Cutting blade of superhard alloy

Abstract

The outer surface of the blade portion is represented by the YZ plane, and the coordinates of a first point of the outer surface are set to (Y1, Z1 (= 1.00 μm)) and a = Z1 / (Y1) 2 The ratio of the defined constant a, and the coordinates of a second point of the outer surface are set to (Y2, Z2 (= 5.00 μm)) and b = Z2 / (Y2) 2 The ratio of the defined constant b is greater than or equal to 0.30 and less than or equal to 1.00, the Y-axis direction thickness T1 of the blade portion at Z1 is greater than or equal to 0.60 μm and less than or equal to 1.50 μm, when T1 is greater than or equal to 0.60 μm and less than or equal to 0.91 μm, 0.30 ≤ b / a ≤ 1.52T1-0.61, when T1 is greater than or equal to 0.91 μm and less than or equal to 1.06 μm, 0.64T1-0.28 ≤ b / a ≤ 1.52T1-0.61, and when T1 is greater than or equal to 1.06 μm and less than or equal to 1.50 μm, 0.64T1-0.28 ≤ b / a ≤ 1.00.

Description

Technical Field

[0001] This invention relates to a cutting blade made of superhard alloy. This application claims priority based on Japanese Patent Application No. 2020-105952, filed June 19, 2020. All descriptions in that Japanese patent application are incorporated herein by reference. Background Technology

[0002] Currently, cutting blades are 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] Patent Document 1: Japanese Patent Application Publication No. 10-217181

[0004] Patent Document 2: Japanese Patent Application Publication No. 2001-158016

[0005] Patent Document 3: International Publication No. 2014 / 050883

[0006] Patent Document 4: International Publication No. 2014 / 050884

[0007] Patent Document 5: Japanese Patent Application Publication No. 2017-42911

[0008] Patent Document 6: Japanese Patent Application Publication No. 2004-17444 Summary of the Invention

[0009] The superhard alloy cutting blade of the present invention comprises: a base; and a cutting edge disposed on the extension line of the base, having a cutting tip as the foremost tip, having a Vickers hardness HV greater than or equal to 1250 and less than or equal to 2030. In a longitudinal section orthogonal to the cutting edge transition direction, the cutting tip is set as the origin of the coordinate system, the direction from the cutting tip toward the base is set as the Z-axis direction, and the direction orthogonal to both the Z-axis direction and the cutting edge transition direction is set as the Y-axis direction. The outer surface of the cutting edge is represented by the YZ plane, and the coordinates of the first point on the outer surface are set as (Y1, Z1 (=1.00μm)) and a=Z1 / (Y1). 2 The constant 'a' is defined, and the coordinates of the second point on the outer surface are set to (Y2, Z2 (=5.00μm)), and b=Z2 / (Y2) is used. 2The ratio b / a of the defined constant b is greater than or equal to 0.30 and less than or equal to 1.00, and the Y-axis thickness T1 of the Z1 cutting edge is greater than or equal to 0.60 μm and less than or equal to 1.50 μm. When T1 is greater than or equal to 0.60 μm and less than or equal to 0.91 μm, 0.30 ≤ b / a ≤ 1.52T1 - 0.61; when T1 is greater than or equal to 0.91 μm and less than or equal to 1.06 μm, 0.64T1 - 0.28 ≤ b / a ≤ 1.52T1 - 0.61; when T1 is greater than or equal to 1.06 μm and less than or equal to 1.50 μm, 0.64T1 - 0.28 ≤ b / a ≤ 1.00. Attached Figure Description

[0010] Figure 1 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 1.

[0011] Figure 2 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 2.

[0012] Figure 3 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 3.

[0013] Figure 4 This is a perspective view of the apparatus used to illustrate the cutting test.

[0014] Figure 5 It is along Figure 4 A cross-sectional view of the VV line in the diagram.

[0015] Figure 6 This is a graph showing the relationship between the thickness T1 of the cutting edge 120 at a position 1.00 μm away from the cutting tip 121t (Z = Z1 = 1.00 μm) and b / a for each of the superhard alloy cutting blades 1 with sample numbers shown in Tables 1 to 3.

[0016] Figure 7 It is a microscopic photograph (microscope) showing the notch of the cutting edge. Detailed Implementation

[0017] [The problem this invention aims to solve]

[0018] If the cutting edge is too thin, the cutting tip cannot withstand the cutting impact and will produce debris. If the cutting edge is too thick, the cutting resistance is high, the profile quality is poor, and the profile becomes rough.

[0019] [Description of Embodiments of the Invention]

[0020] First, the embodiments of the present invention will be described.

[0021] (Implementation Method 1)

[0022] Figure 1 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 1. (See attached image.) Figure 1 As shown, the superhard alloy cutting blade 1 has a cutting tip 121t extending along the blade transition direction. Figure 1 It is a longitudinal section in a direction orthogonal to the cutting edge transition direction. For example... Figure 1 As shown, the flat-edged, superhard alloy cutting blade 1 has a base 110 and a cutting edge 120 as a cutting execution part. A connecting part may be provided between the base 110 and the cutting edge 120.

[0023] (Material)

[0024] The material used for the superhard alloy cutting blade 1 is a superhard alloy with tungsten carbide and cobalt as the main components. The cobalt content used in the superhard alloy is in the range of 3% to 25% by mass. Preferably, the cobalt content is in the range of 5% to 20% by mass. The composition of the elements constituting the superhard alloy is determined by ICP-based spectrophotometry and Co titration. In addition to tungsten carbide and cobalt as the main components, the superhard alloy of the present invention sometimes contains elements such as chromium, vanadium, tantalum, and niobium used to adjust properties such as grain size. The size of the tungsten carbide crystals in the superhard alloy is preferably 0.1 μm to 4 μm. More preferably, the crystal size is less than or equal to 2 μm.

[0025] Furthermore, preferably, the alloy contains TaC (tantalum carbide), a component used to suppress the grain growth of tungsten carbide in the superhard alloy, with a preferred content of 0.1 to 2% by mass. The additive used to suppress grain growth can be V8C7 (vanadium carbide) or Cr3C2 (chromium carbide). At least one of TaC, V8C7, and Cr3C2 can be substituted, or combinations thereof can be made. In this case, the content of each is 0.1 to 2% by mass.

[0026] The Vickers hardness (HV) of superhard alloys is greater than or equal to 1250 and less than or equal to 2030. Vickers hardness is measured using a Vickers hardness tester. When the Vickers hardness is less than 1250, the material's resistance to deformation decreases, making it difficult to meet the requirements for resistance to bending and perpendicular cutting in cutting. If the Vickers hardness exceeds 2030, even with a smooth microstructure and a smooth cutting edge, it still represents high hardness and is prone to notching. Furthermore, as a countermeasure against notching, not only the material itself but also the shape of the cutting edge is crucial.

[0027] (shape)

[0028] The shape of the superhard alloy cutting blade 1 is basically a rectangular plate. The shortest side of the plate is set as the thickness.

[0029] The superhard alloy cutting blade 1 has: a base 110; and a cutting edge 120, which is disposed on the extension line of the base 110 and has a shape that is thinned towards the cutting tip 121t, which is the foremost part.

[0030] Preferably, the thickness of the base 110 is constant. The base 110 has, for example, a thickness of 50 to 1000 μm, the required thickness varying depending on the size of the workpiece being cut. Furthermore, the cutting edge 120 is formed on an edge extending from the base 110. The dimension of the cutting edge 120 in the direction from the cutting edge 120 toward the base 110 (Z-axis direction) is expressed as the length or height of the cutting edge 120. The dimension in the direction perpendicular to the cutting transition direction and the length direction of the cutting edge 120 (Y-axis direction) is expressed as the thickness of the cutting edge 120.

[0031] In a longitudinal section orthogonal to the cutting edge transition direction, within a range of 5.00 μm from the cutting edge tip, the cutting edge 120 has an outwardly convex portion 120t, which is located further outward than the straight line S connecting the cutting edge 121t and a position at a distance Z2 (5.00 μm) in the longitudinal direction relative to the cutting edge 121t. The presence of the convex portion 120t increases the strength of the cutting edge 120 compared to a straight cutting edge without the convex portion 120t.

[0032] The outer surface 121s is curved. The angle between the two outer surfaces 121s, which are positioned opposite each other, increases as they approach the cutting tip 121t. In this embodiment, the outer surfaces 121s are symmetrical about the center line C. However, the outer surfaces 121s may also be asymmetrical about the center line C. The slope of the outer surfaces 121s differs at point 1201 at a distance Z1 relative to the cutting tip 121t and at point 1203 at a distance Z2 relative to the cutting tip 121t.

[0033] The cutting objects of the superhard alloy cutting blade 1 are, for example, ceramic raw sheets, metal foils, paper, fibers, or hard resins before firing, such as multilayer capacitors or multilayer inductors.

[0034] In extrusion-based cutting, the material to be cut is expanded while being extruded and cut. If the material to be cut is, for example, a green ceramic sheet, the high hardness of the blank increases the load on the cutting edge, making it prone to chipping.

[0035] like Figure 1As shown, a large load is applied to the tip of a superhard alloy cutting blade 1 that is lowered in the Z-axis direction for cutting. When the blade is thin and the angle between its two outer surfaces 121s is small (i.e., acute), nicks (also called chips) are easily formed. If nicks form, the sharpness naturally decreases, and scratches are easily created on the cut surface of the object being cut, thus extending its service life. In the case where the tip of the blade 121t has a very small acute angle, superhard alloys, which have high hardness and low toughness compared to other materials, exhibit excellent resistance to bending and wear, but are particularly prone to nicking.

[0036] To prevent notches on the cutting tip 121t, the inventors of this invention focused on a quadratic function passing through a specific point on the cutting edge 120. The longitudinal section was set as the YZ plane, and the cutting tip 121t was set as the origin (0, 0). The quadratic curve Z = aY passing through the origin and the first point (Y1, Z1 (=1.00μm)) was calculated. 2 The constant 'a'. When the shape of the cutting edge 120 is symmetrical about the center line C (the Z-axis passing through the origin), let Y1 = T1 / 2. When the shape of the cutting edge 120 is asymmetrical about the center line C, the points on the shape of the cutting edge 120 are (Y11, Z1) and (Y12, Z1). Compare Y11 and Y12, and let the one with the larger absolute value be Y1.

[0037] Find the quadratic curve Z = bY passing through the origin and the second point (Y2, Z2 (=5.00μm)). 2 The constant b. When the shape of the cutting edge 120 is symmetrical about the center line C, let Y2 = T2 / 2. When the shape of the cutting edge 120 is asymmetrical about the center line C, the points on the shape of the cutting edge 120 are (Y21, Z2) and (Y22, Z2). Compare Y21 and Y22, and let the one with the larger absolute value be Y2. Using a = Z1 / (Y1) 2 And b = Z² / (Y²) 2 Then find a and b.

[0038] Here, the value of b / a is greater than or equal to 0.30 and less than or equal to 1.00. When b / a is less than 0.30, the tip angle θ obtained from the two cutting surfaces is larger, increasing the cutting resistance and the compressive spreading force during cutting, posing a risk of cracking in the cut material. When b / a exceeds 1.00, the tip is relatively flat, indicating a smaller tip angle θ obtained from the two cutting surfaces, reducing the sharpness of the tip. Additionally, the impact during cutting is greater at the tip, posing a risk of nicking. The thickness T1 of the Z1 cutting edge is greater than or equal to 0.60 μm and less than or equal to 1.50 μm. If T1 is less than 0.60 μm, there is a risk of thinning of the cutting edge, making it prone to nicking. If T1 exceeds 1.50 μm, the cutting edge becomes too thick, increasing the cutting resistance.

[0039] When T1 is greater than or equal to 0.60 μm and less than or equal to 0.91 μm, 0.30 ≤ b / a ≤ 1.52T1 - 0.61; when T1 is greater than or equal to 0.91 μm and less than or equal to 1.06 μm, 0.64T1 - 0.28 ≤ b / a ≤ 1.52T1 - 0.61; and when T1 is greater than or equal to 1.06 μm and less than or equal to 1.50 μm, 0.64T1 - 0.28 ≤ b / a ≤ 1.00. If the T1 falls outside these ranges, problems arise such as reduced cutting tip strength leading to a tendency for notches to form at the cutting tip, or increased cutting resistance resulting in a rougher cut surface.

[0040] Throughout the entire range of Y from 0 to Y2, the outer surface 121s of the cutting edge 120 is located further outward than the straight line s connecting the origin and the point (Y2, Z2).

[0041] This invention relates to a flat-blade cutting edge primarily used for extrusion cutting of ceramic green sheets (hereinafter also referred to as green sheets) and other objects to be cut, such as multilayer ceramic capacitors. By setting b / a and T1 within the aforementioned ranges, high-precision cutting can be achieved, damage to the object being cut can be suppressed, and the shape of the object being cut can be stabilized. In addition, effects such as extending the life of the cutting edge can be obtained.

[0042] Here, the superhard alloy cutting blade has the following shape: a base (also called a shank) with parallel surfaces, which serves as the cutting actuation part, i.e., the blade tip, and is fixed to the cutting device. More specifically, it requires good sharpness, wear resistance, resistance to welding of the object being cut, strength against bending, and a long service life.

[0043] Regarding sharpness, the shape of the blade tip is particularly important, taking into account the damage to the workpiece being cut. A thin blade with a small (acute) angle at the tip is preferable. However, it's unavoidable that a thinner blade will have lower strength. Therefore, current cutting blades are designed with one or more levels of angle between the blade tip and the base, thereby increasing the angle of the very tip.

[0044] Such thin-bladed blades, for example, use hard materials such as superhard alloys in addition to high-carbon steel. However, they are not easy to machine, especially when the material is hard, as it is rigid but difficult to cut and has low toughness, making it prone to chipping. In addition, chips are also easily formed during product use.

[0045] Currently, various cutting edge designs have been proposed to meet the above characteristics, but no detailed insights have been offered regarding materials that are difficult to notch and the shape of the blade tip.

[0046] Furthermore, preferably, the shape is curved in the longitudinal section such that the width of the cutting edge decreases as it approaches the tip. The curved shape can have a single radius of curvature or a so-called composite R (radian) shape with multiple radii of curvature.

[0047] By shaping the profile into a curved shape in the longitudinal section such that the width of the cutting edge decreases as it approaches the tip, notches at stress concentration points can be suppressed most effectively.

[0048] The present invention optimizes the combination of the aforementioned material and the shape of the foremost end, i.e. the blade thickness, which are factors that affect the notch, and finds that a notch is easily generated by satisfying all of the above conditions.

[0049] Furthermore, regarding nick resistance, a sharp cutting tip 121t provides good sharpness, but carries the risk of nicking. To further reduce this risk, a curved surface at the tip of the cutting edge 120 is more effective. Obviously, the cutting tip 121t wears down with continuous cutting, and it is more preferable to satisfy the aforementioned ranges of b / a and T1 and have a curved surface.

[0050] The cutting edge 120, which is the cutting actuator formed in the direction of the base 110, can achieve the same effect whether it has one or multiple cutting edges. In addition, if the shape of its longitudinal section is composed of straight lines, the same effect can be achieved even if it has curves in a part.

[0051] The method for machining the cutting edge 120 to obtain the aforementioned shape is performed, for example, by grinding with an abrasive, similar to the current method. Alternatively, sandblasting can be used as a method for forming a micro-curved surface. Furthermore, it is possible to form a micro-curved surface by cutting with a material softer than the object being cut, such as the viscosity of the abrasive dispersion.

[0052] For example, a cutting blade 1 made of superhard alloy is used to cut a solid material mixed with hard abrasive powder, thereby enabling the blade 120 to come into contact with the hard material in the solid material mixed with hard abrasive powder and to process it, thus forming the blade 120.

[0053] Here, as a solid material incorporating a hard abrasive, clay-based materials can be cited as an example. Additionally, as hard materials, powders of diamond, W, Mo, WC, Al2O3, TiO2, TiC, TiCN, SiC, Si3N4, BN, etc., can be cited as examples.

[0054] Regarding the powder particle size of the aforementioned hard material, preferably, in terms of Fsss (Fisher Sub-Sieve Sizer) particle size, the average particle size of the secondary particles is less than or equal to 1 μm. In particular, as a finishing process, the type and size of the hard material particles, the amount added to the solid, and the processing time can be adjusted. Furthermore, the manufacturing method of the superhard alloy cutting blade 1 is not limited to the method described above.

[0055] (Implementation Method 2)

[0056] Figure 2 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 2. (See attached image.) Figure 2 As shown, regarding the superhard alloy cutting blade 1 involved in Embodiment 2, the second part 122 exists in the portion that is more than Z2 (5.00 μm) away from the blade tip 121t.

[0057] (Implementation Method 3)

[0058] Figure 3 This is a longitudinal cross-sectional view of the superhard alloy cutting blade 1 involved in Embodiment 3. (See attached image.) Figure 3 As shown, there is a point near height Z1 where the slope of the outer surface 121s changes discontinuously, which is different from the superhard alloy cutting blade 1 involved in Embodiment 1.

[0059] [Details of embodiments of the present invention]

[0060] (Example 1)

[0061] Figure 4 This is a perspective view of the apparatus used to illustrate the cutting test. Figure 5 It is along Figure 4A cross-sectional view of the VV line is shown. The superhard alloy cutting edge 1 (flat-edged cutting edge) used in the experiment was set to 40 mm in the edge transition direction (X-axis direction), 0.1 mm in the base thickness (Y-axis direction), 22.0 mm in the edge height (Z-axis direction), and 2.0 mm in the edge machining height of the cutting actuator (Z-axis height of edge 120) was set to 2.0 mm. Regarding the material, tungsten carbide and cobalt were used as the basic components. The particle size of tungsten carbide was adjusted by using metallic carbides such as chromium carbide, vanadium carbide, and tantalum carbide as additives, and the amount of cobalt added was also adjusted to obtain a sintered superhard alloy. As an example, a superhard alloy material with a Vickers hardness of 1580 was used. The particle size of tungsten carbide and the amount of cobalt added were adjusted to change the hardness.

[0062] <Grinding>

[0063] The sintered body is ground into a plate shape with a thickness of 100μm, a blade height of 22mm, and a length of 40mm using a diamond grinding machine to form a blank for machining the front cutting edge.

[0064] <The Formation of the Blade>

[0065] Next, the aforementioned blank is used to form the front cutting edge. During this forming process, the blank is fixed to a dedicated workpiece holder with adjustable angle using a specialized grinding machine employing diamond cylindrical grinding tools. When the cutting edge has two sections, the cutting edge 120 is formed having the following components: a first section 121, which has one edge at its foremost point in a direction with a length of 40 mm relative to the long side of the blank and a forehead angle; and a second section 122, which is continuously arranged relative to the first section 121 and continuous relative to the base 110.

[0066] <Surface Molding of Planes>

[0067] In order to form Figure 2 The outer surface 122s of the plane shown is convex in shape on both sides of the foremost end using a cylindrical grinding tool.

[0068] <Convex Bending Outer Surface Molding>

[0069] In order to form Figure 1 The outer surface 121s, shown as a convex curved surface, is formed by stamping tungsten carbide and cobalt using a binder such as paraffin wax to create a block shape with a length of 50 mm, a width of 50 mm, and a height of 30 mm. The cutting tip is then continuously pressed against this block at high speed to form a convex shape. The size of the convex portion is adjusted according to the pressing speed, angle, and depth. Since the convex shape is formed with extremely high precision, the precise setting of grinding conditions, such as the tungsten carbide particles used as the cutting medium, the pressing speed, and the depth, is crucial.

[0070] The arithmetic mean roughness Sa (arithmetic mean height ISO 25178) of the outer surfaces 121s and 122s was set to be less than or equal to 0.02 μm. The arithmetic mean roughness Sa of the outer surfaces 121s and 122s was measured using a non-contact surface roughness measuring device employing a white interferometer. Specifically, a non-contact three-dimensional roughness measuring device (Nexview (registered trademark)) manufactured by Zygo Corporation was used, with the measurement range in the aforementioned longitudinal section set to 0.15 mm in the X direction and 0.05 mm in the Z direction. Regarding the measurement field of view, the magnification of the zoom lens was set to 2x, and the magnification of the objective lens was set to 50x.

[0071] <Sectional Confirmation>

[0072] Regarding the confirmation of the cross-section, images were taken at 10,000x magnification using a Schottky electric field release scanning electron microscope (JSM-7900F, Nippon Electronics Co., Ltd.). The thickness of the cutting edge (thickness of the cutting edge 120) at distances of 1.00 μm and 5.00 μm from the tip 121t was measured using mechanical coordinates and length measurement functions. The Vickers hardness was measured using a Picodentor HM500 (Fisher Instrument Men's Co., Ltd.). The results are shown in Tables 1 to 3.

[0073] [Table 1]

[0074]

[0075] [Table 2]

[0076]

[0077] [Table 3]

[0078]

[0079] The “Hardness HV” in Tables 1 to 3 refers to the Vickers hardness of the superhard alloy cutting blade 1.

[0080] “T1(μm)” refers to the thickness of the cutting edge 120 in the Y-axis direction at a position 1.00μm away from the cutting tip 121t in the Z-axis direction (Z=Z1). “T2(μm)” refers to the thickness of the cutting edge 120 in the Y-axis direction at a position 5.00μm away from the cutting tip 121t in the Z-axis direction (Z=Z2).

[0081] "Constant a" refers to the value of a = Z1 / (Y1) when the coordinates of the first point on the outer surface are set to (Y1, Z1 (=1.00μm)). 2The defined constant is "b", which refers to the value of the second point on the outer surface with coordinates (Y2, Z2 (=5.00μm)) expressed as b=Z2 / (Y2). 2 The defined constant is "b / a", which refers to the value obtained by dividing constant a by constant b. "Graph" represents a diagram corresponding to the shape of each sample. For all samples, a protrusion 120t was confirmed to exist between the origin and point 1203, located further outward than line S. Furthermore, it was confirmed that all outer surfaces 121s between the origin and point 1203 are located further outward than line S.

[0082] Figure 6 This is a graph showing the relationship between the thickness T1 of the cutting edge 120 at a position 1.00 μm away from the cutting tip 121t (Z = Z1 = 1.00 μm) and b / a for each of the superhard alloy cutting blades 1 with sample numbers shown in Tables 1 to 3. The "coordinate position" in each table indicates... Figure 6 The coordinates of each sample in the diagram.

[0083] For the cutting evaluation test, focusing on uniform composition and hardness, the cutting object was a commonly available PVC sheet. It was fixed using an adhesive sheet with a thickness greater than or equal to 0.1 mm and less than or equal to 3.0 mm. Furthermore, the adhesive sheet served to prevent the foremost tip of the cutting edge from contacting the worktable supporting the cutting object during extrusion cutting, thus preventing the formation of a notch. The cutting object had a width of 30 mm in the X-axis direction and a thickness of 0.5 mm in the Z-axis direction. The cutting speed was set to 300 mm / s in the Z-axis direction.

[0084] The conditions of this test ( Figure 4 and Figure 5 )

[0085] Workpiece material: Polyvinyl chloride sheet, 0.5mm thick, 290mm wide, 30mm long, Vickers hardness (HV) 15.

[0086] Test setup: A cutting power meter 9255 (cutting power meter 2003) manufactured by Kisler was mounted on a machining center V55 (platform 2004) manufactured by Makino Frees Manufacturing Co., Ltd.

[0087] Workpiece installation: From bottom to top, there are 10mm thick acrylic sheet 2002, 1mm thick double-sided adhesive sheet 2001, and PVC sheet 100 as the workpiece.

[0088] Cutting conditions: cutting speed 300 mm / s, indentation 0.55 mm, cutting edge angle relative to the workpiece along the long side ±0.5°, cutting edge profile angle relative to the workpiece 90°±0.5°, number of cuts 100 (2.5 mm intervals).

[0089] exist Figure 4 and Figure 5 In the apparatus shown, chucks 3001 and 3002 hold the superhard alloy cutting blade 1. The superhard alloy cutting blade 1 descends at a speed of 30 mm / s to perform continuous cutting. Here, in order to perform continuous cutting, the cutting is done in a manner that avoids cutting at the same position on the polyvinyl chloride sheet 100, which is the object being cut, so that the cutting position can be moved each time the superhard alloy cutting blade 1 rises.

[0090] The condition of the cutting tip after 100 cuts was evaluated based on the number of notches generated along the entire cutting transition direction. The notch count was defined as either a notch with a width greater than or equal to 10 μm or a depth exceeding 3 μm in the edge portion of the cutting tip. Figure 7 The count was performed.

[0091] Figure 7 This is a microscopic photograph (microscope) showing the notch of the cutting edge. In the notch measurement method, the entire surface of the 40mm edge transition surface after 100 pressing cuts was observed at 1000x magnification using a measuring microscope. Specifically, a 50x eyepiece and a 20x objective lens were mounted on an "Olinpass" measuring microscope (STM6-LM), and the cutting edge (XZ plane) was placed on a flat surface. Note Figure 7 The cutting edge tip 121t is parallel to the measuring stage. Align the focal point with the cutting edge tip 121t, and align the cutting edges 121t at both ends of the notch 121k with the reference line in the X-axis direction of the measuring instrument. Set the measured value of Y to "0" and use it as the reference. Figure 7 The distance between the two points where the baseline in the X-axis direction intersects with the end of the notch 121k is defined as the width of the notch 121k. The depth of the notch 121k is defined as the lowest point in the Y-direction of the notch 121k, measured from the X-axis. At this time, a notch 121k is defined as having been generated at the tip of the cutting edge if the width is greater than or equal to 10 μm and the depth is greater than or equal to 3 μm.

[0092] The blade tip with 5 or fewer notches is rated "A", the blade tip with 6 to 20 notches is rated "B", and the blade tip with more than 20 notches is rated "C".

[0093] Regarding the condition of the cut surface, in the evaluation of the cut surface, for the 100th cut, the cut surface was magnified at 50x and photographed. The number of scratches with a length greater than or equal to 30μm in the cutting direction was counted. The evaluation was set with 3 levels: less than or equal to 10 scratches was rated "A", greater than or equal to 11 but less than or equal to 20 scratches was rated "B", and more than 20 scratches was rated "C".

[0094] Figure 6 The results of the cutting evaluation are shown. The horizontal axis shows T1 from Tables 1 to 3, and the vertical axis shows b / a. Specifically, the range enclosed by the solid pentagonal lines is as follows: 0.30 ≤ b / a ≤ 1.52T1 - 0.61 when T1 is greater than or equal to 0.60 μm and less than or equal to 0.91 μm; 0.64T1 - 0.28 ≤ b / a ≤ 1.52T1 - 0.61 when T1 is greater than or equal to 0.91 μm and less than 1.06 μm; and 0.64T1 - 0.28 ≤ b / a ≤ 1.00 when T1 is greater than or equal to 1.06 μm and less than 1.50 μm. These ranges are those that achieve the above-mentioned effects. It can be seen that within this range, the "state of the notch at the cutting tip" and "cutting surface characteristics" in Tables 1 to 3 can obtain a result of "A".

[0095] The embodiments and examples disclosed herein are illustrative in all respects and should be understood as not imposing limitations. The scope of the invention is not defined by the foregoing description but by the claims, and is intended to include the equivalent scope of the claims and all modifications within that scope.

[0096] Explanation of the label

[0097] 1. Superhard alloy cutting blade, 100 PVC sheet, 110 base, 120 cutting edge, 120t protrusion, 121 first part, 121k notch, 121s, 122s outer surface, 121t cutting tip, 122 second part, 2001 double-sided adhesive sheet, 2002 acrylic sheet, 2003 cutting power meter, 2004 stage, 3001, 3002 chuck.

Claims

1. A cutting blade made of superhard alloy, wherein, The superhard alloy cutting blade has the following characteristics: Base; as well as The cutting edge, which is located on the extension line of the base, has a cutting tip as its foremost point. Vickers hardness HV is greater than or equal to 1250 and less than or equal to 2030. In a longitudinal section orthogonal to the cutting edge transition direction, the cutting edge is set as the origin, the direction from the cutting edge towards the base is set as the Z-axis, and the direction orthogonal to both the Z-axis and the cutting edge transition direction is set as the Y-axis. The outer surface of the cutting edge is represented by the YZ plane, and the coordinates of the first point on the outer surface are set as (Y1, Z1 (=1.00μm)), and a=Z1 / (Y1) 2 The constant 'a' is defined, and the coordinates of the second point on the outer surface are set to (Y2, Z2 (=5.00μm)), and b=Z2 / (Y2) is derived from this. 2 The ratio b / a of the defined constant b is greater than or equal to 0.30 and less than or equal to 1.

00. The thickness T1 of the cutting edge at Z1 in the Y-axis direction is greater than or equal to 0.60 μm and less than or equal to 1.50 μm. When T1 is greater than or equal to 0.60 μm and less than or equal to 0.91 μm, 0.30 ≤ b / a ≤ 1.52T1 - 0.

61. When T1 is greater than or equal to 0.91 μm and less than or equal to 1.06 μm, 0.64T1-0.28≤b / a≤1.52T1-0.61, When T1 is greater than or equal to 1.06 μm and less than or equal to 1.50 μm, 0.64T1-0.28≤b / a≤1.

00.

2. The superhard alloy cutting blade according to claim 1, wherein, Throughout the range of Y from 0 to Y2, the outer surface of the cutting edge is located further outward than the straight line connecting the origin of the coordinate system to the point (Y2, Z2).

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