bladed weapons

Abstract

To provide a cutting tool capable of meeting various requirements for various workpieces. [Solution] The cutting tool 100 includes a flat plate-shaped base and a cutting edge portion formed at an end of the base. The cutting edge portion has a cutting edge with an arc cross-section and a tip portion of up to 3 µm extending from the extreme end of the cutting edge in a direction parallel to the base. When the extreme end of the cutting edge is taken as an origin, a line parallel to the base is defined as the Y-axis, and a line orthogonal to the Y-axis is defined as the X-axis, the cross-sectional shape of the tip portion is formed by a curved line or a straight line connected to the end of the cutting edge. The arc radius is 2 nm or more and 1000 nm or less. In the range of X>0 [unit: µm] and 0<Y≦3 [unit: µm], when X1 is the X coordinate of the contact point between the arc and the curved line on the X-axis, X2 is the X coordinate of the curved line at Y=3, G1 is the slope of the tangent to the curved line at X1, and G2 is the slope of the tangent to the curved line at X2, 0.18≦G2≦5.67 0.24≦G1 / G2≦0.82 is satisfied.

Description

[Technical Field]

[0001] The present invention relates to a cutting tool. [Background Art]

[0002] Industrial precision cutting tools are used in cutting processes and cutting scenes in various industries. Workpieces to be cut vary widely, including resin films used in industrial products, high-performance composite films used for smartphone panels and the like, industrial rubber, food packages, and cells embedded in resin for pathological examinations. Furthermore, the required cutting quality (cutting performance) also differs depending on the workpiece and other factors, and there are various requirements: some require no streaks or burrs on the cut surface, some avoid bending of the cutting tool during cutting that causes oblique cutting, and others require thin and uniform slicing.

[0003] In general, for the physical properties of a workpiece and the required cutting quality, an optimal cutting tool can be provided by adjusting cutting tool specifications such as shape. Here, the following patent documents are available as documents describing an invention related to cutting tool shape. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent No. 7292487 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, although Patent Document 1 describes a cutting edge shape, it specifies the thickness of the blade portion at a position 3 µm or more from the cutting edge toward the base, and does not describe an extremely fine portion of the cutting edge (a range of about 2 µm to 3 µm from the tip).

[0006] The applicant has discovered, through SEM (Scanning Electron Microscope) image analysis of the cutting edge of the blade when cutting various workpieces, that the shape from the cutting edge to 3 μm significantly affects the cutting quality. In particular, the applicant found that the shape of the arc portion of the cutting edge and the curved or straight line portion (from the cutting edge to 3 μm) that connects to the arc and extends to the base are important.

[0007] The curved portion of the cutting edge has the greatest impact on the sharpness of the blade. Furthermore, the curved or straight shape extending from the curved edge to the base (up to about 3 μm from the cutting edge) is the part that separates the workpiece after it has been fractured by the cutting edge. Strong loads are applied both in the direction of the cutting edge's movement and perpendicular to it, resulting in significant friction with the workpiece. Therefore, the radius that determines the shape of the curved portion of the cutting edge, and the shape of the curved or straight shape extending from the curved edge to the base, are factors that greatly affect the cutting quality and durability of the workpiece. On the other hand, there are many different types of workpieces to be cut, varying in size, strength (soft / hard), and surface treatment, and the required cutting quality and durability differ for each. In short, depending on the type of workpiece and its intended use, the requirements for prioritizing cutting quality, durability, or a good balance of both will differ, so it is necessary to design and manufacture blades that meet these specific requirements.

[0008] In light of these facts, the applicant, through diligent research, has discovered that cutting tools can be designed and manufactured to meet various requirements for various workpieces by specifying the shape from the cutting edge down to 3 μm. Therefore, the present invention aims to provide a cutting tool in which the shape from the cutting edge down to 3 μm is specified, and which can meet various requirements for various workpieces. [Means for solving the problem]

[0009] When cutting composite films or high-performance films used in touch panels, or when performing half-cuts, or when microtome sectioning cells embedded in paraffin, the sharpness and long lifespan of the cutting tool are particularly important. As a result of diligent research, the inventors have found that because these workpieces are relatively soft, such as resins, it is desirable to set a small radius at the tip of the cutting edge to ensure sharpness, and to make the cross-sectional shape of the tip of the cutting edge a gently bulging curve to ensure lifespan, leading to the present invention.

[0010] The blade according to the present invention is It has a flat base and a cutting blade formed at the end of the base, The blade portion has a cutting edge and a tip portion extending 3 μm from the very tip of the cutting edge in a direction parallel to the base, The cross-sectional shape of the cutting edge is a circular arc with a radius of 2 nm or more and 1000 nm or less. When the tip of the cutting edge is defined as the origin, the line passing through the origin and parallel to the base is defined as the Y-axis, and the line passing through the origin and perpendicular to the Y-axis is defined as the X-axis, The cross-sectional shape of the tip portion is, In the range X>0, a first curve is formed by the function Y=F(X) that connects to the end of the cutting edge, where X1 is the X-coordinate of the point of tangency between the circular arc and the first curve on the X-axis, X2 is the X-coordinate of the first curve at Y=3, G1 is the slope of the tangent to the first curve at X1, and G2 is the slope of the tangent to the first curve at X2. 0.18 ≤ G2 ≤ ​​5.67 0.24 ≤ G1 / G2 ≤ 0.82 This is the first curve, In the range X<0, a straight line connecting to the end of the cutting edge, or a second curve formed by the function Y=F^(X), where X1' is the X-coordinate of the point of tangency between the circular arc and the second curve on the X-axis, X2' is the X-coordinate of the second curve at Y=3, G1' is the slope of the tangent line to the second curve at X1', and G2' is the slope of the tangent line to the second curve at X2', -5.67≦G2'≦-0.18 0.24≦G1′ / G2′≦0.82 which is a second curve.

Effects of the Invention

[0011] According to the cutting tool of the present invention, when the object to be cut is a relatively soft material such as resin and cutting quality and durability are particularly emphasized, sharpness can be maintained for a long time, and both cutting quality and durability can be achieved.

Brief Description of Drawings

[0012] [Figure 1] FIG. 1 is a diagram showing an example of use of a cutting tool according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view for explaining the shape 3 µm from the cutting edge of the cutting tool according to the embodiment of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view for explaining the shape 3 µm from the cutting edge of the cutting tool according to the embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of a cutting edge portion of the cutting tool according to the embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view of the cutting tool according to the embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view of a cutting tool according to another embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view of a cutting tool according to still another embodiment of the present invention. [Figure 8] FIG. 8 is a schematic diagram of a cutting tool used for evaluation.

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described in detail. The following description of each constitutional requirement is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to the following content unless the gist thereof is changed.

[0014] [Cutting tool] When the workpiece is a resin film or cells embedded in resin, and both sharpness and lifespan of the cutting tool are required, it is desirable to set the tip radius of the cutting edge small to ensure sharpness, and to make the cross-sectional shape of the tip of the cutting edge a gently bulging curve to ensure lifespan. While various materials such as stainless steel, high-speed steel, ceramic, diamond, and cemented carbide are used for cutting tools, cemented carbide is preferable for achieving both cutting performance and durability. For cemented carbide used in cutting tools, in the case of WC-Co type, the particle size of WC is preferably 0.1 μm to 2.5 μm, and the Co content is preferably 6% to 24%. If chipping is to be reduced and wear resistance is to be ensured, the particle size of WC is preferably 0.1 μm to 0.7 μm, and the Co content is preferably 6% to 14%.

[0015] Specifically, the present invention aims to provide a cutting tool that has an optimal cutting edge radius and curve at the cutting edge, depending on the physical properties of the workpiece, the required cutting quality, and durability.

[0016] First, Figure 1 shows an example of the use of a blade according to an embodiment of the present invention. Figures 2 and 3 are schematic cross-sectional views of the blade as seen from the direction of the arrow in Figure 1, illustrating the shape of the blade 3 μm from the cutting edge according to an embodiment of the present invention. In this embodiment, the blade is a straight blade, and an example of its use in cutting by pressing is shown. However, the shape of the blade according to the present invention is not limited to a straight blade; it may be a disc-shaped round blade, a cylindrical round blade, a Goebel blade, a blade mold, etc. Furthermore, the blade according to the present invention can be used not only for pressing but also for cutting methods such as aerial cutting, shearing, upper and lower blade cutting, score cutting, slicing, etc., and of course, it may be other than those exemplified, and there are no limitations on the cutting method.

[0017] As shown in Figure 1, the cutting tool 100 according to this embodiment has a flat base portion 10 and a cutting portion 20 formed at the end of the base portion 10. With the base portion 10 mounted on the mounting portion 30, the cutting portion 20 performs the cutting process on the workpiece 50.

[0018] Further, the blade portion 20 has a cutting edge 21 and a tip portion 22. In the present description, the tip portion 22 refers to a portion of the blade portion 20 extending from the tipmost end of the cutting edge 21 up to 3 µm in a direction parallel to the base (Y-axis direction) (see the cutting tool 110 shown in FIG. 5).

[0019] Note that, as shown in FIG. 2, the cross-sectional shape of the cutting edge 21 is an arc (formed by an arc). On the other hand, the cross-sectional shape of the tip portion 22 is formed by a curved line or a straight line connected to the cutting edge 21. In the example shown in FIG. 2, it is formed by a curved line. Further, the arc and the curved line (or the straight line) are connected at an arbitrary point, and hereinafter the point where the arc and the curved line are connected is referred to as the "contact point". This is clearly illustrated in FIGS. 3(A) and 3(B), and as shown in FIG. 3(B), the cross-sectional shape from the cutting edge 21 of the blade portion 20 up to 3 µm is formed by the arc (cutting edge 21) and the curved line (tip portion 22) connected to the arc at the contact point. Note that, as shown in FIG. 2, the tipmost end of the cutting edge 21 is taken as the origin, a line passing through the origin and parallel to the base 10 is taken as the Y axis, and a line passing through the origin and orthogonal to the Y axis is taken as the X axis. Hereinafter, the configuration of the blade portion 20 will be described using these.

[0020] First, the radius r of the arc of the cutting edge 21 is 2 nm or more and 1000 nm or less (see FIG. 2). Note that, for ease of explanation in FIG. 2, instead of the arc, a circle centered at X = 0 and Y = r is described. Next, the tip portion 22 is formed by a curved line connected to the cutting edge 21 at the contact point, and when the tipmost end of the cutting edge 21 is taken as the origin (X = 0, Y = 0), the curved line (first curved line) in the range of X > 0 [unit: µm] is 0 < Y ≦ 3 [unit: µm] formed by the function (Y = F(X)) represented in this range. Further, as shown in FIG. 2, when the X coordinate of the contact point between the arc and the curved line on the X axis is X1, the X coordinate of the curved line at Y = 3 is X2, the slope of the tangent line L1 to the curved line at X1 is G1, and the slope of the tangent line L2 to the curved line at X2 is G2, 0.18 ≦ G2 ≦ 5.67 0.24 ≦ G1 / G2 ≦ 0.82 these conditions are satisfied.

[0021] On the other hand, the curve (the second curve) in the range where X<0 [unit: μm] is 0<Y≦3 [unit: μm] formed by a function (Y=F^(X)) represented in the above range. Further, for said curve, assuming that on the X-axis, the X coordinate of the contact point between the arc and the curve is X1', the X coordinate of the curve at Y=3 is X2', the slope of the tangent line L1' to the curve at X1' is G1', and the slope of the tangent line L2' to the curve at X2' is G2', -5.67≦G2’≦-0.18 0.24≦G1’ / G2’≦0.82 satisfies the above conditions.

[0022] Note that in the case of a symmetric blade where the curves of the tip portion 22 (the first curve and the second curve) are symmetrical with respect to the Y-axis, G1’=-G1 G2’=-G2 holds true. That is, the tip portion 22 is obtained by inverting the curve formed under the aforementioned conditions with the Y-axis as the axis of symmetry in the range where X>0. However, it does not matter whether the portion of the tip portion 22 formed by the curve in the range X>0 and the portion formed by the curve in the range X<0 have the same shape or not. In short, as shown in Figs. 4(A) to (C), the curve forming the tip portion 22 may be bilaterally symmetrical with the Y-axis as the axis of symmetry, or may be asymmetrical. Further, the cutting quality may differ on both sides of the blade. That is, when viewed from the direction of the arrow in Fig. 1, the cutting quality of the workpiece 50 may differ between the right side and the left side of the blade. This occurs when, for example, friction between the blade and the workpiece during cutting differs between the left and right sides of the blade depending on the conditions of the object to be cut, cutting conditions, and the like. In this case, the tip shape is adjusted to be optimal for the left side and the right side of the blade respectively, resulting in an asymmetrical tip shape. Furthermore, straight lines in the range X < 0 [unit: μm] may be parallel to the axis of symmetry of the cross-sectional shape. This is a so-called single-edged cutter, and since the cutting surface parallel to the direction of blade movement does not spread the workpiece laterally, the cut surface on the single-edged side is generally a clean cross-section. Therefore, single-edged cutters are used when cutting quality is required on only one side of the cut surface. Furthermore, if G1 / G2 and G1' / G2' are negative numbers, it becomes difficult to form the cutting edge shape; therefore, negative numbers are not considered in this invention. Similarly, if G1 / G2 and G1' / G2' exceed 1, it becomes difficult to form the cutting edge shape; therefore, values ​​exceeding 1 are not considered in this invention.

[0023] Furthermore, the curves forming the tip 22 include all types of curves, including linear and nonlinear functions. In the example shown in Figure 2, the curve forming the tip 22 is a quadratic function (Y=aX 2 The curve is represented by (+bX), but it may also be represented by a higher-order function such as a cubic or quartic function, or even by a function that includes an exponent. The quadratic function representing the curve forming the tip portion 22 can also be expressed using r, G1, G2, etc., as shown below (G1 and G2 may also be G1' and G2'). y = F(x) =a(x-X1) 2 +G1(x-X1)+Y1 however, a=(G2 2 -G1 2 ) / (12000-4·Y1) X1 = r·G1 / (G1 2 +1) 1 / 2 Y1 = rr / (G1 2 +1) 1 / 2 *The units for x and y are [nm].

[0024] Figure 5 is a schematic cross-sectional view of a blade according to an embodiment of the present invention, viewed from the direction of the arrow in Figure 1. The blade 110 shown in Figure 5 is a symmetrical blade and satisfies the following conditions. [1] The arc of the cutting edge 21 has a radius r of 2 nm or more and 1000 nm or less. [2] The slope G2 is 0.18 ≤ G2 ≤ ​​5.67. [3] The ratio of slope G1 to slope G2 is 0.24 ≤ G1 / G2 ≤ 0.82.

[0025] With this configuration, the blade edge 21 and tip portion 22 take on a bullet-like shape as shown in Figure 5, which increases durability compared to a straight shape. Therefore, this blade 110 is suitable for soft materials such as thin resin films or cells embedded in resin, and its shape is suitable when both sharpness and durability are required.

[0026] Next, the configuration of the blade 160 according to another embodiment of the present invention will be described. In the blade 160, the cross-sectional shape of the cutting edge 21 is not an arc but a straight line (see Figure 6(A)). The length s of the straight portion (see Figure 6(A)) is 2 nm or more and 1310 nm or less. In this embodiment, the cross-sectional shape of the cutting edge 21 is straight in the thickness direction (X-axis direction), but it may be inclined to about 0° to less than 45° with respect to the X axis. In the blade 160, the cross-sectional shape of the cutting edge 21 is not an arc, but as cutting is repeated, the corners are rounded and the cross-sectional shape of the cutting edge 21 becomes an arc, as shown in the blade 110 in Figure 5 (see Figure 6(B)).

[0027] A cutting tool 160 whose cutting edge 21 has an arc-shaped cross-section satisfies the following conditions [1], [2], and [3]. [1] The arc of the cutting edge 21 has a radius r of 2 nm or more and 1000 nm or less. [2] In the range X > 0 [unit: μm], the curve is defined as follows, with the tip of the cutting edge 21 as the origin, a line passing through the origin and parallel to the base 10 as the Y-axis, and a line passing through the origin and perpendicular to the Y-axis as the X-axis: 0 ≤ Y ≤ 3 [Unit: μm] It is formed by a function (Y=F(X)) shown within the range. Further, when X<sbub>1< / sbub> represents the X coordinate of the contact point between the circular arc and the curve on the X axis, X<sbub>2< / sbub> represents the X coordinate of the curve at Y=3, G<sbub>1< / sbub> represents the slope of the tangent line to the curve at X<sbub>1< / sbub>, and G<sbub>2< / sbub> represents the slope of the tangent line to the curve at X<sbub>2< / sbub>, 0.18≦G2≦5.67 0.24≦G1 / G2≦0.82 is satisfied. [3] In the range of X<0 (unit: μm), when the tip of the cutting edge 21 is taken as the origin, a line passing through the origin and parallel to the base 10 is the Y axis, and a line passing through the origin and orthogonal to the Y axis is the X axis, the curve 0<Y≦3 (unit: μm) is formed by the function (Y=F(X)) shown in the above range. Further, when X1' represents the X coordinate of the contact point between the circular arc and the curve on the X axis, X2' represents the X coordinate of the curve at Y=3, G1' represents the slope of the tangent line L1' to the curve at X1', and G2' represents the slope of the tangent line L2' to the curve at X2', -5.67≦G2’≦-0.18 0.24≦G1’ / G2’≦0.82 is satisfied.

[0028] It should be noted that the curve in the range of [3] X<0 (unit: μm) may be obtained by inverting the curve formed in the above [2] with the Y axis as the axis of symmetry, however, it does not matter whether the curve in the range of [2] X>0 (unit: μm) and the curve in the range of [3] X<0 (unit: μm) are symmetric about the Y axis or not. Further, the curve in the range of [3] X<0 (unit: μm) may also be a straight line. It does not matter whether this straight line is parallel to the Y axis or not.

[0029] As mentioned above, the cutting edge 21 of the blade 160 is not an arc shape, but as cutting is repeated, the corners are rounded off, and the cross-sectional shape of the cutting edge 21 becomes an arc shape, as shown in Figure 5 for the blade 110 (see Figure 6(B)). The cutting quality and durability then become comparable to that of the blade 110. Therefore, in this embodiment, although the desired cutting quality may not be achieved initially, there is an advantage in that the cutting edge is easy to process, allowing for the provision of cutting tools at a low cost. For example, this embodiment is suitable when there is a certain period of time to allow for trial operation after replacing the cutting tool until the cutting quality reaches a certain level, or when cost (low price) is prioritized over quality.

[0030] Even when the cutting edge 21 is not an arc but a straight line (flat), if the corners are rounded off with use and the conditions for the aforementioned cutting tool 110 are met, the cutting tool of the present invention is included in its scope. Furthermore, the area near the tip of the cutting tool according to the present invention has microscopic irregularities (see the SEM image shown in Figure 3). Since the presence of such microscopic irregularities does not affect the cutting quality, the curve in the present invention also includes those with microscopic irregularities. As shown in Figure 7(A), even when the cutting edge is not a perfect arc and has irregularities, if the shape after smoothing out the irregularities, as shown in Figure 7(B), satisfies the conditions for the aforementioned cutting tool 110, the cutting tool of the present invention is included in its scope.

[0031] [evaluation] Figure 8 is a schematic diagram of the cutting tool used for evaluation. Here, Figure 8(B) is an enlarged view of the rectangular area in Figure 8(A), and an enlarged view of the circular area in Figure 8(B) reveals the blade shape shown in Figure 5. All evaluations were performed using symmetrical blades. As mentioned above, if the cutting quality differs between the left and right sides of the blade, an asymmetrical blade may be used. This asymmetrical shape is a combination of the optimal shape for the left side of a symmetrical blade and the optimal shape for the right side of another symmetrical blade. Therefore, evaluating the optimal shape of an asymmetrical blade can be done using the same method as evaluating the optimal shape of a symmetrical blade. The cutting tool according to the present invention was evaluated by manufacturing the cutting tool 150 shown in Figure 8, cutting an evaluation workpiece, and assessing its cutting quality and durability. The cutting tool 150 was made of WC-Co cemented carbide, with a blade length L of 250 mm, a blade thickness t of 1.0 mm, and a width W of 20 mm. The width W1 of the base portion 150A was 18.8 mm, and the width W2 of the cutting portion 150B was 1.2 mm. The cutting tool according to the present invention was mounted on a servo press (manufactured by Densetsu Precision Machining Laboratory Co., Ltd.) as a press machine, and an evaluation workpiece was fed and cut at a pitch of 1 mm. Cutting quality and durability were evaluated from the perspectives of "cutting quality" and "durability". A Nikon Instec MM-800 measuring microscope was used to observe the cut surface and measure the amount of wear on the cutting edge. The shape of the cutting edge was measured by observing the cross-section of the cutting tool using a Keyence VE-8 electron microscope. 8 Observation was performed at 00, and r, G1, and G2 were measured using the attached measurement function. The roughness Ra (arithmetic mean roughness) of the cross-section was measured using a Newview7200 from Zygo. Furthermore, since machining is difficult with cutting edge radii of less than 2 nm, evaluation was conducted starting from 2 nm or larger for the evaluation tools.

[0032] The following shows the evaluation results of the cutting tool according to the embodiment of the present invention. As shown in the table below, the radius r, the inclinations G1 and G2, and the ratio of inclinations G1 to G2 are used as parameters, and the cutting quality, durability, and overall evaluation are judged in three stages (○, △, ×) by changing each of these parameters.

[0033] Tables 1 to 5 show the evaluation results of the cutting tools according to the embodiments of the present invention. A PET sheet with a thickness of 0.6 mm and a width of 50 mm was used as the workpiece for evaluation of the cutting tools according to the embodiments of the present invention. The evaluation procedure involved first evaluating the cutting quality, followed by evaluating durability (life test). For cutting quality, the roughness Ra of the cut surface was measured and evaluated using a Newview7200. For the life test, the cut surface was observed using a measuring microscope MM-800 after 1000 cutting tests.

[0034] Here, the criteria for evaluation were as follows: for cutting quality, a cut surface roughness Ra of 0.16 μm or less and no cutting debris was judged as "○", a cut surface roughness Ra greater than 0.16 μm but 0.6 μm or less and no cutting debris was judged as "△", and a cut surface roughness Ra greater than 0.6 μm or cutting debris was produced was judged as "×". On the other hand, regarding durability, the size of the chip at the tip of the blade was observed after 1000 cuts. A chip of less than 3 μm was rated "○", a chip of 3 μm or more but less than 5 μm was rated "△", and a chip of 5 μm or more was rated "×". In terms of both cutting quality and durability, blades that receive a rating of "○" or "△" are considered to have met the requirements.

[0035] As a result of these evaluations, as shown in each table, the blades according to the embodiments of the present invention can be made to have excellent sharpness and durability by adopting an appropriate shape (parameters).

[0036] [Table 1]

[0037] [Table 2]

[0038] [Table 3]

[0039] [Table 4]

[0040] [Table 5]

[0041] Tables 6 to 10 show the evaluation results of the cutting tool according to the embodiment of the present invention, with the evaluation workpiece changed to a different one. A 0.2 mm thick, 50 mm wide polycarbonate (PC) sheet was used as the evaluation workpiece. The evaluation procedure was the same as that for the 0.6 mm thick PET sheet. Regarding the judgment criteria, for cutting quality, a cut surface roughness Ra of 0.16 μm or less and no cutting debris was judged as "○", a cut surface roughness Ra greater than 0.16 μm but 0.6 μm or less and no cutting debris was judged as "△", and a cut surface roughness Ra greater than 0.6 μm or cutting debris was judged as "×". On the other hand, for durability, the size of the chip at the tip was observed after 1000 cuts, and a cut surface chip of less than 3 μm was judged as "○", a cut surface chip of 3 μm or more but less than 5 μm was judged as "△", and a cut surface chip of 5 μm or more was judged as "×". In terms of both cutting quality and durability, blades that receive a rating of "○" or "△" are considered to have met the requirements.

[0042] As a result of the evaluation, as shown in each table, the blade according to the embodiment of the present invention can be made with a 0.2 mm thick PC sheet, and by adopting an appropriate shape (parameter), it can be made into a blade with excellent cutting performance and durability.

[0043] [Table 6]

[0044] [Table 7]

[0045] [Table 8]

[0046] [Table 9]

[0047] [Table 10] [Industrial applicability]

[0048] The blade shape of the present invention is suitable for cutting various resins such as polyethylene terephthalate (PET), polybutyl terephthalate (PBT), polycarbonate (PC), and polyvinyl chloride (PVC), as well as for cutting resin sheets with a thickness of 0.1 mm to 0.8 mm. It is also suitable for composite films and high-performance films used in touch panels for smartphones, cells embedded in paraffin for thin sectioning with a microtome, and resin sheets with a hard coat of approximately 5H pencil hardness.

[0049] Conventional cutting tools require secondary post-processing steps such as burr removal and surface polishing after cutting. In contrast, the cutting tool of the present invention eliminates the need for these secondary post-processing steps, significantly reducing energy loss. This allows us to provide a cutting tool with great social significance, contributing to the preservation of the global environment. [Explanation of Symbols]

[0050] 10,150A base 20,150B Blade 21 cutting edge 22 Tip 30 Mounting part 50 Work 100, 110, 150, 160 bladed tools L Blade length t Blade thickness W,W1,W2 width

Claims

1. A cutting tool having a flat base and a cutting blade formed at the end of the base, used for cutting or half-cutting resin materials, resin sheets, composite films or high-performance films used in smartphone touch panels, cells embedded in paraffin for microtome sectioning, or resin sheets with a hard coat of approximately 5H pencil hardness, The blade portion is made of a WC-Co cemented carbide and has a cutting edge and a tip portion extending 3 μm from the very tip of the cutting edge in a direction parallel to the base. The cross-sectional shape of the cutting edge is a circular arc with a radius of 2 nm or more and 1000 nm or less. When the tip of the cutting edge is defined as the origin, the line passing through the origin and parallel to the base is defined as the Y-axis, and the line passing through the origin and perpendicular to the Y-axis is defined as the X-axis, The cross-sectional shape of the tip portion is, In the range X > 0, a first curve is formed by the function Y = F(X) connected to the end of the cutting edge, where X1 is the X-coordinate of the point of tangency between the circular arc and the first curve on the X-axis, X2 is the X-coordinate of the first curve at Y = 3, G1 is the slope of the tangent to the first curve at X1, and G2 is the slope of the tangent to the first curve at X2. 0.18 ≤ G2 ≤ ​​5.67 0.24 ≤ G1 / G2 ≤ 0.82 This is the first curve, In the range X < 0, a straight line connecting to the end of the cutting edge, or a second curve formed by the function Y = F^(X), where X1' is the X-coordinate of the point of tangency between the circular arc and the second curve on the X-axis, X2' is the X-coordinate of the second curve at Y = 3, G1' is the slope of the tangent line to the second curve at X1', and G2' is the slope of the tangent line to the second curve at X2', -5.67 ≤ G2' ≤ -0.18 0.24≦G1' / G2'≦0.82 The second curve is the blade.

2. The cutting tool according to claim 1, wherein the curve is represented by a substantially quadratic function.

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