CN111590153A

CN111590153A - Electrode wire for micro electric spark machining, preparation method and application

Info

Publication number: CN111590153A
Application number: CN202010509917.XA
Authority: CN
Inventors: 梁志宁; 万林辉; 林火根; 吴桐; 顾洪方; 陈益波
Original assignee: Ningbo Bode High Tech Ltd By Share Ltd
Current assignee: Ningbo Bowei Alloy Precision Fine Wire Co.,Ltd.
Priority date: 2020-06-05
Filing date: 2020-06-05
Publication date: 2020-08-28
Anticipated expiration: 2040-06-05
Also published as: CN111590153B; JP2021049637A; KR102550403B1; KR20210070249A; JP6980886B2

Abstract

The invention provides an electrode wire for micro electric spark machining, which comprises a core material and a surface layer coated outside the core material, wherein the core material is made of brass, the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer, and the outer layer is an amorphous layer. Through the short-range ordered and long-range disordered amorphous layer, the electrode wire can improve the processing precision, eliminate stress and reduce deformation, so that the processed surface is free of burn, smooth and free of microcracks, and the purpose of improving the on-line processing precision and the surface quality of the micro tool electrode is achieved. The invention also provides a preparation method and application of the electrode wire for micro electric spark machining, and the problem that the precision of micro electric spark machining is not enough in the prior art can be solved.

Description

Electrode wire for micro electric spark machining, preparation method and application

[ technical field ] A method for producing a semiconductor device

The invention belongs to the field of mechanical manufacturing, and particularly relates to an electrode wire for micro electric spark machining, a preparation method and application.

[ background of the invention ]

With the trend of increasingly miniaturization and precision development of products, the micro electric discharge machining technology is one of non-contact precision manufacturing methods, is concerned by academia and industry by the characteristics of ultra-precision and high-precision machining, becomes an important component in the field of micro-machine manufacturing at present, and has wide application in the manufacturing industry.

The micro electric discharge machining is a special machining method for removing a conductive material by utilizing an electroerosion effect generated during pulse discharge between two electrodes immersed in a working fluid, is also called micro electric discharge machining or micro electroerosion machining, and is mainly used for machining dies and parts with micro holes and cavities in complex shapes, such as air film hole machining on blades of an aero-engine, engine oil nozzle punching, chemical fiber spinneret hole machining, precision part hole machining of gears or decorations of clocks and watches and the like, part hole machining in instruments on medical instruments, micro die machining and the like.

Factors influencing the micro electric spark machining are many, such as a high-frequency power supply, a tool electrode, assembly precision, a control system, process design, a working medium and the like, and the factors can directly influence the machining precision and the surface quality of the micro hole and the micro cavity. The tool electrode is the restrictive key for realizing superfine electric spark and high-precision machining. Because minute holes and minute cavities having a small size are to be formed, a tool electrode having a smaller and higher accuracy than that of the minute holes and minute cavities must be obtained. The research on the online manufacturing of the tool electrode by the micro electric spark enables the tool electrode to meet the high-precision requirement of the micro electric spark machining to the maximum extent, and is the key of the hyperfine and high-precision machining technology for realizing the special micro electric spark machining for machining micro holes and micro parts.

Wire electric discharge machining (WEDG) is a method for manufacturing tool electrodes on line in micro electric discharge machining, and various micro and special-shaped tool electrodes are machined by continuously corroding and removing redundant parts of the tool electrodes through point discharge between a copper/brass wire electrode and the tool electrodes. However, due to the influences of high energy release, uneven spark distribution, discontinuous spark erosion, interference of discharge explosive force, unsmooth chip removal and the like caused by the capacitance effect of the conventional electrode wire, the gap between the electrode wire and the tool electrode is changed, the surface quality and the smoothness of the tool electrode are affected, a plurality of micro cracks exist, and the machining precision of the micro-spark tool electrode is seriously reduced.

Therefore, although the WEDG method can process micron-sized tool electrodes, for a tool electrode with a given design size, repeated tests are performed under the same processing electrical parameters, the same working fluid, the same machine tool and the same electrode material, and the accuracy of the obtained tool electrode still cannot meet the requirement, and particularly, the electrode positioning accuracy and the shape accuracy (herein, the true roundness) fluctuate within a large deviation range, and need to be further improved.

[ summary of the invention ]

The invention provides an electrode wire for micro electric spark machining, which is beneficial to improving the on-line machining precision and the surface quality.

The invention also provides a preparation method of the electrode wire for micro electric spark machining, which can prepare the electrode wire with an amorphous outer layer and is suitable for high-precision micro electric spark machining.

The invention also provides the application of the electrode wire for micro electric spark machining, and the precision of the micro electric spark machining can be improved.

One of the technical solutions of the present invention is as follows:

the electrode wire for micro electric spark machining comprises a core material and a surface layer coated outside the core material, wherein the core material is brass, and the electrode wire is characterized in that: the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer, and the outer layer is an amorphous layer. The amorphous state refers to that the structure is amorphous or glassy, and the microstructure has short-range order and long-range disorder. The atoms of the amorphous layer are arranged irregularly, are disordered remotely, have high resistivity and high anti-capacitance effect, and greatly reduce the high-energy release of the electrode wire due to the capacitance effect, so that uniform electric spark distribution is formed in the discharging process; the organization structure of the amorphous layer is a short-range ordered amorphous or glassy structure, a large amount of fine space is arranged in the structure, the density is low, the melting point is high, and the high-temperature ablation phenomenon is hardly caused; because the electrode wire is in an amorphous or glassy structure, the structure of the electrode wire is not continuous, and the electrode wire is hard and brittle, so that the thermal expansion coefficient of the electrode wire is relatively large, and the electrode wire has strong capacity of bearing high peak current, thereby preventing the electrode wire from self-burning or deforming in the discharge process, and reducing the phenomena of thermal corrosion and unevenness on the surface of the tool electrode. Furthermore, the electrode wire with the structure can improve the online processing precision and the surface quality.

Further, the outer surface of the inner layer is in a relaxed and/or reconstructed surface structure. By relaxed or restructured surface structure is meant that the longitudinal and transverse arrangement of atoms at the outer surface of the inner layer is changed compared to their internal arrangement. In the longitudinal direction, atoms such as copper, zinc, iron, sulfur, silicon and the like are displaced relative to the original positions, namely surface relaxation is generated, and as a result of the relaxation, trace element atoms are positioned in the outermost region of the surface; laterally, these atoms are irregularly spaced, the surface is restructured, and as a result of the restructuring, two or more atoms come into close proximity to form an atomic aggregate. Therefore, the atom arrangement on the outer surface of the inner layer becomes very irregular, the unit cell volume expands, the surface relaxes, and the crystal structure is reconstructed. The structure can reduce the energy of the system, and is very favorable for adsorbing foreign atoms or molecules to form an outer amorphous layer. Meanwhile, according to the surface tension theory, bubbles can escape from a relaxation or reconstruction surface structure, so that the direct interference of instantaneous explosive force on the gap between the electrode wire and the micro electrode is greatly reduced, and the micro electric spark machining precision is improved.

Further, the amorphous layer is composed of the following chemical elements: 49.5-90 wt% of Zn, 1.5-42 wt% of Cu, 0.158-6.6 wt% of X and the balance of O; wherein X at least comprises three different elements X1, X2 and X3, X1 is Fe, Al or Ca, X2 is Si, C, S or B, X3 is any one of Fe, Al, Ca, Si, C, S or B which is different from X1 and X2, and inevitable impurities with the content sum less than or equal to 0.3 wt% can be further present in the amorphous layer. The mixed structure of the amorphous layer reduces the discharge loss of the electrode wire, can realize continuous and stable micro electric spark corrosion, and ensures the constant gap between the electrode wire and the micro tool electrode, thereby improving the surface quality of the micro tool electrode, having high smoothness and no microcrack. And the main metal element on the surface layer is zinc, so that the zinc gasification effect is good, the discharge efficiency is improved, the processing speed can be improved, and the processing time is saved.

Furthermore, the inner layer is beta or beta' phase copper-zinc alloy, so that the electric conductivity is good, and the tool electrode is favorable for the discharge corrosion of a micro electric spark point.

Further, the amorphous layer may or may not completely cover the outer surface of the inner layer.

Furthermore, the thickness of the amorphous layer is 1-10 μm, and the thickness of the inner layer is 5-50 μm.

The technical scheme has the following beneficial effects:

the nonstatic layer with the special structure has the characteristics of high resistivity, high melting point, small expansion coefficient and high anti-capacitance effect, so that the whole electrode wire has better conductivity, tensile strength and product ductility and toughness, the processing precision can be improved, the stress can be eliminated, the deformation can be reduced, the processed surface is free of burn, smooth and free of microcrack, and the purpose of improving the processing quality is achieved (for example, the surface roughness can reach Ra0.05 mu m).

The other technical scheme of the invention is as follows:

a preparation method of an electrode wire for micro electric discharge machining is characterized by comprising the following steps:

(1) preparing a core material: forming a brass bus with the diameter of 0.5-1.5 mm;

(2) electroplating: carrying out oil removal, acid cleaning, water washing and electroplating treatment on the bus obtained in the step (1) to form a zinc coating with the thickness of 0.5-50 um on the bus to obtain a first wire blank;

(3) alloying: alloying the first wire blank prepared in the step (2) at 50-550 ℃ to form a second wire blank consisting of a brass core material, an inner layer and an initial outer layer;

(4) powder metallurgy: performing powder metallurgy coating treatment on the second wire blank prepared in the step (3), wherein the treatment temperature is 300-1000 ℃, the temperature fluctuation is within 20 ℃ in the treatment process, then cooling to 100 ℃ or below, discharging, and forming a third wire blank formed by a brass core material, an inner layer and an amorphous outer layer;

(5) stretching to a finished product: and (4) carrying out multi-mode continuous stretching and online stress relief annealing processing on the third wire blank prepared in the step (4) to prepare a finished electrode wire product with the diameter of 0.05-0.25 mm.

Further, the chemical components of the electroplating solution in the step (2) comprise: carbon, nitrogen, oxygen and hydrogen with the total concentration of 0.1-400 g/L, boron, sulfur and chlorine with the total concentration of 0.5-600 g/L, aluminum with the concentration of 1.2-1000 g/L and zinc with the concentration of 100-1500 g/L; the electroplating speed of the step (2) is 10-500m/min, the current is 1200-2500A, and the voltage is 120-220V.

Further, the cooling time of the step (4) is 5-30 minutes.

Further, the drawing speed of the step (5) is 600-1500 m/min, the annealing voltage is 12-60V, and the annealing current is 15-50A.

The technical scheme has the following beneficial effects:

the electrode wire which is suitable for micro electric spark machining and has the outer amorphous layer can be obtained by the preparation method, has high performance, long service life and high geometric shape consistency, and is suitable for high-precision tool electrode machining and up to the limit size machining; the method can meet the requirements of micro electric spark machining of various complex shapes such as cylindrical, conical, prismatic and threaded electrodes and electrodes with slopes (a multi-axis linkage numerical control system needs to be configured) according to actual machining requirements, and is easy to realize automatic forming of tool electrodes; in addition, the preparation method has the advantages of simple production process, strong operability, few preparation steps, simple production equipment, easy preparation of products meeting the requirements, and easy realization of large-scale and automatic production.

The invention also provides another technical scheme as follows:

the electrode wire is applied to micro electric spark machining.

The technical scheme has the following beneficial effects:

the electrode wire has an amorphous structure covered on the outer surface, so that high-energy release caused by capacitance effect is greatly reduced, and uniform electric spark distribution is formed in the discharging process;

the amorphous mixed structure reduces the discharge loss of the electrode wire, can realize continuous and stable micro electric spark corrosion, and ensures the constant gap between the electrode wire and the micro tool electrode, thereby improving the surface quality of the micro tool electrode, having high smoothness and no micro crack;

because the electrode wire is fed in a continuous and unidirectional movement manner and the fine tool electrode continuously rotates in the discharging process, the electrode wire provided by the invention is provided with a special structure, so that the viscous resistance of a medium can be effectively reduced, the discharge of machining scraps is easier, and the excessive accumulation of electric erosion products in a discharging gap is avoided, so that the occurrence of abnormal discharging is reduced, and the quality of a machined surface is improved;

the roughness value produced by the electrode wire of the invention is obviously smaller than that produced by the brass wire discharge, so the deterioration layer of the electrode of the micro tool processed by the electrode wire of the invention is smaller, which is beneficial to prolonging the service life of the electrode wire.

[ description of the drawings ]

FIG. 1 is a schematic view of basic components of micro electro discharge machining;

FIG. 2 is a schematic partial cross-sectional view of a finished wire electrode of the present invention;

FIG. 3 is a schematic cross-sectional view of a first wire of the present invention;

FIG. 4 is a schematic cross-sectional view of a second wire of the present invention;

fig. 5 is a schematic cross-sectional view of a third wire of the present invention.

Description of the labeling: 1, a first pulse power supply; 2, a second pulse power supply; 3, electrode wires; 4, a tool electrode; 5, material parts; 6, working fluid; 7, a guider; 8, an automatic feed adjusting device; 301, a core material; 302, an inner layer; 303, an outer layer; 304, plating; 305, an initial outer layer.

[ detailed description ] embodiments

The present invention will be described in further detail with reference to the following examples, but the present invention is not limited to the following examples.

The following examples are not provided to limit the scope of the present invention, nor are the steps described to limit the order of execution, and the directions described are limited to the drawings. Modifications of the invention which are obvious to those skilled in the art in view of the prior art are also within the scope of the invention as claimed.

The difference between the micro electric discharge machining and the traditional electric discharge machining is that the size of a micro electric discharge machining object is in a micron order, which determines that the pulse energy of a micro machining power supply is very small, generally 10^-6～10^-7J, and thus micro electric discharge machining generally requires a long time. In addition, the discharge erosion in the micro electric discharge machining is mainly a process of heat fusion of a workpiece material, so that the higher the pulse energy is, the larger the volume of the workpiece to be eroded is, and the higher the corresponding machining efficiency is, but this results in the larger the roughness and discharge gap of the workpiece surface, and the machining accuracy is difficult to ensure. Therefore, it is difficult to achieve both machining efficiency and precision in single-electrode micro-electro-discharge machining. In addition, compared with the conventional slow-running wire electric spark machining, the electrode loss of the micro electric spark machining is more severe, and if the traditional electrode replacement method is adopted for electrode compensation, the consistency of the shape of the electrode of the micro tool is difficult to ensure, and the position precision during repeated clamping is difficult to ensure.

The micro electric spark machining technology has the advantages of non-contact, high precision, no burr, capability of machining after heat treatment and the like, and is suitable for the precision manufacture of conductive material micro-structure parts. For fine electric discharge machining of a fine structure, a fine tool electrode adapted to a process is required. Fig. 1 shows basic components of conventional micro electric discharge machining.

The technical scheme provided by the invention is as follows:

the electrode wire for micro electric spark machining comprises a core material and a surface layer coated outside the core material, wherein the core material is brass, and the electrode wire is characterized in that: the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer, and the outer layer is an amorphous layer, as shown in fig. 2. According to the electrode wire, through the amorphous structure covered on the outer surface, atoms are arranged irregularly (atoms are arranged in a remote disordered way), the resistivity is high, and the electrode wire has a high anti-capacitance effect, so that the high-energy release caused by the capacitance effect is greatly reduced, and the uniform electric spark distribution is formed in the discharging process; the outer layer of the electrode wire is made of amorphous materials, and is characterized in that the organization structure is an amorphous or glassy structure, the atomic arrangement is short-range ordered, namely the arrangement form of mass points in a local area is similar to that of a crystal, but the local regularly arranged area is highly dispersed, and the structures have a large amount of fine spaces, lower density and higher melting point, so that the high-temperature ablation phenomenon is hardly caused; because the electrode wire is in an amorphous or glassy structure, the structure of the electrode wire is not continuous, and the electrode wire is hard and brittle, so that the thermal expansion coefficient of the electrode wire is relatively large, and the electrode wire has strong capacity of bearing high peak current, thereby preventing the electrode wire from self-burning or deforming in the discharge process, and reducing the phenomena of thermal corrosion and unevenness on the surface of the tool electrode. Further, the online machining precision and the surface quality of the micro electric discharge machining are improved.

The inner outer surface is preferably a relaxed and/or a reconstituted surface structure. According to the surface tension theory, bubbles can escape from a relaxation or reconstruction surface structure, so that the direct interference of instantaneous explosive force to the gap between the electrode wire and the micro electrode is greatly reduced, and the micro electric spark machining precision is improved. The chemical elemental composition of the amorphous layer is preferably the following chemical elemental composition: 49.5-90 wt% of Zn, 1.5-42 wt% of Cu, 0.158-6.6 wt% of X and the balance of O; wherein X at least comprises three different elements X1, X2 and X3, X1 is Fe, Al or Ca, X2 is Si, C, S or B, X3 is any one of Fe, Al, Ca, Si, C, S or B which is different from X1 and X2, and the sum of the contents of other inevitable impurities is less than or equal to 0.3 wt%. Where X comprises at least three different elements X1, X2, X3, X1 is Fe, Al or Ca, X2 is Si, C, S or B, and X3 is any one of Fe, Al, Ca, Si, C, S or B other than X1, X2, it should be understood that: for example, X contains at least three different elements, e.g., X1 is Fe and X2 is Si, then X3 can only be one of Al, Ca, C, S, or B. The mixed structure of the amorphous layer reduces the discharge loss of the electrode wire, can realize continuous and stable micro electric spark corrosion, and ensures the constant gap between the electrode wire and the micro tool electrode, thereby improving the surface quality of the micro tool electrode, having high smoothness and no microcrack. And the main metal element on the surface layer is zinc, so that the zinc gasification effect is good, the discharge efficiency is improved, the processing speed can be improved, and the processing time is saved.

The inner layer of the electrode wire is preferably beta or beta' phase copper-zinc alloy, so that the electrode wire has good conductivity and is beneficial to the discharge corrosion of tool electrodes at micro electric spark points. Beta or beta' phase copper zinc alloys means copper zinc alloys containing about 45% to 51% zinc. At certain ambient temperatures, the alloy structure is regular and has some brittleness, commonly referred to as the β' phase; if a certain temperature is exceeded, the structure becomes irregular, called beta-phase. The transition between the beta and beta' phases is unavoidable, but its effect is small.

The amorphous layer completely or incompletely covers the outer surface of the inner layer. The thickness of the amorphous layer is preferably 1-10 μm, and the thickness of the inner layer is 5-50 μm.

The preparation method of the electrode wire comprises the following basic steps:

(1) preparing a core material: forming a brass bus with the diameter of 0.5-1.5 mm; the brass core material comprises the following components: 57.5-71.5 wt% of Cu, 0.003-0.30 wt% of Fe, Si: 0.001-0.10 wt%, and the balance of Zn;

(2) electroplating: carrying out oil removal, acid cleaning, water washing and electroplating treatment on the bus obtained in the step (1) to form a zinc coating with the thickness of 0.5-50 um on the bus to obtain a first wire blank, wherein the cross section of the first wire blank is shown in figure 3; the chemical components of the electroplating solution comprise: carbon, nitrogen, oxygen and hydrogen with the total concentration of 0.1-400 g/L, boron, sulfur and chlorine with the total concentration of 0.5-600 g/L, aluminum with the concentration of 1.2-1000 g/L and zinc with the concentration of 100-1500 g/L; the electroplating speed is 10-500m/min, the current is 1200-2500A, and the voltage is 120-220V;

(3) alloying: alloying the first wire blank prepared in the step (2) at 50-550 ℃ to form a second wire blank consisting of a brass core material, an inner layer and an initial outer layer, wherein the cross section of the second wire blank is shown in FIG. 4;

(4) powder metallurgy: treating the second wire blank prepared in the step (3) by a powder metallurgy coating at the treatment temperature of 300-1000 ℃, after the treatment temperature is stable, cooling (within 5-30 minutes) to 100 ℃ or below within a given arbitrary time interval until the difference between the highest temperature and the lowest temperature of any point in a working space is less than or equal to 20 ℃, and discharging to form a third wire blank formed by a brass core material, an inner layer and an amorphous outer layer, wherein the cross section of the third wire blank is shown in figure 5;

(5) stretching to a finished product: and (4) carrying out multi-mode continuous drawing and online stress relief annealing processing on the third wire blank prepared in the step (4), wherein the drawing speed is 600-1500 m/min, the annealing voltage is 12-60V, and the annealing current is 15-50A, so that a finished electrode wire product with the diameter of 0.05-0.25 mm is prepared, and the partial cross section of the finished product is shown in figure 2.

The tensile strength of the electrode wire is tested by a microcomputer control electronic universal tester, and the conductivity is tested by a bridge method.

The electrode wire is suitable for micro electric spark machining, and can effectively improve the on-line machining precision and the surface quality of a micro tool electrode, and the reasons include:

1) through the amorphous alloy structure covered on the outer surface, atoms are arranged randomly, the resistivity is high, and the high anti-capacitance effect is achieved, so that the high-energy release caused by the capacitance effect is greatly reduced, and the uniform electric spark distribution is formed in the discharging process;

2) the amorphous mixed structure reduces the discharge loss of the electrode wire, can realize continuous and stable micro electric spark corrosion, and ensures the constant gap between the electrode wire and the micro electrode, thereby improving the surface quality of the micro electrode, having high smoothness and no micro-crack;

3) by setting a special relaxation and/or reconstruction structure on the outer surface of the inner layer of the surface layer of the electrode wire, bubbles can escape from the relaxation or reconstruction structure according to the surface tension theory, so that the direct interference of instantaneous explosive force on the electrode wire and the electrode gap of a micro tool is greatly reduced, and the micro electric spark machining precision is improved;

4) because the electrode wire is fed in a continuous and unidirectional movement manner and the fine tool electrode continuously rotates in the discharging process, the electrode wire provided by the invention is provided with a special structure, so that the viscous resistance of a medium can be effectively reduced, the discharge of machining scraps is easier, and the excessive accumulation of electric erosion products in a discharging gap is avoided, so that the occurrence of abnormal discharging is reduced, and the quality of a machined surface is improved;

5) the electrode wire has an inner layer made of beta or beta' phase copper-zinc alloy, has good conductivity and is beneficial to discharging and corroding tool electrodes at micro electric spark points;

6) the main metal element on the surface layer of the electrode wire is zinc, the gasification effect of the zinc is good, the discharge efficiency is improved, the processing speed can be improved, and the processing time is saved;

7) the electrode wire has high tensile strength, the product has plasticity and toughness, the small-shaft type wire collection and wire release are convenient, and the wire breakage is not easy;

8) the electrode wire has high processing precision and good flexibility, effectively improves the processing surface quality of the electrode manufactured by micro electric sparks on line, and promotes the long-term development of the micro electric spark processing technology;

9) the electrode wire can meet the requirements of micro electric spark machining of various complex shapes according to the actual machining requirements, such as cylindrical, conical, prismatic and threaded electrodes and electrodes with slopes (a multi-axis linkage numerical control system needs to be configured), and the automatic forming of tool electrodes is easy to realize;

10) the thickness of the electric spark affected layer is about 3-4 times of the Rmax value and is basically formed in rough machining; the roughness value produced by the electrode wire processing is obviously smaller than that produced by the brass wire discharging; the smaller the roughness value is, the smaller the pulse width of the wire electrode is, the shorter the current action time is, the insufficient time for heat to be transferred to the depth direction of the material is, and the depth which can be reached by the heat is smaller, so that the deteriorated layer of the processed material is thinner, and the service life is longer.

Example 1

The electrode wire for micro electric discharge machining has diameter D0 of 0.20mm, and includes core material of brass and surface layer coated outside the core material and comprising inner layer coated on the outer surface of the core material and outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer, and the composition of the amorphous layer is 53.38 wt% of Zn, 30.67wt% of Cu30.67wt%, 0.41 wt% of Al, 0.87 wt% of C, 0.003 wt% of Si, 0.002 wt% of S and the balance of O; the thickness of the amorphous layer is 5.5 μm and completely or incompletely covers the outer surface structure of the inner layer; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 10 mu m.

The preparation process of the electrode wire for micro electric spark machining comprises the following steps:

(1) preparing a brass busbar core material with the diameter of 1.2mm, wherein the brass busbar core material contains 62.8 wt% of copper and 0.01 wt% of silicon;

(2) carrying out oil removal, acid cleaning, water washing and continuous electro-galvanizing treatment on the bus prepared in the step (1), and adding 380g of zinc sulfate, 25g of aluminum sulfate, 13g of additives such as polyethylene glycol, Arabic gum, peach gum, dextrin or glucose and the like into each liter of plating solution; the thickness of the plating layer is 10 mu m; preparing a first wire blank, wherein the electroplating speed is 150m/min, the current is 1200A, and the voltage is 150V;

(3) placing the first wire blank electroplated in the step (2) in a closed container, vacuumizing to the vacuum degree of-0.10 MPa, and then carrying out alloying treatment at the temperature of 270 ℃ for 600min to enable the core material and the coating to complete alloying and chemical segregation reaction to obtain the inner layer material of the wire electrode and internal elements which segregate to the surface of the wire blank so as to prepare a second wire blank;

(4) heating the second wire blank prepared in the step (3) to 550 ℃ in the presence of oxygen, wherein the oxygen concentration is about 20.9%, the sintering reaction time is 180min, and the temperature fluctuation is controlled within 10 ℃; then, quickly cooling to room temperature within 30min by adopting air cooling or water cooling, and discharging to finally form a required outer amorphous material to prepare a third wire blank;

(5) and finally, carrying out multi-mode continuous stretching and online stress relief annealing processing on the prepared third wire blank, wherein the stretching speed is 1000m/min, the annealing voltage is 32V, and the annealing current is 25A, so as to prepare a finished electrode wire product with the diameter of 0.25 mm.

Example 2

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 49.5 wt% of Zn, 41.5 wt% of Cu, 0.61 wt% of Fe, 0.78 wt% of Ca, 0.002wt% of Si, 0.002 wt% of S and the balance of O; the thickness of the amorphous layer is 3 μm, and the balance is O; the thickness of the amorphous layer is 1 μm and completely or incompletely covers the outer surface structure of the inner layer; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 5 mu m.

Example 3

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 75.5 wt% of Zn, 12 wt% of Cu, 0.42 wt% of Fe, 0.005 wt% of Si, 0.003wt% of P0.003wt% and the balance of O; the thickness of the amorphous layer is 7.5 μm, and the balance is O; the amorphous layer has a thickness of 8 μm and completely or incompletely covers the outer surface of the inner layer to reconstruct the structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 46.5 wt% of zinc, and the thickness is 40 mu m.

Example 4

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 60.5 wt% of Zn, 12.5 wt% of Cu, 0.55 wt% of C, 0.024 wt% of Al, 0.024 wt% of B and the balance of O; the amorphous layer has a thickness of 10 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.8 wt% of zinc, and the thickness is 50 mu m.

Example 5

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains Zn 71.5 wt%, Cu 11.5 wt%, Ca 0.60 wt%, Fe 0.78 wt%, Si 0.002wt%, C0.85 wt% and the balance of O; the amorphous layer has a thickness of 3 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer material of the electrode wire is made of beta or beta' phase copper-zinc alloy with 51.2 wt% of zinc content, and the thickness is 30 mu m.

Example 6

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 74.5 wt% of Zn, 1.5 wt% of Cu, 0.50 wt% of Ca, 2.0 wt% of Fe, 2.5 wt% of B2, 1.6 wt% of C and the balance of O; the amorphous layer has a thickness of 7 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 38 mu m.

Example 7

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 77.5 wt% of Zn, 14.7 wt% of Cu, 0.60 wt% of Ca, 0.78 wt% of Al, 0.002wt% of Si, 0.85 wt% of C and the balance of O; the amorphous layer has a thickness of 4 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 25 mu m.

Example 8

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 82.5 wt% of Zn, 5.2 wt% of Cu, 0.50 wt% of Al, 0.98 wt% of Fe, 0.003wt% of Si and the balance of O; the amorphous layer has a thickness of 9 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 48.5 wt% of zinc, and the thickness is 45 mu m.

Example 9

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 88.5 wt% of Zn, 1.9 wt% of Cu, 0.88 wt% of Fe, 0.002 wt% of B, 0.85wt% of S and the balance of O; the amorphous layer has a thickness of 5 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 30 mu m.

Example 10

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 55.5 wt% of Zn, 42.5 wt% of Cu, 0.05 wt% of Ca, 0.1 wt% of Fe, 0.008wt% of Si and the balance of O; the amorphous layer has a thickness of 2 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 30 mu m.

Example 11

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 84.5 wt% of Zn, 12.5 wt% of Cu, 0.60 wt% of Ca, 0.08 wt% of Si, 0.85wt% of C and the balance of O; the amorphous layer has a thickness of 1 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 50.5 wt% of zinc, and the thickness is 25 mu m.

Example 12

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 73.5 wt% of Zn, 17.5 wt% of Cu, 0.68 wt% of Ca, 2.2 wt% of Si, 0.8 wt% of C and the balance of O; the amorphous layer has a thickness of 6 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer material of the electrode wire is made of beta or beta' phase copper-zinc alloy with 46.5 wt% of zinc, and the thickness is 36 mu m.

Example 13

The electrode wire for micro electric discharge machining has a diameter D0 of 0.20mm, and comprises a core material and a surface layer coated on the core material, wherein the core material is made of brass, and the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer. The outer layer is an amorphous layer and contains 90 wt% of Zn, 3.5 wt% of Cu, 0.2 wt% of Ca, 1.8 wt% of Fe, 0.02wt% of Si and the balance of O; the amorphous layer has a thickness of 7 μm and covers the outer surface of the inner layer completely or incompletely with a relaxed structure; the inner layer of the electrode wire is made of beta or beta' phase copper-zinc alloy with 48.5 wt% of zinc, and the thickness is 35 mu m.

Comparative example

Comparative examples 1 and 2 are the application of commercial red copper wire with D0 of 0.20mm in micro electric discharge machining for test comparison;

comparative examples 3,4 and 5 were test comparisons of the application of a commercially available ordinary brass wire A, B, C with a D0 of 0.20mm in micro electric discharge machining;

comparative example 6 is a wire electrode prepared according to the technical scheme described in patent No. 201310562102.8 entitled slow wire moving electric spark discharge machining wire electrode and its preparation method, and the application in micro electric spark machining is tested and compared;

comparative example 7 is a wire electrode manufactured according to the technical scheme described in patent No. 201610795405.8 entitled unidirectional wire-moving electric discharge machining wire electrode and manufacturing method thereof, and the application of the wire electrode in micro electric discharge machining was tested and compared.

Tensile strength and conductivity

The finished wire electrode is tested for tensile strength on a microcomputer-controlled electronic universal testing machine, and the conductivity is tested by an electric bridge method, and the results are shown in table 1.

TABLE 1 partial Performance data for the wire electrodes of examples 1-13 and comparative examples 1-7

The data in table 1 are obtained by testing under the same conditions, wherein the diameter of the wire electrode is 0.20mm, and of course, the diameter of the core material in each example, the processing parameters in

steps

2,3 and 4, and the processing conditions of the multi-mode continuous drawing and the online stress relief annealing in step 5 can be effectively adjusted by those skilled in the art, so that the diameter of the finished wire electrode in each example is changed within the range of 0.05-0.25 mm.

In table 1, the electrode wire for micro electric discharge machining of the present invention has relatively high tensile strength, good ductility and toughness, and electrical conductivity obviously exceeding the level of similar products.

Micro electric discharge machining test

The micro electric discharge machine for experimental tests was an SX-100HPM machine manufactured by SARIX, Switzerland.

The test conditions were as follows: the dimensions of the machined micro-electrodes were tested as: diameter of

(diameter of electrode), length 150 μm; the material is as follows: tungsten copper; equipment parameters: the stroke distance of the X/Y/Z/Z2 shaft is 250X150X150X150 mm; z-axis feed rate: maximum 650 mm/min; x, Y-axis feed rate: maximum 800 mm/min; resolution ratio: 0.1 μm; cooling mode: 70bar cooling oil/water high pressure pump.

The positioning accuracy of the machined fine tool electrode was measured on an electric discharge machine SX-100HPM, the shape accuracy (herein, roundness) thereof was measured on a laser wire diameter tester and the machined surface roughness thereof was measured on a sanfeng roughness detector, and the micro-crack condition of the machined surface thereof was observed with an optical microscope of 200 magnifications, with the results shown in table 2.

The data in table 2 are obtained by testing under the same conditions, wherein the diameter of the wire electrode is 0.20mm, and of course, the diameter of the core material in each example, the processing parameters in

steps

In table 2, the electrode wires of examples 1 to 13 are used, compared with the performance data of the fine tool electrode obtained by processing the electrode wires of comparative examples 1 to 7, the electrode wire for fine electric discharge machining of the present invention has significant advantages, and the fine tool electrode obtained by processing the electrode wire has higher positioning accuracy and shape accuracy, and the processed surface has better smoothness, and the processed surface has no microcrack.

TABLE 2 Performance of Fine tool electrodes obtained by working the wires of examples 1 to 13 and the wires of comparative examples 1 to 7

Claims

1. The electrode wire for micro electric spark machining comprises a core material and a surface layer coated outside the core material, wherein the core material is brass, and the electrode wire is characterized in that: the surface layer comprises an inner layer coated on the outer surface of the core material and an outer layer coated on the outer surface of the inner layer, and the outer layer is an amorphous layer.

2. The micro electric discharge machining electrode wire according to claim 1, wherein the outer surface of the inner layer has a relaxed and/or restructured surface structure.

3. The micro electric discharge machining electrode wire according to claim 1, wherein the amorphous layer is composed of the following chemical elements: 49.5-90 wt% of Zn, 1.5-42 wt% of Cu, 0.158-6.6 wt% of X and the balance of O; wherein X at least comprises three different elements X1, X2 and X3, X1 is Fe, Al or Ca, X2 is Si, C, S or B, and X3 is any one of Fe, Al, Ca, Si, C, S or B, which is different from X1 and X2.

4. The micro electric discharge machining electrode wire according to claim 1, wherein the inner layer is a β or β' phase copper-zinc alloy.

5. The micro electric discharge machining electrode wire according to claim 1, wherein the amorphous layer covers the inner layer outer surface completely or incompletely.

6. The fine electric discharge machining electrode wire according to claim 1, wherein the amorphous layer has a thickness of 1 to 10 μm, and the inner layer has a thickness of 5 to 50 μm.

7. A preparation method of an electrode wire for micro electric discharge machining is characterized by comprising the following steps:

8. The method for producing an electrode wire for micro electric discharge machining according to claim 7, wherein the chemical composition of the plating bath of the step (2) comprises: carbon, nitrogen, oxygen and hydrogen with the total concentration of 0.1-400 g/L, boron, sulfur and chlorine with the total concentration of 0.5-600 g/L, aluminum with the concentration of 1.2-1000 g/L and zinc with the concentration of 100-1500 g/L; the electroplating speed of the step (2) is 10-500m/min, the current is 1200-2500A, and the voltage is 120-220V.

9. The method for producing an electrode wire for micro electric discharge machining according to claim 7, wherein the cooling time in the step (4) is 5 to 30 minutes.

10. The method for producing an electrode wire for micro electric discharge machining according to claim 7, wherein the drawing speed in the step (5) is 600 to 1500m/min, the annealing voltage is 12 to 60V, and the annealing current is 15 to 50A.

11. An application of the electrode wire for micro electric discharge machining, characterized in that the electrode wire is the electrode wire according to any one of claims 1 to 6 and is applied to micro electric discharge machining.