Cemented carbide cutting tool

Abstract

The thickness T1 of the cutting edge at a position 3 μm from the cutting edge toward the base is 0.26 μm or more and 7.00 μm or less. When the thickness of the cutting edge at a position X μm from the cutting edge toward the base (where X is an integer from 3 to 25) is defined as TX, and the thickness of the cutting edge at a position X+1 μm from the cutting edge toward the base is defined as TX1, the first thickness variation TX1-TX is 0.08 μm or more and 1.85 μm or less when X is an integer from 3 to 25. In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge has an outwardly convex portion within a range of 25 μm from the cutting edge toward the base, and the convex portion is located further outward than the straight line S connecting the cutting edge and the position 25 μm from the cutting edge toward the base.

Description

Technical Field

[0001] This disclosure relates to cutting tools made of cemented carbide. This application claims priority based on Japanese Patent Application No. 2020-106058, filed on June 19, 2020. The entire contents of that Japanese patent application are incorporated herein by reference. Background Technology

[0002] Previously, cutting tools have been disclosed in, for example, Japanese Patent Application Publication No. 10-217181 (Patent Document 1), Japanese Patent Application Publication No. 2001-158016 (Patent Document 2), International Publication No. 2014 / 050883 (Patent Document 3), International Publication No. 2014 / 050884 (Patent Document 4), Japanese Patent Application Publication No. 2017-42911 (Patent Document 5), and Japanese Patent Application Publication No. 2004-17444 (Patent Document 6).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 10-217181

[0006] Patent Document 2: Japanese Patent Application Publication No. 2001-158016

[0007] Patent Document 3: International Publication No. 2014 / 050883

[0008] Patent Document 4: International Publication No. 2014 / 050884

[0009] Patent Document 5: Japanese Patent Application Publication No. 2017-42911

[0010] Patent Document 6: Japanese Patent Application Publication No. 2004-17444 Summary of the Invention

[0011] The carbide cutting tool disclosed herein comprises: a base, and a cutting edge disposed on an extension line of the base and having a shape in which the thickness of the cutting edge decreases toward the cutting edge, which is the foremost tip. The thickness of the cutting edge at a position 3 μm from the cutting edge toward the base is 0.26 μm or more and 7.00 μm or less. When the thickness of the cutting edge at a position X μm (where X is an integer from 3 to 25) from the cutting edge toward the base is defined as TX, and the thickness of the cutting edge at a position X+1 μm from the cutting edge toward the base is defined as TX1, the first thickness variation TX1-TX is 0.08 μm or more and 1.85 μm or less when X is an integer from 3 to 25. In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge has an outwardly convex portion within a range of 25 μm from the cutting edge toward the base. The convex portion is located further outward than the straight line connecting the cutting edge and the position 25 μm from the cutting edge toward the base. Attached Figure Description

[0012] [ Figure 1 ] Figure 1 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 1.

[0013] [ Figure 2 ] Figure 2 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 2.

[0014] [ Figure 3 ] Figure 3 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 3.

[0015] [ Figure 4 ] Figure 4 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 4.

[0016] [ Figure 5 ] Figure 5 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 5.

[0017] [ Figure 6 ] Figure 6 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 6.

[0018] [ Figure 7 ] Figure 7 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 7.

[0019] [ Figure 8 ] Figure 8 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 8.

[0020] [ Figure 9 ] Figure 9This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 9.

[0021] [ Figure 10 ] Figure 10 This is a perspective view of the apparatus used to illustrate the cutting test.

[0022] [ Figure 11 ] Figure 11 It is along Figure 10 A cross-sectional view of the XI-XI line in the diagram.

[0023] [ Figure 12 ] Figure 12 It is a microscope photograph showing the notch of the cutter. Detailed Implementation

[0024] [The problem this disclosure aims to solve]

[0025] When the cutting edge is thin, it may chip due to the inability of the cutting edge to withstand the cutting impact. When the cutting edge is thick, the cutting resistance increases and the profile quality deteriorates, resulting in a rough profile.

[0026] [Description of embodiments of this disclosure]

[0027] First, embodiments of this disclosure will be listed and described.

[0028] [Details of the embodiments disclosed herein]

[0029] (Material)

[0030] The material used for the cutting blade is a cemented carbide with tungsten carbide and cobalt as the main components. The cobalt content in the cemented carbide is in the range of 3% to 25% by mass. Preferably, the cobalt content is in the range of 5% to 20% by mass.

[0031] The hardness of cemented carbide, measured in HRA (Rockwell hardness), ranges from 82 to 95. The composition of the cemented carbide elements is determined by ICP emission spectroscopy and Co titration. In the cemented carbide disclosed herein, the main components are tungsten carbide and cobalt. In addition, elements such as chromium, vanadium, tantalum, and niobium are sometimes included to adjust properties such as grain size.

[0032] The size of the tungsten carbide crystals in the cemented carbide is preferably 0.1 μm to 4 μm. More preferably, the crystal size is 2 μm or less.

[0033] In addition, to control the grain size of tungsten carbide, a tantalum-based compound for inhibiting grain growth can be included. Its content is preferably 0.1 to 2% by mass. The additive used to inhibit grain growth can also be a vanadium-based compound or a chromium-based compound. The content of each of the tantalum-based compound, the vanadium-based compound, and the chromium-based compound is set to 0.1 to 2% by mass.

[0034] (shape)

[0035] The cutter is basically a rectangular plate. The shortest side of the plate is used as the thickness.

[0036] A carbide cutting tool has: a base and a cutting edge that is provided on the extension line of the base and has a shape that is thinner toward the cutting edge at the foremost point.

[0037] The thickness of the base is preferably constant. The base thickness is 50–6000 μm, varying depending on the size of the material to be cut. Furthermore, the cutting edge is formed on one side extending from the base. The dimension of the cutting edge in the direction from the base toward the cutting edge is expressed as the width of the cutting edge (Z-axis direction). The dimension in the direction perpendicular to the longitudinal length of the cutting edge (X-axis direction) and the width direction of the cutting edge is expressed as the thickness of the cutting edge (Y-axis direction).

[0038] In most cases where it is used as a cutting knife, the longitudinal length of the blade is mostly between 30mm and 500mm, and the width is mostly between 10mm and 30mm.

[0039] The thickness of the cutting edge at a position 3 μm from the cutting edge towards the base should be between 0.26 μm and 7.00 μm. If the thickness of the cutting edge at this position is less than 0.26 μm, it is difficult to maintain the strength of the cutting edge. Furthermore, if it is too thin, it cannot be manufactured. When the thickness of the cutting edge at this position exceeds 7.00 μm, the cutting resistance increases.

[0040] When the thickness of the cutting edge at a position X μm (where X is an integer from 3 to 25) from the cutting edge toward the base is defined as TX, and the thickness of the cutting edge at a position X+1 μm from the cutting edge toward the base is defined as TX1, the first thickness variation TX1-TX is between 0.08 μm and 1.85 μm for all integers from 3 to 25. If the thickness variation is less than 0.08 μm, sufficient cutting edge strength cannot be obtained, resulting in a notch. When the thickness variation exceeds 1.85 μm, the cutting resistance increases.

[0041] In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge has an outwardly convex portion within a range of 25 μm from the cutting edge toward the base. This convex portion is located further outward than the straight line connecting the cutting edge and the position 25 μm from the cutting edge toward the base. Due to the presence of this convex portion, the strength of the cutting edge can be increased compared to a straight-shaped cutting tool without this convex portion.

[0042] (Implementation Method 1)

[0043] Figure 1 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 1. (See attached image.) Figure 1 As shown, the carbide cutting tool 1 has a cutting edge 121t extending in the longitudinal direction of the blade. Figure 1 It is a cross-section in a direction orthogonal to the longitudinal direction of the blade.

[0044] The carbide cutting tool 1 has a base 110 and a cutting edge 120 connected to the base 110. The cutting edge 120 has a first portion 121. The foremost part of the first portion 121 is a cutting edge 121t.

[0045] The thickness (Y-axis direction) of the cutting edge 120 gradually decreases from the base 110 toward the cutting edge 121t. The thickness at point 203, with a distance of 3 μm along the longitudinal direction (Z-axis direction) from the cutting edge 121t, is T1. The thickness at point 225, with a distance of 25 μm along the longitudinal direction from the cutting edge 121t, is T2. The thickness at point 20X, with a distance of X μm along the longitudinal direction from the cutting edge 121t, is TX. The thickness at point 20X1, with a distance of X+1 μm along the longitudinal direction from the cutting edge 121t, is TX1.

[0046] The convex 120t is located further outward than the straight line S connecting the junction point 225 and the cutting edge 121t. The convex 120t is positioned on the outer surface 121s. A straight line 325 is drawn at point 225 on the outer surface 121s, and the angle between the two straight lines 325 is set as θ. The slope of straight line 325 is half the value of the cutting edge thickness variation at point 225. The direction orthogonal to the Y-axis and Z-axis is the longitudinal direction of the cutting edge.

[0047] The outer surface 121s has a curved shape. The angle formed by the tangent of the outer surface 121s increases as it approaches the cutting edge 121t. In this embodiment, the outer surface 121s is symmetrical about the center line C. However, the outer surface 121s can also be asymmetrical about the center line C.

[0048] The outer surface 121s curves gently and connects the cutting edge 121t to the base 110. As it approaches the cutting edge 121t, the angle between the outer surface 121s and the centerline C increases. Within the cutting edge 120, the curvature is limited to a range of 3 to 25 μm in the Z-axis direction, while the base 110 side can be straight compared to the curved portion.

[0049] The material to be cut by the carbide cutter 1 is, for example, ceramics before firing such as multilayer capacitors or multilayer inductors, or green sheets of glass, metal, metal foil, paper, fiber, or hard resin.

[0050] The carbide cutting tool 1 includes a base 110 and a cutting edge 120 disposed along an extension of the base 110 and having a shape that thins towards the cutting edge 121t, which is the foremost point. In all the following embodiments, the following relationships (1), (2), and (3) hold true.

[0051] (1) The thickness T1 of the cutting edge 120 at a position 3 μm from the cutting edge 121t toward the base 110 is 0.26 μm or more and 7.00 μm or less.

[0052] (2) When the thickness of the cutting edge at the position from the cutting edge 121t toward the base 110Xμm (X is an integer from 3 to 25) is set as TX, and the thickness of the cutting edge 120 at the position from the cutting edge 121t toward the base 110X+1μm is set as TX1, the first cutting edge thickness variation TX1-TX is 0.08μm or more and 1.85μm or less when X is any integer from 3 to 25.

[0053] (3) In a longitudinal section orthogonal to the longitudinal direction of the blade, the shape of the blade portion 120 has an outwardly convex portion 120t in the range from the cutting edge 121t toward the base 110 25μm. The convex portion 120t is located further outward than the straight line S connecting the cutting edge 121t and the position from the cutting edge 121t toward the base 110 25μm.

[0054] More preferably, when X is 3, the change in the thickness of the first cutting edge is 0.26 μm or more and 0.93 μm or less.

[0055] (Implementation Method 2)

[0056] Figure 2 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 2. (See attached image.) Figure 2As shown, in the carbide cutting tool 1 according to Embodiment 2, the outer surfaces 121s, 122s, and 123s are segmented, which differs from the carbide cutting tool 1 of Embodiment 1, where the outer surface 121s is curved. The outer surfaces 121s, 122s, and 123s of the three-segment cutting edge 120 are all straight. The angles formed by the outer surfaces 121s, 122s, and 123s with respect to the centerline C are largest in the outer surface 121s near the cutting edge 121t and smallest in the outer surface 123s near the base 110.

[0057] A point 225, located 25 μm away from the cutting edge 121t along the Z-axis, exists in the first portion 121. In this embodiment, the convex 120t is angular, but it can also be curved.

[0058] (Implementation Method 3)

[0059] Figure 3 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 3. (See attached image.) Figure 3 As shown, in the carbide cutting tool 1 according to Embodiment 3, the outer surfaces 121s and 122s are divided into two segments, which is different from the carbide cutting tool 1 according to Embodiment 2, which is divided into three segments according to the outer surfaces 121s, 122s and 123s.

[0060] The cutting edge 120 has a first portion 121 and a second portion 122 from the front end side. The outer surface 121s has a convexity 120t. The convexity 120t is located further outward than the straight line S. The angles formed by the outer surfaces 121s and 122s with respect to the center line C are the largest in the outer surface 121s near the cutting edge 121t and the smallest in the outer surface 122s near the base 110.

[0061] (Implementation Method 4)

[0062] Figure 4 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 4. (See attached image.) Figure 4 As shown, in the carbide cutting tool 1 according to Embodiment 4, the outer surface 122s is concave, which differs from the carbide cutting tool 1 of Embodiment 3, where the outer surface 122s is linear. A point 225, 25 μm away from the cutting edge 121t in the Z-axis direction, exists in the first portion 121.

[0063] The cutting edge 120 has a first portion 121 and a second portion 122 from the front end side. The first portion 121 has a protrusion 120t. The protrusion 120t is located further outward than the straight line S.

[0064] The outer surface 122s of the second part 122 of the cutting edge 120 bends in such a way that the angle between it and the center line C decreases as it approaches the cutting edge 121t.

[0065] (Implementation Method 5)

[0066] Figure 5 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 5. (See attached image.) Figure 5 As shown, the carbide cutting tool 1 according to Embodiment 5 differs from the carbide cutting tool 1 according to Embodiment 1 in that the cutting edge 121t is flat. The flat surface constituting the cutting edge 121t can be perpendicular to the center line C or inclined relative to the center line C.

[0067] (Implementation Method 6)

[0068] Figure 6 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 6. (See attached image.) Figure 6 As shown, in the carbide cutting tool 1 according to Embodiment 6, the cutting edge 121t is rounded, which differs from the carbide cutting tool 1 according to Embodiment 1, where the cutting edge 121t is pointed. The radius of curvature of the cutting edge 121t can be single, or multiple radii of curvature of the cutting edge 121t can exist to form a so-called composite R shape.

[0069] (Implementation Method 7)

[0070] Figure 7 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 7. (See attached image.) Figure 7 As shown, in the carbide cutting tool 1 according to Embodiment 7, in the first portion 121 near the cutting edge 121t, the outer surface 121s is convex, and in the second portion 122 away from the cutting edge 121t, the outer surface 122s is concave. A point 225 at a distance of 25 μm from the cutting edge 121t in the Z-axis direction exists in the first portion 121.

[0071] (Implementation Method 8)

[0072] Figure 8 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to embodiment 8. (See attached image.) Figure 8As shown, in the carbide cutting tool 1 according to embodiment 8, when the thickness of the cutting edge at the point 20Y (where Y is an integer from 26 to 100) from the cutting edge 121t toward the base 110Yμm is set as TY, and the thickness of the cutting edge 120 at the point 20Y1 (where Y is an integer from 26 to 100) from the cutting edge 121t toward the base 110Y+1μm is set as TY1, the second cutting edge thickness variation TY1-TY is 0.01μm or more and 1.85μm or less when Y is an integer from 26 to 100.

[0073] The thickness of the cutting edge 120 at point 226, which is 26 μm away from the cutting edge 121t in the Z-axis direction, is set as T11. The thickness of the cutting edge 120 at point 2100, which is 100 μm away from the cutting edge 121t in the Z-axis direction, is set as T12.

[0074] In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge 120 has an outwardly convex portion 120t in the range from the cutting edge 121t to 100μm. The convex portion 120t is located further outward than the straight line S connecting the cutting edge 121t and the position 100μm away from the cutting edge 121t.

[0075] (Implementation Method 9)

[0076] Figure 9 This is a longitudinal cross-sectional view of the carbide cutting tool 1 according to Embodiment 9. (See attached image.) Figure 9 As shown, in the carbide cutting tool 1 according to Embodiment 9, when the thickness of the cutting edge at the point 20Z (where Z is an integer from 101 to 3000) from the cutting edge 121t toward the base 110Zμm is set to TZ, and the thickness of the cutting edge 120 at the point 20Z1 (where Z is an integer from 101 to 3000) from the cutting edge 121t toward the base 110Z+1μm is set to TZ1, the third cutting edge thickness variation TZ1-TZ is 0.01μm or more and 1.85μm or less when Z is an integer from 101 to 3000.

[0077] The thickness of the cutting edge 120 at point 2101, which is 101 μm away from the cutting edge 121t in the Z-axis direction, is defined as T21. The thickness of the cutting edge 120 at point 2300, which is 3000 μm away from the cutting edge 121t in the Z-axis direction, is defined as T22.

[0078] In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge 120 within the range from the cutting edge 121t to 3000μm has an outwardly convex portion 120t, which is located further outward than the straight line S connecting the cutting edge 121t and the position 3000μm away from the cutting edge 121t.

[0079] (Example 1)

[0080] The characteristics of the carbide cutting tool 1 with a base 110 thickness of 100 μm, a width of 20 mm, and a length of 40 mm in the longitudinal direction of the blade were confirmed.

[0081] <Materials>

[0082] The sintered body used for the cutting tool is a cemented carbide with tungsten carbide and cobalt as the main components. The cobalt content used in the cemented carbide is 10% by mass. The hardness of the cemented carbide is 92 on the HRA (Rockwell hardness) scale.

[0083] <Grinding>

[0084] The sintered body was ground into a plate with a thickness of 100μm, a width of 20mm, and a length of 40mm using a diamond grinding machine, and used as a material for machining the front cutting edge.

[0085] <Forming a blade>

[0086] Next, the aforementioned material is used to form the front cutting edge. During this forming process, a special grinding machine using a diamond cylindrical grinding stone is used. The material is fixed on a special workpiece holder with an adjustable angle, and the material is processed. In the case of a two-section cutting edge, one side is processed relative to the long side of the material (40mm length), forming cutting edges with different front angles on both sides: a first cutting edge with the furthest front angle, and a second cutting edge connected to and continuous with the base 110.

[0087] <Convex Bending Outer Surface Shaping>

[0088] In order to form such Figure 1 The outer surface 121s shown is a convex curved surface, which is machined into a convex shape on both sides relative to the foremost end using a cylindrical grinding stone with a concave curved surface. In the formation of the convex shape, since it is a very precise machining process, the setting of grinding conditions such as the depth of cut and the workpiece holder angle is very important.

[0089] <Outer Surface Shaping of a Plane>

[0090] In order to form such Figure 3 The outer surface 121s of the plane shown is machined with a convex shape on both sides relative to the foremost end using a cylindrical grinding stone. Figure 2 In the case of such a three-stage blade, the third part 123 is set when the blade is formed.

[0091] <Concave-bend outer surface forming>

[0092] In order to form such Figure 4 The outer surface 122s shown is a concave curved surface, in which a cylindrical grinding stone with a convex curved surface is used to perform concave shape processing on both sides relative to the foremost end.

[0093] <Sectional Confirmation>

[0094] The cross-section was confirmed using a Schottky field emission scanning electron microscope JSM-7900F manufactured by NJE Inc. at 3000x magnification. The cutting edge thickness (thickness of the cutting edge 120) at distances of 3, 4, 5, 6, ..., 26 μm from the cutting edge was measured using mechanical coordinate and length measurement functions. The thickness variation was calculated based on this thickness. These results are shown in Tables 1 to 5.

[0095] [Table 1]

[0096]

[0097] [Table 2]

[0098]

[0099] [Table 3]

[0100]

[0101] [Table 4]

[0102]

[0103] [Table 5]

[0104]

[0105] In Table 1, "25μm angle [°]" refers to... Figure 1 In the longitudinal section shown, at point 225 on the outer surface 121s, which is 121t 25 μm away from the cutting edge in the Z-axis direction, a straight line 325 is drawn from the two outer surfaces 121s. The angle formed by the two straight lines 325 is the slope of the straight line 325, which is half the value of the change in cutting edge thickness at point 225. "3 μm angle [°]" refers to... Figure 1In the longitudinal section shown, at point 203 on the outer surface 121s, 3 μm from the cutting edge 121t along the Z-axis, draw straight lines from the two outer surfaces 121s. The angle between the two lines is the slope of the two lines, representing the change in cutting edge thickness at point 203. "N" in the "Outer Convex" column indicates that there is no convexity 120t on the outer surface 121s that protrudes further outward than line S. "Y" in the "Outer Convex" column indicates that there is a convexity 120t on the outer surface 121s that protrudes further outward than line S. "3 μm position" in "Cut-edge thickness change [μm]" refers to the value obtained by subtracting the cutting edge thickness at the position 3 μm from the cutting edge 121t from the cutting edge thickness at the position 4 μm from the cutting edge 121t. "25 μm position" refers to the value obtained by subtracting the cutting edge thickness at the position 25 μm from the cutting edge 121t from the cutting edge thickness at the position 26 μm from the cutting edge 121t. “Figure” indicates a figure corresponding to the shape of each specimen. “Maximum / Minimum” indicates the maximum and minimum values ​​of the change in cutting edge thickness at the outer surface 121s in the Z-axis direction within the range of 3 μm to 25 μm from the cutting edge.

[0106] <Cut-off Test>

[0107] In addition, to confirm the effectiveness of the carbide cutter made here, commercially available vinyl chloride sheets were extruded and cut. The quality of the cross-section cut, including deformation and defects, as well as the notches (later cracking) produced by the cutter, were observed, thus confirming the effectiveness of the carbide cutter. Figure 10 This is a perspective view of the apparatus used to illustrate the cutting test. Figure 11 It is along Figure 10 A cross-sectional view of the XI-XI line. (See figure) Figure 10 and Figure 11 As shown, the carbide cutting tool 1 is held in place by chucks 3001 and 3002.

[0108] The conditions of this test ( Figure 10 and Figure 11 )

[0109] Workpiece material: Polyvinyl chloride sheet, 0.5mm thick, 290mm wide, 30mm long

[0110] Test setup: A device consisting of a Kistler cutting dynamometer 9255 (cutting dynamometer 2003) mounted on a Machining Center V55 (stage 2004) manufactured by Makino Milling Machine Co., Ltd.

[0111] Workpiece assembly: starting from the bottom, a 10mm thick acrylic sheet 2002, a 1mm thick double-sided adhesive sheet 2001, and a vinyl chloride sheet 100 serving as the workpiece are stacked together.

[0112] Cutting conditions: Cutting speed 300mm / s, feed rate 0.55mm, longitudinal angle between workpiece and blade ±0.5°, workpiece and blade profile angle 90°±0.5°, number of cuts 100, cutting interval 2.5mm.

[0113] Confirmation items: Cracking (depth greater than 5μm and width greater than 10μm), profile quality (profile condition and roughness caused by cracking)

[0114] Tables 1 to 5 record the results of repeated cut tests for each specimen number.

[0115] Regarding cracking, the number of cracks (depth greater than 5μm and width greater than 10μm) is counted. If the number of cracks is 0 to 3, the evaluation is set to A; if it is 4 to 10, the evaluation is set to B; if it is 11 or more, the evaluation is set to C.

[0116] The evaluation of notch formation was performed by observing the cutting edge after the aforementioned cutting test. A measuring microscope was used in the notch measurement method. Specifically, a 50x eyepiece and a 20x objective lens were mounted on a measuring microscope (STM6-LM) manufactured by Olympus Corporation, and the cutter (XZ plane) was placed on a flat surface. Figure 12 This is a microscope image showing the notch of the cutting tool. Note that the measuring stage should be aligned with... Figure 12 The cutting edge 121t of the cutter is parallel. The focus is aligned with the cutting edge 121t, and the two ends of the cutting edge 121t located at the ends of the notch 121k are aligned with the reference line in the X-axis direction of the measuring instrument. The measured value of Y is set to "0" as the reference. Figure 12 The distance between the two points where the baseline in the X-axis direction intersects with the end of the notch 121k is taken as the width of the notch 121k. The lowest point of the notch 121k in the Y direction, as measured from the X-axis, is taken as the depth of the notch 121k. At this time, if either the width is greater than 10μm or the depth is greater than 5μm, it is defined as the cutting edge producing the notch 121k.

[0117] Regarding the cross-sectional condition caused by fracture, the evaluation was set as A in the case of no damage; B in the case of damage that is permissible (damage length less than 10 μm); and C in the case of damage that is unacceptable (damage length exceeding 10 μm). The length of the damage was determined by imaging at 3,000x using a Schottky field emission scanning electron microscope JSM-7900F manufactured by NJE.

[0118] Regarding surface roughness, if the surface roughness Sa (arithmetic mean height ISO 25178) of the profile is less than or equal to 0.05 μm, the evaluation is set to A; if the surface roughness Sa is greater than 0.05 μm but less than or equal to 0.15 μm, the evaluation is set to B; and if the surface roughness Sa exceeds 0.15 μm, the evaluation is set to C. The surface roughness Sa is measured using a non-contact surface roughness measuring device utilizing a white interferometer. Specifically, a non-contact three-dimensional roughness measuring device (Nexview (registered trademark)) manufactured by Zygo Corporation is used for measurement.

[0119] Regarding profile quality, if both the profile condition and profile roughness caused by fractures are rated A, the profile quality rating is set to A. If either the profile condition or profile roughness caused by fractures is rated C, the profile quality rating is set to C. All other ratings are set to B.

[0120] Regarding the overall evaluation, if both the fracture and profile quality are rated A, then the overall evaluation is set to A. If either the fracture or profile quality is rated C or cannot be manufactured, then the overall evaluation is set to C. All other evaluations are set to B.

[0121] As shown in Tables 1 to 5, it can be seen that when the thickness of the aforementioned cutting edge at the 3μm position is 0.26μm to 7.00μm, and the thickness variation from 3μm to 25μm is 0.08μm to 1.85μm, and a convex 120t is present, the overall evaluation is A or B.

[0122] Furthermore, it is known that if the thickness variation at the 3μm position (X=3μm) is between 0.26μm and 0.93μm, the overall evaluation is A, which is a better option.

[0123] (Example 2)

[0124] Manufactured Figure 1 , 2 Cutting tools in the shapes of 4 and 7 (sample numbers 97-100, 109-112, 121-124, 133-136) were manufactured. The foremost ends of these cutting tools, as well as those manufactured in Example 1 above, were further processed as follows to produce cutting tools. The cutting tools were fixed on a stationary table and machined using a diamond flat grinding stone with a grit size of #10000, so that the front end angle was perpendicular to the base 110. The cross-section verification method was the same as in Example 1. Thus, carbide cutting tools with sample numbers 89-92, 101-104, 113-116, 125-128, and 137-140 were manufactured.

[0125] Using the same material as in Example 1, a groove with a radius of 0.25 μm was machined on a grinding stone with a grit size of #10000, and this groove was used to perform R-machining on the foremost tip of the cutter. Alternatively, tiny diamond or tungsten carbide particles (recommended below 1 μm) were suspended in a liquid such as water, and R-machining was performed by adjusting the flow rate, injection angle, and time to allow the suspension to collide with the cutting edge. The profile verification method was the same as in Example 1. Thus, carbide cutters with sample numbers 93-96, 105-108, 117-120, 129-132, and 141-144 were fabricated. Details of these are shown in Tables 6 to 10.

[0126] [Table 6]

[0127]

[0128] [Table 7]

[0129]

[0130] [Table 8]

[0131]

[0132] [Table 9]

[0133]

[0134] [Table 10]

[0135]

[0136] The carbide cutting tools in Tables 6-10 were evaluated in the same manner as in Example 1. The results are shown in Tables 6-10.

[0137] In the "Figure" of Table 6, "3, 5" indicates that... Figure 3 Carbide cutting tool 1 Figure 5 That makes the cutting edge 121t flat. "1, 5", "2, 5", "4, 5", and "7, 5" similarly indicate that... Figure 1 , 2 Carbide cutting blades of grades 4 and 7, such as... Figure 5 That makes the cutting edge 121t flat.

[0138] "3,6" indicates that... Figure 3 Carbide cutting tool 1 Figure 6 That way, the cutting edge 121t will be rounded. "1, 6", "2, 6", "4, 6", and "7, 6" similarly indicate that... Figure 1 , 2 Carbide cutting blades of grades 4 and 7, such as... Figure 6That way, the cutting edge 121t is rounded. As can be seen in Tables 6 to 10, it exhibits the same tendency as in Tables 1 to 5.

[0139] (Example 3)

[0140] Manufactured Figure 8 Cutting tools of the shape (sample numbers 145-160) were manufactured. The thickness of the base 110 was set to 100 μm to 400 μm. Other material dimensions, cutting edge formation, and outer surface formation were as in Example 1. Similar to Example 2, the foremost end of these cutting tools was machined so that the tip angle was perpendicular to the base 110. The cross-section verification method was the same as in Example 1. Thus, carbide cutting tools of sample numbers 161-176 were manufactured. Furthermore, R-machining was performed on the foremost end, similar to Example 2. The cross-section verification method was the same as in Example 1. At this time, the magnification of the Schottky field emission scanning electron microscope could be set to a magnification that allows observation of the cross-section in one field of view. Alternatively, a microscope with length measurement function could be used instead. Thus, carbide cutting tools of sample numbers 177-192 were manufactured. Details of these are shown in Tables 11 to 13.

[0141]

[0142]

[0143]

[0144] The carbide cutting tools in Tables 11-13 were evaluated in the same manner as in Example 1. The results are shown in Tables 11-13.

[0145] As can be seen from Tables 11 to 13, the same trend as in Tables 1 to 6 is observed.

[0146] (Example 4)

[0147] Manufactured Figure 9 Cutting tools of the shape (sample numbers 193-208) were manufactured. The thickness of the base 110 was set to 100 μm to 6000 μm. Other material dimensions, edge formation, and outer surface formation were as per Example 1. Similar to Example 2, the foremost end of these cutting tools was machined so that the tip angle was perpendicular to the base 110. The cross-section verification method was the same as in Example 1. Thus, carbide cutting tools of sample numbers 209-224 were manufactured. Furthermore, R-machining was performed on the foremost end, similar to Example 2. The cross-section verification method was the same as in Example 3. Thus, carbide cutting tools of sample numbers 225-240 were manufactured. Details of these are as follows...

[0148] Tables 14 to 16 are shown.

[0149]

[0150]

[0151]

[0152] The carbide cutting tools listed in Tables 14-16 were evaluated in the same manner as in Example 1. The results are shown in Tables 14-16.

[0153] As can be seen from Tables 14 to 16, the same trend as in Tables 1 to 6 is observed.

[0154] It should be noted that in the "Figures" in Table 12, "8, 5" indicates that... Figure 8 Carbide cutting tool 1 Figure 5 That makes the cutting edge 121t flat. "9, 5" similarly indicates that... Figure 9 Carbide cutting tool 1 Figure 5 That makes the cutting edge 121t flat.

[0155] "8, 6" indicates that... Figure 8 Carbide cutting tool 1 Figure 6 That way, the cutting edge 121t will be rounded. "9, 6" similarly indicates that... Figure 9 Carbide cutting tool 1 Figure 6 That way, the cutting edge 121t will be rounded.

[0156] It should be understood that the embodiments and examples disclosed herein are exemplary in all respects and not restrictive. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0157] Explanation of symbols

[0158] 1 Carbide cutting tool, 100 vinyl chloride sheet, 110 base, 120 cutting edge, 120t convex, 121 first part, 121k notch, 121s, 122s, 123s outer surface, 121t cutting edge, 122 second part, 203, 225 points, 325 tangent, 2001 double-sided adhesive sheet, 2002 acrylic sheet, 2003 cutting power unit, 2004 stage, 3001, 3002 chuck.

Claims

1. A carbide cutting tool, comprising: base, and A cutting edge is provided on the extension line of the base and has a shape that thins towards the cutting edge at the foremost point. The thickness of the cutting edge at a position 3 μm from the cutting edge toward the base is 0.26 μm or more and 7.00 μm or less. When the thickness of the cutting edge at a position X μm from the cutting edge toward the base is defined as TX, and the thickness of the cutting edge at a position X+1 μm from the cutting edge toward the base is defined as TX1, and X is an integer from 3 to 25, the first cutting edge thickness variation TX1-TX is 0.08 μm or more and 1.85 μm or less when X is an integer from 3 to 25. In a longitudinal section orthogonal to the longitudinal direction of the cutting edge, the shape of the cutting edge has an outwardly convex portion within a range of 25 μm from the cutting edge toward the base, the convex portion being located further outward than the straight line connecting the cutting edge and the position from the cutting edge toward the base 25 μm.

2. The carbide cutting tool according to claim 1, wherein, When X is 3, the first blade thickness variation TX1-TX is 0.26μm or more and 0.93μm or less.

3. The carbide cutting tool according to claim 1 or 2, wherein, When the thickness of the cutting edge at a position Y μm from the cutting edge toward the base is defined as TY, and the thickness of the cutting edge at a position Y+1 μm from the cutting edge toward the base is defined as TY1, and Y is an integer from 26 to 100, the second cutting edge thickness variation TY1-TY is 0.01 μm or more and 1.85 μm or less when Y is an integer from 26 to 100.

4. The carbide cutting tool according to claim 1 or 2, wherein, When the thickness of the cutting edge at a position Z μm from the cutting edge toward the base is set as TZ, the thickness of the cutting edge at a position Z+1 μm from the cutting edge toward the base is set as TZ1, and Z is an integer from 101 to 3000, the third cutting edge thickness variation TZ1-TZ is 0.01 μm or more and 1.85 μm or less when Z is an integer from 101 to 3000.

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