Method for manufacturing special-shaped dies and special-shaped wires

Abstract

This irregular-shaped diamond die is an irregular-shaped die for fabricating an irregular-shaped line and is provided with a processing hole having a bearing portion. In a cross-section of the bearing portion perpendicular to a wire drawing direction, a first side and a second side facing each other are provided, and the first side and the second side have protrusion shapes on the center side of the processing hole in the cross-section.

Description

[Technical field]

[0001] The present invention relates to a shaped die and a method for producing a shaped wire using the same. This application claims priority based on Japanese Patent Application No. 2021-184040, filed on November 11, 2021. All contents of the Japanese patent application are incorporated herein by reference. [Background technology]

[0002] Conventionally, a special shaped die has been disclosed, for example, in International Publication No. WO 2018 / 123513 (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 123513 Summary of the Invention

[0004] The deformed die of the present disclosure is an deformed die for producing deformed wire, which is provided with a machining hole having a bearing portion, and in a bearing cross-section of the bearing portion perpendicular to the wiredrawing direction, a first side and a second side facing each other are provided, and the first side and the second side have a convex shape toward the center of the machining hole in the bearing cross-section. [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a cross-sectional view of a deformed diamond die 10 according to an embodiment, a diamond 1 constituting the deformed diamond die 10, a case 2 for housing the diamond 1, and a sintered alloy 3 interposed between them. [Diagram 2] FIG. 2 is a front view of the diamond 1 in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4]FIG. 4 is an enlarged cross-sectional view of the bearing portion 6d taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 6] FIG. 6 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 8] FIG. 8 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 9] FIG. 9 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 10] FIG. 10 is an enlarged cross-sectional view of the bearing portion 6d of the machined hole 7 according to the embodiment. [Figure 11] FIG. 11 is a cross-sectional view of the reduction portion 6c of the machined hole 7 according to the embodiment, which corresponds to FIG. [Figure 12] FIG. 12 is a cross-sectional view of the processed hole 7 in the wire drawing direction, shown for explaining the opening angle. [Figure 13] FIG. 13 is a plan view of holes formed in three diamond dies shown to explain the method for producing a profiled wire according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] [Problem that this disclosure aims to solve] There was a problem that the precision of the profiled wire produced using the conventional profiled dies was low. [Effects of this disclosure] According to the present disclosure, the processing accuracy of the irregular shaped wire can be improved.

[0007] [Details of the embodiment of the present invention] (Overall composition) The outline of the diamond die for drawing a deformed wire will be explained with reference to the drawings. FIG. 1 is a cross-sectional view of a deformed diamond die 10 according to an embodiment, a diamond 1 constituting the deformed diamond die 10, a case 2 for storing the diamond 1, and a sintered alloy 3 interposed therebetween. FIG. 1 is a cross-sectional view of a state in which the deformed diamond die can be used after being stored in a die case. The diamond 1 is stored in the case 2. The diamond 1 is attached to the case 2 by using the sintered alloy 3. In the deformed diamond die 10 as a deformed die, the portion for processing the wire is composed of the diamond 1, for example.

[0008] FIG. 2 is a front view of the diamond 1 in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3, showing an enlarged view of the bearing portion 6d. As shown in FIGS. 2 to 4, the diamond 1 has a polycrystalline diamond 5 surrounded by a support ring 4 made of cemented carbide. The center portion is composed of a hole inner surface 6 through which the wire to be drawn passes while being in contact with the hole 7 and a processing hole 7. The hole inner surface 6 is further divided, and the details are shown in FIG. 3. The hole inner surface 6 is divided into a bell portion 6a, an approach portion 6b, a reduction portion 6c, a bearing portion 6d, a back relief portion 6e, and an exit portion 6f, and as shown in FIG. 2, the shape seen from the front is similar to a rectangle. The bearing portion 6d is the area including the portion with the smallest diameter in the processing hole 7.

[0009] At least the surface from the bell portion 6a to the bearing portion 6d of the inner surface 6 formed by the processed hole 7 is formed with a smooth curved surface in the thickness direction of the diamond. That is, unlike a case where the bell portion 6a, the approach portion 6b, the reduction portion 6c, and the bearing portion 6d are each formed linearly and the boundaries between them are rounded, each portion is formed with a smooth curved surface as a whole. This curved surface is formed with a single R curved surface or a compound R curved surface, and the boundaries between them are not clearly distinguishable.

[0010] The wire diameter of the wire after drawing with the irregular diamond die 10 is less than 0.1 mm, which is a thin wire diameter. When drawing such an ultra-fine wire, if the surface from the bell portion 6a to the bearing portion 6d is formed as a smoothly curved surface, there is no significant change in the wire drawing resistance, and even the ultra-fine wire is less likely to break. In terms of supplying lubricant, a smooth curve also provides good lubrication conditions.

[0011] The polycrystalline diamond 5 around the machining hole 7 is a single polycrystalline diamond that is continuous in the circumferential direction of the machining hole 7. Since the polycrystalline diamond 5 around the machining hole 7 is a single polycrystalline diamond that is continuous in the circumferential direction of the machining hole, it has higher strength than divided diamond. As a result, the precision of the machining hole is high, and the surface roughness of the wire after drawing can be reduced.

[0012] (Length of bearing part 6d and reduction part 6c) If the front shape of the bearing portion 6d is a rectangle and the distance between the opposing faces of the rectangle (the minimum distance between the first side 7b1 and the second side 7b2) is L2, the range of the length 1.0L2 in the wiredrawing direction is the bearing portion 6d. The part with the smallest inner diameter is the center of the bearing portion 6d, and the areas above and below this part in the wiredrawing direction by 0.5L2 each are the bearing portion 6d. In general, the length of the bearing portion 6d is preferably long from the viewpoint of improving the life of the irregular diamond die 10, that is, preventing wear and deformation of the polycrystalline diamond 5. Furthermore, the range of 1.0L2 from the upstream end of the bearing portion 6d in the wiredrawing direction (the range from the center of the bearing portion 6d to the upstream side in the wiredrawing direction exceeding 0.5L2 to 1.5L2) is the reduction portion 6c.

[0013] However, when drawing ultra-fine wires, the problem of wire breakage is a major issue, so the bearing portion 6d cannot be made longer. To prevent wire breakage, measures are required from two perspectives: to reduce the contact area between the polycrystalline diamond 5 and the wire, and to reduce the frictional force per unit area. Therefore, it is preferable to shorten the bearing portion 6d in order to reduce the contact area with the wire. This reduces the frictional force.

[0014] Also, by making the surface smooth, the contact area is reduced, the supply of lubricant is prevented from running out, and the wire drawing resistance can be stabilized, resulting in an extremely effective prevention of wire breakage. Furthermore, when grinding the bearing portion 6d, it is difficult to make a smooth surface with small surface roughness if the bearing portion 6d is long, but since it is short, it is possible to grind it with high precision, which also has the effect of stabilizing the wire drawing resistance.

[0015] (Surface roughness Sa of bearing part 6d) The surface roughness Sa of the bearing portion 6d is, for example, 0.05 μm or less. The surface roughness Sa is defined by ISO 25178. The measurement range is a range with 20 or more peaks and valleys in the measurement range. Measurement is performed under the conditions of measurement pretreatment, tilt correction, and no Gaussian filter. The bearing portion 6d is the part with the smallest diameter in the machining hole 7, and the surface roughness of the bearing portion 6d is deeply related to the surface roughness of the wire. If the surface roughness Sa of the bearing portion 6d exceeds 0.05 μm, the surface roughness of the wire becomes rough. In order to obtain a die with high accuracy and long life, it is more preferable that the surface roughness Sa of the bearing portion 6d is 0.03 μm or less, and most preferably 0.01 μm or less. The smaller the surface roughness Sa of the bearing portion 6d, the more preferable. However, in terms of industrial production, considering the cost-effectiveness, the surface roughness Sa of the bearing portion 6d is preferably 0.002 μm or more.

[0016] To measure the surface roughness Sa of the bearing portion 6d, a transfer material (e.g., RepliSet, manufactured by Marumoto Struers K.K.) is filled into the machining hole 7 of the irregular die to create a replica with the surface of the machining hole 7 transferred thereto. This replica is observed with a laser microscope (e.g., Keyence Corporation, shape analysis laser microscope, VK-X series) to measure the surface roughness Sa at any three points. The average value of the surface roughness Sa at the three points is defined as the surface roughness Sa of the bearing portion 6d. Note that the surface roughness Sa of the wire after drawing is also measured at any three points by observing the surface with the laser microscope. The average value of the surface roughness Sa at the three points is defined as the surface roughness Sa of the wire.

[0017] (Surface roughness of reduction part 6c) Preferably, the surface roughness Sa of the reduction portion 6c is 0.1 μm or less. If the surface roughness Sa of the reduction portion 6c is 0.1 μm or less, the surface roughness of the reduction portion 6c upstream of the bearing portion 6d is small, so that the surface roughness of the wire after drawing can be made small.

[0018] In order to obtain a die with high accuracy and long life, the surface roughness Sa of the reduction portion 6c is preferably 0.05 μm or less, and most preferably 0.03 μm or less. The smaller the surface roughness Sa of the reduction portion 6c, the better. However, in terms of industrial production, taking into account the cost-effectiveness, the surface roughness Sa of the reduction portion 6c is preferably 0.01 μm or more.

[0019] The surface roughness of the reduction portion 6c is measured in the same manner as the surface roughness of the bearing portion 6d.

[0020] (Side length and corner radius) The drawn wire is used for motor windings and the like. For such applications, it is necessary to wind the wire at a high density, so the smaller the R of the corners of the wire, the better. For this reason, the R of the rectangular corners 7a of the bearing part is set to 20 μm or less. The smaller the R of the corners, the better. However, in terms of industrial production, taking into account the cost-effectiveness, it is preferable that the R of the corners 7a be 1 μm or more.

[0021] In this embodiment, the processed hole 7 is shown to have a rectangular shape, but the processed hole 7 is not limited to a rectangular shape and may have other polygonal shapes such as a triangle or a hexagon. It is preferable that the multiple cross sections perpendicular to the longitudinal direction of the wire include straight line portions. Furthermore, when the lengths of the sides are different, the length of the longest side is 100 μm or less. There is no lower limit to the length of the longest side. However, if the longest side is too short, the manufacturing costs will be high in industrial production. Therefore, in consideration of cost-effectiveness, it is preferable that the length of the longest side is 5 μm or more.

[0022] The first side 7b1 and the second side 7b2 are disposed so as to face each other. The distance between the first side 7b1 and the second side 7b2 varies depending on the location. The maximum distance is L1, and the minimum distance is L2.

[0023] The first side 7b1 and the second side 7b2 are curved so as to protrude toward the center 7c. In this embodiment, all four sides protrude toward the center 7c, but it is sufficient that at least one pair of the first side 7b1 and the second side 7b2 has a convex shape toward the center 7c, and the other sides do not have to have a convex shape toward the center 7c.

[0024] Figures 5 to 10 are enlarged cross-sectional views showing the bearing portion 6d of the machined hole 7 according to the embodiment. Figures 5 to 10 show machined holes 7 with modified maximum distance L1 and minimum distance L2. Figure 10 shows the shape in which the value of maximum distance L1 / minimum distance L2 is the largest, and in Figure 10, maximum distance L1 / minimum distance L2 is 150%. Figures 5 to 10 show the bearing cross sections.

[0025] If the shape of the processing hole 7 is a square, the wire is strongly processed by the straight portions of the processing hole 7. Although the metal constituting the processed wire moves to the corner portions 7a, a sufficient amount of metal does not move, making it difficult for the metal to fill the corner portions 7a, and there is a problem that the shape of the processed wire does not become a square.

[0026] 1 to 10, the first side 7b1 and the second side 7b2 are formed so that the distance is the maximum L1 at the corner portion 7a, so that the wire material can easily move to the corner portion 7a. As a result, the wire can easily have a rectangular shape after processing.

[0027] In conventional irregular dies, in order to reduce the R of the corner portion 7a, the reduction rate was set high during wire drawing. This resulted in a high drawing force, which increased the risk of wire breakage, especially in the case of ultra-fine wires, and caused problems such as increased processing strain of the wire after wire drawing. With the irregular dies disclosed herein, the R of the corner portion 7a can be accurately formed even if the reduction rate is set low, which reduces the risk of wire breakage and reduces the processing strain of the wire after wire drawing.

[0028] The deformed diamond die 10 is an deformed die for producing deformed wire, and is provided with a machining hole 7 having a bearing portion 6d. In a cross section of the bearing portion 6d perpendicular to the wiredrawing direction, a first side 7b1 and a second side 7b2 facing each other are provided, and the first side 7b1 and the second side 7b2 have a convex shape toward the center 7c of the machining hole 7 in the cross section.

[0029] In this embodiment, the shape of the processed hole 7 is a shape similar to a rectangle, but it is not limited to this and may be a track shape in which straight lines and semicircles are connected. In this case, the straight line parts have a convex shape toward the center.

[0030] (Opening angle at reduction portion 6c) FIG. 11 is a cross-sectional view of the reduction portion 6c of the processed hole 7 according to the embodiment, which corresponds to FIG. 5. FIG. 12 is a cross-sectional view of the processed hole 7 in the wiredrawing direction, which is shown to explain the opening angle. In the present disclosure, as shown in FIG. 11, the cross-sectional shape (reduction cross section) in the reduction portion 6c is almost similar to the cross-sectional shape in the bearing portion 6d. In the reduction portion 6c, the angle θ between the tangent 6c1 of the wall surface and the center line 7d is the opening angle in the reduction portion 6c (hereinafter referred to as the reduction angle). In the reduction portion 6c, the tangent 6c1 and the reduction portion 6c come into contact at the center position in the wiredrawing direction.

[0031] The reduction angle of the corner portion 7a may be different from the reduction angle of the first side 7b1 and the second side 7b2.

[0032] The reduction angle of the corner portion 7a may be set to be larger than the reduction angle of the first side 7b1 and the second side 7b2.

[0033] In this way, when the reduction angle of the corner portion 7a is set larger than the reduction angle of the first side 7b1 and the second side 7b2, the area reduction rate of the corner portion 7a can be set larger than the area reduction rate of the first side 7b1 and the second side 7b2. As a result, the wire being drawn is drawn more rapidly at the corner portion 7a than at the first side 7b1 and the second side 7b2. In this way, even if the corner portion 7a has a very small R in the extremely thin wire that is the target of the deformed die of the present disclosure, the wire is easily drawn to every corner of the corner portion 7a. This improves the shape accuracy of the drawn wire. In addition, if the area reduction rate is increased, the resistance during drawing increases, but by shortening the length of the bearing portion 6d or reducing the surface roughness as described above, the increase in resistance during drawing is suppressed, and the problem of the wire breaking is less likely to occur.

[0034] Furthermore, the reduction angle of the corner portion 7a may be set to be larger as it moves away from the first side 7b1 and the second side 7b2 and approaches the tip 7a1 of the corner portion 7a. The tip 7a1 of the corner portion 7a refers to the point in the corner portion 7a that is farthest from the center 7c.

[0035] By forming the corner portion 7a in this shape, the tip 7a1 of the corner portion 7a has the largest area reduction rate, and the wire can be easily processed up to the tip 7a1 of the corner portion 7a. Furthermore, in the process of manufacturing the irregular shaped die, the corner portion 7a can be easily processed and the precision of the corner portion 7a can be easily improved.

[0036] (diamond grain size) In order to reduce the R of the corner portion 7a and further reduce the surface roughness Sa of the bearing portion 6d, the grain size of the diamond constituting the polycrystalline diamond 5 must be small. A polycrystalline diamond (sintered diamond) 5 with an average grain size of 500 nm or less is used. Furthermore, the average grain size of the diamond is related to the surface roughness of the wire, and if the average grain size of the diamond exceeds 500 nm, the surface roughness of the wire becomes large.

[0037] To obtain a die with high accuracy and long life, it is more preferable that the average grain size of diamond is 300 nm or less, and most preferably 100 nm or less. The smaller the average grain size of diamond, the better. However, because ultrafine diamond grains are expensive in industrial production, it is preferable that the average grain size of diamond is 5 nm or more.

[0038] To measure the average grain size of diamond grains, a scanning electron microscope is used to photograph three arbitrary locations of the polycrystalline diamond 5 within an area of ​​5 μm x 5 μm. From the photographed image, individual diamond grains are extracted, and the extracted diamond grains are binarized to calculate the area of ​​each diamond grain. Then, a circle having the same area as each diamond grain is assumed, and the diameter of this circle is taken as the grain size of the diamond grain. The arithmetic mean value of the diameters of each diamond grain (diameter of the circle) is taken as the average grain size.

[0039] (Binder) The polycrystalline diamond 5 may contain a binder. The proportion of the binder in the polycrystalline diamond is preferably 5% by volume or less. To obtain a highly accurate and long-life die, the proportion of the binder is more preferably 3% by volume or less, and most preferably no binder is contained.

[0040] To measure the binder ratio, as described in the "Diamond grain size" paragraph above, three arbitrary locations within an area of ​​5 μm x 5 μm are photographed with a scanning electron microscope on the polycrystalline diamond 5. The photographed image is read into Adobe Photoshop or similar software, and a threshold value that matches the original image is calculated by tracing the outline, and the image is bi-toned using that threshold value. This bi-tonalization makes it possible to calculate the area of ​​the binder that appears white. Note that diamond particles appear gray, and grain boundaries appear black. The area ratio of the binder is taken as the volume ratio of the binder.

[0041] (material) In the above example, a wire is processed by using the diamond 1. However, the bearing portion 6d may be made of a hard material other than the diamond 1 in the irregular shaped die.

[0042] The material of the bearing portion 6d may be, for example, cubic boron nitride (CBN) or a cemented carbide, and the material of the bearing portion 6d may be determined depending on the material of the wire to be processed.

[0043] (Method of manufacturing irregular diamond die 10) Sintered diamond is prepared as the material for the irregular diamond die 10. After processing the sintered diamond into a cylindrical shape, a pilot hole is drilled by laser processing. Next, rough processing is performed by electric discharge processing. Next, finishing processing is performed by lapping. The details of the lapping processing method are as follows.

[0044] 1) Using a rolling method or other method, a stainless steel wire is produced with a rectangular cross-sectional shape smaller than the drilled hole and with each corner rounded.

[0045] 2) The long side of the stainless steel wire is brought into contact with one side of the die hole, and finished by reciprocating while supplying diamond slurry. The remaining three sides are also finished in the same manner. During the lapping process, the stainless steel wire mainly processes the bearing portion 6d. By adjusting the amount of lapping of the reduction portion 6c, the surface roughness of the reduction portion can also be adjusted.

[0046] (Method of manufacturing irregularly shaped wire) FIG. 13 is a plan view of holes formed in three diamond dies shown to explain the method for producing a profiled wire according to an embodiment.

[0047] As a first step, in order to process the wire 100 to produce a deformed wire, the wire 100 is first processed through the processing hole 107. As a result, the wire 100 is processed into a shape close to a square.

[0048] In the second step, wire drawing is performed using the processing hole 7. As a result, the central portion of the cross section of the wire is deformed and processed to extend toward the corner portion 7a. The shape of the wire 100 becomes pointed toward the corner portion 7a.

[0049] In the third step, the wire 100 is processed through the processing hole 207 of the finishing processing special die. As a result, the portion of the cross section of the wire 100 closer to the corner portion 7a than the side portion is largely deformed and processed, and the wire 100 is processed into a shape that contacts the processing hole 207 even at the corner portion 7a with a small R.

[0050] In addition, the number of shaped dies used in each of the first to third stages may be one or more. In order to improve the accuracy, the number of dies can be increased depending on the wire and the size of R of the corner portion 7a.

[0051] The wire to be drawn can be of various metals such as copper, silver, iron, gold, aluminum, etc.

[0052] (Example) Wire drawing was evaluated using combinations 1 to 3 of the special dies.

[0053] In all of the combinations 1 to 3, wire drawing is performed using three special dies. (1) Diamond die material The material of the irregular die is the same for all combinations 1 to 3. The irregular die is essentially made of diamond, and is made of polycrystalline diamond with an average diamond grain size of 50 nm.

[0054] (2) Diamond die specifications In combinations 1 to 3, the first to third irregular dice have the following characteristics:

[0055] (2-1) 1st photo The first variant die is common to combinations 1 to 3.

[0056] In combinations 1 to 3, the first irregular die does not have a protrusion toward the center on the side as shown in Figures 4 to 11, and the specifications are as follows. Reduction angle: 16 degrees Bearing length: 10μm Bearing surface roughness: Sa0.021μm Distance between opposing sides of bearing: 109μm Corner radius R: 30μm (2-2) 2nd photo (2-2-1) In combination 1, the specifications of the second irregular die are as follows (Figure 5). Reduction angle: 15 degrees (same for both sides and R) Bearing section 6d length: 10μm Bearing section 6d surface roughness: Sa0.025μm Distance L1 of bearing part 6d: 90μm Distance L2 of bearing part 6d: 98μm Radius R of corner portion 7a: 10 μm (2-2-2) In combination 2, the specifications of the second irregular die are as follows (Figures 5 and 11). Reduction angle: 15 degrees (sides 7b1 and 7b2) Reduction angle: 15 to 18 degrees (R part of corner portion 7a). The reduction angle is 15 degrees at the boundary between sides 7b1, 7b2 and corner portion 7a, and gradually increases toward tip 7a1, until the angle of tip 7a1 is 18 degrees. Length of bearing part 6d: 10μm Surface roughness of bearing part 6d: Sa0.025μm Distance L1 of bearing part 6d: 90μm Distance L2 of bearing part 6d: 98μm Radius R of corner portion 7a: 10 μm (2-2-3) In combination 3, the edges of the second irregular die do not have a protrusion toward the center as shown in Figures 4 to 11, and the specifications are as follows. Reduction angle: 17 degrees Bearing length: 10μm Bearing surface roughness: Sa0.020μm Distance between opposing sides of bearing section: 91μm Corner radius R: 7μm (2-3) 3rd piece In combinations 1 to 3, the edge of the third irregular die does not have a protrusion toward the center as shown in Figures 4 to 11, and the specifications are as follows. Reduction angle: 16 degrees Bearing length: 10μm Bearing surface roughness: Sa0.018μm Distance between opposing sides of bearing part: 80μm Corner radius R: 7μm (3) Wire rod before drawing The specifications of the wire to be drawn are as follows:

[0057] Material: pure copper Wire diameter (before drawing): Φ130μm (4) Wire rod after drawing The wire state after drawing was as follows:

[0058] (4-1) Combination 1 (4-1-1) Wire diameter The wire diameters at measurement points 1 to 3 are as follows. Measurement point 1: 80.1 μm long, 80.0 μm wide Measurement point 2: 80.0 μm long, 80.2 μm wide Measurement point 3: 80.2 μm long, 80.1 μm wide Average value: 80.1μm (4-1-2) Resistance during drawing: 1.7N (4-1-3) Corner R: R7μm (4-1-4) Surface roughness of wire Measurement point 1...Sa0.030μm Measurement point 2...Sa0.033μm Measurement point 3…Sa0.035μm Average value: Sa0.033μm (4-2) Combination 2 (4-2-1) Wire diameter Measurement point 1: 79.8 μm long, 80.1 μm wide Measurement point 2: 79.9 μm long, 79.8 μm wide Measurement point 3: 80.1 μm long, 79.9 μm wide Average value: 79.9μm (4-2-2) Resistance during drawing: 1.75N (4-2-3) Corner R: R7μm (4-2-4) Surface roughness of wire Measurement point 1...Sa0.033μm Measurement point 2…Sa0.027μm Measurement point 3: Sa 0.032 μm Average value: Sa0.031μm (4-3) Combination 3 (4-3-1) Wire diameter Measurement point 1: 79.6 μm long, 79.8 μm wide Measurement point 2: 79.6 μm long, 79.5 μm wide Measurement point 3: 79.8 μm long, 79.6 μm wide Average value: 79.7μm (4-3-2) Resistance during drawing: 2.0N (4-3-3) Corner R: R12μm (4-3-4) Surface roughness of wire Measurement point 1…Sa0.026μm Measurement point 2: Sa 0.036 μm Measurement point 3: Sa 0.034 μm Average value: Sa0.032μm (5) Measurement method for drawn wire The wire diameter was measured by measuring the length and width of three arbitrary points (measurement points 1 to 3) of the drawn wire with an electronic micrometer.

[0059] The size of the corner R was measured by cutting the drawn wire at three random points and observing the cut cross sections with a laser microscope (Keyence Corporation, shape analysis laser microscope, VK-X series).

[0060] The surface roughness of the wire was measured by observing three arbitrary points of the drawn wire with a laser microscope (Keyence Corporation, shape analysis laser microscope, VK-X series) and measuring the surface roughness Sa of the three arbitrary points.

[0061] (6) Evaluation From these measurement results, the best results were obtained with combination 2, followed by combination 1. Combination 3 is a conventional product, and it is clear that the wire quality is lower than combinations 1 and 2.

[0062] The embodiments and examples disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0063] 1 diamond, 2 case, 3 sintered alloy, 4 alloy support ring, 5 polycrystalline diamond, 6 hole inner surface, 6a bell portion, 6b approach portion, 6c reduction portion, 6c1 tangent line, 6d bearing portion, 6e back relief portion, 6f exit portion, 7 machining hole, 7a corner portion, 7b1 first side, 7b2 second side, 7c center, 7d central axis, 10 irregularly shaped diamond die.

Claims

1. A shaping die for producing a shaped wire having a wire diameter of less than 0.1 mm, A machining hole having a bearing portion is provided, In a bearing cross section of the bearing portion perpendicular to a wiredrawing direction, a first side and a second side facing each other are provided, and a third side and a fourth side facing each other are provided which are different from the first and second sides, The first side, the second side, the third side and the fourth side have a convex shape toward the center of the machining hole in the bearing cross section.

2. The irregular shaped die of claim 1 , wherein a maximum distance between the first side and the second side is greater than 100% and less than or equal to 150% of a minimum distance.

3. 3. The irregular-shaped die according to claim 1 or 2, wherein a reduction section is provided upstream of the bearing section in the wire drawing direction, and in a reduction section and the bearing section of the reduction section perpendicular to the wire drawing direction, the reduction section has a similar shape to the bearing section, the reduction section has fifth and sixth sides facing each other, the fifth and sixth sides have a convex shape toward the center of the machining hole in the reduction section, corner portions of the machining hole are provided at ends of the fifth and sixth sides in the reduction section, and an opening angle of the reduction at the corner portions is different from an opening angle of the reduction at the fifth and sixth sides.

4. The irregular shaped die according to claim 3 , wherein an opening angle of the reduction at the corner portion is larger than an opening angle of the reduction at the fifth side and the sixth side.

5. The irregular shaped die according to claim 4 , wherein an opening angle of the reduction at the corner portion increases as the opening angle moves away from the fifth side and the sixth side and approaches the tip of the corner portion.

6. A method for producing a profiled wire, comprising the steps of processing a wire through a first profiled die, the profiled die according to claim 1 or 2, and a second profiled die, in that order.

7. A method for producing a profiled wire, comprising the steps of processing a wire through a first profiled die, the profiled die according to claim 3, and a second profiled die, in that order.

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