Wire drawing die

Abstract

The wire drawing die is a wire drawing die having a diameter D of less than 100 [mu] m in which holes are provided in polycrystalline diamond substantially composed only of diamond and having an average particle diameter of 500 nm or less, a compression angle of 4 DEG or more and 14 DEG or less, and a diameter D of a fixed-diameter portion having a length of 20% D or more and 100% D or less, the diameter D being less than 100 [mu] m, the diameter D being less than 100 [mu] m, the diameter D being less than 100 [mu] m, and the diameter D being less than 100 [mu] m. The concentricity between the sizing part and the bell-shaped part or the deformation part is smaller than or equal to 1.0 [mu] m, and the roundness of the hole of the sizing part is smaller than or equal to 0.5 [mu] m.

Description

Technical Field

[0001] This invention relates to a wire drawing die. This application claims priority to Japanese Patent Application No. 2023-060736, filed April 4, 2023. The entire contents of that Japanese patent application are incorporated herein by reference. Background Technology

[0002] Currently, for example, International Publication No. 2008 / 088048 discloses a wire drawing die.

[0003] Patent Document 1: International Publication No. 2008 / 088048 Summary of the Invention

[0004] The wire drawing die of the present invention is a wire drawing die with a diameter D of less than 100 μm in the sizing section, wherein,

[0005] Pores are created in polycrystalline diamond, which is essentially composed only of diamond and has an average particle size of less than or equal to 500 nm.

[0006] The compression angle is greater than or equal to 4° and less than or equal to 14°.

[0007] The length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D.

[0008] The concentricity between the sizing section and the bell-shaped or deformed section is less than or equal to 1.0 μm.

[0009] The roundness of the hole in the sizing section is less than or equal to 0.5 μm. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of the adhesive-free polycrystalline diamond mold involved in the implementation method. Detailed Implementation

[0011] [The problem this invention aims to solve]

[0012] In the past, there was a problem with the difficulty of producing fine wires in wire drawing dies.

[0013] [Description of embodiments of the present invention]

[0014] First, embodiments of the present invention will be described in detail.

[0015] The wire drawing die of the present invention is a wire drawing die with a diameter D of less than 100 μm in the sizing section, and a hole made of polycrystalline diamond that is substantially composed of only diamond with an average particle size of less than or equal to 500 nm. The compression angle is greater than or equal to 4° and less than or equal to 14°, the length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D, the concentricity between the sizing section and the bell-shaped section or the deformed section is less than or equal to 1.0 μm, and the roundness of the hole in the sizing section is less than or equal to 0.5 μm.

[0016] (Diamond)

[0017] Polycrystalline diamond, essentially composed solely of diamond, is what is known as binderless diamond. As a representative example, binderless diamond is known to be produced by directly converting non-diamond carbon into diamond under ultra-high pressure and temperature. Furthermore, the average grain size in this application is determined as follows: First, the sintered microstructure of the polycrystalline diamond is observed using SEM or TEM. Through image processing, each grain (primary grain) is extracted, and the area of ​​that grain is calculated. The diameter of this area, assumed to be circular, is taken as the grain size. Then, the average grain size per unit area (e.g., 50 μm × 50 μm) is taken as the average grain size.

[0018] As a die hole, it is usually set to be circular in a cross-section perpendicular to the wire drawing direction.

[0019] (structure)

[0020] Starting from the upstream side, the wire drawing die has a bell-shaped section, an approach section, a reduction section, a bearing section, a back relief section, and an exit section in sequence.

[0021] The opening angle of the die orifice at the compression section, i.e., the compression angle, is greater than or equal to 4° and less than or equal to 14°. If the compression angle exceeds 14° or is less than 4°, the life of the wire drawing die will be shortened. Preferably, the compression angle is greater than or equal to 5° and less than or equal to 12°.

[0022] The length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D; the concentricity between the sizing section and the bell-shaped section or the deformed section is less than or equal to 1.0 μm; and the roundness of the hole in the sizing section is less than or equal to 0.5 μm. Preferably, the length of the sizing section is greater than or equal to 30%D and less than or equal to 70%D. Preferably, the concentricity between the aforementioned sizing section and the aforementioned bell-shaped section or the aforementioned deformed section is less than or equal to 0.8 μm.

[0023] Figure 1 This is a cross-sectional view of the binder-free polycrystalline diamond mold involved in the implementation method. For example... Figure 1As shown, the wire drawing die 1 according to Embodiment 1 has a die hole 1h. The die 1 has, in sequence from the upstream side, a bell-shaped part 1a, a deformation part 1b, a compression part 1c, a sizing part 1d, a safety angle part 1e, and an outlet part 1f.

[0024] The bell-shaped portion 1a is located on the upstream side of the die hole 1h. The angle α formed by the tangents 12a and 13a on the side of the die hole 1h of the bell-shaped portion 1a is defined as the bell angle. The bell-shaped portion 1a corresponds to the inlet of the drawn wire and the lubricating material.

[0025] The deformable part 1b is located downstream of the bell-shaped part 1a. At the boundary between the bell-shaped part 1a and the deformable part 1b, the slope of the die hole 1h can vary continuously or discontinuously. The angle β formed by the tangents 12b and 13b on the side of the die hole 1h of the deformable part 1b is defined as the deformation angle.

[0026] The compression section 1c is located downstream of the deformation section 1b. At the boundary between the deformation section 1b and the compression section 1c, the slope of the die hole 1h can vary continuously or discontinuously. The angle γ formed by the tangents 12c and 13c on the side of the die hole 1h in the compression section 1c is defined as the compression angle.

[0027] The sizing section 1d is located downstream of the compression section 1c. At the boundary between the compression section 1c and the sizing section 1d, the slope of the die orifice 1h can vary continuously or discontinuously. The diameter D of the die orifice 1h in the sizing section 1d is specified to be constant. The sizing section 1d is cylindrical. The sizing section 1d is the portion with the smallest diameter within the die orifice 1h.

[0028] The safety angle 1e is located downstream of the sizing section 1d. At the boundary between the sizing section 1d and the safety angle 1e, the slope of the die hole 1h can vary continuously or discontinuously. The angle θ of the side of the die hole 1h of the safety angle 1e is defined as the safety angle.

[0029] The outlet section 1f is located downstream of the safety angle section 1e. At the boundary between the sizing section 1d and the safety angle section 1e, the slope of the die orifice 1h can vary continuously or discontinuously. The angle φ of the side of the die orifice 1h in the safety angle section 1e is defined as the outlet angle.

[0030] If the diameter of the compression section 1c is RD, then the relationship between RD and D holds, where D < RD ≤ 1.050D. Therefore, the portion with the diameter RD that has the above relationship is the compression section 1c. The cross-sectional area of ​​the compression section 1c exceeds 100% of the cross-sectional area of ​​the sizing section 1d, and is less than or equal to 110% of the cross-sectional area of ​​the sizing section 1d.

[0031] The length of the sizing section 1d is L. Between L and D, the relationship 20%D ≤ L ≤ 100%D holds. Preferably, the relationship 30%D ≤ L ≤ 70%D holds. The portion of the die cavity 1h with a diameter of D is the sizing section 1d.

[0032] (Method for determining the shape of die hole 1h)

[0033] To determine the shapes of the bell-shaped section 1a, the deforming section 1b, the compression section 1c, the sizing section 1d, the safety angle section 1e, and the outlet section 1f, a transfer material (such as "RepliSet" manufactured by Struers KK Co., Ltd.) was filled into the die hole 1h to create a replica with the shape of the die hole 1h transferred onto it. The outline of the die hole 1h was then clearly defined on the replica using a tool microscope equipped with transmitted light, resulting in... Figure 1 A cross-sectional view of a die hole 1h.

[0034] In the cross-sectional view, the narrowest cylindrical section is designated as the sizing section 1d. The diameter of the sizing section is designated as D. In the cross-sectional view, the section adjacent to and upstream of the sizing section 1d, with an inner diameter RD satisfying D < RD ≤ 1.050D, is designated as the compression section 1c. In the cross-sectional view, the section adjacent to and downstream of the sizing section 1d, with an inner diameter BD satisfying D < BD ≤ 1.025D, is designated as the safety angle section 1e.

[0035] When measuring the compression angle γ, in the cross-sectional view of the die hole 1h, at the reference point 11c (the part where RD = 1.050D) of the compression part 1c, tangents 12c and 13c are drawn from both sides, and the angle formed by the two tangents 12c and 13c is set as the compression angle γ.

[0036] (Methods for determining concentricity)

[0037] To determine the concentricity between the bell-shaped portion 1a or the deformed portion 1b and the sizing portion 1d, a digital microscope (VHX8000) manufactured by Keyence was used as the measuring device, for example. The measuring conditions were: magnification: ×2,500, and transmitted illumination. The die hole 1h was observed from a direction parallel to the center line 1p, and the outline of the region visible in white light was determined. The outermost outline (bell-shaped portion or deformed portion) of this region was defined as the outline of the bell-shaped portion 1a or the deformed portion 1b. This region was a region visible in white light that fell within the range of 150% to 250%D relative to the diameter D of the die hole 1h. An approximate circle was drawn based on this outline, and the center of the circle was set as the center of the bell-shaped portion 1a or the deformed portion 1b. Similarly, the outline of the sizing portion 1d was determined. An approximate circle was drawn based on this outline, and the center of the circle was set as the center of the sizing portion 1d. The distance W between the center of the bell-shaped part 1a or the deformed part 1b and the center of the sizing part 1d is called concentricity.

[0038] (Methods for determining roundness)

[0039] In this application, regarding roundness, the difference between the maximum and minimum diameters measured in all 360-degree directions after wire drawing via a die is defined as roundness. For measurement, a wire diameter measuring machine (LDSN) manufactured by Cesa.KK is used to measure the diameter of the drawn wire at 250 points covering 360 degrees. The difference between the maximum and minimum values ​​of these 250 measurements is defined as roundness. The shape of the die hole 1h (the shape of the sizing section 1d) is transferred onto the wire, and the roundness of the sizing section 1d is reflected in the wire.

[0040] The roundness of the sizing section 1d is the difference between the maximum and minimum distances measured from the center of the sizing section 1d obtained by approximating a circle in the outline of the sizing section 1d obtained through the above process.

[0041] [Details of embodiments of the present invention]

[0042] (Example 1)

[0043] (Evaluation of the wire drawing process of BL (adhesive-free) diamond mold)

[0044] To verify the performance of different mold materials, three molds of the same shape were prepared and evaluated.

[0045] Mold material

[0046] Three types of PCD molds were prepared: A. binder-free PCD molds, B. single-crystal diamond molds, and C. PCD molds containing binders. The average diamond particle size of the A. binder-free PCD molds was 0.05 μm (50 nm). Their shapes are shown in Tables 1 and 2.

[0047] [Table 1]

[0048]

[0049] [Table 2]

[0050]

[0051] In Tables 1 and 2, "BLPCD" refers to diamond manufactured by converting non-diamond carbon diameter into diamond under ultra-high pressure and high temperature. It is called polycrystalline diamond that does not contain a binder and is essentially composed only of diamond.

[0052] "PCD particle size 1μm" refers to polycrystalline diamond composed of polycrystalline diamond with an average particle size of 1μm, containing more than or equal to 5% by volume of binder, with the remainder being polycrystalline diamond.

[0053] Using this die, SUS wire was drawn at a drawing speed of 500 m / min under oil lubrication conditions. If the diameter D is φ0.08 mm, the wire diameter before drawing is φ.

[0054] 0.087mm. If the diameter D is φ0.10mm, the wire diameter before drawing is φ0.109mm. If the diameter D is φ0.04mm, the wire diameter before drawing is φ0.0435mm. If the diameter D is φ0.15mm, the wire diameter before drawing is φ0.0164mm. These SUS wires are drawn using various dies. If the roundness of the drawn wire becomes 0.3μm, or the increase in wire diameter compared to the wire diameter drawn 100m after the start of drawing is 0.3μm, then the die life is reached. Alternatively, if the wire curls (warpage, R less than 30mm), then the die life is reached. The results are shown in Tables 3 and 4.

[0055] [Table 3]

[0056]

[0057] [Table 4]

[0058]

[0059] In Tables 3 and 4, under "Lifetime", "A" indicates a lifetime greater than or equal to 60 km, "B" indicates a lifetime greater than 30 km but less than 60 km, and "C" indicates a lifetime less than or equal to 30 km.

[0060] "Wire diameter gain" refers to the difference between the wire diameter at 100m after drawing and the wire diameter at 30km after drawing. The wire diameter is defined as the average value measured in all 360 degrees of the wire after drawing through the die. For measurement, a wire diameter measuring machine (LDSN) manufactured by Cesa.KK was used, measuring the diameter of the drawn wire at 250 points across 360 degrees. Samples with a negative wire diameter gain were also considered. This is because if a high-hardness diamond such as BLPCD is used, annular wear can sometimes occur, causing the wire to be cut and thinned during drawing.

[0061] Regarding the "curled state", if the warp radius R of the drawn wire is greater than or equal to 50mm, it is set to "A"; if R is greater than or equal to 30mm and less than or equal to 50mm, it is set to "B"; and if R is less than 30mm, it is set to "C".

[0062] In a die with a lifespan of "C", the curling condition is poor from the beginning and worsens as the wire drawing process progresses, making it impossible to achieve 30km of wire drawing. Therefore, the roundness of the sizing section at the end of its lifespan is recorded as "roundness (after 30km of wire drawing)".

[0063] In sample number 166, a wire breakage occurred during the 5km wire drawing stage. Evaluation could not continue, and wire drawing was therefore discontinued.

[0064] As shown in Tables 3 and 4, if the compression angle is less than or equal to 14°, the length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D, the concentricity between the sizing section and the bell-shaped section or the deformed section is less than or equal to 1.0μm, and the roundness of the hole in the sizing section is less than or equal to 0.5μm, then an evaluation of greater than or equal to B will be obtained in the evaluation of life, curling state (initial stage), and curling state (30km).

[0065] It is understood that, more preferably, if the compression angle is greater than or equal to 5° and less than or equal to 12°, then evaluation A increases. Furthermore, it is understood that if the length of the sizing section falls within the range of greater than or equal to 30%D and less than or equal to 70%D, then evaluation A increases. Furthermore, it is understood that if the concentricity is less than or equal to 0.8 μm, then evaluation A increases.

[0066] (Postscript 1)

[0067] A wire drawing die, wherein the diameter D of the sizing section is less than 100 μm, wherein,

[0068] Pores are created in polycrystalline diamond, which is essentially composed only of diamond and has an average particle size of less than or equal to 500 nm.

[0069] The compression angle is greater than or equal to 4° and less than or equal to 14°.

[0070] The length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D.

[0071] The concentricity between the sizing section and the bell-shaped section or the deformed section is less than or equal to 1.0 μm, and the roundness of the hole in the sizing section is less than or equal to 0.5 μm.

[0072] (Postscript 2)

[0073] According to the wire drawing die described in Appendix 1, among which,

[0074] The compression angle is greater than or equal to 5° and less than or equal to 12°.

[0075] (Note 3)

[0076] According to the drawing die described in Appendix 1 or 2, among which,

[0077] The length of the sizing section is greater than or equal to 30%D and less than or equal to 70%D.

[0078] (Postscript 4)

[0079] According to the drawing die described in any of the appendices 1 to 3, among which,

[0080] The concentricity between the sizing portion and the bell-shaped portion or the deformable portion is less than or equal to 0.8 μm.

[0081] It should be considered that the embodiments and examples disclosed herein are merely illustrative in all respects and are not intended to be limiting. The scope of the invention is not defined by the above embodiments, but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0082] Explanation of the label

[0083] 1. Mold, 1a. Bell-shaped part, 1b. Deformation part, 1c. Compression part, 1d. Sizing part, 1e. Safety angle part, 1f. Exit part, 1h. Mold hole, 1p. Center line, 11c. Reference point, 12a, 12b, 12c, 13a, 13b, 13c. Tangents.

Claims

1. A wire drawing die, wherein the diameter D of the sizing section is less than 100 μm, wherein, Pores are created in polycrystalline diamond, which is essentially composed only of diamond and has an average particle size of less than or equal to 500 nm. The compression angle is greater than or equal to 4° and less than or equal to 14°. The length of the sizing section is greater than or equal to 20%D and less than or equal to 100%D. The concentricity between the sizing section and the bell-shaped section or deformed section is less than or equal to 1.0 μm. The roundness of the hole in the sizing section is less than or equal to 0.5 μm.

2. The wire drawing die according to claim 1, wherein, The compression angle is greater than or equal to 5° and less than or equal to 12°.

3. The wire drawing die according to claim 1 or 2, wherein, The length of the sizing section is greater than or equal to 30%D and less than or equal to 70%D.

4. The wire drawing die according to claim 1 or 2, wherein, The concentricity between the sizing portion and the bell-shaped portion or the deformable portion is less than or equal to 0.8 μm.

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