JP5530970B2 - Electrode wire for wire electric discharge machining and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wire electric discharge machining electrode wire used in wire electric discharge machining for machining a workpiece (workpiece) by electric discharge, a manufacturing method thereof, and an electric discharge machining method using the electrode wire.

  Wire EDM is a process in which an electric discharge is generated between an EDM electrode wire and the workpiece, and the workpiece is cut by the thermal energy caused by the electric discharge. Suitable for metal processing.

  In such electric discharge machining, a) the machining speed is high, b) the finished state and dimensional accuracy of the surface of the workpiece are good, and c) positioning for measuring the relative position between the electrode wire and the workpiece. D) that the amount of metal powder generated when the electrode wire is continuously run is small.

  As this electrode wire, one that has been widely used conventionally is one in which the electrode wire is made of a single brass having a zinc concentration of 35 to 40% by weight. This brass single electrode wire is manufactured because, when the zinc content is increased to 40% by weight or more, an intermetallic compound of a body-centered cubic lattice is formed, and the ductility and toughness are lowered, so that cold drawing cannot be performed. Can not.

  Therefore, various studies have been made to increase the electric discharge machining speed as compared with a single electrode wire of brass having a zinc concentration of 35 to 40% by weight. The higher the zinc concentration in the composition of the electrode wire, the higher the electric discharge machining. It is well known that speed can be improved.

  As this method, a method of providing a copper-zinc alloy layer having a zinc concentration of 40% by weight or more only on the surface layer of the electrode wire, or further providing a zinc layer thereon is known.

  Japanese Patent No. 3718617 discloses a copper-zinc alloy layer having a zinc concentration of 40% by weight or more on the surface layer, or a porous electrode wire provided with a zinc layer thereon.

  A porous electrode wire having cracks on the surface of the electrode wire is provided with a copper-zinc alloy layer on the surface layer of the copper-containing core wire by hot dip plating, or a zinc layer on the surface, and the surface layer is actively cracked by wire drawing. And increasing the surface area of the electrode wire, increasing the contact area with the machining fluid during electrical discharge machining, and further increasing the cooling rate to improve the machining rate.

Further, International Publication No. WO2009 / 028117 discloses an electrode wire having the following structure as a method for solving the problems of the invention.
-Copper or copper alloy core wire diffused into the molten zinc from the copper-zinc alloy inner layer (zinc concentration 50-80 wt%) formed by thermal diffusion of molten zinc from its surface and the core wire itself A copper-zinc alloy outer layer (zinc concentration of 81 to 100% by weight) formed. (Three-layer structure in which a zinc layer is provided on two copper-zinc alloy layers whose outer layers are produced by diffusion)
-The zinc layer is thicker than the diffusion alloy layer-The thickness of the zinc layer is 1.2% or more of the outer diameter, and there is no crack in the outermost layer of the electrode wire.

Japanese Patent No. 3718617 WO2009 / 0281117

  The electrode wire for high-speed machining obtained by providing a zinc layer and a diffusion alloy layer on the outer peripheral surface of a conventional copper or copper alloy core wire and drawing can improve the machining speed, but it is an electric discharge machining other than the machining speed. This causes a problem that other characteristics necessary for the above-mentioned are deteriorated.

Moreover, although the technique of forming a crack in an electrode line surface layer is also known, the following problems arise when a crack is formed in an electrode line surface layer.
a) Wire electrical discharge machining is a process in which a workpiece is melted and a saw blade type machining is performed while electric discharge is performed between the electrode wire and the workpiece, but there is a crack in the surface layer of the electrode wire. As a result, the discharge becomes unstable, and the finished state of the surface of the workpiece becomes worse.
b) In order to make the wire electrical discharge machine recognize the relative position between the workpiece and the electrode wire, electrical conduction is used between the workpiece and the electrode wire, but there is a crack in the surface layer of the electrode wire. As a result, the contact area is reduced and the positioning accuracy is deteriorated.
c) Since the surface layer is so brittle that cracks are generated in the surface layer due to cold wire drawing, the metal powder is caused by friction and rubbing with the guide and pulley of the processing machine when the electrode wire is continuously run during electric discharge machining. The amount generated increases, and the maintainability deteriorates.
d) Since there are cracks in the surface layer, disconnection is likely to occur during handling or processing, resulting in poor reliability.

  On the other hand, there is also known a countermeasure that does not cause cracks in the outermost layer of the electrode wire while having a diffusion alloy layer, but this structure makes the thickness of the zinc layer 1.2% or more of the outer diameter. By covering the cracks of the diffusion alloy layer with the zinc layer, the outermost zinc layer is inevitably thickened due to the structure in which the outermost layer of the electrode wire is not cracked, and as shown in FIG. During machining, the wire diameter is reduced due to the evaporation and consumption of zinc, and a difference in the machining groove width occurs between the entry side and the exit side, so that the electric discharge machining surface becomes tapered, causing a problem in terms of machining accuracy.

In addition, in order to obtain an electrode wire having a required diameter of 0.1-0.3 mmφ or the like due to the thick zinc layer and the diffusion alloy layer, when the wire drawing is performed, the diffusion alloy layer including the zinc layer becomes a core wire. It becomes easy to peel from.
When wire EDM is performed using an electrode wire that easily peels off the diffusion alloy layer including the zinc layer, a short circuit occurs due to the peeled piece forming a bridge between the electrode wire and the workpiece, reducing the number of discharges. As shown in the schematic diagram of FIG. 5, fine streaks due to the concentration of discharge traces are present on the processed surface along the movement direction of the electrode lines. .

  The present invention has been made to solve these problems, and it is possible to reduce the machining accuracy due to the consumption of zinc, the machining speed due to short circuit, and the fine streaks on the machining surface that occur along the moving direction of the electrode wire. An object of the present invention is to provide an electrode wire for electric discharge machining for high-speed machining that is suppressed.

  Furthermore, the present invention has a small amount of metal powder generated when the electrode wire is continuously run and has good positioning properties for measuring the relative position between the electrode wire and the workpiece, and is broken during handling or processing. It aims at providing the electrode wire for electric discharge machining which does not generate | occur | produce.

  In addition, an object of the present invention is to provide a method for manufacturing the electrode wire for electric discharge machining and an electric discharge machining method using the electrode wire for electric discharge machining.

In the method for producing an electrode wire for wire electric discharge machining according to the present invention, a core wire made of copper or a copper alloy is immersed in a plating bath in which zinc is maintained at a predetermined temperature, and the outermost layer is a zinc layer having a predetermined thickness passed. A wire for producing a plating bus bar of an electrode wire by thermally diffusing each other at a boundary surface where the core wire and the zinc are in contact with each other by cooling, and producing a plating bus bar of the electrode wire, and drawing the plating bus bar In the manufacturing method of the electrode wire for electric discharge machining, a zinc thin film without cracks is formed by drawing the plated bus in a temperature range in which the zinc spreadability is good. The zinc thin film is drawn and has no cracks, and the diffusion alloy layer is formed by embedding a drawn and crushed granular material in the outer peripheral surface of the core wire, and the zinc thin film and the diffusion alloy layer are Characterized in that is inhibited by peeling integrated with the line.

  Furthermore, in the method for manufacturing an electrode wire for wire electric discharge machining according to the present invention, the crushed granular material of the diffusion alloy layer receives a large vertical surface pressure and is deeply embedded in the outer peripheral surface of the core wire. To do.

  Furthermore, in the method of manufacturing an electrode wire for wire electric discharge machining according to the present invention, the granular material obtained by pulverizing the diffusion alloy layer has a reduced cross-sectional area obtained by subtracting a cross-sectional area after drawing from a pre-drawing cross-sectional area before drawing. It is characterized in that it is drawn deeply in the outer peripheral surface of the core wire after undergoing wire drawing with a high wire drawing rate obtained by multiplying the area divided by 100.

  The electrode wire for wire electric discharge machining of the present invention is obtained by allowing a core wire made of copper or a copper alloy to pass through a dipping time in which a zinc layer whose outermost layer exceeds a predetermined thickness is passed through a plating tank holding zinc at a predetermined temperature. For wire electrical discharge machining, by cooling, the core wire and the zinc contact each other at the interface where the core wire is in contact with each other to thermally diffuse to produce a diffusion alloy layer to produce a plating bus bar of the electrode wire, and wire-drawing the plating bus bar It is an electrode wire, and the plated bus is drawn at a temperature range in which the spreadability of the zinc is good, a zinc thin film free from cracks is formed, and the zinc hot-dip plated layer is drawn The zinc alloy thin film is free from cracks, and the diffusion alloy layer is formed by drawing and pulverizing granular materials embedded in the outer peripheral surface of the core wire, and the zinc thin film and the diffusion alloy layer are integrated with the core wire. Being peeled Wherein the Rukoto is suppressed.

  Furthermore, the electrode wire for wire electric discharge machining according to the present invention is characterized in that the granular material in which the diffusion alloy layer is crushed is subjected to a large vertical surface pressure and is deeply embedded in the outer peripheral surface of the core wire. .

  Furthermore, the electrode wire for wire electric discharge machining of the present invention is characterized in that the heat diffusion alloy layer is formed as a layer in which crushed granular materials are gathered in a dense state.

  Furthermore, the electrode wire for wire electric discharge machining of the present invention is obtained by dividing the reduced granular area obtained by subtracting the post-drawing cross-sectional area from the pre-drawing cross-sectional area by the pre-drawing cross-sectional area. It is characterized in that it is drawn deeply in the outer peripheral surface of the core wire after being subjected to wire drawing with a high wire drawing rate that is multiplied by 100.

  According to the present invention, the crushed granular material of the copper-zinc heat diffusion layer on the outer peripheral surface is formed as a densely assembled layer and embedded in the core wire by a simple facility and manufacturing process. And the hot dip galvanized layer are integrated by the heat diffusion alloy layer, and delamination can be suppressed.

  This makes it possible to prevent a short circuit between the workpiece and the electrode wire during electric discharge machining. It is possible to provide an electrode wire for high-speed machining that can prevent streaks from appearing on the machining surface along the moving direction of the electrode wire.

  In addition, the conventional machining method uses a high-speed machining electrode wire with a zinc layer and a copper-zinc diffusion alloy layer on the outer peripheral surface for rough machining, and uses a brass single electrode wire for finishing. Although the electrode wire was exchanged between processes, the electrode wire of the present invention can be used not only for high-speed machining but also for precision machining. Can save.

Sectional view of the electrode wire of the present invention Sectional view of the plating bus bar of the present invention Diagram showing the zinc concentration and layer thickness in the radial direction of the plating bus The figure which showed the state of the electrode wire during electric discharge machining Schematic diagram of streaks on machined surface Diagram showing the direction of stress applied to the plating bus bar during wire drawing Diagram showing hot dipping and wire drawing equipment Relationship diagram between lubricating liquid temperature of electrode wires with different zinc layer thickness and occurrence of cracks on outer peripheral surface of electrode wires Relationship diagram between electrode wire zinc layer thickness and machining groove width Photo of the diffusion alloy layer granular material embedded in the core wire (digital microscope 1000 times) Relationship diagram between lubricant type and number of occurrences of short circuit Photo of streaks in the direction of electrode wire movement (digital microscope 40x) Relationship between number of shorts and machining speed Photo of the diffusion alloy layer granular material embedded in the core wire (digital microscope 1000 times) Relationship diagram between processing rate and number of shorts Flow chart of plating bus inside the wire drawing die Relationship diagram between the length of boundary line between granular material and core wire of diffusion alloy layer due to difference in lubricating liquid

  The electrode wire for wire electric discharge machining of the present invention is made to solve the above-mentioned problems of the conventional electrode wire having a diffusion alloy layer on the outer peripheral surface and a zinc layer thereon.

  In the conventional method of manufacturing an electrode wire for wire electric discharge machining having a diffusion alloy layer, an outer metal layer of zinc is formed on the outer peripheral surface of a core wire made of copper or a copper alloy by electroplating or hot dipping, and the wire is heat-treated. By doing so, a wire rod having a diffusion alloy layer generated by mutual thermal diffusion between the galvanized layer and the core wire can be obtained by reducing the cross-sectional area by wire drawing.

  Here, the problem is that the diffusion alloy layer is a copper-zinc diffusion alloy layer having a zinc concentration of 40% or more, which is an intermetallic compound of a body-centered cubic lattice, and is hard and brittle. Due to the different deformation characteristics, the diffusion alloy layer breaks during wire drawing, causing cracks on the surface of the electrode wire, and the crushed diffusion alloy layer peels off the core wire, causing a short circuit between the workpiece and the electrode wire. That is, the processing speed is lowered and the quality of the processed surface is lowered.

While the applicant has conducted research to realize an electrode wire having an improved diffusion alloy layer, the core wire and the zinc hot-dip plating layer are integrated with the heat diffusion alloy layer by using the following three methods. It has been found that an electrode wire that is prevented from being peeled off and has no cracks on the electrode wire surface can be obtained economically.
(1) Even if the zinc layer of the plating bus bar is thinned, the zinc layer covers the cracks of the diffusion alloy layer so that no cracks appear on the outermost surface of the electrode wire. Wire drawing is performed at a temperature of 100 to 150 ° C. at which the zinc has good ductility.
(2) The frictional resistance between the wire drawing die and the plating bus bar is increased to generate a large vertical surface pressure at the boundary between the die wall surface and the bus bar, and the diffusion alloy layer is reliably crushed into a granular material. In order to embed the wire in the outer peripheral surface of the core wire deeply like a wedge, water having a higher frictional resistance than that of an oil-based wire drawing lubricant usually used for wire drawing is used for the wire drawing lubricant.
(3) The time for the diffusion alloy layer to be embedded in the core wire is lengthened, and the number of passes through the die is increased so that the diffusion alloy layer is reliably crushed into a granular material. For the purpose of embedding deeply, the wire drawing is performed by increasing the wire drawing rate.

  According to the method of (1), according to WO2009 / 0281117, the thickness of the zinc layer is 1.2% or more of the outer diameter of the electrode wire in order not to cause cracks on the surface of the electrode wire in wire drawing. It is stated that it is necessary. However, if the zinc layer is thick, if the processing accuracy deteriorates due to the evaporation and consumption of zinc, there arises a problem that peeling pieces are likely to be generated in the wire drawing.

  The present invention solves the problem by performing the wire drawing at a temperature at which the spreadability of zinc is good because the surface of the electrode wire is not cracked even if the zinc layer is a thin film.

  Zinc is brittle at room temperature, but malleability and ductility increase at 100 to 150 ° C. Using this property, the zinc wire of the plating bus bar is drawn at a temperature of 100 to 150 ° C., so that the temperature rise is expected due to the generation of frictional heat on the wall surface of the plating bus bar and the drawing die. By setting the temperature of the lubricating liquid to 75 ° C. or more and 100 ° C. or less, the zinc layer completely covers the cracks in the diffusion alloy layer, so that no cracks appear on the outermost surface of the electrode wire.

  In the above method (2), the granular material of the diffusion alloy layer crushed by the wire drawing is made of copper or copper having a friction resistance larger than that of the oil-based wire drawing lubricant. By being deeply embedded in the alloy, the zinc thin film and the heat diffusion alloy layer are integrated with the core wire so as not to peel off.

Since the diffusion alloy layer having a body-centered cubic lattice, which is an intermetallic compound, is not malleable, it is crushed into a granular material during wire drawing, and the zinc layer and the diffusion alloy layer are easily peeled off from the core wire. If the zinc layer and the diffusion alloy layer are peeled off during electrical discharge machining, the electrode wire and the workpiece are short-circuited, the machining speed is reduced due to a decrease in the number of discharges, and the fine streaks move due to unstable discharge. It occurs on the machined surface along the direction.
In the present invention, the grain size of the diffusion alloy layer is set so that the boundary line length between the crushed granular material of the diffusion alloy layer and the core wire is 1.20 times longer than the length of the same electrode wire having the boundary line length. An electrode wire for wire electric discharge machining having a structure in which the zinc thin film and the diffusion alloy layer are integrated with the core wire by deeply embedding an object in the core wire, and delamination of the zinc thin film and the diffusion alloy layer from the core wire is suppressed, and a manufacturing method thereof, and This is an electric discharge machining method using the electrode wire.

The principle of integration is as follows.
As shown in FIG. 6, the stress applied to the plating bus during wire drawing differs between the inside of the bus and the surface of the bus.
During the wire drawing process, a large vertical surface pressure is generated at the boundary between the wire drawing die and the plating bus wire due to wire drawing die restraint at the surface portion of the plating bus wire. On the other hand, tensile stress due to the influence of the drawing force acts inside the plating bus bar.
FIG. 16 schematically shows a metal flow of how the plating bus bar is deformed inside the die during wire drawing.
The vertical axis of the grid line before drawing in FIG. 16 is curved after drawing (advanced phenomenon). This is due to the friction between the plating bus bar and the drawing die wall. The greater the frictional resistance, the more the surface layer receives vertical surface pressure, and the amount of deformation in the length direction is smaller than the amount of deformation in the center. Become smaller. Therefore, in order to increase the vertical surface pressure generated in the surface layer portion of the plating bus, it is better that the frictional force (deformation resistance) is large.

  Utilizing this principle, the frictional force of the contact surface is increased, the surface pressure for embedding the crushed granular material in the core wire is increased, and the oil-based lubrication usually used as a wire drawing lubricating liquid to embed deeply. Without using a liquid (dynamic friction coefficient by a pendulum type measurement method of about 0.1), water (dynamic friction coefficient by a pendulum type measurement method of about 0.36) having a lubricating function lower than that of an oil-type lubricating liquid is used.

  In the method (3), by setting the processing rate in the wire drawing to 94.0% or more, the granular material of the diffusion alloy layer crushed by the wire drawing is embedded deeply in the core wire, The diffusion alloy layer is integrated with the core wire to prevent peeling.

The processing rate is obtained by the following formula.
Processing rate (%) = [(cross-sectional area before wire drawing−cross-sectional area after wire drawing) / cross-sectional area before wire drawing] × 100

  Because the diffusion alloy layer has different deformation characteristics from the core wire (the diffusion alloy layer has a lower elongation), the diffusion alloy layer is crushed into particles by drawing, and the zinc thin film and the diffusion alloy layer are separated from the core wire. It becomes easy to peel.

  This method increases the difference between the initial plating bus outer diameter before wire drawing and the final product diameter after wire drawing (by increasing the processing rate), and lengthens the time during which the crushed diffusion alloy layer is embedded in the core wire. In addition, by increasing the number of passes through the dice, the boundary line length between the granular material formed by crushing the diffusion alloy layer after drawing and the core wire has the same boundary length. By making the granular material of the diffusion alloy layer deeply embedded in the core wire by making it longer than the length of the wire by 1.20 times or more, the zinc layer and the diffusion alloy layer are integrated with the core wire to prevent peeling.

Embodiments of the present invention will be described below.
FIG. 7 schematically shows equipment for carrying out the method of manufacturing the electrode wire 1 for wire electric discharge machining of the present invention. The wire drawing device 13 and the annealer 14 of the plating bus 5 in FIG. May be installed in front of the winding device 15, or may be installed separately from the present equipment and may be drawn after winding.

Moreover, it is possible to change the layer thickness of the copper-zinc alloy layer 7 which is a diffusion alloy layer, and the zinc layer 8 by adjusting the temperature and immersion time of hot dipping, and the tendency is as follows. .
(1) Diffusion alloy layer (copper-zinc alloy layer)
-At the same temperature, the shorter the immersion time, the thinner the diffusion alloy layer.
-If the immersion time is the same, the lower the temperature, the thinner the diffusion alloy layer.
(2) If the zinc layer is at the same temperature, the shorter the immersion time, the thicker the zinc layer.
-If the immersion time is the same, the lower the temperature, the thicker the zinc layer.

  The plating bus 5 for obtaining the electrode wire 1 of the present invention shown in FIG. 1 is created based on the above knowledge, and the thickness of the diffusion alloy layer 7 is selected by appropriately selecting the temperature and immersion time of the hot dipping. By adjusting the thickness of the zinc layer 8, a plating bus 5 having a three-layer structure of a core wire 6 made of copper or a copper alloy having a zinc concentration gradient as shown in FIG. Can be obtained.

  Next, the plated bus 5 is drawn and the cross section is reduced, whereby the core wire 2 made of copper or copper alloy as shown in FIG. 1 and the granular diffusion alloy layer 3 crushed by drawing are formed into the core wire. A wire electric discharge machining electrode wire 1 having a predetermined diameter constituted by the buried layer and the zinc layer 4 is obtained.

  The electrode wire 1 of the present invention can be obtained by combining the following three methods in the wire drawing process to obtain the high-speed machining electrode wire 1 having the structure of the present invention. First, effects of the individual methods will be described.

  In addition, the electric discharge machining characteristics were carried out using roughing conditions using a wire electric discharge machine SX10 manufactured by Mitsubishi Electric. (Workpiece: Material SKD-11, thickness 50mm)

Effect of Method 1 In order to confirm the effect of this method, the pre-plating bus 9 of a brass wire (copper 60% / zinc 40%) having a wire diameter of 0.9 mm that has undergone the melting, casting, and wire drawing steps is manufactured as shown in FIG. Was used to adjust the temperature and immersion time of the hot dipping bath, and the three types of plating bus bars 5 shown in the table below with the same thickness of the diffusion alloy layer 7 and different zinc layers 8 were produced.

Next, these three types of plated bus bars 5 are drawn using three types of oil-type wire drawing lubricants having different temperatures, and three types of zinc layer 4 having different thickness ratios (ratio of zinc layer thickness) Electrode wire 1 having a diameter of 0.25 mm and having an outer diameter of 0.6%, 1.2%, and 2.4%.
The following evaluation was performed about nine types of electrode wires manufactured in this way.
a) Relationship between the lubricant temperature of electrode wires having different zinc layer thicknesses and the occurrence of cracks on the outer peripheral surface of the electrode wires after wire drawing b) Relationship between the zinc layer thickness of the electrode wires and the machining groove width

The evaluation results are shown in FIGS.
As is clear from FIG. 8, when the lubricating liquid temperature is 75 ° C. to 100 ° C., no cracks appear on the surface of the electrode wire after wire drawing at any zinc layer thickness, but when the lubricating liquid temperature is 20 ° C. In the plating bus bar 5 having a thin zinc layer thickness (0.6% of the outer diameter), cracks appear on the surface of the electrode wire after wire drawing.
As is clear from FIG. 9, the thicker the zinc layer, the lower the evaporation temperature of the zinc, and the more the zinc layer evaporates and scatters at the start of the discharge. Since a difference occurs in the machining groove width of the workpiece on the side and the outlet side, the electric discharge machining surface becomes tapered, resulting in poor machining accuracy. From this result, an electrode wire with good processing accuracy and no cracks on the outer peripheral surface of the electrode wire by drawing a plated bus with a thin zinc layer at a temperature of the drawing lubricant at 75 ° C. or more and 100 ° C. or less. 1 is obtained.

Effect of Method 2:
In order to confirm the effect of this method, three types of plated bus bars 5 having the same diffusion alloy layer 7 as in Method 1 but different zinc layer thickness 8 were manufactured. Next, wire-drawing is performed using these plated buses 5 as a wire drawing lubricant, using an oil-type lubricant and water at a temperature of 20 ° C., and the plating layer thickness (zinc layer 4 + diffusion alloy layer 3) is different from three types ( An electrode wire 1 having a diameter of 0.25 mmφ having a plating layer thickness ratio of 1.5%, 2.1%, and 3.3% of the outer diameter was manufactured.
The six types of electrode wires thus manufactured were evaluated as follows.
a) State of lubricating liquid and diffusion alloy layer granular material embedded in core wire b) Relation between type of lubricating liquid of electrode wire with different plating layer thickness and number of short circuits c) Presence of short circuit and generation of streaks on machined surface D) Relationship between the number of short circuits and processing speed e) Relationship between the boundary line length between the granular material of the diffusion alloy layer and the core wire due to the difference in the type of lubricating liquid

The evaluation results are shown in FIG. 10, FIG. 11, FIG. 12, FIG.
As shown in the photograph of FIG. 10, the electrode wire using water for the wire drawing lubricant is in a state where the granular material of the diffusion alloy layer 3 is deeply embedded in the core wire 2, but the electrode using the oil-based wire drawing lubricant The wire is in a state where the granular material of the diffusion alloy layer 3 is lifted from the core wire 2.
FIG. 17 shows the diffusion alloy layer granularity for an electrode wire in which the granular material of the diffusion alloy layer 3 in FIG. 10 is deeply embedded in the core wire 2 and an electrode wire in which the granular material of the diffusion alloy layer 3 is lifted from the core wire 2. Indicates the boundary length between the object and the core wire.
The measurement of the boundary line length was carried out using the circumference measurement function of a digital microscope VHX-900 manufactured by KEYENCE.
As shown in FIG. 17, the measurement result shows that the boundary line length in the state in which the granular material of the crushed diffusion alloy layer 3 is deeply embedded in the core wire 2 is 1.20 from the same electrode line having the boundary line length. The boundary line length in the state in which the crushed particles of the diffusion alloy layer 3 are lifted from the core wire 2 is the length of the same electrode line having the boundary line length, while being ˜1.22 times longer The electrode line in which the granular material of the diffusion alloy layer 3 is deeply embedded is 1.10 to 1.11 times larger than the boundary line length.
Moreover, as shown in FIG. 11, even when the electrode wire having a long boundary line length drawn with water has a large plating thickness, the zinc layer and the diffusion alloy layer are not integrated with the core wire and peeled off during the electric discharge machining. Therefore, a short circuit does not occur between the electrode wire and the workpiece.
As shown in FIG. 12, the electrode wire (plating thickness is 2.1% of the outer diameter, using oil type lubricant) causes fine streaks due to concentration of discharge traces on the processed surface, but a short circuit occurs. The electrode wire (plating thickness is 2.1% of the outer diameter, using water lubricant) does not generate fine streaks on the processed surface.
As shown in FIG. 13, as the number of short circuits increases, the number of discharges decreases and the machining speed decreases.
From this result, it is possible to suppress the occurrence of a short circuit by using water as the wire drawing lubricating liquid, thereby obtaining an electrode wire that does not generate streaks on the processed surface and does not cause a decrease in the processing speed.

Effect of Method 3:
In order to confirm the effect of this method, when manufacturing the electrode wire 1 having a final product diameter of 0.25 mmφ, the processing rates are 92.3%, 93.8%, 95.7%, 97.8%. The plating bus 5 was manufactured by the same method as the method 1 using the pre-plating bus 9 having the diameter selected in (1). Next, these plated buses 5 are drawn using an oil-type lubricant at a temperature of 20 ° C., and three types with different plating thicknesses (zinc layer 4 + diffusion alloy layer 3) (1.5% of the outer diameter, 2.1%, 3.3%) electrode wires having a diameter of 0.25 mmφ were manufactured.
The following evaluation was performed on the 12 types of electrode wires thus manufactured.
a) State of processing rate and diffusion alloy layer granular material embedded in core wire b) Relationship between wire drawing processing rate and number of short circuits c) Relationship between presence / absence of short circuit and generation of streaks on processed surface d) Number of short circuits and processing Relation with speed e) Relation with the length of boundary line between granular material and core wire of diffusion alloy layer by wire drawing ratio

The evaluation results are shown in FIGS.
Each of the photographs in FIG. 14 is an electrode wire manufactured by drawing a bus having a plating thickness of 2.1% with respect to the outer diameter. In the electrode wire 1 having a drawing rate of 93.8%, 95.7%, and 97.8%, even if an oil type lubricating liquid having a temperature of 20 ° C. is used, the granular material of the diffusion alloy layer is embedded in the core wire 2 deeply. However, the electrode wire with a processing rate of 92.3% (electrode wire with a plating thickness ratio of 2.1% and 3.3% with respect to the outer diameter) has the granular material of the diffusion alloy layer 3 floating from the core wire 2. It is in the state.
For the electrode wire in which the granular material of the diffusion alloy layer 3 in FIG. 14 is deeply embedded in the core wire 2 and the electrode wire in which the granular material of the diffusion alloy layer 3 is lifted from the core wire 2, the diffusion alloy layer granularity The boundary line length between the object and the core wire was measured by the same method as in Method 2. As a result of the measurement, the boundary line length in the state where the granular material of the crushed diffusion alloy layer 3 is deeply embedded in the core wire is 1.21 to 1 with respect to the length of the same electrode line having the boundary line length. Although it is 23 times longer, the boundary length in the state where the crushed particles of the diffusion alloy layer 3 are lifted from the core wire 2 is 1.10 with respect to the length of the same electrode wire having the boundary length. It is ˜1.12 times, and the boundary line length is longer for the electrode wire having a higher processing rate.
In addition, as shown in FIG. 15, the electrode layer having a long boundary line length that has been drawn at a higher drawing rate, even if the plating thickness is thick, the zinc layer and the diffusion alloy layer are integrated with the core wire during electric discharge machining. Therefore, no short circuit occurs between the electrode wire and the workpiece.
From this result, it is possible to suppress the occurrence of a short circuit by performing a wire drawing process with a high processing rate, and it is possible to obtain an electrode wire in which no streaking occurs on the processed surface and the processing speed does not decrease.

The present invention can be implemented in a number of forms combining the three methods described above.
Table 1 shows some examples of the present invention. The example here includes two to three of the three methods (conditions to which the present invention is applied are shown in bold and diagonal lines), and the comparative example does not include any of the three methods. is there.

  As is clear from Table 1, those incorporating at least two methods of the present invention (Examples 1 to 4) all gave good results, but none of the three methods. In Comparative Examples 1 and 2, since a short circuit occurs between the electrode wire and the workpiece, fine machining streaks occur on the processed surface, and the number of discharges decreases due to a short circuit between the workpiece and the electrode wire. As a result, the processing speed also decreases.

  Moreover, the processing speed of the electrode wire of the example of the present invention is about 20% higher than the electrode wire of the brass single body of Comparative Example 3 (copper 60% / zinc 40%).

  In the above examples and comparative examples, the outer diameter of the electrode wire for electric discharge machining is shown as 0.25 mm, but any outer diameter, for example, an electrode wire with an outer diameter of 0.1 to 0.3 mm is shown. The same quality can be ensured in

In the electrode wire for wire electric discharge machining of the present invention, a zinc hot-dip plating layer is formed on the outer peripheral surface of a core wire made of copper or a copper alloy, and diffusion generated by thermal diffusion between the zinc hot-dip plating layer and the core wire. In the electrode wire for wire electric discharge machining in which a bus bar having an alloy layer is drawn, the zinc hot-dip plating layer is formed on the basis of a difference in ductility between the zinc hot-dip plating layer and the diffusion alloy layer during wire drawing. The zinc alloy thin film is formed with no cracks and the diffusion alloy layer is drawn and crushed particles are embedded in the outer peripheral surface of the core wire, and the zinc thin film and the diffusion alloy layer are formed with the core wire. It is prevented from being integrated and peeled off.

Furthermore, the electrode wire for wire electric discharge machining according to the present invention is formed by drawing the zinc thin film free from cracks in a temperature range in which zinc is easily stretched by the influence of heat during wire drawing. It is a thing.

Furthermore, in the electrode wire for wire electric discharge machining of the present invention, the granular material in which the diffusion alloy layer is crushed is subjected to a large vertical surface pressure and is deeply embedded in the outer peripheral surface of the core wire.

Furthermore, the electrode wire for wire electric discharge machining of the present invention is obtained by dividing the reduced granular area obtained by subtracting the post-drawing cross-sectional area from the pre-drawing cross-sectional area by the pre-drawing cross-sectional area. The resulting wire is subjected to wire drawing with a high wire drawing rate obtained by multiplying it by 100, and is deeply embedded in the outer peripheral surface of the core wire.

In the method for producing an electrode wire for wire electric discharge machining according to the present invention, a core wire made of copper or a copper alloy is immersed in a plating bath in which zinc is maintained at a predetermined temperature, and the outermost layer is a zinc layer having a predetermined thickness passed. Wire discharge for producing a plating bus bar of the electrode wire by drawing the alloying wire layer by thermally diffusing each other at the boundary surface where the core wire and zinc contact each other by cooling after caulking In the manufacturing method of the processing electrode wire, the zinc thin film and the diffusion alloy layer are integrated with the core wire and the thin film is peeled off by embedding a granular material formed by crushing the diffusion alloy layer in an outer peripheral surface of the core wire. Is suppressed.

In addition, the method for producing an electrode wire for wire electric discharge machining according to the present invention includes immersing a core wire made of copper or a copper alloy so that the outermost layer is a zinc layer having a predetermined thickness inside a plating tank holding zinc at a predetermined temperature. By allowing the core wire and the zinc to contact with each other at a boundary surface where the core wire and the zinc contact with each other to produce a diffusion alloy layer and producing a plating bus bar of the electrode wire by cooling after passing through the time, the plating bus bar is drawn In the wire electric discharge machining electrode wire manufacturing method, a zinc thin film free from cracks is formed by drawing the plated bus bar in a temperature range in which the zinc spreadability is good.

Furthermore, in the method of manufacturing the electrode wire for wire electric discharge machining, the zinc layer of the plating bus bar is drawn during the wire drawing process when the plating bus wire is drawn in a temperature range in which the zinc spreadability is good. Drawing is performed at a temperature of ˜150 ° C.

Furthermore, in the method for manufacturing an electrode wire for wire electric discharge machining according to the present invention, the wire drawing is performed so as to circulate and supply to the boundary between the die and the wire when the plated bus is drawn in a temperature range in which the zinc spreadability is good. The temperature in the circulating storage tank of the lubricating liquid is controlled to 75 ° C. to 100 ° C.

Furthermore, the method for manufacturing an electrode wire for wire electric discharge machining according to the present invention increases the frictional resistance between the die and the wire by using water as the wire drawing lubricating liquid, so that a large vertical direction is formed at the boundary between the die and the wire. A surface pressure is generated, and the diffusion alloy layer is reliably crushed into a granular material, and the granular material is strongly embedded in the outer peripheral surface of the core wire.

Furthermore, in the method for manufacturing an electrode wire for wire electric discharge machining according to the present invention, a wire drawing obtained by multiplying a reduced cross-sectional area obtained by subtracting a post-drawing cross-sectional area from a pre-drawing cross-sectional area by a cross-sectional area before drawing is multiplied by 100. By controlling the wire drawing process so that the processing rate does not fall below a predetermined value, the diffusion alloy layer is surely crushed into a granular material, and the granular material is deeply embedded in the outer peripheral surface of the core wire.

Furthermore, in the method for manufacturing an electrode wire for wire electric discharge machining according to the present invention, the predetermined value is 94.0% or more.

In the electrode wire for wire electric discharge machining of the present invention, a zinc hot dip plating layer is formed on the outer peripheral surface of a core wire made of copper or a copper alloy, and a heat diffusion alloy layer is formed between the core wire and the zinc hot dip plating layer. The electrode wire for wire electric discharge machining, wherein the thermal diffusion alloy layer is formed as a layer in which crushed granular materials are gathered in a dense state, whereby the core wire and the zinc hot-dip plated layer are It is integrated by the heat diffusion alloy layer and delamination is suppressed.

Furthermore, in the electrode wire for wire electric discharge machining of the present invention, the boundary line length between the crushed particles of the heat diffusion alloy layer and the core wire is 1.20 from the length of the same electrode wire having the boundary line length. More than twice as long.

The method of manufacturing an electrode wire for wire electric discharge machining according to the present invention includes forming a diffusion alloy layer by hot diffusing galvanizing copper or a copper alloy to thermally diffuse between the core wire and the zinc hot dip plating layer. In the manufacturing method of the electrode wire for wire electric discharge machining, which produces a plating bus bar of the electrode wire and wire-draws the plating bus wire, the granular material formed by crushing the diffusion alloy layer after the wire drawing processing, and the core wire Is longer than the length of the same electrode line having the boundary line length by 1.20 times or more.

The electrical discharge machining method of the present invention is a wire electrical discharge machining in which a zinc hot-dip plated layer is formed on the outer periphery of a core wire made of copper or a copper alloy, and a heat diffusion alloy layer is formed between the core wire and the zinc hot-dip plated layer An electric discharge machining method for performing an electric discharge machining using an electrode wire, wherein the thermal diffusion alloy layer is formed as a layer in which crushed granular materials are gathered in a dense state, whereby the core wire and the zinc hot-dip plated layer Are subjected to electric discharge machining using an electrode wire for wire electric discharge machining which is integrated by the heat diffusion alloy layer and delamination is suppressed.

DESCRIPTION OF SYMBOLS 1 Electrode wire for wire electric discharge machining 2 Core wire made of copper or copper alloy 3 Granular diffusion alloy layer crushed by drawing 4 Zinc layer 5 Plating bus 6 Core wire made of copper or copper alloy 7 Diffusion alloy layer 8 Zinc hot-dip plating layer 9 Busbar before plating (core wire)
10 Preheater
DESCRIPTION OF SYMBOLS 11 Flux tank 12 Hot dipping apparatus 13 Wire drawing apparatus 14 Annealer 15 Winding apparatus

Claims (7)

The core wire and the zinc are cooled by allowing the core wire made of copper or a copper alloy to pass through a plating bath in which zinc is maintained at a predetermined temperature and then cooling the core wire so that the outermost layer has a zinc layer exceeding a predetermined thickness. In the method of manufacturing an electrode wire for wire electric discharge machining, which produces a diffusion bus layer by thermally diffusing each other at a contact interface to produce a plating bus wire of the electrode wire, and drawing the plating bus wire,
By drawing the plated bus in a temperature range in which the ductility of the zinc is good, a zinc thin film without cracks is formed,
The zinc hot-dip plated layer is a zinc thin film that is drawn and does not have cracks, and the diffusion alloy layer is formed by drawing and pulverizing particulate matter embedded in the outer peripheral surface of the core wire. a method of manufacturing features and to Ruwa unpleasant electrical discharge machining electrode wire that diffusion alloy layer is prevented that the peeling is integrated with the core wire. 2. The electrode wire for wire electric discharge machining according to claim 1 , wherein the pulverized granular material of the diffusion alloy layer receives a large vertical surface pressure and is deeply embedded in the outer peripheral surface of the core wire. Method. The pulverized granular material of the diffusion alloy layer has a high wire drawing ratio obtained by multiplying the reduced cross-sectional area obtained by subtracting the post-drawing cross-sectional area from the pre-drawing cross-sectional area by the pre-drawing cross-sectional area by 100. 3. The method of manufacturing an electrode wire for wire electric discharge machining according to claim 1, wherein the wire wire is subjected to wire drawing and is deeply embedded in an outer peripheral surface of the core wire. 4. The core wire and the zinc are cooled by allowing the core wire made of copper or a copper alloy to pass through a plating bath in which zinc is maintained at a predetermined temperature and then cooling the core wire so that the outermost layer has a zinc layer exceeding a predetermined thickness. It is an electrode wire for wire electrical discharge machining that produces a diffusion bus layer by thermally diffusing each other at a contact interface to produce a plating bus bar of the electrode wire, and wire-drawing the plating bus bar,
The plated bus is drawn in a temperature range in which the spreadability of the zinc is good, and a zinc thin film free from cracks is formed,
The zinc hot-dip plated layer is a zinc thin film that is drawn and does not have cracks, and the diffusion alloy layer is formed by drawing and pulverizing particulate matter embedded in the outer peripheral surface of the core wire. And an electrode wire for wire electric discharge machining, wherein the diffusion alloy layer is prevented from being integrated with and peeled off from the core wire. 5. The electrode wire for wire electric discharge machining according to claim 4 , wherein the pulverized granular material of the diffusion alloy layer is deeply embedded in the outer peripheral surface of the core wire under a large vertical surface pressure. . 6. The electrode wire for wire electric discharge machining according to claim 5 , wherein the heat diffusion alloy layer is formed as a layer in which crushed granular materials are gathered in a dense state. The pulverized granular material of the diffusion alloy layer has a high wire drawing ratio obtained by multiplying the reduced cross-sectional area obtained by subtracting the post-drawing cross-sectional area from the pre-drawing cross-sectional area by the pre-drawing cross-sectional area by 100. The electrode wire for wire electric discharge machining according to claim 5 or 6 , wherein the electrode wire is deeply embedded in an outer peripheral surface of the core wire after being drawn.

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