Grinding tool and manufacturing method thereof

Abstract

To provide a grinding tool capable of improving grinding accuracy and a manufacturing method thereof. [Solution] The grinding tool 1 comprises a plurality of diamond abrasive grains 2 made of synthetic diamond, and a substrate 3 to which the plurality of diamond abrasive grains 2 are fixed. The plurality of diamond abrasive grains 2 are fixed in a single layer to the surface 31 of the substrate 3. The surface of each of the plurality of diamond abrasive grains 2 has a plurality of flat surfaces 21 which are crystal faces, and corners 22 connecting the flat surfaces 21. When the grinding tool 1 is used to grind an object to be ground, the portion of the diamond abrasive grains 2 that comes into contact with the object to be ground is defined as the contact portion 11. The grinding tool 1 has more diamond abrasive grains 2 whose contact portions 11 are corners 22 than diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21.

Description

[Technical Field]

[0001] The present invention relates to a grinding tool and a method for manufacturing the same. [Background technology]

[0002] For example, as disclosed in Patent Document 1, a rotary dresser is known in which a single layer of synthetic diamond abrasive grains is fixed to the outer peripheral surface of a base metal. In the rotary dresser described in Patent Document 1, the abrasive grains in the abrasive layer have a flat working surface. In addition, the rotary dresser described in Patent Document 1 reduces the number of abrasive grains per circumference of the rotary dresser in areas with larger diameters in the abrasive layer, thereby reducing the area ratio of the working surface on the surface of the abrasive layer. This reduces the difference in dressing resistance between the large-diameter and small-diameter sections of the rotary dresser, thereby improving the precision of the dressed grinding wheel and extending the life of the rotary dresser. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7450134 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the number of abrasive grains is reduced too much in order to reduce the dressing resistance during grinding, unevenness may occur on the surface of the grinding wheel after dressing, which may cause waviness on the surface of the workpiece that is the object of grinding with the grinding wheel. Therefore, it can be said that there is room for further improvement in the rotary dresser described in Patent Document 1 from the viewpoint of improving grinding accuracy.

[0005] The present invention has been made in view of the above background, and aims to provide a grinding tool that can improve grinding accuracy and a method for manufacturing the same. [Means for solving the problem]

[0006] The first aspect of the present invention is a grinding tool comprising a plurality of diamond abrasive grains made of synthetic diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average contact area, and the coefficient of variation obtained by dividing the standard deviation of the area of ​​the surface of the contact portion by the average contact area is defined as the coefficient of variation of the contact portion, The contact portion variation coefficient is 50 or more. Grinding tools 。

[0007] The present invention No. 2 The embodiment of the present invention comprises a plurality of diamond abrasive grains made of synthetic diamond, a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the grinding tool is used to grind an object, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface of the diamond abrasive grain other than the main surface is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average contact area, and the coefficient of variation obtained by dividing the standard deviation of the area of ​​the surface of the contact portion by the average contact area is defined as the coefficient of variation of the contact portion, The contact portion variation coefficient is 50 or more. Found in grinding tools.

[0008] The present invention Third The embodiment of the present invention is 1 of A method for manufacturing a grinding tool according to an embodiment, comprising: a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the diamond abrasive grains whose contact portions become the corner portions are more numerous than the diamond abrasive grains whose contact portions become the flat surface, In the method for manufacturing a grinding tool, after the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface. The present invention Fourth The embodiment of a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the diamond abrasive grains whose contact portions become the corner portions are more numerous than the diamond abrasive grains whose contact portions become the flat surface, After the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface; In the first attaching step, the diamond abrasive grains before being attached to the mold are held using vacuum tweezers or adhesive tweezers, and the diamond abrasive grains are attached to the attachment surface. The present invention relates to a manufacturing method of a grinding tool.

[0009] The present invention No. 5 The embodiment of the present invention is 1 of A method for manufacturing a grinding tool according to an embodiment, comprising: A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions become the corner portions is greater than the number of diamond abrasive grains whose contact portions become the flat surface, In the method for manufacturing a grinding tool, after the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface. The present invention No. 6 The embodiment of a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions become the corner portions is greater than the number of diamond abrasive grains whose contact portions become the flat surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface by a binder while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface; In the second attaching step, the diamond abrasive grains are attached to the fixing surface while being held using vacuum tweezers or adhesive tweezers. The present invention relates to a manufacturing method of a grinding tool.

[0010] The present invention Seventh The embodiment of the present invention is Second A method for manufacturing a grinding tool according to an embodiment, comprising: a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, In the method for manufacturing a grinding tool, after the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface. The present invention No. 8 The embodiment of a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the grinding tool is used to grind an object, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface of the diamond abrasive grain other than the main surface is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface; In the first attaching step, the diamond abrasive grains before being attached to the mold are held using vacuum tweezers or adhesive tweezers, and the diamond abrasive grains are attached to the attachment surface. The present invention relates to a manufacturing method of a grinding tool.

[0011] The present invention No. 9 The embodiment of the present invention is Second A method for manufacturing a grinding tool according to an embodiment, comprising: A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, In the method for manufacturing a grinding tool, after the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface. The present invention No. 10 The embodiment of a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the grinding tool is used to grind an object, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface of the diamond abrasive grain other than the main surface is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface by a binder while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface; In the second attaching step, the diamond abrasive grains are attached to the fixing surface while being held using vacuum tweezers or adhesive tweezers. The present invention relates to a manufacturing method of a grinding tool. [Effects of the Invention]

[0012] No. 1 of In the grinding tool of this embodiment, the number of diamond abrasive grains whose contact area is a corner is greater than the number of diamond abrasive grains whose contact area is a flat surface. Therefore, it is possible to reduce the grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the substrate. As a result, it is possible to improve the grinding accuracy.

[0013] No. 2 In the grinding tool of this embodiment, the number of diamond abrasive grains whose contact portion is either the minor surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the major surface. Therefore, it is possible to reduce the grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the substrate.

[0014] Third , Fourth In the method for manufacturing a grinding tool of this embodiment, in the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains that contact the corners is greater than the number of diamond abrasive grains that contact the flat surface. Therefore, it is possible to manufacture a grinding tool that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the substrate.

[0015] No. 5 , No. 6 In the method for manufacturing a grinding tool of this aspect, in the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains that contact the corners is greater than the number of diamond abrasive grains that contact the flat surface. Therefore, it is possible to manufacture a grinding tool that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the base material.

[0016] Seventh , No. 8 In the method for manufacturing a grinding tool of this aspect, in the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portion is either the minor surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the major surface. Therefore, it is possible to manufacture a grinding tool that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the base portion.

[0017] No. 9 , No. 10 In the method for manufacturing a grinding tool of this aspect, in the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portion is either the minor surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the major surface. Therefore, it is possible to manufacture a grinding tool that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains fixed to the base portion.

[0018] As described above, according to the above-described aspect, it is possible to provide a grinding tool and a manufacturing method thereof that can improve grinding accuracy. [Brief explanation of the drawings]

[0019] [Figure 1] 3 is a photograph of a grinding tool according to the first embodiment. [Figure 2] FIG. 1 is a perspective view of a grinding tool according to a first embodiment. [Figure 3] 3 is an external view of the grinding tool in the first embodiment, taken along the line III in FIG. 4. [Figure 4] IV arrow view of Figure 3. [Figure 5]3 is a cross-sectional view of the vicinity of a contact portion of a grinding tool in the first embodiment. [Figure 6] 1 is a perspective view of a diamond abrasive grain having a (100) face and a (111) face in the first embodiment. [Figure 7] 1 is a perspective view of a diamond abrasive grain having a (100), (110), (111), and (113) face in embodiment 1. FIG. [Figure 8] 3A and 3B are diagrams showing how an object to be ground is ground by a grinding tool in the first embodiment. [Figure 9] FIG. 4 is a cross-sectional view showing a state in which a first attaching step is performed using vacuum tweezers in the first embodiment. [Figure 10] FIG. 3 is a cross-sectional view showing a state in which a substrate portion is placed in a mold according to the first embodiment. [Figure 11] FIG. 10 is a cross-sectional view showing a comparative example in which diamond abrasive grains are arranged on the inner surface of a mold. [Figure 12] FIG. 10 is a cross-sectional view showing a state in which a second attaching step is performed using vacuum tweezers in the second embodiment. [Figure 13] FIG. 10 is a cross-sectional view showing a state in which a substrate portion is placed in a mold according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] (Embodiment 1) 1. Applications of grinding tools As shown in FIG. 8, the grinding tool 1 of this embodiment can be applied to, for example, a dressing device that dresses the grinding surface of a grinding wheel 10 that grinds a workpiece W into a desired shape.

[0021] 2. Overview of grinding tool configuration 1 to 5, the grinding tool 1 of this embodiment includes a plurality of diamond abrasive grains 2 made of synthetic diamond, and a substrate 3 to which the plurality of diamond abrasive grains 2 are fixed. As shown in FIG. 5, the plurality of diamond abrasive grains 2 are fixed in a single layer on a surface 31 of the substrate 3.

[0022] As shown in Figures 6 and 7, the surface of each of the multiple diamond abrasive grains 2 has multiple flat surfaces 21 that are crystal planes, and corners 22 that connect the flat surfaces 21. As shown in Figures 5 and 8, when the grinding tool 1 is used to grind the object 10, the parts of the diamond abrasive grains 2 that come into contact with the object 10 are defined as contact parts 11. At this time, the grinding tool 1 has more diamond abrasive grains 2 whose contact parts 11 are corners 22 than diamond abrasive grains 2 whose contact parts 11 are flat surfaces 21.

[0023] 3.Detailed configuration of grinding tool In this embodiment, the substrate 3 is a metal base formed into a disk shape as shown in Figures 1 to 4. The substrate 3 can be made of a metal material such as steel, a titanium alloy, or an aluminum alloy.

[0024] As shown in FIGS. 1 to 3, the substrate 3 has a shaft hole 30 formed therein, which is fitted onto the rotation shaft of a grinding device (not shown). In this embodiment, the diamond abrasive grains 2 are fixed to the outer peripheral surface of the substrate 3, within the surface 31 of the substrate 3, as shown in FIG. 5. The grinding tool 1 is then rotated around the rotation shaft of the grinding device, and the outer peripheral surface 12 of the grinding tool 1, on which the diamond abrasive grains 2 are exposed, is brought into sliding contact with the object 10 to be ground, as shown in FIG. 8, thereby grinding the object 10 to be ground. In this embodiment, the object 10 to be ground is a grinding wheel for grinding a workpiece W. In other words, the grinding tool 1 dresses the grinding surface of the grinding wheel 10 for grinding the workpiece W with the diamond abrasive grains 2.

[0025] 1, 2, 4, and 5, the outer peripheral surface 12 of the grinding tool 1 has a recess 121 recessed inward at the center in the penetration direction of the shaft hole 30. The grinding tool 1 of this embodiment performs dressing by bringing the outer peripheral surface 12 of the grinding tool 1, including the recess 121, into sliding contact with the outer peripheral surface of the object 10 to be ground.

[0026] The plurality of diamond abrasive grains 2 fixed to the substrate 3 are evenly arranged on the outer peripheral surface 12 of the grinding tool 1. In this embodiment, the diamond abrasive grains 2 are fixed to the substrate 3 without contacting each other. The distance between adjacent diamond abrasive grains 2 can be set appropriately depending on the purpose. The outer diameter of the diamond abrasive grains 2 can be, for example, from several hundred μm to over 1000 μm. In this embodiment, the diamond abrasive grains 2 are single crystal diamond. Note that the diamond abrasive grains are not shown in Figures 2 to 4.

[0027] As shown in Figure 5, the plurality of diamond abrasive grains 2 are fixed to the outer peripheral surface of the substrate 3 via a binder 43. In this embodiment, the binder 43 is provided over the entire outer peripheral surface of the substrate 3. Each diamond abrasive grain 2 protrudes outward from the binder 43. The binder 43 can be made of a metal such as copper, zinc, tungsten, or nickel, or an alloy thereof.

[0028] 6 and 7, the plurality of flat surfaces 21 of the diamond abrasive grains 2 have at least one of a (100) surface and a (111) surface. The (100) surface and the (111) surface of the diamond abrasive grains 2 are defined as the main surfaces 211, and the flat surfaces 21 of the diamond abrasive grains 2 other than the main surfaces 211 are defined as the sub-surfaces 212. In this case, the grinding tool 1 has more diamond abrasive grains 2 whose contact portions 11 are either the sub-surfaces 212 or the corner portions 22 than diamond abrasive grains 2 whose contact portions 11 are the main surfaces 211. Furthermore, it is preferable that the grinding tool 1 has more diamond abrasive grains 2 whose contact portions 11 are the sub-surfaces 212 than diamond abrasive grains 2 whose contact portions 11 are the main surfaces 211. In this embodiment, the multiple diamond abrasive grains 2 include diamond abrasive grains 2 whose contact portion 11 is the main surface 211, diamond abrasive grains 2 whose contact portion 11 is the sub-surface 212, and diamond abrasive grains 2 whose contact portion 11 is the corner portion 22.

[0029] In this embodiment, the plurality of diamond abrasive grains 2 include diamond abrasive grains 2 having (111) and (100) crystal faces as shown in FIG. 6, and diamond abrasive grains 2 having (110) and (113) crystal faces in addition to (111) and (100) faces as shown in FIG. 7. In the diamond abrasive grains 2 shown in FIG. 7, the (110) and (113) faces are sub-faces 212. In the diamond abrasive grains 2 shown in FIG. 7, the area of ​​each main face 211 is larger than the area of ​​each sub-face 212. In other words, in the diamond abrasive grains 2 shown in FIG. 7, the area of ​​the (111) and (100) faces is larger than the area of ​​the (110) and (113) faces.

[0030] 6 and 7, the corner portion 22 has a ridge portion 221 connecting two flat surfaces 21 together, and an apex portion 222 connecting three or more flat surfaces 21 together. In the grinding tool 1 of this embodiment, there are more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than there are diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21. In addition, in the grinding tool 1, there are more diamond abrasive grains 2 whose contact portions 11 are corner portions 22 than there are diamond abrasive grains 2 whose contact portions 11 are main surfaces 211. It is preferable that the grinding tool 1 have more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than there are diamond abrasive grains 2 whose contact portions 11 are main surfaces 211.

[0031] In the grinding tool 1 of this embodiment, there are more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than diamond abrasive grains 2 whose contact portions 11 are vertices 222. Preferably, there are more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than diamond abrasive grains 2 whose contact portions 11 are sub-surfaces 212. In addition, in the grinding tool 1, it is preferable that the ridge portions 221 that are contact portions 11 are more often formed in a direction perpendicular to or inclined to the sliding direction of the grinding tool 1 than those formed along the sliding direction of the grinding tool 1 against the grinding object 10. In addition, it is more preferable that the ridge portions 221 that are contact portions 11 are more often formed along a direction perpendicular to the sliding direction of the grinding tool 1 than those formed along the sliding direction of the grinding tool 1.

[0032] In the grinding tool 1, the average area of ​​the surface of the contact portion 11 per diamond abrasive grain 2 (hereinafter referred to as the average contact area) is preferably 75% or less of the average area of ​​the flat surface 21, which is the crystal face, and more preferably 50% or less of the average area of ​​the flat surface 21. In addition, in the grinding tool 1, the coefficient of variation, which is the value obtained by dividing the standard deviation of the area of ​​the surface of the contact portion 11 between the diamond abrasive grains 2 by the average contact area, is preferably 50 or more, and more preferably 100 or more.

[0033] 5, the position where the virtual working surface 11S connecting the contact portions 11 overlaps with the diamond abrasive grain 2 is defined as the contact position 11P. At this time, the tip of the diamond abrasive grain 2 arranged at the contact position 11P in the normal direction of the virtual working surface 11S at the contact position 11P becomes the contact portion 11.

[0034] 4. Overview of grinding tool manufacturing methods The manufacturing method of the grinding tool 1 of this embodiment includes a fixing step, an attaching and applying step, and a first attaching step. In the fixing step, as shown in FIG. 10, after placing the substrate 3 and the diamond abrasive grains 2 in a mold 41, molten metal is poured into the mold 41 and solidified to fix the diamond abrasive grains 2 to the substrate 3. In the attaching and applying step, prior to the fixing step, adhesive 42 is applied to at least one of the attaching surface 411 on the inner surface of the mold 41 to which the diamond abrasive grains 2 are attached and the surface of the diamond abrasive grains 2. In the first attaching step, after the attaching and applying step, as shown in FIG. 9, the diamond abrasive grains 2 are attached to the attaching surface 411. In the first attaching step, the diamond abrasive grains 2 are attached to the attaching surface 411 so that the diamond abrasive grains 2 whose contact portions 11 are corner portions 22 are more numerous than the diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21. In the manufacturing method of the grinding tool 1 of this embodiment, after the first adhering step, a fixing step is carried out while maintaining the arrangement of the diamond abrasive grains 2 relative to the adhering surface 411.

[0035] In addition, in the first attachment step, the diamond abrasive grains 2 are attached to the attachment surface 411 so that there are more diamond abrasive grains 2 whose contact portion 11 is either the secondary surface 212 or the corner portion 22 than there are diamond abrasive grains 2 whose contact portion 11 is the primary surface 211.

[0036] 5. Details of the manufacturing method of grinding tools In this embodiment, in the pasting and application step, adhesive 42 is applied to pasting surface 411. The adhesive 42 can be, for example, a spray glue.

[0037] In this embodiment, in the first attachment step, as shown in Fig. 9, the diamond abrasive grains 2 before being attached to the mold 41 are held using vacuum tweezers 44 and attached to an attachment surface 411 of the mold 41 to which adhesive 42 has been applied, as shown by arrow M in Fig. 9. The portion of the diamond abrasive grains 2 attached to the attachment surface 411 by the adhesive 42 on the attachment surface 411 side becomes the contact portion 11.

[0038] After the first attachment step, as shown in FIG. 10, the substrate 3 is placed on the mold 41 to which the diamond abrasive grains 2 have been attached, with the attachment surface 411 and the outer peripheral surface of the substrate 3 facing each other. When the substrate 3 is placed on the mold 41, a space 40 is formed between the mold 41 and the outer peripheral surface of the substrate 3. Then, in the fixing step, molten metal is poured into this space 40 and solidified. This fixes the diamond abrasive grains 2 to the substrate 3. In other words, the solidified molten metal becomes the binder 43.

[0039] After the fixing step, the grinding tool 1 is taken out of the mold 41 and unnecessary binder 43 and the like are removed, thereby completing the manufacture of the grinding tool 1 of this embodiment.

[0040] 6. Action and Effects In the grinding tool 1 of this embodiment, there are more diamond abrasive grains 2 whose contact portions 11 are corner portions 22 than diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21. This makes it possible to reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate 3. As a result, it is possible to improve grinding accuracy.

[0041] Natural diamonds used as abrasives in grinding tools such as diamond dressers generally have irregular shapes, including a mixture of acute and obtuse angles, compared with synthetic diamonds. Furthermore, when natural diamonds are used as abrasives in grinding tools, their lifespan and friability vary depending on the quality grade, and values ​​such as resistance and roughness tend to vary from lot to lot. Considering the mining environment of natural diamonds, it is considered preferable to use synthetic diamonds over natural diamonds from the perspective of the SDGs. On the other hand, synthetic diamonds tend to have a more consistent shape than natural diamonds. Therefore, when synthetic diamonds are used as abrasives in grinding tools, values ​​such as resistance and roughness tend to be more stable from lot to lot. Furthermore, the higher the quality grade of synthetic diamonds, the longer their abrasive lifespan. However, synthetic diamonds with relatively high quality grades tend to have larger crystal facets. Therefore, when synthetic diamonds are used as abrasives in grinding tools, depending on the arrangement of the synthetic diamonds in the grinding tool, the number of diamond abrasives whose main surfaces are in contact with each other may increase, resulting in higher grinding resistance.

[0042] In particular, when manufacturing a grinding tool, as in the comparative example shown in FIG. 11 , when the synthetic diamonds used as diamond abrasive grains 2 are arranged in a single layer on a mold 41 or base metal, the synthetic diamonds are likely to be arranged so that their main surfaces 211 face the inner surface of the base metal or mold. Therefore, the main surfaces 211 are likely to be arranged so that they form the contact portion that comes into contact with the workpiece. This can increase the grinding resistance during grinding, potentially causing burns on the surface of the workpiece. Furthermore, if the number of synthetic diamonds used as abrasive grains is reduced to reduce the grinding resistance, an excessively small number of abrasive grains can result in unevenness on the surface of the workpiece being ground. Furthermore, if the grinding object is a grinding wheel, this can result in undulations on the surface of the workpiece being ground by the grinding wheel. Furthermore, reducing the number of synthetic diamonds used as abrasive grains can shorten the lifespan of the abrasive grains. Therefore, the grinding tool 1 of this embodiment has more diamond abrasive grains 2 whose contact portions 11 are corners 22 than diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21. This allows for reduced grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate 3. In other words, because the proportion of diamond abrasive grains 2 that act on the object to be ground 10 with their corners 22 is high in the grinding tool 1, grinding resistance can be reduced even if the number of diamond abrasive grains 2 acting on the object to be ground 10 is increased. As a result, it is possible to sufficiently prevent the occurrence of unevenness or burns on the surface of the object to be ground 10, improving grinding accuracy and extending the life of the grinding tool 1. Furthermore, by increasing the number of diamond abrasive grains 2 that act on the corners 22 of the object to be ground 10, the cutting ability of the object to be ground 10 can be improved.

[0043] Furthermore, the grinding tool 1 of this embodiment has more diamond abrasive grains 2 whose contact portions 11 are either the sub-surfaces 212 or the corner portions 22 than diamond abrasive grains 2 whose contact portions 11 are the main surfaces 211. Therefore, it is possible to reduce the grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3.

[0044] As shown in Figures 6 and 7, the (111) and (100) planes of artificial diamonds tend to develop significantly. Therefore, as shown in Figure 7, the areas of the (110) and (113) planes, which are the secondary surfaces 212, tend to be smaller than the (111) and (100) planes, which are the primary surfaces 211. Therefore, the grinding resistance of the diamond abrasive grains 2 tends to be lower when the contact portion 11 is the secondary surface 212 than when the contact portion 11 is the primary surface 211. Therefore, by increasing the number of diamond abrasive grains 2 whose contact portion 11 is either the secondary surface 212 or the corner portion 22 compared to the number of diamond abrasive grains 2 whose contact portion 11 is the primary surface 211, the grinding resistance can be reduced while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate 3.

[0045] The grinding tool 1 has more diamond abrasive grains 2 whose contact portions 11 are corner portions 22 than diamond abrasive grains 2 whose contact portions 11 are main surfaces 211. Therefore, it is possible to reduce the grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3.

[0046] In the grinding tool 1 of this embodiment, there are more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than diamond abrasive grains 2 whose contact portions 11 are flat surfaces 21. This makes it possible to further reduce grinding resistance and further improve cutting performance. As a result, it is possible to further improve grinding accuracy.

[0047] In the grinding tool 1, it is preferable that the number of diamond abrasive grains 2 whose contact portions 11 are the ridge portions 221 is greater than the number of diamond abrasive grains 2 whose contact portions 11 are the main surfaces 211. In this case, the grinding resistance can be further reduced and the cutting quality can be further improved. As a result, the grinding accuracy can be further improved.

[0048] The grinding tool 1 has more diamond abrasive grains 2 whose contact portions 11 are ridge portions 221 than diamond abrasive grains 2 whose contact portions 11 are apexes 222. This makes it possible to further improve cutting performance while further reducing grinding resistance. As a result, it is possible to further improve grinding accuracy.

[0049] Furthermore, in the grinding tool 1, it is preferable that the ridges 221 that become the contact portions 11 are more likely to be formed in a direction perpendicular to or inclined to the sliding direction of the grinding tool 1 than to be formed along the sliding direction of the grinding tool 1 against the grinding object 10. In this case, the cutting ability can be further improved. As a result, the grinding accuracy can be further improved.

[0050] The average area of ​​the contact portion is preferably 75% or less of the average area of ​​the flat surface 21. In this case, the grinding resistance can be further reduced while increasing the number of diamond abrasive grains 2 fixed to the substrate 3. Furthermore, the average area of ​​the contact portion is more preferably 50% or less of the average area of ​​the flat surface 21. In this case, the grinding resistance can be further reduced while increasing the number of diamond abrasive grains 2 fixed to the substrate 3.

[0051] The coefficient of variation, which is the standard deviation of the surface area of ​​the contact portion 11 between the diamond abrasive grains 2 divided by the average contact area, is preferably 50 or more. In this case, it is easy to sufficiently increase the variation in the surface area of ​​the contact portion 11 between the diamond abrasive grains 2. This makes it possible to sufficiently reduce the grinding resistance while extending the life of the grinding tool 1. Furthermore, it is more preferable that this coefficient of variation is 100 or more. In this case, it is possible to further reduce the grinding resistance while extending the life of the grinding tool 1.

[0052] In the manufacturing method of the grinding tool 1 of this embodiment, in the first attaching step, the diamond abrasive grains 2 are attached to the attaching surface 411 so that there are more diamond abrasive grains 2 whose contact portions 11 form corner portions 22 than diamond abrasive grains 2 whose contact portions 11 form flat surfaces 21. Therefore, it is possible to manufacture a grinding tool 1 that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3.

[0053] In the manufacturing method of the grinding tool 1 of this embodiment, in the first attaching step, the diamond abrasive grains 2 are attached to the attaching surface 411 so that the number of diamond abrasive grains 2 whose contact portion 11 is either the secondary surface 212 or the corner portion 22 is greater than the number of diamond abrasive grains 2 whose contact portion 11 is the primary surface 211. Therefore, it is possible to manufacture a grinding tool 1 that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3.

[0054] The first attaching step is performed using vacuum tweezers 44. Therefore, it is easy to attach the diamond abrasive grains 2 to the attachment surface 411 so that the diamond abrasive grains 2 have more contact portions 11 at the corners 22 or the sub-surfaces 212 than at the main surface 211. That is, let us assume that the first attaching step is performed using tweezers (not shown) instead of vacuum tweezers. In this case, to stably hold the diamond abrasive grains with the tweezers, it is necessary to clamp the diamond abrasive grains by abutting the tips of the tweezers against each of the two main surfaces of the diamond abrasive grains. Therefore, when performing the first attaching step using diamond abrasive grains having a shape such as that shown in FIGS. 6 and 7, it is difficult to place the diamond abrasive grains in the mold so that the corners or sub-surfaces of the diamond abrasive grains become contact portions. Therefore, in this embodiment, the first attaching step is performed using vacuum tweezers 44. Therefore, the diamond abrasive grains 2 can be attached to the attachment surface 411 while any portion of the diamond abrasive grains 2 is held by the vacuum tweezers 44. Therefore, it is easy to attach the diamond abrasive grains 2 to the mold 41 so that the contact portions 11 become the corners 22 and the minor surfaces 212. This can improve productivity.

[0055] Synthetic diamonds tend to have higher resistance to fracture and heat than natural diamonds, so grinding tools 1 that use synthetic diamonds as abrasive grains can have a longer life.

[0056] As described above, according to this embodiment, it is possible to provide the grinding tool 1 and the manufacturing method thereof that can improve the grinding accuracy.

[0057] (Experimental Example 1) In this example, the grinding resistance and other parameters during grinding of an object to be ground were investigated using the grinding tool of embodiment 1 shown in FIG. 1 and a comparative grinding tool having the same basic structure as embodiment 1 but using natural diamond abrasive grains. In this example, the object to be ground was a disc-shaped grinding wheel. In addition, in this example, as shown in Table 1 below, both the normal grinding resistance and the tangential grinding resistance were investigated. In this example, the normal grinding resistance refers to the grinding resistance in the normal direction of the virtual working surface 11S (see FIG. 5) at the position where the contact portion 11 and the virtual working surface 11S overlap each other. In addition, the tangential grinding resistance refers to the grinding resistance in the tangential direction of the virtual working surface 11S at the position where the contact portion 11 and the virtual working surface 11S overlap each other. In other words, the normal grinding resistance is the grinding resistance in the direction in which the grinding tool pushes the grinding wheel to be ground during grinding, and the tangential grinding resistance is the grinding resistance in the sliding direction of the grinding tool against the grinding wheel.

[0058] [Table 1]

[0059] As shown in Table 1, the grinding tool of embodiment 1 has lower grinding resistance in both the normal direction and the tangential direction compared to the grinding tool of the comparative example. Here, because natural diamonds have irregular shapes, when used as abrasive grains in a grinding tool, compared to a grinding tool in which the contact area is only the main surface of the synthetic diamond abrasive grains, the grinding resistance is likely to be significantly lower and the cutting edge is likely to be better. Furthermore, although the grinding tool of embodiment 1 uses synthetic diamond as abrasive grains, it is configured so that the diamond abrasive grains that contact either the sub-surface or the corner are more likely to contact the main surface than the diamond abrasive grains that contact the main surface, so the grinding resistance is likely to be lower and the cutting edge is likely to be better. Therefore, as shown in Table 1 above, it is considered that the grinding resistance of the grinding tool of embodiment 1 is lower than that of the comparative example using natural diamond. Therefore, it can be said that the grinding tool of embodiment 1 can sufficiently reduce the grinding resistance. Furthermore, synthetic diamonds tend to have higher resistance to fracture and heat than natural diamonds, so the grinding tool of embodiment 1 using synthetic diamonds as abrasive grains can have a longer life.

[0060] In addition, in this example, as shown in Table 2 below, the presence or absence of burn on the grinding wheels dressed with the grinding tools of the comparative example or the grinding tools of embodiment 1, and the waviness Wt of the workpiece surface when the workpiece was ground using these grinding wheels were investigated.

[0061] [Table 2]

[0062] As shown in Table 2, no burn was observed when the grinding wheel was dressed, either when the grinding tool of the comparative example was used or when the grinding tool of embodiment 1 was used. Furthermore, the waviness Wt value when a workpiece was ground using a grinding wheel dressed with the grinding tool of the comparative example and the waviness Wt value when a workpiece was ground using a grinding wheel dressed with the grinding tool of embodiment 1 were both 0.4 μm. That is, the waviness Wt value in the comparative example and the waviness Wt value in embodiment 1 were both sufficiently low. These results also demonstrate that the grinding tool of embodiment 1 can sufficiently reduce grinding resistance and sufficiently improve grinding accuracy.

[0063] (Embodiment 2) This embodiment is different from the first embodiment in the method of manufacturing the grinding tool 1.

[0064] The manufacturing method of the grinding tool 1 of this embodiment includes a fixing and application step and a second attachment step. In the fixing and application step, as shown in FIG. 12, an adhesive 42 is applied to at least one of the fixing surface 311 on the substrate 3 that fixes the diamond abrasive grains 2 and the surface of the diamond abrasive grains 2. In the second attachment step, after the fixing and application step, the diamond abrasive grains 2 are attached to the fixing surface 311. In the second attachment step, the diamond abrasive grains 2 are attached to the fixing surface 311 so that the diamond abrasive grains 2 whose contact portions 11 are the corner portions 22 are more numerous than the diamond abrasive grains 2 whose contact portions 11 are the flat surfaces 21. In the manufacturing method of the grinding tool 1 of this embodiment, after the second attachment step, the diamond abrasive grains 2 are fixed to the fixing surface 311 with a binder 43 while maintaining the arrangement of the diamond abrasive grains 2 relative to the fixing surface 311.

[0065] In addition, in the second attachment process, the diamond abrasive grains 2 are attached to the fixing surface 311 so that there are more diamond abrasive grains 2 whose contact portion 11 is either the secondary surface 212 or the corner portion 22 than there are diamond abrasive grains 2 whose contact portion 11 is the primary surface 211.

[0066] In this embodiment, in the fixing and applying step, adhesive 42 is applied to fixing surface 311. Also, in this embodiment, in the second attaching step, as shown in Fig. 12, the diamond abrasive grains 2 before being fixed to fixing surface 311 are held using vacuum tweezers 44 and attached to fixing surface 311 of base material 3 to which adhesive 42 has been applied, as shown by arrow M in Fig. 12. The diamond abrasive grains 2 temporarily fixed to fixing surface 311 by adhesive 42 have a portion opposite to fixing surface 311 that becomes contact portion 11.

[0067] After the second attachment step, the substrate 3 with the diamond abrasive grains 2 temporarily fixed thereto is placed in a mold 41, as shown in Figure 13. When the substrate 3 is placed in the mold 41, a space 400 is formed between the mold 41 and the fixing surface 311. In the fixing step, molten metal is poured into the space 400 and solidified, thereby fixing the diamond abrasive grains 2 to the substrate 3. After the fixing step, the grinding tool 1 is removed from the mold 41, and unnecessary binder 43 and the like are removed to expose the tips of the diamond abrasive grains 2, thereby manufacturing the grinding tool 1 of this embodiment. Other aspects are the same as those of embodiment 1. Note that, among the symbols used in embodiment 2 and onwards, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0068] In the manufacturing method of the grinding tool 1 of this embodiment, in the second attachment step, the diamond abrasive grains 2 are attached to the fixing surface 311 so that there are more diamond abrasive grains 2 whose contact portions 11 form corner portions 22 than diamond abrasive grains 2 whose contact portions 11 form flat surfaces 21. Therefore, it is possible to manufacture a grinding tool 1 that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3.

[0069] In the manufacturing method of the grinding tool 1 of this embodiment, in the second attaching step, the diamond abrasive grains 2 are attached to the fixing surface 311 so that the number of diamond abrasive grains 2 whose contact portions 11 are either the secondary surface 212 or the corner portion 22 is greater than the number of diamond abrasive grains 2 whose contact portions 11 are the primary surface 211. Therefore, it is possible to manufacture a grinding tool 1 that can reduce grinding resistance while ensuring a sufficient number of diamond abrasive grains 2 fixed to the substrate portion 3. In addition, the same effects as those of the first embodiment are achieved.

[0070] In the above-mentioned first and second embodiments, the diamond abrasive grains are fixed to the substrate by pouring molten metal into the inside of the mold. However, the diamond abrasive grains can also be fixed to the substrate by, for example, temporarily fixing them to the substrate and then performing a plating process. In this case, the metal layer formed by the plating process serves as the binder.

[0071] In the above-described first and second embodiments, the diamond abrasive grains 2 are fixed to the substrate 3 without contacting each other. However, the diamond abrasive grains may also be fixed to the substrate 3 in a state where they are in contact with each other, for example.

[0072] In the above-described first and second embodiments, the grinding tool 1 is a rotary dresser that dresses a grinding wheel. However, the grinding tool can also be used, for example, to directly grind a workpiece. The grinding tool can also be shaped like a cup or a flat plate, in addition to a disk. When the grinding tool is flat, for example, multiple diamond abrasive grains can be fixed to one main surface of the grinding tool. In other words, one main surface of the grinding tool can have a contact portion. The grinding tool can also be a block dresser in which diamond abrasive grains are fixed to a metal block.

[0073] In addition, in the grinding tool, the plurality of diamond abrasive grains may include, for example, those having only the (111) plane as the flat surface and having an octahedral shape.

[0074] The grinding tool may have a contact portion that is a corner portion for all diamond abrasive grains having a contact portion. Also, the grinding tool may have a contact portion that is a ridge portion for all diamond abrasive grains having a contact portion. Also, the corner portion may include, for example, a curved portion connecting flat surfaces.

[0075] In addition, the abrasive grains used in grinding tools may include, in addition to diamond abrasive grains made from artificial diamond, for example, natural diamond or CBN (cubic boron nitride) grains, etc., within the range that can improve grinding accuracy.

[0076] In the above-described first and second embodiments, the diamond abrasive grains 2 are attached using vacuum tweezers 44. However, other than vacuum tweezers, adhesive tweezers or the like can also be used as a tool that can hold the diamond abrasive grains without clamping them. In this case, too, productivity can be improved, as in the case of using vacuum tweezers.

[0077] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope of the present invention.

[0078] <Other> The features of the present invention are as follows. [Section 1] a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; A grinding tool, wherein the number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces. [Section 2] The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, Item 2. The grinding tool according to item 1, wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces. [Section 3] In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the (100) plane and the (111) plane of the diamond abrasive grain are defined as the main planes, and the flat surfaces other than the main planes of the diamond abrasive grain are defined as the sub-planes, Item 1 or 2, wherein the diamond abrasive grains having the contact portion as either one of the sub-surface and the corner portion are more numerous than the diamond abrasive grains having the contact portion as the main surface. [Section 4] a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the grinding tool is used to grind an object, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface of the diamond abrasive grain other than the main surface is defined as a sub-surface. A grinding tool in which the number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface. [Section 5] Item 5. The grinding tool according to item 4, wherein the number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the main surfaces. [Section 6] The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, Item 6. The grinding tool according to item 4 or 5, wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the main surfaces. [Section 7] The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, Item 7. The grinding tool according to any one of items 1 to 6, wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the apex portions. [Section 8] Item 1 or 2, a manufacturing method of a grinding tool, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the diamond abrasive grains whose contact portions become the corner portions are more numerous than the diamond abrasive grains whose contact portions become the flat surface, A method for manufacturing a grinding tool, wherein after the first attaching step, the fixing step is performed while maintaining the arrangement of the diamond abrasive grains relative to the attaching surface. [Section 9] Item 1 or 2, a manufacturing method of a grinding tool, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions become the corner portions is greater than the number of diamond abrasive grains whose contact portions become the flat surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface. [Section 10] Item 4 or 5, a manufacturing method of a grinding tool, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, A method for manufacturing a grinding tool, wherein after the first attaching step, the fixing step is performed while maintaining the arrangement of the diamond abrasive grains relative to the attaching surface. [Section 11] Item 4 or 5, a manufacturing method of a grinding tool, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface. [Explanation of symbols]

[0079] 1...grinding tool, 2...diamond abrasive grain, 3...substrate portion, 10...grinding object, 11...contact portion, 21...flat surface, 22...corner portion, 31...surface

Claims

1. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average contact area, and the coefficient of variation obtained by dividing the standard deviation of the area of ​​the surface of the contact portion by the average contact area is defined as the contact variation coefficient, The contact portion variation coefficient is 50 or more. Grinding tools.

2. 2. The grinding tool according to claim 1, wherein the coefficient of variation of the contact portion is 100 or more.

3. The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, The grinding tool according to claim 1 , wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces.

4. In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When the (100) plane and the (111) plane of the diamond abrasive grain are defined as the main surface, and the flat surface other than the main surface of the diamond abrasive grain is defined as the sub-surface, 2. The grinding tool according to claim 1, wherein the number of diamond abrasive grains whose contact portion is one of the sub-surfaces and the corner portions is greater than the number of diamond abrasive grains whose contact portion is the main surface.

5. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When grinding an object to be ground with the grinding tool, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface other than the main surface of the diamond abrasive grain is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average contact area, and the coefficient of variation obtained by dividing the standard deviation of the area of ​​the surface of the contact portion by the average contact area is defined as the contact variation coefficient, The contact portion variation coefficient is 50 or more. Grinding tools.

6. 6. The grinding tool according to claim 5, wherein the coefficient of variation of the contact portion is 100 or more.

7. The grinding tool according to claim 5 , wherein the number of diamond abrasive grains whose contact portions are at the corner portions is greater than the number of diamond abrasive grains whose contact portions are at the main surfaces.

8. The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, The grinding tool according to claim 5 , wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the main surfaces.

9. The corner portion is a ridge portion connecting the two flat surfaces; and a vertex portion connecting three or more of the flat surfaces, The grinding tool according to claim 1 or 5, wherein the number of diamond abrasive grains whose contact portions are the ridge portions is greater than the number of diamond abrasive grains whose contact portions are the apexes.

10. 2. A method for manufacturing the grinding tool according to claim 1, comprising the steps of: a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the diamond abrasive grains whose contact portions become the corner portions are more numerous than the diamond abrasive grains whose contact portions become the flat surface, A method for manufacturing a grinding tool, wherein after the first attaching step, the fixing step is performed while maintaining the arrangement of the diamond abrasive grains relative to the attaching surface.

11. 2. A method for manufacturing the grinding tool according to claim 1, comprising the steps of: A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions become the corner portions is greater than the number of diamond abrasive grains whose contact portions become the flat surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface.

12. 6. A method for manufacturing a grinding tool according to claim 5, comprising the steps of: a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, A method for manufacturing a grinding tool, wherein after the first attaching step, the fixing step is performed while maintaining the arrangement of the diamond abrasive grains relative to the attaching surface.

13. 6. A method for manufacturing a grinding tool according to claim 5, comprising the steps of: A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface with a bonding material while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface.

14. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the diamond abrasive grains whose contact portions become the corner portions are more numerous than the diamond abrasive grains whose contact portions become the flat surface, After the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface; In the first attaching step, the diamond abrasive grains before being attached to the mold are held using vacuum tweezers or adhesive tweezers, and the diamond abrasive grains are attached to the attachment surface. A method for manufacturing grinding tools.

15. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, When grinding an object to be ground with the grinding tool, a portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion; The number of diamond abrasive grains whose contact portions are the corner portions is greater than the number of diamond abrasive grains whose contact portions are the flat surfaces, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions become the corner portions is greater than the number of diamond abrasive grains whose contact portions become the flat surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface by a binder while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface; In the second attaching step, the diamond abrasive grains are attached to the fixing surface while being held using vacuum tweezers or adhesive tweezers. A method for manufacturing grinding tools.

16. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When grinding an object to be ground with the grinding tool, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface other than the main surface of the diamond abrasive grain is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, a fixing step of placing the substrate and the diamond abrasive grains in a mold, pouring molten metal into the mold, and solidifying the molten metal to fix the diamond abrasive grains to the substrate; Before the fixing step, a bonding / application step of applying an adhesive to at least one of the bonding surface on the inner surface of the mold to which the diamond abrasive grains are attached and the surface of the diamond abrasive grains; After the application step, a first application step of applying the diamond abrasive grains to the application surface is provided. In the first attaching step, the diamond abrasive grains are attached to the attaching surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the first attaching step, the fixing step is carried out while maintaining the arrangement of the diamond abrasive grains on the attaching surface; In the first attaching step, the diamond abrasive grains before being attached to the mold are held using vacuum tweezers or adhesive tweezers, and the diamond abrasive grains are attached to the attachment surface. A method for manufacturing grinding tools.

17. a plurality of diamond abrasive grains made of artificial diamond; a substrate portion to which the plurality of diamond abrasive grains are fixed; A method for manufacturing a grinding tool comprising: The plurality of diamond abrasive grains are fixed in a single layer on the surface of the substrate, The surface of each of the plurality of diamond abrasive grains is a plurality of flat surfaces that are crystal faces; and a corner portion connecting the flat surfaces, In the diamond abrasive grains, the plurality of flat surfaces have at least one of a (100) plane and a (111) plane; When grinding an object to be ground with the grinding tool, the portion of the diamond abrasive grain that comes into contact with the object to be ground is defined as a contact portion, the (100) plane and the (111) plane of the diamond abrasive grain are defined as main surfaces, and the flat surface other than the main surface of the diamond abrasive grain is defined as a sub-surface. The number of diamond abrasive grains whose contact portion is either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portion is the main surface, In the grinding tool, when the average area of ​​the surface of the contact portion per diamond abrasive grain is defined as the average area of ​​the contact portion, and the coefficient of variation of the contact portion is defined as the standard deviation of the area of ​​the surface of the contact portion divided by the average area of ​​the contact portion, the coefficient of variation of the contact portion is 50 or more, A fixing and applying step of applying an adhesive to at least one of a fixing surface for fixing the diamond abrasive grains in the base material and the surface of the diamond abrasive grains; After the fixing and applying step, a second attaching step of attaching the diamond abrasive grains to the fixing surface is included, In the second attaching step, the diamond abrasive grains are attached to the fixing surface so that the number of diamond abrasive grains whose contact portions are either the sub-surface or the corner portion is greater than the number of diamond abrasive grains whose contact portions are the main surface, After the second attaching step, the diamond abrasive grains are fixed to the fixing surface by a binder while maintaining the arrangement of the diamond abrasive grains relative to the fixing surface; In the second attaching step, the diamond abrasive grains are attached to the fixing surface while being held using vacuum tweezers or adhesive tweezers. A method for manufacturing grinding tools.

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