Cutting blade and manufacturing method of cutting blade

Abstract

To suppress distortion of a cut blade.SOLUTION: A cut blade 10 comprises: a base material 20; a first coating film 30 which covers a part of a surface of the base material 20; and a second coating film which covers a part of the surface of the base material 20 different from the first coating film 30. The base material 20 has a plate-like shape with a main surface MF. The base material 20 has a blade tip 23 at a part of an end of the base material 20. The first coating film 30 covers the blade tip 23. The second coating film 40 covers an end on a side opposite to the blade tip 23 and is separated from the first coating film 30 when viewed from a direction orthogonal to the main surface MF.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cutting blade and a method for manufacturing the cutting blade. [Background technology]

[0002] The cutting blade described in Patent Document 1 includes a substrate having a cutting edge. The substrate is plate-shaped and has a main surface. When viewed from a direction perpendicular to the main surface, the substrate has a rectangular shape. When viewed from a direction perpendicular to the main surface, the cutting edge is provided within the range of one side of the rectangle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-185648 Summary of the Invention [Problem to be solved by the invention]

[0004] In cutting blades such as those described in Patent Document 1, depending on the material to be cut and the material of the substrate, the hardness of the substrate alone may be insufficient. Therefore, in order to improve the surface hardness of the cutting edge of the cutting blade, a coating containing diamond may be applied to the cutting edge. However, the diamond, which is the material of the coating, and the material of the substrate have different thermal expansion coefficients. Therefore, the difference between the amount of thermal expansion of the substrate when the coating is formed and the amount of thermal expansion of the coating remains as stress on the cutting edge of the cutting blade after the coating is formed. If stress remains in a specific location on the cutting blade, it can cause distortion of the cutting blade, etc. [Means for solving the problem]

[0005] In order to solve the above problems, one aspect of the present disclosure is a cutting blade comprising: a substrate having a main surface, a cutting edge at a portion of its edge, and a ridge at the end opposite the cutting edge when viewed from a direction perpendicular to the main surface; a first coating covering a portion of the surface of the substrate; and a second coating covering a portion of the surface of the substrate different from the first coating, wherein the first coating covers at least the cutting edge, and the second coating covers a portion of the surface of the substrate closer to the ridge than the first coating, and the main surface is exposed between the first coating and the second coating.

[0006] In order to solve the above problems, one aspect of the present disclosure is a method for manufacturing a cutting blade, comprising: a substrate preparation step of preparing a substrate that is plate-shaped and has a main surface, a cutting edge on a portion of its edge, and a ridge on the edge opposite the cutting edge when viewed from a direction perpendicular to the main surface; and a coating formation step of coating a portion of the surface of the substrate, wherein the coating formation step forms a first coating that covers at least the cutting edge, a second coating that covers a portion of the surface of the substrate closer to the ridge than the first coating, and an exposed portion where the main surface is exposed between the first coating and the second coating. [Effects of the Invention]

[0007] Distortion of the cutting blade can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] 3 is a cross-sectional view of the cutting blade taken along line 3-3 in FIG. 2. [Figure 4] 5A to 5C are explanatory diagrams illustrating a manufacturing method of a cutting blade. [Figure 5] 5A to 5C are explanatory diagrams illustrating a manufacturing method of a cutting blade. [Figure 6] FIG. 10 is a cross-sectional view of a cutting blade according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] <One embodiment of a cutting blade and a method of manufacturing the cutting blade> An embodiment of a cutting blade and a method for manufacturing the 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] (Cutting blade) As shown in Fig. 1, the cutting blade 10 includes a substrate 20. The substrate 20 is plate-shaped and has a main surface MF. As shown in Fig. 2, the substrate 20 has a rectangular shape when viewed from a direction perpendicular to the main surface MF.

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

[0012] As shown in Fig. 2, the base material 20 can be roughly divided into a ridge side portion 21 and a blade side portion 22. The ridge side portion 21 is a portion of the base material 20 that includes the end in the second negative direction Y2. When viewed from the direction along the third axis Z, the ridge side portion 21 has a rectangular shape that is elongated in the direction along the first axis X. The dimensions of the ridge side portions 21 in the direction along the third axis Z are the same.

[0013] The blade-side portion 22 is a portion of the substrate 20 that includes an end in the second positive direction Y1. 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.

[0014] 3, the surface of the blade side portion 22 facing the third positive direction Z1 is inclined so as to be positioned in the third negative direction Z2 as it approaches the second positive direction Y1. The surface of the blade side portion 22 facing the third negative direction Z2 is inclined so as to be positioned in the third positive direction Z1 as it approaches the second positive direction Y1. Therefore, the dimension of the blade side portion 22 in the direction along the third axis Z, i.e., the thickness, decreases as it approaches the second positive direction Y1.

[0015] As described above, the end of the blade side portion 22 in the second positive direction Y1 forms the cutting edge 23 of the substrate 20. That is, the substrate 20 has the cutting edge 23 over the entire area of ​​the end of the substrate 20 in the second positive direction Y1. As shown in FIG. 2 , the cutting edge 23 is parallel to the first axis X. Furthermore, the end of the ridge side portion 21 in the second negative direction Y2 forms the ridge 24 of the substrate 20. That is, when viewed from the direction along the third axis Z, the end of the substrate 20 opposite the cutting edge 23 forms the ridge 24.

[0016] The dimension of the substrate 20 in the direction along the first axis X is, for example, 100 to 250 mm. The dimension of the substrate 20 in the direction along the second axis Y is, for example, 20 to 30 mm. The dimension of the ridge side portion 21 in the direction along the third axis Z is, for example, 0.05 to 0.5 mm.

[0017] The material of the substrate 20 is a cemented carbide. A cemented carbide is a sintered powder of a hard metal carbide. For example, tungsten carbide is mixed with cobalt as a binder and sintered.

[0018] 2, the cutting blade 10 includes a first coating 30 and a second coating 40. The first coating 30 covers the entire surface of the base material 20, including the entire blade-side portion 22 and a portion of the surface of the base material 20, including the vicinity of the connection between the ridge-side portion 21 and the blade-side portion 22. Therefore, the first coating 30 covers the cutting edge 23 of the base material 20. The dimension of the first coating 30 in the direction along the second axis Y is approximately constant over the entire area in the direction along the first axis X.

[0019] The material of the first coating 30 is diamond, which has a higher hardness than the cemented carbide that is the material of the substrate 20. The thickness of the first coating 30 is, for example, 1 to 20 μm.

[0020] The second coating 40 covers a portion of the surface of the substrate 20, including the end of the ridge side portion 21 in the second negative direction Y2. Therefore, the second coating 40 covers the ridge 24 of the substrate 20. The dimension of the second coating 40 in the direction along the second axis Y is approximately constant over the entire area in the direction along the first axis X. Furthermore, the average dimension of the second coating 40 in the direction along the second axis Y is the same as the average dimension of the first coating 30 in the direction along the second axis Y.

[0021] The average dimension of each coating in the direction along the second axis Y is the average value of the dimensions of three locations in the direction along the second axis Y of each coating in a single image taken of the cutting blade 10 from the direction along the third axis Z. The material of the second coating 40 is diamond, which is the same as the material of the first coating 30. The thickness of the second coating 40 is 1 to 20 μm.

[0022] The first coating 30 and the second coating 40 are not in contact with each other. Therefore, the surface of the substrate 20 is exposed between the first coating 30 and the second coating 40. The area of ​​the substrate 20 exposed between the first coating 30 and the second coating 40 is referred to as the exposed area ER. The average dimension of the exposed area ER in the direction along the second axis Y is 50% or more of the dimension of the substrate in the direction along the second axis Y.

[0023] The average dimension of the exposed range ER in the direction along the second axis Y is the average value of the dimensions of three points in the direction along the second axis Y of the exposed range ER in a single image taken of the cutting blade 10 from the direction along the third axis Z.

[0024] (Cutting blade manufacturing method) Next, a method for manufacturing the cutting blade 10 will be described. As shown in FIG. 4, the method for manufacturing the cutting blade 10 includes a substrate preparation step S11 and a coating formation step S12.

[0025] First, a substrate preparation step S11 is performed to prepare a substrate 20 in the form of a plate having a main surface MF and a cutting edge 23 at its end. For example, the substrate 20 is prepared by cutting and polishing a cemented carbide plate to form a blade side portion 22.

[0026] Next, a coating step S12 is performed in which diamond is coated on a portion of the surface of the substrate 20 prepared in the substrate preparation step S11. In the coating step S12, diamond coating is performed by chemical vapor deposition (CVD).

[0027] 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.

[0028] Next, a seeding process is performed to seed diamond nanoparticles onto the pretreated surface of the substrate 20. In the seeding process, the substrate 20 is immersed in a solvent in which diamond nanoparticles have been dispersed. This causes the diamond nanoparticles to adhere to the tungsten carbide on the surface of the substrate 20.

[0029] Next, diamond coating is performed using a film forming apparatus 50 shown in Figure 5. The film forming apparatus 50 is equipped with 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 exhaust port 63 for exhausting the reacted gas from the reaction space 61.

[0030] The film forming apparatus 50 is equipped with a holder 70 that holds the substrate 20 in the chamber 60. The holder 70 can be separated into two halves, one above the other in the direction of gravity and the other in the opposite direction, and can sandwich from above and below an area corresponding to the exposed area ER of the substrate 20. Therefore, when the holder 70 sandwiches the substrate 20, a portion of the substrate 20 on the cutting edge 23 side and a portion of the substrate 20 on the ridge 24 side are not covered by the holder 70 and are exposed from the holder 70.

[0031] The film forming apparatus 50 is equipped with a heat source 80 that heats the substrate 20 in the chamber 60. The heat source 80 has a first heat filament 81 and a second heat filament 82. The first heat filament 81 and the second heat filament 82 are located on opposite sides of the holder 70. In other words, when the substrate 20 is sandwiched between the holder 70, the first heat filament 81 is located on the cutting edge 23 side of the substrate 20, and the second heat filament 82 is located on the ridge 24 side of the substrate 20. Therefore, by sandwiching the substrate 20 between the holder 70 as described above, the heat source 80 is located on both the cutting edge 23 side of the substrate 20 and the ridge 24 side opposite the cutting edge 23, as viewed from the holder 70.

[0032] In the film-forming device 50, the substrate 20 is sandwiched between the holders 70, and reactive gases, methane and hydrogen, are flowed into the chamber 60. Then, the heat source 80 is controlled for a predetermined time so that the substrate 20 is heated to 600 to 800°C. This causes the diamond nanoparticles attached to the surface of the substrate 20 to grow, forming a diamond coating, and the first coating 30 and the second coating 40 are simultaneously formed. In this way, the first coating 30 and the second coating 40 are formed on the substrate 20, and the cutting blade 10 is manufactured.

[0033] (Operation of the embodiment) In the above embodiment, the diamond, which is the material of the first coating 30, and the cemented carbide, which is the material of the substrate 20, have different thermal expansion coefficients. Therefore, the difference between the amount of thermal expansion of the substrate 20 when the first coating 30 is formed in the coating formation step S12 and the amount of thermal expansion of the first coating 30 remains as stress around the cutting edge 23 in the cutting blade 10 after the coating has been formed. Similarly, the difference between the amount of thermal expansion of the substrate 20 when the second coating 40 is formed in the coating formation step S12 and the amount of thermal expansion of the second coating 40 remains as stress around the ridge 24 in the cutting blade 10 after the coating has been formed.

[0034] (Effects of the embodiment) (1) According to the above embodiment, as described above, stress is generated around the cutting edge 23 of the substrate 20 due to the formation of the first coating 30. Meanwhile, stress is also generated around the ridge 24 of the substrate 20 due to the formation of the second coating 40. In this way, stress is generated on both the cutting edge 23 side and the ridge 24 side of the substrate 20, so that stress is not unevenly distributed across the substrate 20 and is balanced. Therefore, distortion, etc., of the cutting blade 10 after the coating is formed can be suppressed.

[0035] (2) According to the cutting blade 10 of the above embodiment, when viewed from the direction along the third axis Z, the average dimension of the first coating 30 in the direction along the second axis Y and the average dimension of the second coating 40 in the direction along the second axis Y are the same. Therefore, the magnitude of the stress remaining in the portion on the cutting edge 23 side and the magnitude of the stress remaining in the portion on the ridge 24 side tend to be the same. As a result, when the substrate 20 is viewed as a whole, it is possible to prevent large stress from occurring in only specific locations on the substrate 20.

[0036] (3) In the cutting blade 10 of the above embodiment, the dimension of the exposed area ER in the direction along the second axis Y is 50% or more of the dimension of the substrate 20 in the direction along the second axis Y. In other words, although a coating is present on both the cutting edge 23 and the ridge 24 of the substrate 20, 50% or more of the surface area of ​​the substrate 20 is the exposed area ER that is not diamond coated. By increasing the exposed area ER in this way, a large portion of the substrate 20 can be made less susceptible to the stress associated with the coating. As a result, the occurrence of cracks or fractures in the cutting blade 10 can be suppressed during the coating formation step S12.

[0037] (4) If the first coating 30 and the second coating 40 are formed in that order in the coating formation step S12, a situation may occur in which only one of the coatings is formed during the manufacturing process. If the cutting blade 10 is distorted in this manner when only one of the coatings is formed, there is a risk that the distortion may not be resolved even if the other coating is later formed. In this regard, according to the manufacturing method for the cutting blade 10 of the above embodiment, the first coating 30 and the second coating 40 are formed simultaneously, which allows the films to be formed while balancing the stresses on both sides, and distortion of the cutting blade 10 can be more effectively suppressed.

[0038] (5) According to the manufacturing method of the cutting blade 10 of the above embodiment, the heat sources 80 are disposed on both the cutting edge 23 side and the ridge 24 side when viewed from the holder 70. This reduces the temperature difference between the portion of the surface of the substrate 20 exposed on the cutting edge 23 side and the portion exposed on the ridge 24 side. This makes it easier to make the thickness of the first coating 30 and the thickness of the second coating 40 uniform. As a result, it is easier to make the stress generated on the cutting edge 23 side and the stress generated on the ridge 24 side uniform.

[0039] <Other embodiments> The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined and implemented within the scope of technical compatibility.

[0040] The shape of the substrate 20 is not limited to the example in the above embodiment. For example, when viewed from the direction along the third axis Z, the shape of the substrate 20 may be a square or a rectangle whose dimension along the second axis Y is longer than that along the first axis X. Furthermore, when viewed from the direction along the third axis Z, the shape of the substrate 20 may be such that one or both of the cutting edge 23 and the ridge 24 extend in an arc-like or wavy shape.

[0041] The shape of the base material 20 is not limited to a double-edged shape, but may be a single-edged shape. Furthermore, the cutting edge 23 may be a so-called saw blade. The material of the substrate 20 is not limited to the example in the above embodiment. For example, the material of the substrate 20 may be a cemented carbide alloy containing titanium carbide, titanium carbonitride, or the like. Furthermore, the material of the substrate 20 is not limited to a cemented carbide alloy, and may be steel or ceramics.

[0042] The size of the substrate 20 is not limited to the example in the above embodiment. The dimension of the substrate 20 along the first axis X may be smaller than 100 mm or larger than 250 mm. The dimension of the substrate 20 along the second axis Y may be smaller than 20 mm or larger than 30 mm. Furthermore, the dimension of the ridge side portion 21 along the third axis Z may be smaller than 0.05 mm or larger than 0.5 mm.

[0043] The range of the base material 20 where the cutting edge 23 is present is not limited to the example in the above embodiment. For example, when viewed from the direction along the third axis Z, the cutting edge 23 may be located on a short side of a rectangle, or may be located on a part of one side of the rectangle.

[0044] The area of ​​the surface of the base material 20 that is covered by the first coating 30 is not limited to the example in the above embodiment. The first coating 30 only needs to cover at least the cutting edge 23. Furthermore, when viewed from the direction along the third axis Z, the dimension of the first coating 30 along the second axis Y may vary depending on the position along the first axis X. Even in this case, when viewed from the direction along the third axis Z, it is preferable that the average dimension of the first coating 30 along the second axis Y is the same as the average dimension of the second coating 40 along the second axis Y. Note that "the two average dimensions are the same" means that the difference between the two average dimensions is within 5%. This allows for manufacturing errors and the like in the first coating 30 and the second coating 40.

[0045] The area of ​​the surface of the substrate 20 that is covered by the second coating 40 is not limited to the example of the above embodiment. For example, as in the cutting blade 110 of a modified example shown in FIG. 6, the second coating 40 only needs to cover at least the ridge 24. Furthermore, the second coating 40 only needs to be separated from the first coating 30.

[0046] The size of the exposed area ER is not limited to the example in the above embodiment. The exposed area ER only needs to be present by separating the second coating 40 from the first coating 30, and the dimension of the exposed area ER in the direction along the second axis Y may be less than 50% of the dimension of the substrate 20 in the direction along the second axis Y.

[0047] The thickness of the first coating 30 and the thickness of the second coating 40 may be different. The material of the first coating 30 and the material of the second coating 40 may contain diamond and may be a material that can harden the surface of the substrate 20 .

[0048] In the embodiment of the manufacturing method described above, one or both of the pre-treatment and seeding treatment in the coating formation step S12 may be omitted or may be replaced with other treatments. In the embodiment of the manufacturing method described above, the coating formation step S12 does not necessarily require the use of the film forming apparatus 50. In this case, the first coating 30 and the second coating 40 may be formed regardless of the configuration of the holder 70, the heat source 80, etc. For example, the first coating 30 and the second coating 40 may be formed using a single heat source 80.

[0049] In the embodiment of the manufacturing method described above, the first coating 30 and the second coating 40 do not have to be formed simultaneously in the coating formation step S12. The first coating 30 may be formed first, and then the second coating 40 may be formed. In this case, the step of forming the first coating 30 and the step of forming the second coating 40 are combined into the coating formation step S12. [Explanation of symbols]

[0050] 10...Cutting blade 20...Base material 21...Mountain side part 22...Blade side part 23...Cutting edge 24…mine 30...First coating 40…Second coating 50…Film forming equipment 60...Chamber 70...Holder 80…Heat source 81...First thermal filament 82...Second thermal filament ER: Exposure range MF...Main surface S11…Base material preparation process S12…Film formation process

Claims

1. a substrate having a main surface, a cutting edge at a part of an edge thereof, and a ridge at an end opposite to the cutting edge when viewed in a direction perpendicular to the main surface; a first coating covering a portion of the surface of the substrate; a second coating covering a portion of the surface of the substrate that is different from the first coating; the first coating covers at least the cutting edge, the second coating covers a portion of the surface of the base material that is closer to the ridge than the first coating, The main surface has an exposed portion between the first coating and the second coating. Cutting blade.

2. The first coating contains diamond as a material. The cutting blade according to claim 1 .

3. The ratio of the area of ​​the exposed portion to the entire area of ​​the main surface is 50% or more. The cutting blade according to claim 1 or 2.

4. The cutting edge extends in an arc shape. The cutting blade according to any one of claims 1 to 3.

5. The second coating covers the ridge. The cutting blade according to any one of claims 1 to 4.

6. a substrate preparation step of preparing a substrate having a plate shape with a main surface, a cutting edge at a part of an edge thereof, and a ridge at an end opposite to the cutting edge when viewed from a direction perpendicular to the main surface; a coating forming step of coating a portion of the surface of the substrate; Equipped with In the coating forming step, a first coating that covers at least the cutting edge, a second coating that covers a portion of the surface of the base material closer to the ridge side than the first coating, and an exposed portion where the main surface is exposed between the first coating and the second coating are formed. Manufacturing method of cutting blade.

7. In the coating forming step, a film-forming apparatus including a chamber into which a reaction gas flows, a holder for holding the substrate in the chamber, and a heat source for heating the substrate in the chamber; The substrate is held by the holder so that at least the portion of the ridge side of the cutting edge and the portion where the holder contacts is exposed, and then the first coating and the second coating are simultaneously formed by coating in the same chamber. The method for manufacturing the cutting blade according to claim 6.

8. In the coating forming step, heat sources are disposed on the cutting edge side and the opposite side of the cutting edge when viewed from the holder. The method for manufacturing the cutting blade according to claim 7.

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