Blades

Abstract

Provided is a cutting tool that can meet various requirements for various workpieces. 【Solution】A cutting tool 100 comprises 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 foremost point of the cutting edge in a direction parallel to the base. When the foremost point of the cutting edge is taken as an origin, a line parallel to the base is taken as the Y-axis, and a line orthogonal to the Y-axis is taken 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 from 2 nm to 500 nm inclusive. Within 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, 1≦G2≦5.67 0<G1 / G2≦0.24 is satisfied.

Description

[Technical Field]

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

[0002] Industrial precision cutting blades are used in cutting processes and cutting scenarios in various industries. The objects to be cut (workpieces) also vary widely, including resin films used in industrial products, high-performance composite films used for smartphone panels and the like, industrial rubber, food packaging, and cells embedded in resin for pathological examinations. Furthermore, the required cutting quality (cutting performance) also differs depending on the workpiece and other factors; there are various requirements, such as requiring no streaks or burrs on the cut section, avoiding oblique cutting caused by blade deflection during cutting, and requiring thin and uniform slicing.

[0003] In general, for the physical properties of a workpiece and the required cutting quality, an optimal cutting blade can be provided by adjusting blade specifications such as the shape. Here, the following patent documents are available as documents describing inventions relating to blade shapes. [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 include any description regarding the ultrafine portion of the cutting edge (the 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 the workpiece is harder than typical resins, such as carbon fiber, glass epoxy, or ceramic sheets, significant stress is placed on the cutting edge, requiring high cutting edge durability. Through diligent research, the inventors discovered that for a 3μm cross-sectional shape of the cutting edge, it is desirable to have a large curve near the tip of the cutting edge, which then bulges significantly towards the base. This led to the development of 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 to 500 nm. 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, the 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 curve on the X-axis, X2 is the X-coordinate of the curve at Y=3, G1 is the slope of the tangent line to the curve at X1, and G2 is the slope of the tangent line to the curve at X2. 1 ≤ G2 ≤ ​​5.67 0 <G1 / G2≦0.24 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'≦-1 0 <G1’ / G2’≦0.24 It is characterized by being a second curve. [Effects of the Invention]

[0011] According to the cutting tool according to the present invention, when cutting a hard cutting object that imposes large stress on the cutting tool during cutting and durability is particularly required, the cutting tool has good durability and can maintain sharpness for a long time, so both cutting quality and durability can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [Figure 1] FIG. 1 is a diagram showing an example of use of the 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 an 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 an embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of a cutting edge portion of the cutting tool according to an embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view of the cutting tool according to an 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 view of the cutting tool used in evaluation. [Figure 9] FIG. 9 is an explanatory diagram of an oblique cut amount in evaluation. [Figure 10] FIG. 10 is an explanatory diagram of a burr amount in evaluation. MODES FOR CARRYING OUT THE INVENTION

[0013] Embodiments of the present invention will be described in detail below. The following description of each constituent element is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to the following contents unless the gist thereof is changed.

[0014] [Cutting Tool] When the workpiece is made of a hard material such as glass epoxy or carbon fiber, and the cutting edge is subjected to significant stress, requiring durability from the cutting tool, it is desirable to set a large radius for the cutting edge tip and to make the cross-sectional shape of the cutting edge tip a large, bulging curve. 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 includes 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 within 3 µm from the extreme tip of the cutting edge 21 in a direction parallel to the base (Y-axis direction) (see the cutting tool 121 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, the cross-sectional shape is formed by a curved line. Further, the arc and the curved line (or the straight line) are connected at any point, and hereinafter, the point at which the arc and the curved line are connected is referred to as a "contact point". This is clearly illustrated in Figs. 3(A) and 3(B). As shown in Fig. 3(B), the cross-sectional shape of the blade portion 20 within 3 µm from the cutting edge 21 is formed by the arc (the cutting edge 21) and the curved line (the tip portion 22) connected to the arc at the contact point. Note that, as shown in Fig. 2, the extreme tip of the cutting edge 21 is taken as an 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 also using these axes.

[0020] First, the radius r of the arc of the cutting edge 21 is not less than 2 nm and not more than 500 nm (see Fig. 2). Note that, for ease of explanation in Fig. 2, instead of an arc, a circle centered at X=0 and Y=r is shown. Next, the tip portion 22 is formed by a curved line connected to the cutting edge 21 at the contact point. When the extreme tip of the cutting edge 21 is taken as the origin (X=0, Y=0), this curved line satisfies: the curved line in the range of X>0 [unit: µm] (first curved line) is 0 < Y ≦ 3 [unit: µm] formed by a function (Y = F(X)) represented in the above range. Further, as shown in Fig. 2, 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 line L1 to the curved line at X1, and G2 is the slope of the tangent line L2 to the curved line at X2, the curved line 1 ≦ G2 ≦ 5.67 0 < G1 / G2 ≦ 0.24 satisfies the above conditions.

[0021] On the other hand, for the curve within the range of X > 0 (the second curve), 0 < Y ≦ 3 [unit: μm] is formed by a function (Y = F^(X)) represented within the above range. Further, for this curve, when the X coordinate of the contact point between the circular arc and the curve on the X axis is defined as X1', the X coordinate of the curve at Y = 3 is defined as X2', the slope of tangent line L1' to the curve at X1' is defined as G1', and the slope of tangent line L2' to the curve at X2' is defined as G2', -5.67 ≦ G2' ≦ -1 0 < G1' / G2' ≦ 0.24 the above conditions are satisfied.

[0022] 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 which holds. 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 of X > 0. However, it does not matter whether the portion of the tip portion 22 formed by the curve in the range of X > 0 and the portion formed by the curve in the range of X < 0 have the same shape or not. In short, as shown in Figs. 4(A) to 4(C), the curve forming the tip portion 22 may be bilaterally symmetrical about the Y axis as the axis of symmetry, or may be asymmetrical. In addition, 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 friction between the blade and the workpiece during cutting differs between the left and right sides of the blade due to factors such as the conditions of the cutting target and cutting conditions. 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 asymmetric 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 121 shown in Figure 5 is a symmetrical blade and, like the blade 100, satisfies the following conditions. [1] The arc of the cutting edge 21 has a radius r of 2 nm or more and 500 nm or less. [2] The slope G2 is 1 ≤ G2 ≤ ​​5.67. [3] The ratio of slope G1 to slope G2 is 0 <G1 / G2≦0.24である。

[0025] With this configuration, the shape (curve) of the tip portion 22 becomes a rounded, bulging curve, as shown in Figure 5. Therefore, this blade 121 is suitable for carbon fiber, glass epoxy, and other materials that are harder than resin, and it can maintain sharpness (cutting quality) while also providing durability.

[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 310 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 121 in Figure 5 (see Figures 6(B) and (C)).

[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 500 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)) that is shown within the range. Furthermore, if we let X1 be the X-coordinate of the point of tangency between the circular arc and the curve on the X-axis, X2 be the X-coordinate of the curve at Y=3, G1 be the slope of the tangent line to the curve at X1, and G2 be the slope of the tangent line to the curve at X2, 1≦G2≦5.67 0<G1 / G2≦0.24 . In the range of [3]X<0 [unit: μm], with the tip of the cutting edge 21 as the origin, a line passing through the origin parallel to the base 10 defined as the Y-axis, and a line passing through the origin perpendicular to the Y-axis defined as the X-axis, the curve is: 0<Y≦3 [unit: μm] formed by a function (Y=F^(X)) represented within the above range. Further, when the X-coordinate of the contact point between the circular arc and the curve on the X-axis is X1', the X-coordinate of the curve at Y=3 is X2', the slope of tangent line L1' of the curve at X1' is G1', and the slope of tangent line L2' of the curve at X2' is G2', -5.67≦G2'≦-1 0<G1' / G2'≦0.24 .

[0028] It should be noted that the curve in the range of [3]X<0 [unit: μm] may be an inversion of the curve formed in [2] with the Y-axis as the axis of symmetry; however, it does not require 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 bilaterally symmetric with respect to the Y-axis. Further, the curve in the range of [3]X<0 [unit: μm] may also be a straight line, and it does not require whether this straight line is parallel to the Y-axis.

[0029] As described above, although the cross-sectional shape of the cutting edge 21 of the cutting tool 160 is not a circular arc initially, corners will be rounded off during repeated cutting, and the cross-sectional shape of the cutting edge 21 gradually becomes a circular arc like the cutting edge 21 of the cutting tool 121 shown in FIG. 5 (see FIGS. 6(B) and 6(C)). Then, the cutting quality and durability of the cutting tool 160 will become comparable to those of the cutting tool 121. Therefore, in the case of this embodiment, although the desired cutting quality may not be obtained initially, it has the advantage that the cutting tool can be provided at low cost because the processing of the cutting edge is easy. For example, this embodiment is suitable for cases where after replacing the cutting tool, a certain period of time can be secured for the cutting quality to reach a certain level for trial operation and the like, 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. 8Observation was performed at 00, and r, G1, and G2 were measured using the attached measurement function. The amount of bevel cut and burr on the cut surface were measured using a Keyence VHX-8000 microscope. 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 cutting tools according to the embodiments of the present invention. For evaluation of the cutting tools according to the embodiments of the present invention, a glass epoxy plate with a thickness of 1.2 mm and copper foil with a thickness of 35 μm on both sides was used. Since cutting edge radii of less than 2 nm are difficult to process, evaluation was performed starting from 2 nm. Regarding the evaluation procedure, the cutting quality was evaluated first, followed by a durability evaluation (life test). For cutting quality, the amount of bevel cut in the evaluation workpiece after cutting was measured and evaluated using a VHX-8000 microscope. For the life test, the cut surface was observed using a MM-800 measuring microscope after 100 cutting tests. Regarding the judgment criteria, cutting quality was evaluated based on the amount of bevel cut in the evaluation workpiece after cutting. A bevel cut is a phenomenon in which the cross-section of the cut workpiece is tilted due to factors such as the sharpness of the cutting tool and uneven frictional resistance between the tool and the workpiece during cutting. The definition of the amount of bevel cut is shown in Figure 9. If the amount of bevel cut is less than 50 μm, it is marked as "○", if the amount of bevel cut is 50 μm or more but less than 75 μm, it is marked as "△", and if the amount of bevel cut is 75 μm or more, it is marked as "×". On the other hand, regarding durability, the size of the chip at the tip of the blade was observed after 100 cuts. A chip of less than 10 μm was rated "○", a chip of 10 μm or more but less than 30 μm was rated "△", and a chip of 30 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.

[0034] As a result of the evaluation, as shown in each table, the blades according to the embodiments of the present invention can also be made into blades with excellent sharpness and durability by adopting an appropriate shape (parameters).

[0035] [Table 1]

[0036] [Table 2]

[0037] [Table 3]

[0038] [Table 4]

[0039] [Table 5]

[0040] Tables 6 to 10 show the evaluation results of the cutting tool according to the embodiment of the present invention, with a different workpiece used for evaluation. For the different workpiece, a carbon fiber sheet impregnated with epoxy resin, 0.1 mm thick and 50 mm wide, was used. Regarding the evaluation procedure, cutting quality was evaluated first, followed by durability evaluation (life test). For cutting quality, the amount of burrs on the cut surface was measured and evaluated using a microscope VHX-8000. For the life test, evaluation was performed by observing the cut surface using a measuring microscope MM-800 after 1000 cutting tests. Regarding the judgment criteria, for cutting quality, the amount of carbon fiber burrs was evaluated by observing the cut surface. Here, carbon fiber burrs refer to some carbon fibers that do not cut along the cut surface and protrude from the cut surface, as shown in Figure 10, and the amount of burrs refers to the amount of burr protrusion from the cut surface. The judgment was as follows: if the carbon fiber burrs were less than 1 μm, it was "○"; if the burrs were 1 μm or more but less than 5 μm, it was "△"; and if the burrs were 5 μm or more, it was "×". 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.

[0041] As a result of the evaluation, as shown in each table, the blades according to the embodiments of the present invention can achieve a balance between sharpness and durability by adopting an appropriate shape (parameters).

[0042] [Table 6]

[0043] [Table 7]

[0044] [Table 8]

[0045] [Table 9]

[0046] [Table 10] [Industrial applicability]

[0047] The blade shape of the present invention is suitable for cutting soft metal plates such as aluminum and copper with a thickness of about 0.5 mm to 1 mm, or metal plates made by mixing or laminating at least a portion of these materials, glass substitute resin materials, glass epoxy plates with copper foil, epoxy-impregnated carbon fiber sheets, ceramic-containing sheets, amorphous metal plates, and the like.

[0048] 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]

[0049] 10,150A base 20,150B Blade 21 cutting edge 22 Tip 30 Mounting part 50 Work 100, 121, 150, 160 cutlery 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, wherein the cutting blade is used to cut a workpiece selected from a soft metal plate, a metal plate mixed with or laminated with at least a portion of a soft metal, a glass substitute resin material, a glass epoxy plate coated with copper foil, an epoxy-impregnated carbon fiber sheet, a sheet containing ceramic, and an amorphous metal plate, 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 500 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. 1 ≤ G2 ≤ ​​5.67 0<G1 / G2≦0.24 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' ≤ -1 0<G1' / G2'≦0.24 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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