Cutting blade and cutting blade manufacturing method

Abstract

A cutting blade (10) is provided with a base material (20) and a coating film (30). The base material (20) is in the form of a plate such that at least part of an outer edge thereof is a cutting edge (23), and has a blade-side portion (22) that includes the cutting edge (23) and that has a smaller thickness toward the cutting edge (23). The coating film (30) covers the surface of the blade-side portion (22). The coating film (30) has a film body (31) that covers the surface of the blade-side portion (22) along the surface of the blade-side portion (22), and a plurality of protrusions (32) that protrude from the surface of the film body (31). An average value of the ratio of the height dimension of the protrusions (32) to the width dimension of the protrusions (32) is 1 / 5 or less.

Description

Cutting blade and method for manufacturing the same

[0001] The present disclosure relates to cutting blades and methods of manufacturing cutting blades.

[0002] The cutting blade disclosed in Patent Document 1 comprises a substrate and a coating. The substrate is a rectangular plate. At least a portion of the outer edge of the substrate forms a cutting edge. The substrate has a blade side portion whose thickness decreases as it approaches the cutting edge. The coating has a film body that covers at least the blade side portion, and protrusions that protrude from the surface of the film body. The material of the coating contains diamond. The size of the protrusions reflects the size of particles such as diamond that adhere to the surface of the substrate when the coating is formed.

[0003] International Publication No. 2023 / 105988

[0004] In the cutting blade described in Patent Document 1, the coating has protrusions, which make it easier for the object to be cut to separate from the cutting blade after cutting. However, if the height of the protrusions is excessively large, the protrusions will rub against the cut surface of the object when the object is cut with the cutting blade, making the cut surface more likely to be scratched.

[0005] In order to solve the above problems, the present disclosure provides a cutting blade comprising: a substrate having a plate-like outer edge at least part of which is a cutting edge, the substrate having a blade side portion that includes the cutting edge and whose thickness decreases as it approaches the cutting edge; and a coating covering the surface of the blade side portion, the coating being made of a material containing diamond, the coating having a film body that covers the surface of the blade side portion along the surface of the blade side portion, and a plurality of protrusions that protrude from the surface of the film body by 0.1 μm or more, wherein the maximum dimension of a line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is the width dimension, and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is the height dimension, and the average value of the ratio of the height dimension to the width dimension is 1 / 5 or less.

[0006] The present disclosure also provides a method for manufacturing a cutting blade, comprising: a substrate preparation step for preparing a substrate having a plate-shaped cutting edge that is at least a part of the outer edge, and a blade side portion whose thickness decreases as it approaches the cutting edge; a coating formation step for applying a diamond coating to the surface of the substrate to form a film body that covers the surface of the blade side portion along the surface of the blade side portion, and a coating having a plurality of protrusions protruding from the surface of the film body; and a grinding step for grinding the surface of the coating after the coating formation step to reduce the average value of the ratio of the height dimension to the width dimension to 1 / 5 or less, where the maximum dimension of the line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is the width dimension, and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is the height dimension.

[0007] When cutting an object, the cut surface is less likely to be scratched by the protrusions.

[0008] Fig. 1 is a perspective view of a cutting blade. Fig. 2 is a plan view of the cutting blade. Fig. 3 is a partially enlarged cross-sectional view of the cutting blade taken along line 3-3 in Fig. 2. Fig. 4 is a plan view of a protrusion. Fig. 5 is a partially enlarged cross-sectional view of the protrusion taken along line 5-5 in Fig. 4. Fig. 6 is a flowchart showing a method for manufacturing a cutting blade. Fig. 7 is an explanatory diagram for explaining a method for manufacturing a cutting blade.

[0009] <One embodiment of a cutting blade> One embodiment of a cutting blade will be described below. Note that the drawings may show components enlarged to facilitate understanding. The dimensional ratios of the components may differ from those in the actual drawings or from those in other drawings.

[0010] (Regarding the Cutting Blade) As shown in FIG. 1, the cutting blade 10 includes a substrate 20. The substrate 20 is plate-shaped. As shown in FIG. 2, when the substrate 20 is viewed in a direction perpendicular to the main surface MF, the substrate 20 is rectangular. The main surface MF is the surface with the largest area among the surfaces of the substrate 20. The material of the substrate 20 is a cemented carbide. A cemented carbide is a sintered powder of hard metal carbide.

[0011] Here, as shown in FIG. 1 , when the substrate 20 is viewed in a direction perpendicular to the main surface MF, the axis extending along the long side of the four sides of the rectangular substrate 20 is referred to as the first axis X. When the substrate 20 is viewed in a direction perpendicular to the main surface MF, the axis extending along the short side of the four sides of the substrate 20 is referred to as the second axis Y. Furthermore, the axis extending in a direction perpendicular to the main surface MF is referred to as the third axis Z. One of the directions along the first axis X is referred to as the first positive direction X1, and the direction along the first axis X opposite to the first positive direction X1 is referred to as the first negative direction X2. One of the directions along the second axis Y is referred to as the second positive direction Y1, and the direction along the second axis Y opposite to the second positive direction Y1 is referred to as the second negative direction Y2. One of the directions along the third axis Z is defined as a third positive direction Z1, and the direction along the third axis Z opposite to the third positive direction Z1 is defined as a third negative direction Z2.

[0012] As shown in Fig. 2, at least a portion of the outer edge of the substrate 20 forms a cutting edge 23. Specifically, the entire area of ​​the end of the outer edge of the substrate 20 on the second positive direction Y1 side forms the cutting edge 23. Therefore, the cutting edge 23 extends in a direction parallel to the first axis X. The entire area of ​​the end of the outer edge of the substrate 20 on the second negative direction Y2 side forms a ridge 24. Therefore, the ridge 24 extends in a direction parallel to the first axis X.

[0013] The substrate 20 has a ridge side portion 21 and a blade side portion 22. The ridge side portion 21 is a portion of the substrate 20 that includes the ridge 24. When the substrate 20 is viewed in the third negative direction Z2, the ridge side portion 21 has a rectangular shape that is elongated in the direction along the first axis X. The dimension of the ridge side portion 21 in the direction along the third axis Z, i.e., the thickness of the ridge side portion 21, is constant throughout the entire area in the directions along the first axis X and the second axis Y. In other words, the ridge side portion 21 is the portion of the substrate 20 that has the same thickness throughout the entire area in the directions along the first axis X and the second axis Y.

[0014] The blade side portion 22 is a portion of the substrate 20 that includes the cutting edge 23. The ridge side portion 21 is connected to the blade side portion 22 on the second negative direction Y2 side. The dimension of the blade side portion 22 in the direction along the first axis X is the same as the dimension of the ridge side portion 21 in the direction along the first axis X. Therefore, the entire substrate 20 excluding the ridge side portion 21 constitutes the blade side portion 22. In this embodiment, the ridge side portion 21 and the blade side portion 22 are integrally molded.

[0015] As shown in FIG. 3 , the thickness of the blade-side portion 22 decreases toward the cutting edge 23. Here, the surface of the blade-side portion 22 facing the third positive direction Z1 is referred to as the first substrate surface 22A. The surface of the blade-side portion 22 facing the third negative direction Z2 is referred to as the second substrate surface 22B. The first substrate surface 22A has a substantially rectangular planar shape. The end of the first substrate surface 22A on the second negative direction Y2 side is connected to the ridge side portion 21. The first substrate surface 22A is inclined so that it is positioned closer to the third negative direction Z2 as it approaches the second positive direction Y1. The second substrate surface 22B has a substantially rectangular planar shape. The end of the second substrate surface 22B on the second negative direction Y2 side is connected to the ridge side portion 21. The second substrate surface 22B is inclined so that it is positioned closer to the third positive direction Z1 as it approaches the second positive direction Y1. The end of the first substrate surface 22A facing the second positive direction Y1 and the end of the second substrate surface 22B facing the second positive direction Y1 are connected to each other and form the same cutting edge 23. Therefore, the dimension of the blade side portion 22 in the direction along the third axis Z, i.e., the thickness, decreases as it goes further in the second positive direction Y1.

[0016] As shown in Fig. 2, the cutting blade 10 is provided with a coating 30. The coating 30 covers the entire surface of the blade-side portion 22 of the substrate 20. Therefore, the coating 30 covers the cutting edge 23 of the substrate 20. The coating 30 also covers a portion of the surface of the ridge-side portion 21, including the end on the second positive direction Y1 side. The material of the coating 30 contains diamond. Therefore, the coating 30 is harder than the substrate 20.

[0017] As shown in FIG. 3 , the coating 30 has a film body 31 and multiple protrusions 32. Note that in FIG. 3 , only some of the protrusions 32 are labeled. The film body 31 corresponds to the portion of the coating 30 that would appear if the protrusions 32 and fine surface irregularities were not present. Specifically, the coating 30 is first imaged from a direction substantially perpendicular to the surface of the substrate 20 using a laser microscope (VK-X150, Keyence). Note that the "direction substantially perpendicular to the surface of the substrate" refers to a direction substantially perpendicular to the ridge side portion 21 when imaging the coating 30 covering the ridge side portion 21, and a direction substantially perpendicular to the blade side portion 22 when imaging the coating 30 covering the blade side portion 22. A roughness curve is then obtained by measuring a 100 μm range on the surface of the coating 30. The roughness curve is a curve that reflects the outer edge shape of the surface of the coating 30 when viewed cross-sectionally. Next, a surface roughness reference line indicating the average value of surface roughness within the measurement range is drawn over the roughness curve of the coating 30. The portion on the substrate 20 side of this reference line is designated as the film body 31. Note that in Figures 3 and 5, the fine irregularities on the surface of the film body 31 are omitted and the surface of the film body 31 is illustrated as a flat surface.

[0018] As shown in FIG. 3 , the film body 31 covers the surface of the blade-side portion 22 along the surface of the blade-side portion 22. Specifically, the film body 31 covers the entire surface of the blade-side portion 22 of the substrate 20. Therefore, the film body 31 covers the cutting edge 23 of the substrate 20. The film thickness of the film body 31 is approximately uniform in the region covering the portion on the second negative direction Y2 side of the cutting edge 23. Furthermore, the film thickness of the film body 31 covering the cutting edge 23 is greater than the film thickness of the portions covering the first substrate surface 22A and the second substrate surface 22B as a result of the film body 31 on the third positive direction Z1 side and the film body 31 on the third negative direction Z2 side joining together. Note that the film thickness of the film body 31 covering the cutting edge 23 is the dimension in the direction parallel to the third axis Z, including the cutting edge 23. The film thickness of the film body 31 in the direction along the third axis Z becomes smaller in the second positive direction Y1 in the portion on the second positive direction Y1 side of the cutting edge 23.

[0019] As shown in FIG. 3 , the vicinity of the tip 31E, which is the end of the film body 31 on the second positive direction Y1 side, is curved except for the tip 31E. Specifically, first, in a cross section perpendicular to the first axis X, i.e., a cross section perpendicular to the cutting edge 23, a perpendicular line PL is drawn from the cutting edge 23 to the surface of the film body 31. Then, the outer edge of the film body 31 between the foot of this perpendicular line PL and the tip 31E of the film body 31 is curved and convex toward the outside of the film body 31. As a result, in the cross section, the angle formed by the two sides sandwiching the tip 31E of the film body 31 is larger than when the vicinity of the tip 31E of the film body 31 is not curved. Specifically, in the cross section, a first imaginary line L1 is drawn by extending the outer edge of the portion of the film body 31 covering the first substrate surface 22A. A second imaginary line L2 is drawn by extending the outer edge of the portion of the film body 31 covering the second substrate surface 22B. The acute angle formed by the first virtual line L1 and the second virtual line L2 is defined as a first angle θ1. In the same cross section, the angle formed by the two sides sandwiching the tip 31E of the membrane body 31 is defined as a second angle θ2. In this case, the second angle θ2 is larger than the first angle θ1.

[0020] The multiple protrusions 32 protrude from the surface of the film body 31 by 0.1 μm or more. Specifically, the protrusions 32 are portions of the coating 30 that are identified as follows. First, a surface roughness reference line is identified in the roughness curve of the surface of the coating 30 using the same method as described above for identifying the film body 31. Portions that have a height of 0.1 μm or more on the side opposite the substrate 20 from this surface roughness reference line are defined as protrusions 32. Note that the film body 31 and the protrusions 32 are integrally molded. Therefore, a clear boundary between the film body 31 and the protrusions 32 may not be observed. Note that in Figures 3 and 5, the surface roughness reference line identified using the above method is illustrated as an imaginary two-dot chain line that represents the boundary between the film body 31 and the protrusions 32.

[0021] As shown in Figures 3 and 4, the shape of the protrusions 32 varies from one protrusion 32 to another. That is, the shape of each protrusion 32 is irregular. However, as shown in Figure 3, when viewed in a cross section perpendicular to the cutting edge 23, the outer edge shape of the surface of the protrusions 32 is relatively often approximately arc-shaped or approximately frustum-shaped. Furthermore, as shown in Figure 4, when viewed in a direction perpendicular to the film body 31, the outer edge shape of the protrusions 32 is relatively often approximately circular or approximately elliptical.

[0022] (Regarding Protrusions and Recesses) As shown in FIG. 4 , the width W is the maximum dimension of a line segment connecting two points on the outer edge of a protrusion 32 when viewed from a direction perpendicular to the film body 31. Also, as shown in FIG. 5 , the height H is the maximum dimension of the protrusion 32 in a direction perpendicular to the surface of the film body 31. The average ratio (H / W) of the height H of the protrusion 32 to the width W of the protrusion 32 is 1 / 5 or less. More preferably, the average ratio of the height H of the protrusion 32 to the width W of the protrusion 32 is 1 / 10 or less. Even more preferably, the average ratio of the height H of the protrusion 32 to the width W of the protrusion 32 is 1 / 20 or less. There are also protrusions 32 in which the ratio of the height H of the protrusion 32 to the width W of the protrusion 32 is 1 / 25 or less. There are also protrusions 32 in which the ratio of the height H of the protrusion 32 to the width W of the protrusion 32 is 1 / 60 or less. More specifically, the average height H of the protrusion 32 is 2 μm or less. More preferably, the average height H of the protrusions 32 is 1 μm or less.

[0023] Specifically, the average value of the ratio is calculated as follows. First, one protrusion 32 is identified using the method described above. Then, multiple roughness curves are calculated for the identified protrusion 32. Of these multiple roughness curves, the maximum dimension of the protrusion 32 in a direction perpendicular to the surface roughness reference line is defined as the height dimension H of the protrusion 32. Of these multiple roughness curves, the maximum dimension of the protrusion 32 in a direction parallel to the surface roughness reference line is defined as the width dimension W of the protrusion 32. Note that since the roughness curve reflects the outer edge shape of the protrusion 32 in a certain cross section, this method can be used to calculate a line segment connecting two points on the outer edge of the protrusion 32 when viewed from a direction perpendicular to the film body 31. The value obtained by dividing the height dimension H calculated using the above method by the width dimension W is the ratio of the height dimension H to the width dimension W of the protrusion 32. Next, the ratios are calculated using the same method for at least 10 randomly selected protrusions 32. By calculating the average of these ratios, the average ratio of the height dimension H to the width dimension W of the protrusion 32 is calculated.

[0024] The protrusions 32 have recesses 33 on their surfaces. As shown in FIG. 4 , the recesses 33 are multiple elongated depressions extending in a direction along the first axis X. In other words, the recesses 33 are groove-shaped extending in a direction along the cutting edge 23. The recesses 33 are formed by grinding the surface of the coating 30 in the grinding step S12 described below. Therefore, multiple groove-shaped recesses 33 may be connected. Furthermore, "extending in a direction along the cutting edge" means that the acute angle between the direction in which the cutting edge 23 extends and the direction in which the recesses 33 extend is less than 45 degrees. The "direction in which the recesses extend" is defined as the direction in which multiple streaky images extend when the coating 30 is imaged with an electron microscope from a direction perpendicular to the film body 31.

[0025] As shown in FIG. 5 , the depth D of the recess 33 is smaller than the height H of the protrusion 32 on which the recess 33 is located. The depth D of the recess 33 is determined as follows: First, multiple roughness curves are obtained for one protrusion 32 using the same method as for identifying the protrusion 32 described above. Among the multiple roughness curves, the maximum dimension of the recess 33 located on the outer edge of the protrusion 32 is the depth D of the recess 33. However, when measuring the roughness curve, depending on the measurement pitch of the laser microscope, fine recesses 33 may not be visible on the roughness curve. In this case, first, the coating 30 of the cutting blade 10 that has undergone the grinding process S12 described below is imaged using an electron microscope from a direction perpendicular to the film body 31. If multiple streaky images are observed on the surface of the protrusion 32, it can be said that the depth D of the recess 33 is smaller than the height H of the protrusion 32 on which the recess 33 is located.

[0026] (Method for Manufacturing Cutting Blade) Next, a description will be given of a method for manufacturing the cutting blade 10. As shown in Fig. 6, the method for manufacturing the cutting blade 10 includes a substrate preparation step S10, a coating formation step S11, a grinding step S12, and a cutting edge processing step S13.

[0027] First, a substrate preparation step S10 is performed. In the substrate preparation step S10, a plate-shaped plate member having a main surface MF is prepared. Then, a portion of the outer edge of the plate member when viewed in a direction perpendicular to the main surface MF is cut by machining to form a substrate 20 having a blade side portion 22. Details of the substrate 20 are as described above.

[0028] Next, a coating step S11 is performed. In the coating step S11, a diamond coating is applied to a portion of the surface of the substrate 20 prepared in the substrate preparation step S10, the portion including at least the surface of the blade side portion 22. The diamond coating is performed by chemical vapor deposition (CVD).

[0029] Specifically, first, the substrate 20 is pretreated. In the pretreatment of the substrate 20, the cobalt binder is removed from the surface of the substrate 20 using a chemical solution or the like. This exposes tungsten carbide particles on the surface of the substrate 20.

[0030] Next, a seeding process is performed to seed diamond particles onto the pretreated surface of the substrate 20. In the seeding process, the substrate 20 is immersed in a solvent in which diamond nanoparticles and diamond particles larger than the nanoparticles are dispersed. This causes the diamond particles to adhere to the tungsten carbide on the surface of the substrate 20.

[0031] Next, diamond coating is performed using a film formation apparatus 50 shown in FIG. 7 . The film formation apparatus 50 includes a chamber 60 into which a reaction gas flows. The chamber 60 has a reaction space 61 for chemical vapor deposition. The chamber 60 also has an inlet 62 for flowing the reaction gas into the reaction space 61. The chamber 60 also has an outlet 63 for exhausting the reacted gas from the reaction space 61. The film formation apparatus 50 includes a heat source 80 for heating the substrate 20 in the chamber 60. The heat source 80 is a filament. The substrate 20 is held in the chamber 60 so that the heat source 80 is located on the cutting edge 23 side of the substrate 20.

[0032] In the film-forming apparatus 50, the substrate 20 is held in the chamber 60, and reactive gases, methane and hydrogen, are introduced. Then, the heat source 80 is operated so that the substrate 20 is maintained at 600 to 800°C for a predetermined time. This causes the diamond particles attached to the surface of the substrate 20 to grow, resulting in a substantially uniform diamond coating, and a film 30 is formed on the surface of the substrate 20. At this time, the portions where larger diamond particles are attached, among the particles attached in the seeding process, grow to a greater thickness. As a result, protrusions 32 protruding from the surface of the film body 31 are formed.

[0033] Next, a grinding step S12 is performed. In the grinding step S12, the surface of the coating 30 is ground to reduce the average ratio of the height dimension H of the protrusions 32 to the width dimension W to 1 / 5 or less. Furthermore, by undergoing the grinding step S12, the average height dimension H of the protrusions 32 is reduced to 0.1 μm or more and 2 μm or less, preferably 0.1 μm or more and 1 μm or less. Note that "grinding" refers to a process for scraping the surface. In other words, "grinding" also includes polishing and the like.

[0034] Specifically, in the grinding step S12, the surface of the coating 30 of the cutting blade 10 that has undergone the coating formation step S11 is ground using a tool containing an abrasive, such as a grindstone. The grindstone is spherical or flat, and abrasive grains are held on its surface as abrasives. During grinding, the surface of the coating 30 and the surface of the grindstone are moved relative to each other in a direction along the surface of the coating 30 to grind the surface of the coating 30. More specifically, the cutting blade 10 is fixed to a workbench or the like, and the grindstone is moved back and forth in a direction along the cutting edge 23 of the substrate 20 to grind the surface of the coating 30. As a result, the surface of the protrusions 32 is ground in a direction along the surface of the coating 30. That is, groove-like recesses 33 extending in a direction along the cutting edge 23 are formed on the surface of the protrusions 32. Note that the larger the particle size held by the grindstone, the greater the depth D of the recesses 33 in the coating 30. Furthermore, the longer the grinding time or the greater the grinding intensity, the smaller the height H of the protrusions 32 becomes.

[0035] Furthermore, in the cutting blade 10 before the grinding step S12, even if the surface of the protrusions 32 is imaged with an electron microscope from a direction perpendicular to the film body 31, multiple streaky images are not observed on the surface of the protrusions 32. In the cutting blade 10 after the grinding step S12, multiple streaky images are observed on the surface of the protrusions 32 when observed with the same method.

[0036] Next, a cutting edge processing step S13 is performed. In the cutting edge processing step S13, the tip of the coating 30, i.e., the tip 31E of the film body 31, is shaped for the portion of the coating 30 that covers the cutting edge 23. Specifically, the portion of the coating 30 that covers the cutting edge 23 is processed by ion etching. At this time, the output of the ion beam, etc., is controlled.

[0037] As a result, in a cross section perpendicular to the first axis X, the vicinity of the tip 31E of the film body 31 becomes curved except for the tip 31E. In other words, the outer edge of the film body 31 between the foot of the perpendicular line PL drawn from the cutting edge 23 to the surface of the film body 31 and the tip 31E of the film body 31 becomes a curved shape that convexly extends outward from the film body 31. The cutting blade 10 is manufactured by the above method.

[0038] The ion etching performed in the cutting edge processing step S13 may also reduce the height H and width W of the protrusion 32. This may result in a relatively shallow depth D of the recess 33. Furthermore, the streak-like image observed on the surface of the protrusion 32 may become fainter.

[0039] (Effects of this embodiment) (1) In the above embodiment, the average ratio of the height dimension H of the protrusions 32 to the width dimension W of the protrusions 32 is 1 / 5 or less. Because the protrusions 32 are not sharp, the protrusions 32 are less likely to scratch the cut surface when the object is cut. Furthermore, because the height dimension H of the protrusions 32 is 0.1 μm or more, a gap is generated between the surface of the film body 31 and the object when the object is cut with the cutting blade 10. Therefore, it is possible to prevent the film body 31 and the object from coming into close contact with each other. In other words, the object is more likely to separate from the cutting blade 10.

[0040] It is preferable that the average ratio of the height dimension H of the protrusions 32 to the width dimension W of the protrusions 32 is 1 / 20 or less. When the ratio is in this range, scratches on the cut surface caused by the protrusions 32 can be more significantly suppressed.

[0041] (2) In the above embodiment, the height H of the protrusions 32 is 2 μm or less. Preferably, the height H of the protrusions 32 is 1 μm or less. Even if the average ratio of the height H of the protrusions 32 to the width W of the protrusions 32 is within the above-mentioned range, if the height H of the protrusions 32 is too large, there is a risk that the workpiece will be chipped when being cut. With the height H of the protrusions 32 described above, this situation is unlikely to occur.

[0042] (3) In the above embodiment, the protrusions 32 have recesses 33 on their surfaces. As a result, when the cutting blade 10 cuts the object, gaps are formed between the surfaces of the protrusions 32 and the object. This prevents the coating 30 from coming into close contact with the object. In other words, the object is more likely to separate from the cutting blade 10.

[0043] (4) In the above embodiment, the recess 33 is a groove extending in a direction along the cutting edge 23. As a result, even if the outer edge of the recess 33 rubs against the cut surface of the workpiece, scratches caused by the outer edge of the recess 33 are unlikely to occur.

[0044] Furthermore, when cutting an object, a force is applied in a direction intersecting the cutting edge 23. Therefore, if a crack occurs on the surface of the protrusion 32, the crack is likely to propagate in a direction intersecting the cutting edge 23. With this configuration, even if the crack propagates, it connects to the recess 33, and the propagation of the crack is stopped by the recess 33. In other words, it is possible to prevent the crack from becoming larger.

[0045] (5) In the above embodiment, the depth D of the recess 33 is smaller than the height H of the protrusion 32 having the recess 33. That is, the recess 33 does not reach the film body 31, or if it does, it only reaches the film body 31 to a small extent. As a result, even if chips are generated when cutting the workpiece, they are less likely to accumulate in the recess 33. Furthermore, because the depth D of the recess 33 is relatively shallow, the coating 30 is less likely to crack or chip starting from the recess 33.

[0046] (6) In the above embodiment, the vicinity of the tip 31E of the film body 31 has a curved surface that is convex toward the outside of the film body 31. This makes the vicinity of the tip 31E less likely to crack or chip than when the vicinity of the tip 31E is flat. In other words, it is easier to suppress the occurrence of so-called chipping.

[0047] (7) In the above embodiment, the manufacturing method of the cutting blade 10 includes a grinding step S12. This allows the height dimension H of the protrusions 32 to be reduced in a substantially uniform manner regardless of the size of the diamond particles attached to the surface of the substrate 20.

[0048] (8) In the above embodiment, in the grinding step S12, the surface of the coating 30 is ground by relatively moving the surface of the coating 30 and the abrasive held on the surface of the grindstone in a direction along the surface of the coating 30. This makes it easy to make the height dimension H of the multiple protrusions 32 on the coating 30 approximately uniform.

[0049] <Modifications> The above embodiment and the following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0050] The shape of the base material 20 is not limited to the example in the above embodiment. For example, the shape of the base material 20 may be square or partially arc-shaped when viewed from the direction along the third axis Z.

[0051] The shape of the cutting edge 23 is not limited to the example in the above embodiment. The cutting edge 23 may be a so-called saw blade. The outer edge of the substrate 20 may be curved, and the cutting edge 23 may also be curved accordingly. Furthermore, in the above embodiment, when the substrate 20 is viewed from a direction along the third axis Z, the cutting edge 23 may be located on a short side of the substrate 20. When the substrate 20 is viewed from a direction perpendicular to the main surface MF, the cutting edge 23 may be provided on two or more of the four sides of the rectangular substrate 20.

[0052] The material of the substrate 20 is not limited to the example in the above embodiment. For example, the material of the substrate 20 is not limited to cemented carbide, but may be steel, ceramics, or the like. The area of ​​the surface of the substrate 20 that is covered by the coating 30 is not limited to the example in the above embodiment. For example, the coating 30 may cover the entire surface of the substrate 20.

[0053] The film thickness of the film body 31 is not limited to the example of the above embodiment. For example, the film thickness of the film body 31 covering the first substrate surface 22A may be different from the film thickness of the film body 31 covering the second substrate surface 22B.

[0054] The vicinity of the tip 31E of the film body 31 may be flat except for the tip 31E. Specifically, when viewed in a cross section perpendicular to the first axis X, i.e., a cross section perpendicular to the cutting edge 23, the outer edge of the film body 31 between the foot of a perpendicular line PL drawn from the cutting edge 23 to the surface of the film body 31 and the tip 31E of the film body 31 may be linear. Even in this case, the coating 30 having the protrusions 32 can provide at least the effect described in (1).

[0055] The size of the protrusions 32 may be such that the average ratio of the height dimension H to the width dimension W is at least 1 / 5 or less. That is, the average ratio may be greater than 1 / 10 or greater than 1 / 20. The average height dimension H of the protrusions 32 may be greater than 2 μm. For example, the size of the protrusions 32 may be changed appropriately depending on the overall size of the cutting blade 10, the size and hardness of the object to be cut, etc. Even in this case, the protrusions 32 are less likely to scratch the cut surface of the object to be cut.

[0056] The method for determining the width W of the protrusion 32 is not limited to the example in the above embodiment. For example, the width W of the protrusion 32 may be determined by capturing an image of the coating 30 using an electron microscope or the like from a direction perpendicular to the film body 31 and analyzing the image.

[0057] The shape of the recess 33 is not limited to the example in the above embodiment. For example, the recess 33 may be a groove extending in a direction perpendicular to the cutting edge 23, or the recess 33 may not be a groove. The depth D of the recess 33 may be greater than the height H of the protrusion 32 having the recess 33. Even in this case, as long as the height H of the recess 33 is appropriately small, at least the effect described in (1) can be obtained.

[0058] The protrusions 32 do not have to have recesses 33 on their surfaces. Depending on the grinding method used to grind the surface of the coating 30 in the grinding step S12, the protrusions 32 may not have recesses 33. The cutting blade 10 is not limited to those manufactured by the manufacturing method according to the above embodiment. For example, the protrusions 32 may be formed by sputtering or the like after diamond coating.

[0059] In the manufacturing method of the cutting blade 10, the specific method of the grinding step S12 is not limited to the example of the above embodiment. For example, in the grinding step S12, the height dimension H of the protrusion 32 may be reduced by performing laser processing. In this case, the protrusion 32 may not have the recess 33. Furthermore, even if the recess 33 is present, it may not be groove-shaped.

[0060] In the grinding step S12, it is not necessary to use a grindstone as the tool containing the abrasive. Regardless of the type of tool, as long as the surface of the coating 30 can be ground by moving the surface of the coating 30 and the abrasive relative to each other in a direction along the surface of the coating 30, it is easy to make the height dimension H of the multiple protrusions 32 on the coating 30 approximately uniform.

[0061] <Additional Notes> The technical concepts that can be derived from the above embodiments and modified examples are described below. [1] A cutting blade comprising: a substrate that is plate-shaped, at least a part of the outer edge of which is a cutting edge, and that has a blade-side portion that includes the cutting edge and whose thickness decreases toward the cutting edge; and a coating that covers the surface of the blade-side portion, wherein the material of the coating contains diamond, and the coating has a film body that covers the surface of the blade-side portion along the surface of the blade-side portion, and a plurality of protrusions that protrude from the surface of the film body by 0.1 μm or more, wherein when the maximum dimension of a line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is taken as the width dimension and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is taken as the height dimension, the average value of the ratio of the height dimension to the width dimension is 1 / 5 or less.

[0062] [2] The cutting blade according to [1], wherein an average ratio of the height dimension of the protrusions to the width dimension of the protrusions is 1 / 20 or less.

[0063] [3] The cutting blade according to [1] or [2], wherein the average height of the protrusions is 2 μm or less.

[0064] [4] The cutting blade according to any one of [1] to [3], wherein the protrusion has a recess on the surface. [5] The cutting blade according to [4], wherein the recess is a groove extending in a direction along the cutting edge.

[0065] [6] The cutting blade according to [4] or [5], wherein the depth of the recess is smaller than the height dimension of the protrusion in which the recess exists.

[0066] [7] A cutting blade according to any one of [1] to [6], wherein when viewed in cross section perpendicular to the cutting edge, the outer edge of the film body between the foot of a perpendicular line drawn from the cutting edge to the outer surface of the film body and the tip of the coating is a convex curve toward the outside of the film body.

[0067] [8] A method for manufacturing a cutting blade, comprising: a substrate preparation step of preparing a substrate that is plate-shaped and has a cutting edge that is at least a part of the outer edge, and a blade side portion whose thickness decreases toward the cutting edge; a coating formation step of applying a diamond coating to the surface of the substrate to form a film body that covers the surface of the blade side portion along the surface of the blade side portion, and a coating having a plurality of protrusions protruding from the surface of the film body; and a grinding step of grinding the surface of the coating after the coating formation step to make the average value of the ratio of the height dimension to the width dimension to 1 / 5 or less, where the maximum dimension of a line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is the width dimension, and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is the height dimension.

[0068] [9] The method for manufacturing a cutting blade according to [8], wherein in the grinding step, the surface of the coating is ground by relatively moving the surface of the coating and the abrasive in a direction along the surface of the coating, thereby making the average value of the ratio of the height dimension to the width dimension 1 / 5 or less.

[0069] 10... Cutting blade 20... Substrate 23... Cutting edge 24... Ridge MF... Main surface 30... Coating 31... Film body 31E... Tip 32... Projection W... Width dimension H... Height dimension 33... Recess D... Depth PL... Perpendicular line

Claims

1. A cutting blade comprising: a substrate in the shape of a plate, at least a portion of whose outer edge is a cutting edge, having a blade-side portion that includes the cutting edge and that becomes thinner the closer to the cutting edge; and a coating covering the surface of the blade-side portion, wherein the material of the coating contains diamond, and the coating has a film body that covers the surface of the blade-side portion along the surface of the blade-side portion, and a plurality of protrusions protruding from the surface of the film body by 0.1 μm or more, wherein the maximum dimension of a line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is taken as the width dimension, and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is taken as the height dimension, and the average ratio of the height dimension to the width dimension is 1 / 5 or less.

2. The cutting blade according to claim 1, wherein the average ratio of the height dimension of the protrusions to the width dimension of the protrusions is 1 / 20 or less.

3. A cutting blade as claimed in claim 1 or 2, wherein the average height dimension of the protrusions is 2 μm or less.

4. A cutting blade as claimed in any one of claims 1 to 3, wherein the protrusion has a recess on its surface.

5. The cutting blade according to claim 4, wherein the recess is a groove extending in a direction along the cutting edge.

6. A cutting blade as claimed in claim 4 or 5, wherein the depth of the recess is smaller than the height dimension of the protrusion in which the recess exists.

7. A cutting blade as claimed in any one of claims 1 to 6, wherein when viewed in cross section perpendicular to the cutting edge, the outer edge of the film body between the foot of a perpendicular line drawn from the cutting edge to the outer surface of the film body and the tip of the coating is curved convexly outward from the film body.

8. A method for manufacturing a cutting blade, comprising: a substrate preparation step of preparing a substrate having a plate-like cutting edge which is at least a part of the outer edge, and a blade side portion whose thickness decreases toward the cutting edge; a coating formation step of applying a diamond coating to the surface of the substrate to form a film body covering the surface of the blade side portion along the surface of the blade side portion, and a coating having a plurality of protrusions protruding from the surface of the film body; and a grinding step of grinding the surface of the coating after the coating formation step to reduce the average ratio of the height dimension to the width dimension to 1 / 5 or less, where the maximum dimension of a line segment connecting two points on the outer edge of the protrusions when viewed from a direction perpendicular to the surface of the film body is the width dimension, and the maximum dimension of the protrusions in the direction perpendicular to the surface of the film body is the height dimension.

9. A method for manufacturing a cutting blade as described in claim 8, wherein in the grinding process, the surface of the coating is ground by moving the surface of the coating and an abrasive relative to each other in a direction along the surface of the coating, thereby making the average ratio of the height dimension to the width dimension 1 / 5 or less.

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