cracks in the gamma-phase copper-zinc alloy; Step S204: heat treating the third wire blank, the heat treatment temperature is 440°C, and the heat treatment time is 28 hours to produce a fourth wire blank, and convert the γ-phase Cu-Zn alloy into a β-phase Cu-Zn alloy; and step S205 of performing tension and stress annealing on the fourth wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 4. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0053] In the above Examples 4 to 6, the fact that the copper element in the busbar and the zinc element in the galvanized layer diffuse into each other to form a γ-phase copper-zinc alloy in the heat treatment process of step S202 means that the copper-zinc alloy layer formed in this process is mainly composed of a γ-phase copper-zinc alloy, but a small amount of a β-phase copper-zinc alloy may also be produced. As can be understood, this step is intended to obtain mainly a γ-phase copper-zinc alloy, and thus, after being stretched in the subsequent step S203, the copper-zinc alloy layer is prone to cracking (γ-phase copper-zinc alloy is hard and prone to cracking after being stretched).

[0054] By applying the manufacturing methods provided by Examples 4 to 6 above, the outer surface of the intermediate layer 2 in the finished electrode wire has pits 20 and micropits 200, which increase its surface area and improve cutting efficiency during the electric spark wire-cut electrical discharge machining process. As shown in Figures 5 and 6, cracks initially appear in the surface layer 3 of the electrode wire, exposing the inner core 1 and intermediate layer 2 (which is a β-phase copper-zinc alloy 22 for the electrode wire). As the electric spark wire-cut electrical discharge machining process progresses, the surface layer is consumed by electrical discharge corrosion, exposing the intermediate layer located below the surface layer, and pits and micropits are visible on the surface of the intermediate layer. The β-phase copper-zinc alloy that ultimately becomes the intermediate layer also has cracks in addition to pits and micropits. The strong electric field formed between the electrode wire and the workpiece also has local differences, and the electric field is even stronger where cracks 21 form, causing electrical discharges to occur preferentially at the edges of the cracks 21. Therefore, by using an electrode wire having cracks 21, the reaction time for the electrode wire to generate an electric spark can be shortened and the speed of wire cutting due to the electric spark can be improved compared to when no cracks 21 are formed. In addition, since part of the core material 1 and part of the intermediate layer 2 are exposed, the core material and the β-phase copper-zinc alloy can improve the discharge efficiency and further improve the wire cutting speed.

[0055] Example 7 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides a CuZn37 brass bus bar having a wire diameter of 0.88 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 11 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 80 A / dm 2 Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 16 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.45 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; Step S303: heat-treating the second wire blank at a heat treatment temperature of 350°C for 50 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 7. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0056] Example 8 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides a CuZn37 brass bus bar having a wire diameter of 1.2 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 6 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 40 A / dm 2 Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 8 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.6 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; Step S303: heat-treating the second wire blank at a heat treatment temperature of 500°C for 3 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 7. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0057] Example 9 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides a CuZn37 brass bus bar with a wire diameter of 0.8 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 12 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 120 A / dm 2 Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 25 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.55 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; Step S303: heat-treating the second wire blank at a heat treatment temperature of 440°C for 20 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in Figure 7. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0058] By applying the manufacturing methods provided by Examples 7 to 9, the outer surface of the intermediate layer 2 in the finished electrode wire product has pits 20 and micropits 200, which increase its surface area and improve cutting efficiency during the electric spark wire-cut electrical discharge machining process. As shown in Figures 8 and 9, cracks appear in the initial surface layer 3 of the electrode wire, exposing the inner intermediate layer 2 (which for the electrode wire is a β-phase copper-zinc alloy 22). As the electric spark wire-cut electrical discharge machining process progresses, the surface layer is consumed by electrical discharge corrosion, exposing the intermediate layer located below the surface layer, and pits and micropits are visible on the surface of the intermediate layer. The β-phase copper-zinc alloy that ultimately becomes the intermediate layer has cracks 21 in addition to pits and micropits. The strong electric field formed between the electrode wire and the workpiece also has local differences, and the electric field is even stronger where cracks 21 form, causing electrical discharges to occur preferentially at the edges of the cracks 21. Therefore, by using an electrode wire having cracks 21, the reaction time for the electrode wire to generate an electric spark can be shortened and the speed of wire cutting due to the electric spark can be improved compared to when no cracks 21 are formed. Note that cracks may occur in both the surface layer 3 and the intermediate layer 2 of the electrode wire. Furthermore, since a portion of the core material and the β-phase copper-zinc alloy are exposed to the surface layer, the core material and the β-phase copper-zinc alloy can improve the discharge efficiency and further improve the wire cutting speed.

[0059] Example 10 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides a CuZn37 brass bus bar having a wire diameter of 0.95 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 11 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 100 A / dm 2Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 16 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.5 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; step S303 of heat-treating the second wire blank at a heat treatment temperature of 200°C for 50 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy and a γ-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, a γ-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 10. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0060] Example 11 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides a CuZn37 brass bus bar having a wire diameter of 1.2 mm; Electroplating the outer surface of the brass bus bar with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 4.5 μm on the surface of the bus bar to manufacture a first wire blank, wherein the electroplating current density range is 30 A / dm 2Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 8 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.7 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; step S303 of heat-treating the second wire blank at a heat treatment temperature of 300°C for 22 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy and a γ-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, a γ-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 10. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0061] Example 12 This embodiment provides a method for manufacturing an electrode wire for electric spark discharge machining, and the manufacturing method includes: Step S300 provides tough pitch copper bus wire with a wire diameter standard of 0.8 mm; a step of electroplating an outer surface of the tough pitch copper bus wire with zinc using an electroplating solution containing an additive to form a zinc plating layer having a thickness of 12 μm on the surface of the bus wire, thereby producing a first wire blank, wherein the electroplating current density range is 110 A / dm 2Step S301, wherein the additive is one of maltose, lactose, dextrin, and sucrose or a mixture thereof, and the concentration of the additive in the electroplating solution is 25 g / L; Step S302: pulling the first wire blank to produce a second wire blank with a wire diameter of 0.5 mm, during which the dense, hard, and brittle zinc coating layer breaks and the internal bus bar is extruded from the zinc coating layer at the breaking point; step S303 of heat-treating the second wire blank at a heat treatment temperature of 350°C for 3 hours, during which the copper element in the bus bar and the zinc element in the galvanized layer diffuse to each other to form a β-phase copper-zinc alloy and a γ-phase copper-zinc alloy, thereby producing a third wire blank having, from the inside to the outside, a core material, a β-phase copper-zinc alloy, a γ-phase copper-zinc alloy, and a surface layer; and step S304 of performing tension and stress annealing on the third wire blank to produce a finished electrode wire with a wire diameter of 0.25 mm. The cross section of the finished electrode wire is as shown in FIG. 10. The surface layer 3 is pressed and embedded into the intermediate layer 2 during the tensioning process, forming pits 20 in the intermediate layer 2 and micro-pits 200 within the pits 20. The intermediate layer 2 is extruded from the cracks during the tensioning process, so that the surface layer 3 intermittently covers the outside of the intermediate layer 2, and part of the core material 1 can also be extruded from the fractured intermediate layer 2.

[0062] By applying the manufacturing methods provided by Examples 10-12, the outer surface of the intermediate layer 2 in the finished electrode wire has pits 20 and micropits 200, which increase its surface area and improve cutting efficiency during the electric spark wire-cut electrical discharge machining process. As shown in Figures 11 and 12, cracks appear in the initial surface layer 3 of the electrode wire, exposing the inner intermediate layer 2 (which for the electrode wire is a gamma-phase copper-zinc alloy 23). As the electric spark wire-cut electrical discharge machining process progresses, the surface layer is consumed by electrical discharge corrosion, exposing the intermediate layer located below the surface layer, and pits and micropits are visible on the surface of the intermediate layer. In addition to the pits and micropits, the intermediate layer also has cracks. The strong electric field formed between the electrode wire and the workpiece also has local differences, and the electric field is stronger where cracks 21 form, so electrical discharges occur preferentially at the edges of the cracks 21. Therefore, compared to when cracks 21 are not present, the use of an electrode wire having cracks 21 shortens the reaction time for the electrode wire to generate an electric spark, thereby improving the speed of wire cutting due to electric sparks. Cracks may occur in both the surface layer 3 and the intermediate layer 2 of the electrode wire. Furthermore, because a portion of the core material and the β-phase copper-zinc alloy are exposed from the surface layer, the core material and the β-phase copper-zinc alloy improve discharge efficiency and further improve wire cutting speed. After the electrode wire is consumed in the surface layer due to discharge corrosion, the γ-phase copper-zinc alloy is first exposed. Because the γ-phase copper-zinc alloy has a high zinc content, it has a good vaporization effect, improving the wire cutting speed.

[0063] (Comparative Example 1) Purchase commercially available brass electrode wire with a wire diameter standard of 0.25 mm.

[0064] (Comparative Example 2) Purchase commercially available electrode wire with a 0.25 mm diameter and zinc plating layer.

[0065] (Comparative Example 3) Purchase commercially available gamma electrode wire with a wire diameter standard of 0.25 mm.

[0066] The following table compares the structures of the electrode wires manufactured in Examples 1 to 12 with the structures of the purchased electrode wires in Comparative Examples 1 to 3.

[0067] [Table 1]

[0068] The electrode wires manufactured in Examples 1 to 12 and the electrode wires purchased in Comparative Examples 1 to 3 were used to carry out electric spark wire-cut electrical discharge machining tests, and the test conditions are shown in the table below.

[0069] [Table 2]

[0070] The test results are shown in the table below.

[0071] [Table 3]

[0072] As can be seen from the test comparison, the electrode wire manufactured by the manufacturing method provided by the present invention has pits and micro-pits in the inner intermediate layer, which significantly improves the performance of the electrode wire and further improves the cutting speed of electric spark wire-cut electrical discharge machining.

[0073] In the present invention, unless otherwise clearly related or limited in the embodiments, terms such as "attached," "coupled," "connected," and "fixed" appearing in the embodiments should be understood in a broad sense. For example, a connection may be a fixed connection, a detachable connection, or an integral connection, and as can be understood, it may be a mechanical connection, an electrical connection, etc., and of course, it may be a direct connection, an indirect connection via an intermediate medium, an internal communication between two parts, or an interactive relationship between two parts. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific implementation circumstances.

[0074] Although embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are illustrative and should not be construed as limiting the present invention, and that those skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention. [Explanation of symbols]

[0075] 1 Core material 2. Middle class 20 Pit 200 Micropits 21 Cracks 22 β-phase copper-zinc alloy 23 γ-phase copper-zinc alloy 3 Surface layer

Claims

1. A core material and an intermediate layer positioned outside the core material; a surface layer located outside the intermediate layer, the core material is a metal or an alloy, The intermediate layer is an electrode wire for electric spark discharge machining made of a copper-zinc alloy, pits are formed on the surface of the intermediate layer, Micropits are formed on the surfaces of the pits, the dimensions of said micropits are smaller than the dimensions of the pits in which they are located; The surface layer intermittently covers the outside of the intermediate layer so as to fill the pits and the micropits. Electrode wire for electric spark discharge machining.

2. The thickness of the intermediate layer is 1 to 50 μm, The thickness of the surface layer is 0.1 to 20 μm.

2. The electrode wire for electric spark discharge machining according to claim 1.

3. The thickness of the intermediate layer is 5 to 40 μm, The thickness of the surface layer is 0.1 to 15 μm.

3. The electrode wire for electric spark discharge machining according to claim 2.

4. Along the radial direction of the electrode wire, the depth of the pits is 0.1 to 20 μm, and the depth of the micropits is 0.05 to 10 μm. The electrode wire for electric spark discharge machining according to any one of claims 1 to 3.

5. Along the radial direction of the electrode wire, the depth of the pits is 0.1 to 10 μm, and the depth of the micropits is 0.05 to 5 μm.

5. The electrode wire for electric spark discharge machining according to claim 4.

6. The surface layer contains carbon and zinc elements.

2. The electrode wire for electric spark discharge machining according to claim 1.

7. In terms of mass percentage, the carbon element content in the surface layer is ≧0.5% and the zinc element content is ≧60%.

7. The electrode wire for electric spark discharge machining according to claim 6.

8. The intermediate layer further has cracks.

2. The electrode wire for electric spark discharge machining according to claim 1.

9. The intermediate layer and / or the core material are exposed from the discontinuity of the surface layer.

2. The electrode wire for electric spark discharge machining according to claim 1.

10. The core material is copper or a copper alloy.

2. The electrode wire for electric spark discharge machining according to claim 1.

11. Step S100: providing a tough pitch copper bus wire or a copper alloy bus wire; Step S101: A first wire blank is manufactured by plating a surface of a bus bar with zinc using an electroplating solution containing an additive made of a sugar organic compound to form a zinc plating layer on the surface of the bus bar, and the current density range of the electroplating is 5 to 150 A / dm ２ Step S101, Step S102: heat-treating the first wire blank, in which copper elements in the bus bar and zinc elements in the galvanized layer diffuse into each other to form an intermediate layer during the heat treatment process, thereby producing a second wire blank having a core material, an intermediate layer, and a surface layer in this order from the inside to the outside; and step S103 of performing tensile and stress annealing on the second wire blank to manufacture a finished electrode wire.

1. A method for manufacturing an electrode wire for electric spark discharge machining, comprising:

12. In step S102, the heat treatment temperature is 300 to 500°C, the heat treatment time is 1 to 50 hours, and the formed intermediate layer is a β-phase copper-zinc alloy and / or a β'-phase copper-zinc alloy. The method for manufacturing an electrode wire for electric spark discharge machining according to claim 11.

13. Step S200: providing a tough pitch copper bus wire or a copper alloy bus wire; Step S201: A first wire blank is manufactured by plating a surface of a bus bar with zinc using an electroplating solution containing an additive made of a sugar organic compound to form a zinc plating layer on the surface of the bus bar, and the current density range of the electroplating is 5 to 150 A / dm ２ Step S201: Step S202: heat-treating the first wire blank, in which copper elements in the bus bar and zinc elements in the zinc plating layer diffuse into each other to form a copper-zinc alloy layer, thereby producing a second wire blank having, from the inside to the outside, a core material, a copper-zinc alloy layer, and a surface layer; Step S203: drawing the second wire blank to produce a third wire blank; Step S204: heat treating the third wire blank to manufacture a fourth wire blank having a core, an intermediate layer, and a surface layer in this order from inside to outside; and step S205 of performing tensile and stress annealing on the fourth wire blank to manufacture a finished electrode wire.

1. A method for manufacturing an electrode wire for electric spark discharge machining, comprising:

14. In step S202, the heat treatment temperature is 100 to 250°C, the heat treatment time is 3 to 20 hours, and the formed copper-zinc alloy layer contains a gamma-phase copper-zinc alloy. The method for manufacturing an electrode wire for electric spark discharge machining according to claim 13.

15. In step S204, the heat treatment temperature is 300 to 550°C, the heat treatment time is 1 to 50 hours, and the formed intermediate layer is a β-phase copper-zinc alloy and / or a β'-phase copper-zinc alloy. The method for manufacturing an electrode wire for electric spark discharge machining according to claim 13.

16. Step S300: providing a tough pitch copper bus wire or a copper alloy bus wire; Step S301: plating a surface of the bus bar with zinc using an electroplating solution containing an additive made of a sugar organic compound to form a zinc plating layer on the surface of the bus bar, thereby manufacturing a first wire blank; and the current density range of the electroplating is 5 to 150 A / dm. ２ Step S301, Step S302: drawing the first wire blank to produce a second wire blank; Step S303: heat-treating the second wire blank, in which copper elements in the bus bar and zinc elements in the galvanized layer diffuse into each other to form an intermediate layer during the heat treatment process, thereby manufacturing a third wire blank having a core material, an intermediate layer, and a surface layer in this order from the inside to the outside; and step S304 of performing tensile and stress annealing on the third wire blank to manufacture a finished electrode wire.

1. A method for manufacturing an electrode wire for electric spark discharge machining, comprising:

17. In step S303, the heat treatment temperature is 200 to 500°C, the heat treatment time is 1 to 50 hours, and the formed intermediate layer is a β-phase copper-zinc alloy and / or a β'-phase copper-zinc alloy and / or a γ-phase copper-zinc alloy. The method for manufacturing an electrode wire for electric spark discharge machining according to claim 16.

18. The concentration of the additive in the electroplating solution is 8 to 25 g / L. The method for manufacturing an electrode wire for electric spark discharge machining according to any one of claims 11 to 17.

19. The sugar organic compound is one of maltose, lactose, dextrin and sucrose or a mixture thereof; The method for manufacturing an electrode wire for electric spark discharge machining according to any one of claims 11 to 17.

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