Cut blade, and cut blade manufacturing method

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 a 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 is rectangular. 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] JP 2020-185648 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the cutting blade described in Patent Document 1, depending on the material to be cut and the material of the substrate, the hardness may be insufficient with only the substrate. Therefore, in order to improve the surface hardness of the cutting edge of the cutting blade, a coating containing diamond may be provided on the cutting edge. However, the thermal expansion coefficients of diamond, which is the material of the coating, and the material of the substrate are different. 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 remain as stress on the cutting edge of the cutting blade after the coating is formed. If stress remains at a specific point of the cutting blade, it may cause distortion of the cutting blade. [Means for solving the problem]

[0005] In order to solve the above problems, one embodiment of the present disclosure is a cutting blade comprising: a substrate having a main surface, a cutting edge at a portion of its end, and a ridge at an end opposite 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; 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 cutting blade has an exposed portion where 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 having a plate-like main surface, a cutting edge on a portion of its edge, and a ridge on an 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. Effect of the Invention

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

[0008] [Figure 1] FIG. [Diagram 2] FIG. [Diagram 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. [Diagram 5] 5A to 5C are explanatory diagrams illustrating a manufacturing method of a cutting blade. [Figure 6] 13 is a cross-sectional view of a cutting blade according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <One embodiment of cutting blade and method of manufacturing cutting blade> Hereinafter, an embodiment of a cutting blade and a manufacturing method for the cutting blade will be described. Note that the drawings may show components enlarged for ease of 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] Here, as shown in FIG. 1, an axis along the long side of the four sides of the rectangular base material 20 when viewed from a direction perpendicular to the main surface MF is defined as the first axis X. Furthermore, an axis along the short side of the four sides of the rectangular base material 20 when viewed from a direction perpendicular to the main surface MF is defined as the second axis Y. Furthermore, an axis extending in a direction perpendicular to the main surface MF is defined as the third axis Z. Then, one of the directions along the first axis X is defined as the first positive direction X1, and the other of the directions along the first axis X is defined as the first negative direction X2. One of the directions along the second axis Y is defined as the second positive direction Y1, and the other of the directions along the second axis Y is defined as the second negative direction Y2. One of the directions along the third axis Z is defined as the third positive direction Z1, and the other of the directions along the third axis Z is defined as the third negative direction Z2.

[0012] 2, the substrate 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 substrate 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 portion 21 in the direction along the third axis Z are uniform.

[0013] The blade side portion 22 is a portion that includes the end of the base material 20 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 located 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 located 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, becomes smaller as it approaches the second positive direction Y1.

[0015] In this manner, the end of the blade side portion 22 in the second positive direction Y1 becomes the cutting edge 23 of the substrate 20. That is, the substrate 20 has the cutting edge 23 over the entire 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. Also, the end of the ridge side portion 21 in the second negative direction Y2 becomes 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 is 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 a portion of the surface of the substrate 20, including the entire surface of the blade side portion 22 and the vicinity of the connection portion of the ridge side portion 21 with the blade side portion 22. Therefore, the first coating 30 covers the cutting edge 23 of the substrate 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. Therefore, the material of the first coating 30 has a higher hardness than the cemented carbide which is the material of the base material 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. In addition, 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 points 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 range of the substrate 20 exposed between the first coating 30 and the second coating 40 is defined as the exposed range ER. The average dimension of the exposed range 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 of the exposed range ER in the direction along the second axis Y in a single image taken of the cutting blade 10 from a direction along the third axis Z.

[0024] (Manufacturing method of cutting blade) 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 having a plate shape with a main surface MF and a cutting edge 23 at an 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 film forming 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 film forming step S12, diamond coating is performed by chemical vapor deposition, or a so-called CVD (chemical vapor deposition) method.

[0027] Specifically, first, the substrate 20 is pretreated. In the pretreatment of the substrate 20, the cobalt, which is a binder, is removed from the surface of the substrate 20 by using a chemical solution or the like. As a result, tungsten carbide particles are exposed 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 are 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 Fig. 5. The film forming apparatus 50 is equipped with a chamber 60 into which a reactive 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 reactive 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 includes a holder 70 that holds the substrate 20 in the chamber 60. The holder 70 can be separated into two, upper and lower, in the direction of gravity and 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 part of the substrate 20 on the cutting edge 23 side and a part 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 includes a heat source 80 for heating the substrate 20 in the chamber 60. The heat source 80 includes 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, as described above, by sandwiching the substrate 20 between the holder 70, the heat source 80 is disposed on the cutting edge 23 side of the substrate 20 and on the ridge 24 side opposite the cutting edge 23, as viewed from the holder 70.

[0032] In the film-forming apparatus 50, the substrate 20 is sandwiched between the holders 70, and reactive gases, methane and hydrogen, are introduced 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 manner, 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 is 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 is 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 the stress is not unevenly distributed across the substrate 20 as a whole and is balanced. Therefore, it is possible to suppress the occurrence of distortion, etc. in the cutting blade 10 after the coating is formed.

[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 is the same as the average dimension of the second coating 40 in the direction along the second axis Y. 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 uniform. As a result, when the substrate 20 is viewed as a whole, it is possible to prevent large stress from occurring only in a specific portion of the substrate 20.

[0036] (3) According to 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 manner, a large portion of the substrate 20 can be made to be less susceptible to the stress associated with the coating. As a result, the occurrence of cracks or fissures in the cutting blade 10 during the coating formation step S12 can be suppressed.

[0037] (4) If the first coating 30 and the second coating 40 are formed in that order in the coating formation step S12, a state in which only one of the coatings is formed occurs 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 cannot be eliminated even if the other coating is formed later. 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, so that the films can 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 base material 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 may be modified as follows: The above-described embodiments and the following modifications may be combined and implemented within the scope of technical compatibility.

[0040] The shape of the substrate 20 is not limited to the example of the above embodiment. For example, the shape of the substrate 20 may be a square shape or a rectangle whose dimension along the second axis Y is longer than that along the first axis X when viewed from the direction along the third axis Z. Also, for example, 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 shape or a wavy shape when viewed from the direction along the third axis Z.

[0041] In addition, 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 of the above embodiment. For example, the material of the substrate 20 may be a cemented carbide containing titanium carbide, titanium carbonitride, or the like. The material of the substrate 20 is not limited to a cemented carbide, and may be a steel material or a ceramic.

[0042] The size of the substrate 20 is not limited to the example of the above embodiment. The dimension of the substrate 20 in the direction along the first axis X may be smaller than 100 mm or larger than 250 mm. The dimension of the substrate 20 in the direction along the second axis Y may be smaller than 20 mm or larger than 30 mm. In addition, the dimension of the ridge side portion 21 in the direction 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 exists is not limited to the example of 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 in the direction along the second axis Y may vary depending on the position in the direction along the first axis X. Even in this case, it is preferable that the average dimension of the first coating 30 in the direction along the second axis Y is the same as the average dimension of the second coating 40 in the direction along the second axis Y when viewed from the direction along the third axis Z. Here, "the two average dimensions being the same" means that the difference between the two average dimensions is within 5%. This means that the first coating 30 and the second coating 40 allow for manufacturing errors and the like.

[0045] The area of ​​the surface of the base material 20 that is covered by the second coating 40 is not limited to the example of the above embodiment. For example, as in a cutting blade 110 of a modified example shown in FIG. 6, the second coating 40 only needs to cover at least the ridge 24. In addition, 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 of the above embodiment. It is sufficient that the exposed area ER exists 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 be any material that contains diamond and is capable of hardening the surface of the base material 20 .

[0048] In the embodiment of the manufacturing method described above, one or both of the pretreatment and the seeding treatment in the coating formation step S12 may be omitted or may be replaced with another treatment. In the embodiment of the manufacturing method described above, the film forming process S12 does not need to use the film forming apparatus 50. In this case, it is sufficient to form the first coating 30 and the second coating 40 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 by a single heat source 80.

[0049] In the embodiment of the manufacturing method described above, in the coating formation step S12, the first coating 30 and the second coating 40 do not have to be formed simultaneously. 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…Edge 24…mine 30...First coating 40…Second coating 50…Film forming equipment 60…Chamber 70...Holder 80…Heat source 81…First hot filament 82…Second heat 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 on a part of an end thereof, and a ridge on an end opposite to the cutting edge when viewed in a direction perpendicular to the main surface; A first coating covering a portion of a surface of the substrate; a second coating covering a portion of the surface of the base material 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. A cutting blade according to any one of claims 1 to 3.

5. The second coating covers the ridge. A 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, 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 is formed to cover at least the cutting edge, a second coating is formed to cover 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 is formed. Manufacturing method of cutting blade.

7. In the coating process, A film forming apparatus is used, the film forming apparatus comprising: a chamber into which a reactive gas is introduced; 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 the first coating and the second coating are formed simultaneously by coating in the same chamber. A method for manufacturing the cutting blade according to claim 6.

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

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