CN110202228B - Electrode wire for electric spark discharge machining and preparation method thereof - Google Patents
Electrode wire for electric spark discharge machining and preparation method thereof Download PDFInfo
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- 238000003754 machining Methods 0.000 title claims abstract description 34
- 238000010892 electric spark Methods 0.000 title claims abstract description 16
- 238000002360 preparation method Methods 0.000 title abstract description 14
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 43
- 239000000956 alloy Substances 0.000 claims abstract description 43
- 230000005674 electromagnetic induction Effects 0.000 claims abstract description 36
- 239000011162 core material Substances 0.000 claims abstract description 31
- 238000004381 surface treatment Methods 0.000 claims abstract description 14
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 32
- 229910052725 zinc Inorganic materials 0.000 claims description 30
- 239000011701 zinc Substances 0.000 claims description 28
- 239000011248 coating agent Substances 0.000 claims description 27
- 238000000576 coating method Methods 0.000 claims description 27
- 230000008569 process Effects 0.000 claims description 25
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 12
- 229910000881 Cu alloy Inorganic materials 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- 239000010949 copper Substances 0.000 claims description 9
- 238000009792 diffusion process Methods 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 230000008439 repair process Effects 0.000 claims description 3
- 238000009966 trimming Methods 0.000 abstract description 12
- 239000010410 layer Substances 0.000 description 39
- 230000000052 comparative effect Effects 0.000 description 14
- 238000012545 processing Methods 0.000 description 9
- 238000007599 discharging Methods 0.000 description 8
- 238000005520 cutting process Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 238000007730 finishing process Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 229910001369 Brass Inorganic materials 0.000 description 4
- 229910001297 Zn alloy Inorganic materials 0.000 description 4
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- 238000005516 engineering process Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
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- 241001391944 Commicarpus scandens Species 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
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- 239000002344 surface layer Substances 0.000 description 2
- 230000003746 surface roughness Effects 0.000 description 2
- HUPNQNOWXCVQSW-UHFFFAOYSA-N 2h-pyran-4-carboxamide Chemical compound NC(=O)C1=CCOC=C1 HUPNQNOWXCVQSW-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
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- 238000005260 corrosion Methods 0.000 description 1
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- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009760 electrical discharge machining Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
- B23H7/02—Wire-cutting
- B23H7/08—Wire electrodes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
- B23H7/22—Electrodes specially adapted therefor or their manufacture
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
Abstract
The invention discloses an electrode wire for electric spark discharge machining, which comprises a core material and an alloy layer arranged on the outer surface of the core material, wherein the outer surface of the alloy layer is provided with a plurality of irregularly distributed pyramid structures, and the pyramid structures are obtained by performing electromagnetic induction surface treatment on a stretched wire blank. The electrode wire with the micro pyramid structure on the alloy layer on the surface of the electrode wire can still stably and uniformly discharge under the condition of weak fine-trimming discharge energy. The invention also discloses a preparation method of the electrode wire for electric spark discharge machining.
Description
Technical Field
The invention relates to the technical field of electrode wires, in particular to an electrode wire for electric spark discharge machining and a preparation method thereof.
Background
With the development of the slow-running wire electric spark discharge machining industry, market competition is more intense, and customers must continuously improve product quality to obtain competitive advantages. For wire cut electrical discharge machining, the most effective method for improving the product quality is to improve the times of trimming, wherein the rough cutting mainly cuts the outline of a required workpiece and pursues the speed; the finishing is mainly to obtain the required dimensional accuracy and surface finish, and particularly, the finishing last cut is mainly to obtain better finish. The surface finish of Ra0.3-0.4 can be obtained by rough cutting once and fine trimming three times on a common slow-moving wire machine tool, and 6-9 cutters need to be fine trimmed if the surface finish is further improved to Ra0.1.
For example, the surface of a galvanized wire is a smooth pure zinc layer, so the galvanized wire is relatively suitable for high-quality processing with a large number of finishing times, although the surface smoothness of the cut workpiece is better than the surface smoothness of the brass wire, the gamma line, the β line and other coating layers, the pure zinc layer is low in melting point, is combined with the surface of the galvanized wire and is easy to break, and the pure zinc layer is easy to fall off to form zinc powder in the discharging and wearing processes, so that the slow wire cutting machine mechanism is blocked, and meanwhile, the zinc powder which falls off is adhered to the surface of the workpiece in the discharging process, so the surface quality of the workpiece is poor, and the quality of the guide wire is reduced.
Moreover, the discharge energy of the electrode wire in the multi-cutting machining process is greatly changed, and the electrode wire is specifically represented as follows: during rough cutting, the contour of a workpiece is cut, high-speed machining is required, at the moment, the discharge energy is large, and the discharge between the electrode wire and the workpiece is easy; however, in order to obtain the required dimensional accuracy and surface smoothness during the finishing, the discharge energy is small, particularly the discharge energy is very weak in the last finishing cut, and stable discharge is not easy to maintain between the electrode wire and the workpiece.
Because the wire electrode and the workpiece have relative motion in the horizontal direction and the vertical direction in the wire-cut electric discharge machining process, the uneven discharge and the unstable discharge can cause the surface of the workpiece to generate line marks, and the usability of the workpiece is reduced. Meanwhile, if breakdown does not occur in a certain discharging process, charges can be continuously accumulated on the surfaces of the workpiece and the electrode wire until one time of violent discharging, which is called as capacitor discharging, is generated, the surface of the workpiece can be damaged due to large discharging energy of the type, micro cracks are generated, and the service life of a die is influenced. In addition, because the electrode wire advances in the horizontal direction according to the machine tool program, if the discharge times are not too many, the workpiece is not cut in time, and the electrode wire can continue to advance until the electrode wire contacts the workpiece, so that a short circuit is caused. And then the electrode wire can retreat for a certain distance under the control of a machine tool program and then continuously move forwards, and if the electrode wire is short-circuited for many times at a certain point, electric sparks generated in the process can also damage the surface of the workpiece. The above-mentioned discontinuous and non-uniform discharges such as non-discharge, short circuit, capacitive discharge, etc. are called ineffective discharges, which all degrade the surface quality of the workpiece. In order to improve the surface quality of the workpiece, it is necessary to reduce the generation of invalid discharge during the finishing process and to ensure the uniformity and continuity of the finishing discharge process, i.e., to improve the effective discharge.
In conclusion, the electrode wire for electric spark discharge machining in the prior art cannot ensure uniform and stable discharge in the finishing process.
Disclosure of Invention
The invention aims to solve the technical problem of providing an electrode wire for electric spark discharge machining, which can always keep uniform and stable discharge in the fine trimming process.
The technical solution of the present invention to the above technical problems is as follows: an electrode wire for electric spark discharge machining comprises a core material and an alloy layer arranged on the outer surface of the core material, wherein a plurality of irregularly distributed pyramid structures are arranged on the outer surface of the alloy layer, and the pyramid structures are obtained by performing electromagnetic induction surface treatment on a stretched wire blank.
Compared with the prior art, the electrode wire for electric spark discharge machining has the following prominent substantive characteristics and remarkable progress:
during the experiment, the inventor finds that the charges are more easily gathered at the place with large curvature, so compared with the plane, the charges at the corner or the sharp point are denser, the electric field is stronger, and the discharge is more easily generated. Because the electric field intensity at the tip or the cone angle of the pyramid is high, charges are easy to gather, so that an insulating medium between the electrode wire and the workpiece is easy to break down, and discharge is generated; meanwhile, the pyramid structures on the surface of the electrode wire alloy layer are densely and irregularly distributed, so that the uniformity and continuity of the discharge process are ensured, and the surface quality of a cut workpiece is ensured. Therefore, the electrode wire with the pyramid structure on the surface alloy layer can ensure uniform and continuous discharge in the finishing process. Moreover, because the charges are gathered at the tip of the pyramid and the pyramid structures are densely distributed, the electrode wire can be always kept stable in the process of multiple times of fine repair discharging, even if the last knife of the fine repair is carried out, the stable discharging between the electrode wire and the workpiece can be still kept, and finally the required dimensional accuracy and surface finish degree are obtained.
The surface coating of the stretched wire blank can be extruded and deformed by a die, and stress and micro cracks are generated under the surface of the smooth coating. In order to obtain the pyramid structure, the invention adopts the electromagnetic induction surface treatment technology to the stretched wire blank to carry out the structuralization treatment on the surface coating of the wire electrode, namely, the metal atoms of the wire electrode core material and the surface alloy layer are diffused under the action of surface electromagnetic induction current, the stress and the tiny cracks in the alloy layer can cause the surface of the smooth alloy layer to generate special deformation in the process of diffusing the metal atoms, so as to form the alloy layer with the tiny pyramid structure, and the surface of the alloy layer has no cracks, so that the wire blank after stretching can directly obtain the wire electrode with the pyramid structure through the electromagnetic induction surface treatment technology.
In conclusion, the invention provides the electrode wire with the surface alloy layer provided with the micro pyramid structure, which can still stably and uniformly discharge under the condition of weak fine-trimming discharge energy, thereby improving the surface quality of the workpiece and prolonging the service life of the workpiece.
Preferably, the types of pyramid structures comprise individual pyramids and combinations of pyramids. The single pyramid is composed of a vertex protruding out of the surface of the alloy layer and at least three inclined planes intersecting with the vertex, and adjacent inclined planes intersect to form a ridge. The pyramid assembly is composed of a plurality of adjacent pyramids with intersected pyramids, and the pyramids are intersected without intervals, so that the structure is stable and is not easy to fall off.
Further preferably, the pyramid assembly is formed by at least two adjacent pyramids with intersecting conical surfaces. The adjacent pyramids of the pyramid assembly are intersected without a space, and the pyramid assembly is stable in structure and not easy to fall off.
Preferably, the edges of each pyramid structure intersect at an apex at an angle in the range of 60 to 120 ° and at least one angle is greater than 90 °. The pyramid structure satisfies the above condition, that is, the edge of each pyramid forms at least one obtuse angle at the vertex, and compared with a pyramid without an obtuse angle, the pyramid structure is more stable and less prone to falling off, and is beneficial to uniform and continuous discharge in the finishing process.
Preferably, the maximum height of each pyramid structure is 0.1-2 μm, and the interval between adjacent pyramid structures is 1-10 μm. The pyramid feature of the pyramid with the height is obvious, the tip feature is obvious, and the fine trimming discharge process is uniform and continuous; the spaced pyramid structures are densely distributed, and are favorable for uniform and continuous discharge in the fine trimming process.
Preferably, the total area of the pyramid structure accounts for 60-90% of the total external surface area of the alloy layer. When the pyramid structures reach a certain number, the pyramid features are obvious, and ideal effects can be obtained during fine trimming. Moreover, the pyramid structures with the area proportion are densely distributed, and uniform and continuous discharge in the fine trimming process is facilitated.
Preferably, the thickness of the alloy layer is 0.5-5 μm. The alloy layer meets the thickness, the generation of pyramid structures which are obvious in quantity and dense in distribution is facilitated, and the pyramid structures can be tightly attached to the outer surface of the alloy layer and are not prone to falling off.
Preferably, the alloy layer composition is a gamma phase or an epsilon phase. The gamma phase or the epsilon phase is generated by mutual diffusion of zinc atoms in the zinc coating and copper atoms in the core material, the melting point and the hardness are higher than those of pure zinc, and compared with the pure zinc, the gamma phase or the epsilon phase is more resistant to corrosion and is not easy to fall off, so that an alloy layer is ensured to participate in the fine modification process all the time.
Preferably, the core material consists of copper or a copper alloy. The copper or copper alloy has good physical properties such as electric conduction, tensile strength and the like, is easy to uniformly diffuse with a zinc coating, forms an alloy layer with uniform and consistent tissue components and no cracks, and is beneficial to continuous and uniform discharge in the finishing process.
Preferably, the electrode wire for electric discharge machining is prepared by the following preparation method:
1) preparing a core material consisting of copper or copper alloy;
2) coating a pure zinc layer on the surface of the core material obtained in the step 1) to obtain a wire blank with a zinc coating;
3) stretching the wire blank obtained in the step 2);
4) and (3) carrying out surface treatment on the wire blank obtained after stretching in the step 3) through an electromagnetic induction coil to obtain a finished wire electrode.
Further preferably, the wire blank in the step 4) continuously passes through 1-10 electromagnetic induction coils at a speed of 10-200 m/min, and the current frequency in the electromagnetic induction coils is 10-500 KHz.
Another technical problem to be solved by the present invention is to provide a method for manufacturing an electrode wire for electrical discharge machining, wherein the manufactured electrode wire can always maintain uniform and stable discharge in the fine trimming process.
The technical solution of the above technical problem is as follows: a preparation method of an electrode wire for electric spark discharge machining comprises the following steps:
1) preparing a core material consisting of copper or copper alloy;
2) coating a pure zinc layer on the surface of the core material obtained in the step 1) to obtain a wire blank with a zinc coating;
3) stretching the wire blank obtained in the step 2);
4) and (3) carrying out surface treatment on the wire blank obtained after stretching in the step 3) through an electromagnetic induction coil to obtain a finished wire electrode.
Compared with the prior art, the preparation method of the electrode wire for electric spark discharge machining has the following prominent substantive characteristics and remarkable progress:
an alternating current of a certain frequency is switched on the electromagnetic induction coil, thereby generating an alternating magnetic field. The electrode wire with the zinc coating passes through the electromagnetic induction coil, and induced current, namely eddy current, is generated in the electrode wire along the circumferential direction in an alternating magnetic field. Because the eddy current has a skin effect, the surface current density of the wire electrode is the maximum, and the central current of the wire electrode can be ignored.
When the electrode wire is stretched to a final finished product through the die, the surface zinc coating is extruded and deformed through the die, and stress and micro cracks generated in the stretching process of the die can be remained under the surface of a smooth coating. The zinc atoms in the wire electrode core material and the surface zinc coating generate diffusion under the action of surface induced current, the stress and the micro cracks in the zinc coating can cause the surface of the zinc coating with a smooth surface to deform in the process of zinc atom diffusion, an alloy layer with a micro pyramid structure is formed, and no crack exists on the surface of the alloy layer.
In summary, the invention carries out structuralization processing on the galvanized layer on the surface of the wire electrode by the unconventional electromagnetic induction surface processing technology, namely, in the process of diffusing metal atoms on a core material and a surface layer, the surface of the galvanized layer of the wire electrode generates special deformation to obtain a dense micro pyramid structure, so that the wire electrode can easily generate discharge under the condition of weak fine trimming discharge energy, the generation of ineffective discharge is reduced, the surface quality of a workpiece is improved, and the service life of the workpiece is prolonged.
Preferably, the wire blank in the step 4) continuously passes through 1-10 electromagnetic induction coils.
Further preferably, the speed of the wire blank passing through the electromagnetic induction coil in the step 4) is 10-200 m/min.
Preferably, the current frequency in the electromagnetic induction coil in the step 4) is 10-500 KHz. Further preferably, the current frequency in the electromagnetic induction coil in the step 4) is 100-400 KHz.
Preferably, the diameter of the electrode wire finished product is 0.15-0.35 mm. Further preferably, the diameter of the electrode wire finished product is (0.25 +/-0.002) mm.
Drawings
FIG. 1 is a partial side view schematically showing an electrode wire for electric discharge machining according to the present invention.
FIG. 2 is a schematic sectional view of an electrode wire for electric discharge machining according to the present invention taken along the direction A-A in FIG. 1.
The figure shows 1 core material, 2 alloy layer, 3 individual pyramid, 4 pyramid assembly.
Detailed Description
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 invention relates to a plurality of materials, including copper, copper alloy, pure zinc, gamma-phase copper-zinc alloy and epsilon-phase copper-zinc alloy, which can be purchased from the market.
The invention has a plurality of parameters, such as angle, height, interval, ratio, thickness, speed, number and frequency, and the units (such as DEG, mum,%, m/min, KHz) are marked after being unified at the upper limit, such as 60-120 DEG, 0.1-2μm, 60-90%, 0.5-5μm, 10-200 m/min, 1-10 KHz and 10-500 KHz. Of course, the unit can also be marked after the upper limit value and the lower limit value, such as 60-120 degrees, 0.1-2 μm, 60-90 percent, 0.5-5 μm, 10-200 m/min, 1-10, 10-500 KHz. The expression modes of the two parameter ranges can be both, in the embodiment, values are taken from the upper limit, the lower limit and the middle, and the numerical values are all in units.
The following examples are not intended to limit the scope of the present invention. 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.
Wire electrode product examples
As shown in fig. 1, the electrode wire for electric discharge machining comprises a core material 1 made of copper or a copper alloy and a zinc alloy plating layer 2 arranged on the outer surface of the core material 1, wherein the outer surface of the zinc alloy plating layer 2 is provided with a plurality of pyramid structures which are irregularly distributed. The types of pyramid structures include individual pyramids 3 and pyramid assemblies 4, and the pyramid assemblies 4 are composed of at least two adjacent pyramids with intersecting pyramids. The component of the galvanized alloy layer 2 is gamma phase or epsilon phase.
The angle range of the intersection of the edges of each pyramid structure at the vertex is 60-120 degrees, and at least one angle is larger than 90 degrees, namely at least one obtuse angle is formed at the vertex. Fig. 1 is a schematic partial side view, and fig. 2 is a schematic sectional view, which is different in angle and irregular in pyramid structure, so that the schematic view cannot accurately and completely express the pyramid structure, but the intersection angle range of the edges of each pyramid structure at the vertex of an actual product is 60-120 °, and at least one obtuse angle is formed at the vertex.
The maximum height of each pyramid structure is within the range of 0.1-2 μm, such as 0.1 μm, 1 μm, 2 μm.
The interval between the adjacent pyramid structures is within any distance of 1-10 μm, such as 1 μm, 5 μm, 10 μm.
The proportion of the total area of the pyramid structure to the total external surface area of the alloy layer 2 is within any value of 60-90%, such as 60%, 75% and 90%.
The thickness of the alloy layer 2 is within any value of 0.5-5 μm, such as 0.5 μm, 2.5 μm, 5 μm.
The diameter of the electrode wire is 0.25 mm.
The pyramid structure is obtained by performing electromagnetic induction surface treatment on a stretched wire blank.
The electrode wire for electric spark discharge machining is prepared by the following preparation method:
1) preparing a core material consisting of copper or copper alloy;
2) coating a pure zinc layer on the surface of the core material obtained in the step 1) to obtain a wire blank with a zinc coating;
3) stretching the wire blank obtained in the step 2);
4) continuously passing the wire blank obtained after stretching in the step 3) through 5 electromagnetic induction coils at the speed of 100m/min, wherein the current frequency in the electromagnetic induction coils is 200KHz, and performing electromagnetic induction surface treatment to obtain a finished wire electrode.
The number of the electromagnetic induction coils in the step 4) can be any number within the range of 1-10, such as 1, 4, 10; the speed of the wire blank passing through the electromagnetic induction coil can be any value within the range of 10-200 m/min, such as 10m/min, 120m/min and 200 m/min; the current frequency of the electromagnetic induction coil can be any value within the range of 10-500 KHz, such as 10KHz, 300KHz and 500 KHz.
Examples of the preparation method of the wire electrode
A preparation method of an electrode wire for electric spark discharge machining comprises the following steps:
1) preparing a core material consisting of copper or copper alloy;
2) coating a pure zinc layer on the surface of the core material obtained in the step 1) to obtain a wire blank with a zinc coating;
3) stretching the wire blank obtained in the step 2);
4) and (3) carrying out surface treatment on the wire blank obtained after stretching in the step 3) through an electromagnetic induction coil to obtain a finished wire electrode.
The preparation method completely departs from the conventional heat treatment mode in the field, comprises a bell jar type heating furnace and contact resistance heating, the wire electrode with the pyramid structure can be directly obtained by the stretched wire blank through an electromagnetic induction surface treatment technology, and the whole method is simple to operate.
The number of the electromagnetic induction coils in the step 4) can be any number within the range of 1-10, such as 1, 5, 10; the speed of the wire blank passing through the electromagnetic induction coil can be any value within the range of 10-200 m/min, such as 10m/min, 100m/min and 200 m/min; the current frequency of the electromagnetic induction coil can be any value within the range of 10-500 KHz, such as 10KHz, 300KHz and 500 KHz.
Table 1 lists the process parameters of the method for manufacturing the electrode wire for spark discharge machining, including the number of passing induction coils, the current frequency, and the passing coil speed. While table 1 lists only 9 examples, including endpoints and intermediate values, it is within the scope of the claimed invention to include within these parameters.
Table 1: technological parameters of preparation method
The above-described embodiments are intended to illustrate rather than to limit the invention, and any modifications and variations of the present invention are within the spirit and scope of the claims and are within the scope of the present invention.
Comparative example
Comparative example 1 is a common commercially available H62 brass wire electrode having a diameter of 0.25 mm.
Comparative example 2 is a galvanized wire electrode, which is made by forming a core material from H63 brass with a diameter of 0.9-1.2 mm, directly galvanizing the surface of the core material, and performing continuous drawing and continuous annealing processing after the thickness of the coating is 10-20 μm, thereby obtaining the galvanized wire electrode with a diameter of 0.25 mm.
The comparative example 3 is a conventional gamma-plated wire electrode, a core material is composed of H60 brass with the diameter of 0.9-1.2 mm, then the surface of the core material is galvanized, the thickness of a plating layer is 10-30 mu m, a first wire blank is obtained, the first wire blank is subjected to heat treatment, the temperature of the heat treatment process is 410 ℃, the time is 10 hours, a second wire blank is obtained, finally, the second wire blank subjected to heat treatment is subjected to continuous drawing and continuous annealing processing, and the high-speed wire electrode with the diameter of 0.25mm is prepared, and the surface layer structure is gamma phase.
Comparative example 4 was prepared according to the preparation method of the present invention, example 6, which is different from the above in that the order of the step 3) and the step 4) was exchanged, that is, the core material preparation → zinc plating → electromagnetic induction surface treatment → stretching was sequentially performed.
Testing of wire electrodes and workpieces machined therewith
The wire electrode of the present invention was used as an example, the wire electrodes of the related art were used in a comparative example to test their wear resistance, and the workpiece obtained by electric discharge machining was subjected to surface finish testing, the results of which are shown in table 2. The data in table 2 are obtained by testing under the same conditions, wherein the diameters of the electrode wires are all 0.25mm, the materials, the shapes and the sizes of the processed workpieces are all the same, and the cutting method is cutting-repairing-four. Of course, a person skilled in the art can effectively adjust the conditions of the last continuous drawing and continuous annealing process and the machining rate of the finished product in each embodiment, so that the diameter of the finished wire electrode in each embodiment is changed within the range of 0.10-0.35 mm, and the diameter of the comparative example is the same as the diameter of the wire electrode product in the embodiment.
The wear resistance test is measured by a copper powder tester, the quality of copper powder falling off every 5000m of the electrode wire can reflect the wear resistance of the electrode wire, and the larger the powder falling quality is, the worse the wear resistance of the electrode wire is; the smaller the powder falling quality is, the better the wear resistance of the wire electrode is. It can be seen that the powder dropping quality of the wire electrode is far less than that of the comparative examples 1 and 2, and is equivalent to that of the comparative examples 3 and 4. The electrode wire has high abrasion resistance, and the pyramid structure on the outer surface of the alloy layer of the electrode wire is stable and not easy to fall off, so that the electrode wire is beneficial to uniform and continuous discharge in the fine trimming process.
When the electrode wire is used for processing a workpiece, the surface quality of the workpiece can be obviously improved, and the improvement of the surface smoothness of the workpiece and the shallowing of surface line marks of the polished workpiece are embodied. The surface roughness Ra of the workpiece is used for representing the smoothness of the surface of the workpiece, and the smaller the Ra value is, the smaller the roughness is, the higher the smoothness is, and the smoother the surface of the workpiece is. In the embodiment, the surface roughness Ra of the workpiece cut by the electrode wire is 0.170-0.190 μm and is smaller than that of the comparative example of 0.189-0.228 μm, which shows that the smoothness of the workpiece cut by the electrode wire is good, and further shows that the electrode wire can always keep uniform and stable discharge in the fine modification process. Meanwhile, the line marks on the polished surface of the electrode wire processing workpiece of the invention are normal, shallow or slight, while those on the polished surface of the electrode wire processing workpiece of the comparative example are normal, deep or severe except that the line marks of the electrode wire processing workpiece of the comparative example 2 are slight, and the line marks are normal, deep or severe, and the stability of the electrode wire of the invention in the finish machining process is illustrated from another point of view.
Comparative example 4 the electromagnetic induction treatment was followed by drawing, since the surface alloy layer had been transformed into the gamma or epsilon phase, instead cracks were created after drawing, which reduced the wear resistance of the wire electrode and the surface quality of the finished workpiece, see the experimental data in table 2.
In conclusion, the pyramids on the outer surface of the electrode wire alloy layer are densely distributed, the structure is stable, the pyramids are not easy to fall off, and stable and uniform discharge can be kept between the electrode wire and the workpiece, so that the surface quality of the workpiece processed by the electrode wire is remarkably improved, and compared with the prior art, the electrode wire has outstanding substantive characteristics and remarkable progress and is creative.
Table 2: experimental data of example and comparative example wire electrodes and workpieces processed by the same
Claims (9)
1. An electrode wire for electric spark discharge machining comprises a core material and an alloy layer arranged on the outer surface of the core material, and is characterized in that the component of the alloy layer is gamma phase or epsilon phase; the outer surface of the alloy layer is provided with a plurality of pyramid structures which are irregularly distributed, and the electrode wire with the pyramid structures on the surface of the alloy layer is provided, so that uniform and continuous discharge in the fine repair process can be ensured; the pyramid structure is obtained by performing electromagnetic induction surface treatment on a stretched wire blank, metal atoms of a wire electrode core material and a surface alloy layer are diffused under the action of surface electromagnetic induction current, and the smooth alloy layer surface is deformed by stress and micro cracks in the alloy layer in the process of diffusing the metal atoms to form an alloy layer with the micro pyramid structure, and the surface of the alloy layer is not cracked, so that the wire electrode with the pyramid structure can be directly obtained by performing electromagnetic induction surface treatment on the stretched wire blank.
2. The electric discharge machining electrode wire as claimed in claim 1, wherein the type of the pyramid structure includes a single pyramid and a combination of pyramids.
3. The electric discharge machining electrode wire as claimed in claim 2, wherein the pyramid assembly is formed of at least two adjacent pyramids whose conical surfaces intersect.
4. The electrode wire for electric discharge machining according to claim 1, wherein the edges of each pyramid structure intersect at an angle ranging from 60 to 120 ° at the vertex, and at least one angle is greater than 90 °.
5. The electrode wire for electric discharge machining according to claim 1, wherein each of the pyramid structures has a maximum height of 0.1 to 2 μm, and a distance between adjacent pyramid structures is 1 to 10 μm.
6. The wire electrode for electric discharge machining according to claim 1, wherein the total area of the pyramid structure accounts for 60 to 90% of the total outer surface area of the alloy layer.
7. The electrode wire for electric discharge machining according to claim 1, wherein the thickness of the alloy layer is 0.5 to 5 μm.
8. A method for manufacturing an electrode wire for electric discharge machining according to any one of claims 1 to 7, comprising the steps of:
1) preparing a core material consisting of copper or copper alloy;
2) coating a pure zinc layer on the surface of the core material obtained in the step 1) to obtain a wire blank with a zinc coating;
3) stretching the wire blank obtained in the step 2);
4) carrying out surface treatment on the wire blank obtained after stretching in the step 3) through an electromagnetic induction coil to obtain a finished wire electrode; when the electrode wire is stretched to a final finished product through the die, the surface zinc coating is extruded and deformed through the die, and stress and micro cracks generated in the stretching process of the die can be remained under the surface of a smooth coating; the zinc atoms in the wire electrode core material and the surface zinc coating generate diffusion under the action of surface induced current, the stress and the micro cracks in the zinc coating can cause the surface of the zinc coating with a smooth surface to deform in the process of zinc atom diffusion, an alloy layer with a micro pyramid structure is formed, and no crack exists on the surface of the alloy layer.
9. The method for manufacturing an electrode wire for electric discharge machining according to claim 8, wherein the wire rod in the step 4) is continuously passed through 1 to 10 electromagnetic induction coils at a speed of 10 to 200m/min, and a current frequency in the electromagnetic induction coils is 10 to 500 KHz.
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| CN201910596764.4A CN110202228B (en) | 2019-07-03 | 2019-07-03 | Electrode wire for electric spark discharge machining and preparation method thereof |
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| JPH07254B2 (en) * | 1987-07-02 | 1995-01-11 | 三菱電機株式会社 | Wire electrode supply device for wire cut electric discharge machine |
| FR2881973B1 (en) * | 2005-02-11 | 2007-05-11 | Thermocompact Sa | COMPOSITE WIRE FOR ELECTROSION |
| CN201029073Y (en) * | 2006-12-21 | 2008-02-27 | 江苏江扬电缆有限公司 | Production equipment for building cotton covered wire |
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| CN205519972U (en) * | 2016-01-17 | 2016-08-31 | 盛利维尔（中国）新材料技术有限公司 | Novel a wire electrode for wire cut spark -erosion wire cutting machine |
| CN108857286A (en) * | 2018-08-01 | 2018-11-23 | 宁波康强微电子技术有限公司 | Corrugated electric discharge machining electrode line and preparation method thereof |
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Address after: 315137 Chen Cun, Yunlong Town, Yunlong Town, Ningbo, Zhejiang, Yinzhou District Patentee after: Ningbo Bowei Alloy Precision Fine Wire Co.,Ltd. Country or region after: China Address before: 315137 Chen Cun, Yunlong Town, Yunlong Town, Ningbo, Zhejiang, Yinzhou District Patentee before: Ningbo bode high tech Limited by Share Ltd. Country or region before: China |