CN111409018A - superabrasive grinding wheel - Google Patents

Abstract

A super-hard abrasive grinding wheel is provided with a ring-shaped base metal (110) and a plurality of super-hard abrasive grain layers (120) each of which is arranged on the surface of the base metal (110) so as to be spaced apart from each other, at least a part of the super-hard abrasive grain layers (120) among the plurality of super-hard abrasive grain layers (120) being arranged so as to be located on the upstream side in the rotational direction 1 of the base metal (110) along the direction from the inner peripheral side to the outer peripheral side of the base metal (110) on a plurality of curves L1 arranged in a rotationally symmetric manner with respect to the rotational center A of the base metal (110), the concentration of super-hard abrasive grains in the super-hard abrasive grain layers (120) being 1 to 12.

Description

superabrasive grinding wheel

technical field

The invention relates to a superhard abrasive grinding wheel. This application claims priority based on Japanese Patent Application No. 2019-001014 filed on January 8, 2019. The entire contents described in the Japanese patent application are incorporated herein by reference.

Background technique

As existing documents which disclose the structure of a superabrasive grinding wheel, there are Japanese Patent Application Laid-Open No. 56-94267, Japanese Patent Application Laid-Open No. 2002-331459, and Japanese Patent Application Laid-Open No. 2006-205314.

SUMMARY OF THE INVENTION

For superabrasive grinding wheels, it is required to maintain good sharpness for a long time.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a superabrasive grinding wheel capable of maintaining good sharpness for a long time.

The superabrasive wheel based on the present invention includes an annular base metal and a plurality of cylindrical superabrasive grain layers. Each of the plurality of superabrasive grain layers is arranged to be spaced apart from each other on the surface of the base metal. At least a part of the superabrasive grain layers among the plurality of superabrasive grain layers is configured such that, on a plurality of curves arranged in a rotationally symmetrical manner with respect to the center of rotation of the base metal, the outer peripheral side along the inner peripheral side of the base metal It is located on the upstream side of the rotation direction of the base metal. The concentration of the superabrasive grains in the superabrasive grain layer is 1 or more and 12 or less.

The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is a front view of a superabrasive wheel according to Embodiment 1 of the present invention.

Fig. 2 is a side view of the superabrasive wheel of Fig. 1 viewed from the direction of arrow II.

Fig. 3 is a rear view of the superabrasive grinding wheel of Fig. 2 viewed from the direction of arrow III.

4 is a perspective view of the superabrasive grinding wheel according to Embodiment 1 of the present invention when viewed from the front.

FIG. 5 is a cross-sectional view of the superabrasive grinding wheel of FIG. 1 viewed from the direction of the arrow on the line V-V.

6 is a schematic view showing a state in which a wafer is ground by the superabrasive wheel according to Embodiment 1 of the present invention.

7 is a front view of the superabrasive wheel according to Embodiment 2 of the present invention.

8 is a front view of the superabrasive wheel according to Embodiment 3 of the present invention.

9 is a front view of the superabrasive grinding wheel according to Embodiment 4 of the present invention.

10 is a front view of the superabrasive wheel according to Embodiment 5 of the present invention.

11 is a front view of the superabrasive wheel according to Embodiment 6 of the present invention.

12 is a front view of the superabrasive wheel according to Embodiment 7 of the present invention.

13 is a front view of the superabrasive wheel according to Embodiment 8 of the present invention.

14 is a front view of the superabrasive wheel according to Embodiment 9 of the present invention.

15 is a front view of the superabrasive wheel according to Embodiment 10 of the present invention.

16 is a front view of the superabrasive wheel according to Embodiment 11 of the present invention.

17 is a front view of the superabrasive wheel according to Embodiment 12 of the present invention.

Detailed ways

[Description of Embodiments of the Present Invention]

First, embodiments of the present invention are listed and described.

A superabrasive wheel according to one aspect of the present invention includes an annular base metal and a plurality of columnar superabrasive grain layers. Each of the plurality of superabrasive grain layers is arranged to be spaced apart from each other on the surface of the base metal. At least a part of the superabrasive grain layers among the plurality of superabrasive grain layers is configured such that, on a plurality of curves arranged in a rotationally symmetrical manner with respect to the center of rotation of the base metal, the outer peripheral side along the inner peripheral side of the base metal It is located on the upstream side of the rotation direction of the base metal. The concentration of the superabrasive grains in the superabrasive grain layer is 1 or more and 12 or less.

Superabrasive grinding wheels can maintain good sharpness for a long time.

In the superabrasive grinding wheel according to one aspect of the present invention, at least a part of the plurality of superabrasive grain layers is arranged such that a plurality of strips are arranged in a rotationally symmetrical manner with respect to the center of rotation of the base metal. On the curve, it is located on the upstream side in the rotational direction of the base metal along the inner peripheral side of the base metal toward the outer peripheral side, thereby ensuring chip discharge properties and maintaining good sharpness. Moreover, since the density|concentration of the superabrasive grains in a superabrasive grain layer is 1 or more and 12 or less, favorable sharpness can be maintained for a long time. When the concentration of the superabrasive grains in the superabrasive grain layer is less than 1, the amount of the superabrasive grains in the superabrasive grain layer is insufficient, the superabrasive grains wear at an early stage, and the sharpness deteriorates. When the concentration of the superabrasive grains in the superabrasive grain layer exceeds 12, clogging is likely to occur in the superabrasive grain layer, and the sharpness is deteriorated.

Preferably, the ratio of the total area of the respective working surfaces of the plurality of superabrasive grain layers to the area of the annular region sandwiched between the outer circumference and the inner circumference, that is, the occupied area ratio is 10% or more and 32% or less. , wherein the outer circumference is in contact with the outer peripheral side edge of the superhard abrasive grain layer farthest from the rotation center of the base metal among the plurality of superhard abrasive grain layers and is centered on the above-mentioned rotation center, and the inner circumference and The inner peripheral side edge of the superabrasive grain layer closest to the rotation center of the base metal among the plurality of superabrasive grain layers is in contact with the above-mentioned rotation center. Thereby, good sharpness can be maintained for a long time. When the said occupied area ratio is less than 10%, the superabrasive grain layer wears at an early stage, and the sharpness deteriorates. When the said occupation area ratio exceeds 32 %, the cutting property of a superabrasive grain layer deteriorates, and sharpness deteriorates.

Preferably, each of the plurality of superabrasive grain layers is arranged on concentric circles on the surface of the base metal. Thereby, local abrasion of the superabrasive grain layer is suppressed, and good sharpness can be maintained for a long time.

Preferably, the superabrasive grinding wheel is used for grinding of wafers containing at least one selected from the group consisting of silicon, sapphire, glass, ceramic, quartz, SiC, and compound semiconductors. In the surface grinding of the above-mentioned hard material, good sharpness can be maintained for a long time.

(Embodiment 1)

Hereinafter, the superabrasive wheel according to Embodiment 1 of the present invention will be described with reference to the drawings. In the description of the following embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a front view of a superabrasive wheel according to Embodiment 1 of the present invention. Fig. 2 is a side view of the superabrasive wheel of Fig. 1 viewed from the direction of arrow II. Fig. 3 is a rear view of the superabrasive grinding wheel of Fig. 2 viewed from the direction of arrow III. 4 is a perspective view of the superabrasive grinding wheel according to Embodiment 1 of the present invention when viewed from the front. Fig. 5 is a cross-sectional view of the superabrasive grinding wheel of Fig. 1 viewed from the direction of the arrow on the line V-V.

The superabrasive grinding wheel 100 according to Embodiment 1 of the present invention is used for grinding a wafer including at least one selected from the group consisting of silicon, sapphire, glass, ceramics, quartz, SiC, and compound semiconductors .

As shown in FIGS. 1 to 5 , the superabrasive wheel 100 according to Embodiment 1 of the present invention includes an annular base metal 110 and a plurality of columnar superabrasive grain layers 120 . The base metal 110 has an annular shape with the rotation center A as the center. The outer diameter of the base metal 110 is, for example, 255 mm. A circular hole 112 for attaching the superabrasive grinding wheel 100 to a machine such as a grinding machine is provided in the center of the base metal 110 . The diameter of the hole 112 is, for example, 90 mm.

The base metal 110 includes a thick portion 111 on the outer peripheral side, a thin portion 114 on the center side, and a connection portion 113 between the thick portion 111 and the thin portion 114 . The thickness of the thick portion 111 is, for example, 35 mm. A corner portion on the outer peripheral side of the back surface of the thick portion 111 is provided with, for example, a chamfered portion 115 extending across a range of 10 mm in the thickness direction and forming an angle of 30° with respect to the outer peripheral surface.

The thickness of the thin portion 114 is, for example, 20 mm. The diameter of the thin portion 114 is, for example, 150 mm. The thickness of the connecting portion 113 gradually increases from the center side to the outer peripheral side. An inclined surface is provided on the front surface of the connection portion 113 . The diameter of the connecting portion 113 is, for example, 180 mm.

It should be noted that the shape of the base metal 110 is not limited to the above, and may be an annular shape capable of disposing a plurality of superabrasive grain layers 120 on the surface. The base metal 110 is made of, for example, an aluminum alloy.

In the superabrasive grain layer 120, diamond abrasive grains as superhard abrasive grains are bonded by a metal bond as a bonding material. It should be noted that the superabrasive grains are not limited to diamond abrasive grains, and may be CBN abrasive grains. The bonding material is not limited to a metal bond, and may be a ceramic bond, a resin bond, or the like. The superabrasive grain layer 120 is bonded to the base metal 110 by an adhesive.

The average particle diameter of the superabrasive particles is preferably 10 μm or more and 500 μm or less, and more preferably 20 μm or more and 400 μm or less. When the average particle diameter of the superabrasive grains is less than 10 μm, the superabrasive grains are too fine and the grinding ability of the superabrasive wheel 100 may be too low. When the average particle diameter of the superabrasive grains exceeds 500 μm, the superabrasive grains may become blunt, and the grinding ability of the superabrasive wheel may be reduced at an early stage. In this embodiment, the average particle diameter of the diamond abrasive grains is 60 μm.

The cross-sectional shape of the superabrasive grain layer 120 is not limited to a perfect circle, and may be an approximate circle such as an ellipse or an oval. The diameter of the cross section of the superabrasive grain layer 120 is 4 mm or more and 20 mm or less, preferably 5 mm or more and 15 mm or less. When the diameter of the cross section of the superabrasive grain layer 120 is less than 4 mm, the number of the superabrasive grain layers 120 increases, which may increase the manufacturing cost of the superabrasive wheel 100 . When the diameter of the cross-section of the superabrasive grain layer 120 exceeds 20 mm, the action area per superabrasive grain layer 120 is too large, and there is a possibility that the dischargeability of chips may be lowered. In addition, the height of the superabrasive grain layer 120 is three times or less the cross-sectional diameter of the superabrasive grain layer 120 , preferably two times or less the cross-sectional diameter of the superabrasive grain layer 120 . When the height of the superabrasive grain layer 120 exceeds three times the diameter of the cross section, the superabrasive grain layer 120 may be broken during grinding using the superabrasive wheel 100 . In this embodiment, the diameter of the cross section of the superabrasive grain layer 120 is 8 mm, and the height is 12 mm. It should be noted that the average particle diameter of the diamond abrasive grains and the size of the superabrasive grain layer 120 are not limited to the above. The average particle diameter of the superabrasive particles can be measured, for example, using a laser diffraction particle size distribution analyzer SALD series manufactured by Shimadzu Corporation.

The concentration of the super abrasive grains in the super abrasive grain layer 120 is 1 or more and 12 or less. It should be noted that the concentration is defined by "JIS B4131 Diamond Tools/CBN Tools-Diamond or CBN Grinding Wheels", and is a value indicating the volume content of the superabrasive grains in the superabrasive grain layer 120. % is expressed as 100.

The method for measuring the concentration of the superabrasive grains in the superabrasive grain layer 120 is as follows. First, a part of the superabrasive grain layer 120 is cut out, and a surface grinder or the like is used to produce a cube-shaped sample with a side length of 3 mm or more and 5 mm or less, or a rectangular parallelepiped-shaped sample with the same volume. Then, the metal binder contained in the sample is dissolved with an acid such as nitric acid or aqua regia, and the superabrasive grains are taken out. The volume of the superabrasive grains was calculated by dividing the weight of the superabrasive grains taken out by the specific gravity of the superabrasive grains. The volume ratio of the superabrasive grains contained in the cube-shaped or rectangular parallelepiped-shaped sample was calculated by dividing the measured volume of the superabrasive grains by the volume of the sample. The average value of the volume ratio of the ultra-hard abrasive grains in the three samples was taken as the concentration of the ultra-hard abrasive grains in the ultra-hard abrasive grain layer 120 .

As shown in FIGS. 1 and 4 , the superabrasive grain layers 120 are arranged on the surface of the base metal 110 to be spaced apart from each other. Each of the plurality of superabrasive grain layers 120 is arranged on a concentric circle on the surface of the base metal 110 . Specifically, the plurality of superabrasive grain layers 120 are arranged on the circumferences of the first circle C1 , the second circle C2 , the third circle C3 , and the fourth circle C4 with the rotation center A as the center. In the present embodiment, the superabrasive grain layers 120 are arranged on all four concentric circles, but the number of the concentric circles in which the superabrasive grain layers 120 are arranged is not limited to four, and may be plural.

The diameter of the first circle C1 is, for example, 202 mm, the diameter of the second circle C2 is, for example, 216 mm, the diameter of the third circle C3 is, for example, 230 mm, and the diameter of the fourth circle C4 is, for example, 244 mm.

As shown in FIG. 1 , each of the plurality of superabrasive grain layers 120 is configured such that on a plurality of curves L1 arranged in a rotationally symmetrical manner with respect to the rotation center A of the base metal 110 , along the inner surface of the base metal 110 The peripheral side is located on the upstream side in the rotational direction of the base metal 110 toward the outer peripheral side.

In this embodiment, 92 superabrasive grain layers 120 are arranged on 23 curves L1. That is, four superabrasive grain layers 120 are arranged on one curve L1. In the present embodiment, all the superabrasive grain layers 120 are arranged on the curve L1, but the superabrasive grain layers 120 not located on the curve L1 may be provided, as long as at least a part of the superabrasive grain layers 120 are arranged on the curve on L1.

The distance between the adjacent superabrasive grain layers 120 located on the curve L1 is smaller than that of the superabrasive grains adjacent to each other on the circumferences of the first circle C1, the second circle C2, the third circle C3 and the fourth circle C4 The distance of the layers 120 from each other. Therefore, the curve L1 can be defined by connecting the superabrasive grain layers 120 adjacent to each other at the shortest interval from the inner peripheral side toward the outer peripheral side of the base metal 110 and toward the upstream side in the rotational direction 1 of the base metal 110 .

Each of the 23 curves L1 has a circular arc shape. The curvature radius of the curve L1 is larger than the respective radii of the first circle C1, the second circle C2, the third circle C3, and the fourth circle C4. In addition, the curve L1 is not limited to an arc shape, For example, a part of a conic curve may be sufficient.

As shown in FIG. 1 , the ratio of the total area of the respective working surfaces of the plurality of superabrasive grain layers 120 to the area of the annular region R sandwiched between the outer circumference Ca and the inner circumference Cb, that is, the occupied area ratio 10% to 32%, wherein the outer circumference Ca is in contact with the outer peripheral side edge of the superabrasive grain layer 120 farthest from the rotation center A of the base metal 110 among the plurality of superabrasive grain layers 120 and rotates The center A is the center, and the inner peripheral circle Cb is in contact with the inner peripheral side edge of the superabrasive particle layer 120 closest to the rotation center A of the base metal 110 among the plurality of superabrasive particle layers 120, and the rotation center A as a center.

It should be noted that the respective working surfaces of the plurality of superabrasive grain layers 120 are surfaces approximately perpendicular to the rotation center A of the base metal 110 , and are the surfaces of the superabrasive grain layers 120 opposite to the base metal 110 side. end face on one side.

In this embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 92 superabrasive grain layers 120 is 4624.4 mm ² , and the occupied area ratio is 22.8%.

6 is a schematic view showing a state in which a wafer is ground by the superabrasive wheel according to Embodiment 1 of the present invention. As shown in FIG. 6 , in the state where the wafer 10 is fixed on the table 20, the superabrasive grinding wheel 100 mounted on the vertical rotary surface grinder is rotated in the rotation direction 1, so that the wafer 10 is flattened grinding.

(Embodiment 2)

Hereinafter, the superabrasive wheel according to Embodiment 2 of the present invention will be described with reference to the drawings. The superabrasive wheel according to Embodiment 2 of the present invention is different from the superabrasive wheel 100 according to Embodiment 1 of the present invention only in the arrangement of the superabrasive grain layer. The same configuration of the hard abrasive wheel 100 will not be repeated.

7 is a front view of the superabrasive wheel according to Embodiment 2 of the present invention. As shown in FIG. 7 , in the superabrasive grinding wheel 200 according to Embodiment 2 of the present invention, each of the plurality of superabrasive grain layers 120 is arranged so as to be rotationally symmetrical with respect to the rotation center A of the base metal 110 . The plurality of curves L2 arranged in such a manner are located on the upstream side in the rotational direction 1 of the base metal 110 along the direction of the inner peripheral side of the base metal 110 toward the outer peripheral side.

In this embodiment, 92 superabrasive grain layers 120 are arranged on 23 curves L2. That is, four superabrasive grain layers 120 are arranged on one curve L2. Each of the 23 curves L2 has a circular arc shape. The radius of curvature of the curve L2 is larger than the radius of curvature of the curve L1 of the first embodiment. The distance between the superabrasive grain layers 120 adjacent to each other on the curve L2 is narrower than the distance between the superabrasive grain layers 120 adjacent to each other on the curve L1 of the first embodiment. Therefore, the dischargeability of chips is improved, and the sharpness of the superabrasive wheel 200 can be maintained favorably.

(Embodiment 3)

Hereinafter, the superabrasive wheel according to Embodiment 3 of the present invention will be described with reference to the drawings. The superabrasive wheel according to the third embodiment of the present invention is different from the superabrasive wheel 100 according to the first embodiment of the present invention only in the number and arrangement of the superabrasive grain layers. The same structure of the superabrasive grinding wheel 100 will not be repeated.

8 is a front view of the superabrasive wheel according to Embodiment 3 of the present invention. As shown in FIG. 8 , in the superabrasive wheel 300 according to Embodiment 3 of the present invention, 28 superabrasive grain layers 120 are arranged on seven curves L3. That is, four superabrasive grain layers 120 are arranged on one curve L3.

In this embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 28 super abrasive grain layers 120 is 1407.4 mm ² , and the occupied area ratio is 6.9%.

(Embodiment 4)

Hereinafter, the superabrasive wheel according to Embodiment 4 of the present invention will be described with reference to the drawings. The superabrasive wheel according to Embodiment 4 of the present invention differs from the superabrasive wheel 100 according to Embodiment 1 of the present invention only in the number and arrangement of the superabrasive grain layers, so it is The same structure of the superabrasive grinding wheel 100 will not be repeated.

9 is a front view of the superabrasive grinding wheel according to Embodiment 4 of the present invention. As shown in FIG. 9 , in the superabrasive wheel 400 according to Embodiment 4 of the present invention, 40 superabrasive grain layers 120 are arranged on 10 curves L4. That is, four superabrasive grain layers 120 are arranged on one curve L4.

In this embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 40 superabrasive grain layers 120 is 2010.6 mm ² , and the occupied area ratio is 9.9%.

(Embodiment 5)

Hereinafter, the superabrasive wheel according to Embodiment 5 of the present invention will be described with reference to the drawings. The superabrasive wheel according to Embodiment 5 of the present invention differs from the superabrasive wheel 100 according to Embodiment 1 of the present invention only in the number and arrangement of the superabrasive grain layers, so it is The same structure of the superabrasive grinding wheel 100 will not be repeated.

10 is a front view of the superabrasive wheel according to Embodiment 5 of the present invention. As shown in FIG. 10 , in the superabrasive wheel 500 according to Embodiment 5 of the present invention, 48 superabrasive grain layers 120 are arranged on 12 curves L5. That is, four superabrasive grain layers 120 are arranged on one curve L5.

In the present embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 48 superabrasive grain layers 120 is 2412.7 mm ² , and the occupied area ratio is 11.9%.

(Embodiment 6)

Hereinafter, the superabrasive wheel according to Embodiment 6 of the present invention will be described with reference to the drawings. The superabrasive wheel according to the sixth embodiment of the present invention differs from the superabrasive wheel 100 according to the first embodiment of the present invention only in the number and arrangement of the superabrasive grain layers. The same structure of the superabrasive grinding wheel 100 will not be repeated.

11 is a front view of the superabrasive wheel according to Embodiment 6 of the present invention. As shown in FIG. 11 , in the superabrasive wheel 600 according to Embodiment 6 of the present invention, 56 superabrasive grain layers 120 are arranged on 14 curves L6. That is, four superabrasive grain layers 120 are arranged on one curve L6.

In the present embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 56 super abrasive grain layers 120 is 2814.9 mm ² , and the occupied area ratio is 13.9%.

(Embodiment 7)

Hereinafter, the superabrasive wheel according to Embodiment 7 of the present invention will be described with reference to the drawings. The superabrasive wheel according to the seventh embodiment of the present invention is different from the superabrasive wheel 100 according to the first embodiment of the present invention only in the number and arrangement of the superabrasive grain layers. The same structure of the superabrasive grinding wheel 100 will not be repeated.

12 is a front view of the superabrasive wheel according to Embodiment 7 of the present invention. As shown in FIG. 12 , in the superabrasive wheel 700 according to Embodiment 7 of the present invention, 80 superabrasive grain layers 120 are arranged on 20 curves L7. That is, four superabrasive grain layers 120 are arranged on one curve L7.

In the present embodiment, the area of the annular region R is 20316.7 mm ² , the total area of the respective working surfaces of the 80 super abrasive grain layers 120 is 4021.2 mm ² , and the occupied area ratio is 19.8%.

(Embodiment 8)

Hereinafter, the superabrasive wheel according to Embodiment 8 of the present invention will be described with reference to the drawings. The superabrasive wheel according to the eighth embodiment of the present invention differs from the superabrasive wheel 100 according to the first embodiment of the present invention only in the external dimensions, number, and arrangement of the superabrasive grain layers, and therefore is not the same as the embodiment of the present invention. The same structure of the superabrasive grinding wheel 100 according to the mode 1 will not be described repeatedly.

13 is a front view of the superabrasive wheel according to Embodiment 8 of the present invention. As shown in FIG. 13 , in the superabrasive wheel 800 according to Embodiment 8 of the present invention, the superabrasive grain layer 820 has a diameter of 10 mm and a height of 12 mm. 80 superabrasive grain layers 820 are arranged on 20 curves L8. That is, four superabrasive grain layers 820 are arranged on one curve L8.

In the present embodiment, the area of the annular region R is 21717.8 mm ² , the total area of the respective working surfaces of the 80 superabrasive grain layers 120 is 6283.2 mm ² , and the occupied area ratio is 28.9%.

(Embodiment 9)

Hereinafter, the superabrasive wheel according to the ninth embodiment of the present invention will be described with reference to the drawings. The superabrasive wheel according to Embodiment 9 of the present invention differs from the superabrasive wheel 800 according to Embodiment 8 of the present invention only in the arrangement of the superabrasive grain layer. The same configuration of the hard abrasive wheel 800 will not be repeated.

14 is a front view of the superabrasive wheel according to Embodiment 9 of the present invention. As shown in FIG. 14 , in the superabrasive wheel 900 according to Embodiment 9 of the present invention, 80 superabrasive grain layers 820 are arranged on 20 curves L9. That is, four superabrasive grain layers 820 are arranged on one curve L9. Each of the 20 curves L9 has a circular arc shape. The radius of curvature of the curve L9 is larger than the radius of curvature of the curve L8 of the eighth embodiment. The distance between the superabrasive grain layers 820 adjacent to each other on the curve L9 is narrower than the distance between the superabrasive grain layers 820 adjacent to each other on the curve L8 in the eighth embodiment. Therefore, the dischargeability of chips is improved, and the sharpness of the superabrasive wheel 900 can be maintained favorably.

(Embodiment 10)

Hereinafter, the superabrasive wheel according to the tenth embodiment of the present invention will be described with reference to the drawings. The superabrasive wheel according to the tenth embodiment of the present invention is different from the superabrasive wheel 900 according to the ninth embodiment of the present invention only in the arrangement of the superabrasive grain layer. The same configuration of the hard abrasive wheel 900 will not be repeated.

15 is a front view of the superabrasive wheel according to Embodiment 10 of the present invention. As shown in FIG. 15 , in the superabrasive wheel 1000 according to Embodiment 10 of the present invention, 80 superabrasive grain layers 820 are arranged on 20 curves L10. That is, four superabrasive grain layers 820 are arranged on one curve L10. Each of the 20 curves L10 has an arc shape. The radius of curvature of the curve L10 is larger than the radius of curvature of the curve L9 of the ninth embodiment. The distance between the adjacent superhard abrasive grain layers 820 on the curve L10 is narrower than the distance between the adjacent superhard abrasive grain layers 820 on the curve L9 in Embodiment 9.

(Embodiment 11)

Hereinafter, the superabrasive wheel according to the eleventh embodiment of the present invention will be described with reference to the drawings. The superabrasive wheel according to the eleventh embodiment of the present invention differs from the superabrasive wheel 1000 according to the tenth embodiment of the present invention only in the number and arrangement of the superabrasive grain layers. The same composition of the superabrasive grinding wheel 1000 will not be repeated.

16 is a front view of the superabrasive wheel according to Embodiment 11 of the present invention. As shown in FIG. 16 , in the superabrasive wheel 1100 according to Embodiment 11 of the present invention, 80 superabrasive grain layers 820 are arranged on 20 curves L11. That is, four superabrasive grain layers 820 are arranged on one curve L11. In addition, on the fourth circle C4, the ten superabrasive grain layers 820 are arranged in the circumferential direction of the base metal 110 so as to have a gap between the adjacent curved lines 11, respectively. That is, a total of 90 superabrasive grain layers 820 are arranged in the annular region R. As shown in FIG.

In the present embodiment, the area of the annular region R is 21717.8 mm ² , the total area of the respective working surfaces of the 90 super abrasive grain layers 120 is 7068.6 mm ² , and the occupied area ratio is 32.5%.

(Embodiment 12)

Hereinafter, the superabrasive wheel according to the twelfth embodiment of the present invention will be described with reference to the drawings. The superabrasive wheel according to the twelfth embodiment of the present invention differs from the superabrasive wheel 1100 according to the eleventh embodiment of the present invention only in the number and arrangement of the superabrasive grain layers. The same structure of the superabrasive grinding wheel 1100 will not be repeated.

17 is a front view of the superabrasive wheel according to Embodiment 12 of the present invention. As shown in FIG. 17 , in the superabrasive wheel 1200 according to the twelfth embodiment of the present invention, 80 superabrasive grain layers 820 are arranged on 20 curves L12. That is, four superabrasive grain layers 820 are arranged on one curve L12. In addition, on the fourth circle C4 , 20 superabrasive grain layers 820 are arranged in the gaps between adjacent curved lines 11 in the circumferential direction of the base metal 110 . That is, a total of 100 superabrasive grain layers 820 are arranged in the annular region R. As shown in FIG.

In the present embodiment, the area of the annular region R is 21717.8 mm ² , the total area of the respective working surfaces of the 100 super abrasive grain layers 120 is 7854.0 mm ² , and the occupied area ratio is 36.2%.

(Experimental example 1)

Here, in the superabrasive wheel having the shape of Embodiment 1 of the present invention, an experiment to verify the difference in the sharpness of the superabrasive wheel due to the concentration of the superabrasive grains in the superabrasive grain layer Example 1 is used to illustrate.

(Sample No. 1 to 8)

Regarding the concentration of the superabrasive grains in the superabrasive grain layer 120, the sample No. 1 is 0.5, the sample No. 2 is 1, the sample No. 3 is 2, the sample No. 4 is 3, the sample No. 5 is 5, and the sample No. 6 is 10. The sample number 7 is 12, and the sample number 8 is 15, whereby the superabrasive grinding wheels of the sample numbers 1 to 8 were produced. The average particle diameter of the diamond abrasive grains of each sample was 60 μm.

The superabrasive grinding wheels of Sample Nos. 1 to 8 were mounted on a rotary table surface grinder, respectively, and three sapphire wafers with an outer diameter of 100 mm fixed on the rotary table were ground. The number of revolutions of the main shaft of the surface grinder was 900 rpm, the conveying speed of the superabrasive grinding wheel was 50 μm/min, and the grinding process was performed while supplying a water-soluble grinding fluid.

The sharpness of the superabrasive grinding wheel was evaluated based on the load current value of the spindle motor of the surface grinder corresponding to the grinding resistance. The load current value of the spindle motor is a value obtained by subtracting the current value of the spindle motor during idling without grinding from the average current value of the spindle motor during grinding. The load current value of sample No. 5 is set as the reference value, the sample whose load current value exceeds 0.8 times and 1.2 times or less of the reference value is evaluated as A, and the sample whose load current value exceeds 1.2 times and 1.5 times or less of the reference value is evaluated as B, the sample which is less than 0.8 times the reference value or more than 1.5 times the reference value is evaluated as C.

Various conditions and evaluation results of the superabrasive wheels of sample numbers 1 to 8 are shown in Table 1 below.

[Table 1]

As shown in Table 1, in the range where the concentration of the superabrasive grains is 1 or more and 12 or less, the sharpness is B or more, and good sharpness can be maintained for a long time. In the range of the concentration of the superabrasive particles being 2 or more and 10 or less, the sharpness is A, and excellent sharpness can be maintained for a long time. In the range where the concentration of the superabrasive grains is less than 1, the amount of the superabrasive grains in the superabrasive grain layer is insufficient, the superabrasive grains wear at an early stage, and the sharpness deteriorates. When the concentration of the superabrasive grains exceeds 12, clogging occurs in the superabrasive grain layer, and the sharpness deteriorates.

(Experimental example 2)

Next, in the superabrasive wheel having the shape of the eighth embodiment of the present invention, the difference in the sharpness of the superabrasive wheel due to the concentration of the superabrasive grains in the superabrasive grain layer was verified. Experimental Example 2 will be described.

(Sample No. 9 to 16)

Regarding the concentration of the superabrasive grains in the superabrasive grain layer 820 , the sample No. 9 is 0.5, the sample No. 10 is 1, the sample No. 11 is 2, the sample No. 12 is 3, the sample No. 13 is 5, and the sample No. 14 is 10. The sample number 15 was 12, and the sample number 16 was 15, whereby the superabrasive grinding wheels of the sample numbers 9 to 16 were produced. The average particle diameter of the diamond abrasive grains of each sample was 50 μm.

The superabrasive grinding wheels of sample Nos. 9 to 16 were respectively mounted on a rotary table surface grinder, and three sapphire wafers with an outer diameter of 100 mm fixed on the rotary table were ground. The number of revolutions of the main shaft of the surface grinder was 800 rpm, the conveying speed of the superabrasive grinding wheel was 45 μm/min, and the grinding process was performed while supplying a water-soluble grinding fluid.

The sharpness of the superabrasive grinding wheel was evaluated based on the load current value of the spindle motor of the surface grinder corresponding to the grinding resistance. The load current value of the spindle motor is a value obtained by subtracting the current value of the spindle motor during idling without grinding from the average current value of the spindle motor during grinding. The load current value of sample No. 13 was set as the reference value, the sample whose load current value exceeded 0.8 times and 1.2 times or less of the reference value was evaluated as A, and the sample whose load current value exceeded 1.2 times and 1.5 times or less of the reference value was evaluated as B, the sample which is less than 0.8 times the reference value or more than 1.5 times the reference value is evaluated as C.

Various conditions and evaluation results of the superabrasive grinding wheels of sample numbers 9 to 16 are shown in Table 2 below.

[Table 2]

As shown in Table 2, in the range of the concentration of the superabrasive grains being 1 or more and 12 or less, the sharpness was B or more, and good sharpness could be maintained for a long time. In the range of the concentration of the superabrasive particles being 2 or more and 10 or less, the sharpness is A, and excellent sharpness can be maintained for a long time. In the range where the concentration of the superabrasive grains is less than 1, the amount of the superabrasive grains in the superabrasive grain layer is insufficient, the superabrasive grains wear at an early stage, and the sharpness deteriorates. When the concentration of the superabrasive grains exceeds 12, clogging occurs in the superabrasive grain layer, and the sharpness deteriorates.

(Experimental example 3)

Next, Experiment Example 3 in which the difference in the sharpness of the superabrasive wheel due to the occupation area ratio of the working surface of the superabrasive grain layer in the superabrasive wheel will be described.

(Sample No. 17 to 24)

The concentration of the superabrasive grains in the superabrasive grain layer is 5, the sample No. 17 is the shape of Embodiment 3, the sample No. 18 is the shape of Embodiment 4, the sample No. 19 is the shape of Embodiment 6, and the sample No. 20 is the shape of The shape of the seventh embodiment, the sample number 21 is the shape of the embodiment 1, the sample number 22 is the shape of the embodiment 8, the sample number 23 is the shape of the embodiment 11, and the sample number 24 is the shape of the embodiment 12. Superabrasive wheels for sample numbers 17-24.

Therefore, regarding the occupation area ratio of the working surface of the superabrasive grain layer in the superabrasive grinding wheel, the sample No. 17 is 6.9%, the sample No. 18 is 9.9%, the sample No. 19 is 13.9%, the sample No. 20 is 19.8%, and the sample No. 20 is 19.8%. 21 was 22.8%, sample No. 22 was 28.9%, sample No. 23 was 32.5%, and sample No. 24 was 36.2%. The average particle diameter of the diamond abrasive grains of each sample was 70 μm.

The superabrasive grinding wheels of Sample Nos. 17 to 24 were respectively mounted on a rotary table surface grinder, and three sapphire wafers with an outer diameter of 100 mm fixed on the rotary table were ground. The number of revolutions of the main shaft of the surface grinder was 800 rpm, the conveying speed of the superabrasive grinding wheel was 55 μm/min, and the grinding process was performed while supplying a water-soluble grinding fluid.

The sharpness of the superabrasive grinding wheel was evaluated based on the load current value of the spindle motor of the surface grinder corresponding to the grinding resistance. The load current value of the spindle motor is a value obtained by subtracting the current value of the spindle motor during idling without grinding from the average current value of the spindle motor during grinding. The load current value of sample No. 21 was set as the reference value, and the sample whose load current value exceeded 0.8 times and 1.2 times or less of the reference value was evaluated as A, and the sample whose load current value exceeded 1.2 times and 1.5 times or less of the reference value was evaluated as B, the sample which is less than 0.8 times the reference value or more than 1.5 times the reference value is evaluated as C.

Various conditions and evaluation results of the superabrasive wheels of sample numbers 17 to 24 are shown in Table 3 below.

[table 3]

As shown in Table 3, in the superabrasive wheel, the occupancy area ratio of the working surface of the superabrasive grain layer was in the range of 10% to 32%, and the sharpness was B or more, and good sharpness could be maintained for a long time. In the superabrasive wheel, the occupancy area ratio of the working surface of the superabrasive grain layer is in the range of 13% or more and 28% or less, and the sharpness is A, and excellent sharpness can be maintained for a long time. In the superabrasive wheel, in the range where the area ratio of the action surface of the superabrasive grain layer is less than 10%, the superabrasive grain layer wears at an early stage and the sharpness is deteriorated. In the superabrasive wheel, in the range where the area ratio of the working surface of the superabrasive grain layer exceeds 32%, the cutting property of the superabrasive grain layer to the sapphire wafer is deteriorated, and the sharpness is degraded.

Embodiments of the present invention have been described, but it should be understood that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and it is intended that all changes within the meaning and scope equivalent to the claims are included.

Claims (4)

1. A superabrasive grinding wheel comprising:

a base metal of annular shape, and

a plurality of superhard abrasive grain layers arranged in a cylindrical shape on a surface of the base metal while being spaced apart from each other,

at least a part of the plurality of superabrasive grain layers is configured so as to be located on an upstream side in a rotational direction of the base metal along an inner peripheral side to an outer peripheral side direction of the base metal on a plurality of curves arranged in a rotationally symmetric manner with respect to a rotational center of the base metal,

the concentration of the superhard abrasive grains in the superhard abrasive grain layer is more than 1 and less than 12.

2. A superabrasive grinding wheel according to claim 1, wherein a ratio of a total area of the respective active surfaces of the plurality of superabrasive grit layers to an area of an annular region sandwiched between an outer circumference circle which is in contact with and centered on an outer circumferential side edge of a superabrasive grit layer farthest from the rotation center of the base metal among the plurality of superabrasive grit layers and an inner circumference circle which is in contact with and centered on an inner circumferential side edge of a superabrasive grit layer closest to the rotation center of the base metal among the plurality of superabrasive grit layers, i.e., an occupation area ratio is 10% or more and 32% or less.

3. A superabrasive grinding wheel according to claim 1 or claim 2, wherein each of the plurality of superabrasive particle layers is arranged on a concentric circle on the surface.

4. A superabrasive grinding wheel according to claim 1 or claim 2, which is used for grinding processing of a wafer comprising at least one selected from the group consisting of silicon, sapphire, glass, ceramic, quartz, SiC, and compound semiconductors.

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