KR102625907B1 - Scribing wheel - Google Patents

Abstract

A scribing wheel that can increase penetration is provided.
The scribing wheel 1 has a knife tip 20 formed on the outer periphery. The tip portion 20 includes a plurality of grooves 24 formed at intervals in the circumferential direction and a ridge portion 23 formed between grooves 24 adjacent to each other in the circumferential direction. The groove 24 includes a portion with a smaller included angle than the ridge portion 23.

Description

Scribing wheel {SCRIBING WHEEL}

The present invention relates to scribing wheels.

It is known that a scribing wheel is used to form a scribe line for cutting brittle material substrates such as glass substrates. For example, the scribing wheel of Patent Document 1 has a plurality of grooves formed at intervals from each other in the circumferential direction at the edge of the knife formed on the outer periphery.

Japanese Patent Application Publication No. 2010-132542

In a scribing wheel, it is desirable to increase the amount of penetration expressed as the ratio of the depth of the vertical crack to the substrate thickness of the brittle material substrate. The purpose of the present invention is to provide a scribing wheel capable of increasing penetration.

(1) The scribing wheel of the present invention is a scribing wheel having a knife tip formed on the outer periphery, wherein the knife tip has a plurality of grooves formed at intervals in the circumferential direction and ridges formed between the grooves adjacent to each other in the circumferential direction. The groove includes a portion having an included angle smaller than that of the ridge portion.

Focusing on the relationship between the included angle of the groove and the included angle of the ridge, the inventor of the present application found that when the included angle of the groove was changed, the change in penetration amount indicated by the ratio of the depth of the vertical crack to the thickness of the brittle material substrate cut by the scribing wheel tested for. As a result, it was found that when the groove includes a portion smaller than the included angle of the ridge, the amount of penetration increases. Therefore, in this scribing wheel, the groove is configured to include a portion smaller than the included angle of the ridge portion. Therefore, the penetration amount can be increased.

(2) In a preferred example, in the scribing wheel described in (1), the depth of the groove includes a portion deepening from an end of the groove in the circumferential direction toward the center of the groove, and at least the depth of the groove. The included angle of the end portion is smaller than the included angle of the ridge portion.

When the end of the groove in the circumferential direction contacts the brittle material substrate, vertical cracks are more likely to be formed than when the central portion of the groove in the circumferential direction contacts the brittle material substrate. Additionally, when the included angle is small, stress that expands vertical cracks is more likely to occur compared to when the included angle is large. Therefore, in this scribing wheel, by making the included angle at the end of the groove in the circumferential direction smaller than the included angle at the ridge, the stress that expands the vertical crack can be effectively increased, thereby further increasing the amount of penetration.

(3) In a preferred example, in the scribing wheel described in (2), the included angle of the end portion of the groove is smaller than the included angle of the central portion of the groove. When the end of the groove in the circumferential direction contacts the brittle material substrate, vertical cracks are more likely to form than when the central portion of the groove in the circumferential direction contacts the brittle material substrate. Additionally, when the included angle is small, stress that expands vertical cracks is more likely to occur compared to when the included angle is large. Therefore, in this scribing wheel, by making the included angle of the end of the groove in the circumferential direction smaller than the included angle of the central part of the groove in the circumferential direction, the stress that expands the vertical crack can be effectively increased, thereby further increasing the amount of penetration.

(4) In a preferred example, in the scribing wheel described in (2), the included angle of the groove becomes smaller from the end of the groove toward the center of the groove. For this reason, the same effect as (3) above can be obtained.

(5) In a preferred example, in the scribing wheel described in (2), the included angle of the central portion of the groove is greater than or equal to the included angle of the ridge portion.

The scribing wheel of the present invention can increase penetration.

Fig. 1 shows a scribing wheel of a first embodiment, (a) is a side view, and (b) is a cross-sectional view taken along the line 1b-1b in (a).
Figure 2 is an enlarged view of a portion of the tip of the scribing wheel of Figure 1, where (a) is a perspective view and (b) is a side view.
Figure 3 is a plan view of a portion of the tip of the knife.
Figure 4 is a cross-sectional view of the end of the groove at the tip of the knife.
Figure 5 is a cross-sectional view of the central portion of the groove at the tip of the knife.
Figure 6 is a graph showing the relationship between the position of the blade tip in the groove, the included angle of the groove corresponding to that position, and the angle difference between the included angle and the angle difference in the ridge portion of the blade tip.
Figure 7 is a graph showing the relationship between scribe load and penetration amount.

The scribing wheel 1 of this embodiment will be described with reference to FIGS. 1 to 7. The scribing wheel 1 is used to divide a brittle material substrate, which is a substrate made of a brittle material such as, for example, a glass substrate or a ceramic substrate. The scribing wheel 1 forms a scribe line on the surface of a brittle material substrate by rolling while pressing the surface of the brittle material substrate with a predetermined load.

The scribing wheel 1 is made of sintered diamond (poly crystalline diamond), cemented carbide, single crystal diamond, polycrystalline diamond, etc. The scribing wheel 1 may be made by coating a base material such as cemented carbide with a film of hard material such as diamond.

As shown in FIG. 1(a), the scribing wheel 1 has a disk-shaped body portion 10 and a V-shaped cross-sectional tip portion 20. The knife tip portion 20 is formed on the outer periphery of the scribing wheel 1. The main body portion 10 is a portion of the scribing wheel 1 radially inside the blade tip portion 20. The main body 10 and the blade tip 20 are formed as one piece. In addition, the V-shaped cross section means that the scribing wheel 1 is cut in a cross section cut in a plane along the thickness direction (hereinafter referred to as “thickness direction (DT)”) of the scribing wheel 1. ) has a shape where the tip becomes thinner toward the outer edge (see Figure 1(b)). The outer diameter of the scribing wheel (1) is in the range of ϕ 1 mm or more and ϕ 20 mm or less. The outer diameter of the scribing wheel 1 of this embodiment is ϕ 2 mm. Also, an example of the thickness of the scribing wheel 1 is 0.64 mm.

At the center of the main body 10, an insertion hole 13 is formed that penetrates the main body 10 in the thickness direction DT. A support pin (not shown) that rotatably supports the scribing wheel 1 is inserted into the insertion hole 13. As shown in FIG. 1(b), the main body 10 has a first side 11 on which one end of the insertion hole 13 is formed and a second side 12 on which the other end of the insertion hole 13 is formed. have

The tip portion 20 has a first inclined surface 21 and a second inclined surface 22, which are two inclined surfaces forming a V-shaped cross-section. The first inclined surface 21 connects the first side 11 and the tip of the knife tip 20, and the second inclined surface 22 connects the second side 12 and the tip of the knife tip 20. . In other words, the line where the first inclined surface 21 and the second inclined surface 22 intersect forms a ridge at the tip of the tip portion 20.

As shown in FIG. 1(b), in the thickness direction DT, the center position of the scribing wheel 1 in the thickness direction DT and the tip position of the cutting edge 20 are the same. When viewed from the cross section of the scribing wheel 1, a first angle θ1 formed by a line segment CL along a direction perpendicular to the thickness direction DT and the first inclined surface 21, a line segment CL, and a second The second angle θ2 formed by the inclined surface 22 is equal to each other.

As shown in FIG. 2(a), the scribing wheels 1 are aligned with each other along the circumferential direction (hereinafter, “circumferential direction (DC)”) of the scribing wheel 1 at the tip of the blade tip 20. It is provided with a plurality of grooves 24 formed at intervals. The number of grooves 24 can be set arbitrarily. The number of grooves 24 in this embodiment is 150. A first inclined surface 21, a second inclined surface 22, and a ridge portion 23 which is an intersection line thereof are formed between grooves 24 adjacent to each other in the circumferential direction DC. The outer peripheral edge of the ridge portion 23 and the outer peripheral edge of the groove 24 form the tip 25. The tip portion 20 has ridge portions 23 and grooves 24 alternately formed at the same pitch. The included angle θr, which is the angle formed by the first inclined surface 21 and the second inclined surface 22 in the ridge portion 23, is preferably in the range of 90° or more and 160° or less, and preferably 100° or more and 150° or less. do. If the included angle (θr) is 90° or more, it becomes difficult for surface peeling or peeling to occur in the brittle material substrate, and if it is 160° or less, it becomes difficult for jamming defects to occur. The included angle θr of this embodiment is 120° (see Fig. 4).

As shown in FIG. 2(b), the groove 24 has a curved and concave shape at the outer periphery of the tip portion 20. In addition, the groove 24 has a first groove inclined surface 21A corresponding to the first inclined surface 21 and a second groove inclined surface 22A corresponding to the second inclined surface 22, and the first groove inclined surface 21A and a blade tip 25 continuous from the ridge portion 23 at the outer peripheral edge where the second groove inclined surface 22A intersects. The groove 24 has a portion that deepens from the end of the groove 24 in the circumferential direction (DC) toward the center of the groove 24. The groove 24 of this embodiment deepens from the end of the groove 24 in the circumferential direction (DC) toward the center of the groove 24. The depth H of the groove 24 is defined as the distance between the ridge portion 23 in the radial direction of the scribing wheel 1 and the deepest part of the groove 24. The width WD of the groove 24 in the ridge portion 23 is defined as the distance between both ends of the groove 24 in the circumferential direction DC. The depth (H) of the groove 24 in the ridge portion 23 is determined by the material and thickness of the brittle material substrate when scribing the brittle material substrate, and further by the load pressing the scribing wheel 1 against the brittle material substrate (hereinafter , “scribe load”), the scribe line formed by the scribe, and the quality of the brittle material substrate after division, etc., for example, 0.5 ㎛ or more and 6.0 ㎛ or less. The depth of the groove 24 in the tip portion 20 of this embodiment is 5.5 μm. The width (WD) of the groove 24 in the circumferential direction (DC) is 2.0 μm or more and 35 μm or less. When the thickness of the brittle material substrate is 0.7 mm or less, the width (WD) of the groove 24 at the tip 25 is preferably 2.0 μm or more and 15 μm or less, and the thickness of the brittle material substrate is about 1.1 mm. In this case, the width WD of the groove 24 in the ridge portion 23 is preferably 10 μm or more and 30 μm or less. The width (WD) of the groove 24 at the tip 25 of this embodiment is 24 μm.

Such grooves 24 are formed by irradiating laser light from a laser irradiation device while the insertion hole 13 of the scribing wheel 1 is mounted on the rotation axis of a motor (not shown). The irradiation direction of the laser light is the radial direction of the scribing wheel (1). The laser light is focused on the laser irradiation device side rather than the ridge portion 23 of the scribing wheel 1. The irradiation part that irradiates laser light in the laser irradiation device is movable with respect to the scribing wheel 1 in the thickness direction (DT). Meanwhile, the distance between the irradiation part and the blade tip 20 in the radial direction of the scribing wheel 1 does not change. Therefore, the distance between the irradiated part and the knife tip 20 is minimized at the center position in the thickness direction (DT) of the scribing wheel (1), and from the center position in the thickness direction (DT) of the scribing wheel (1) As it moves away in the thickness direction (DT), the distance between the irradiation part and the tip of the knife (20) becomes longer.

When the groove 24 is formed in this way, the area to which the laser light is irradiated to the ridge portion 23 of the scribing wheel 1 is minimized, so that the tip of the knife tip portion 20 in the thickness direction DT As the distance from the location increases, the area to which the laser light is irradiated increases. Therefore, as shown in FIG. 3, the width WD of the groove 24 becomes the minimum at the tip position of the blade tip 20, that is, the groove 24 at the blade tip 25, and the width WD of the groove 24 is minimized in the thickness direction DT. It becomes larger as it moves away from the tip of the knife (25).

4 and 5, the shape of the end of the groove 24 in the circumferential direction (DC) (hereinafter simply referred to as the “end of the groove 24”) and the shape of the groove in the circumferential direction (DC) The shape of the central portion of 24 (hereinafter simply referred to as the “central portion of groove 24”) is different.

As shown in FIG. 4, the first groove included angle θg1, which is the included angle of the end of the groove 24, is smaller than the included angle θr. The first groove included angle θg1 is preferably approximately 2 to 10° smaller than the included angle θr. On the other hand, as shown in FIG. 5, the second groove included angle θg2, which is the included angle of the central portion of the groove 24, is larger than the included angle θr. That is, the first groove included angle θg1 is smaller than the second groove included angle θg2.

Here, the end portion of the groove 24 is adjacent to the ridge portion 23 in the circumferential direction (DC). One end of the groove 24 in the circumferential direction (DC) extends from the groove starting point of the groove 24 in the ridge portion 23 (position of line segment C in FIG. 3) to the inside of the groove 24. It is defined as the portion up to a position (position of line segment E in FIG. 3) over a predetermined distance. Additionally, the same provisions apply to the other end of the groove 24 in the circumferential direction (DC). In this way, the first groove included angle θg1 is defined as the included angle in the portion from the position of the line segment C to the position of the line segment E in the groove 24. In this embodiment, the distance between line segment C and line segment E in the circumferential direction (DC) is 5.0 μm. The distance from the end of the groove 24 where the first groove included angle θg1 is defined is preferably about 10 to 30% on one side of the width WD of the groove 24. The groove included angle θg is the first groove inclined surface 21A, which is a portion corresponding to the groove 24 in the first inclined surface 21, and the second groove 21A, which is a portion corresponding to the groove 24 in the second inclined surface 22. It is defined by the angle formed by the groove inclined surface 22A. The first groove included angle θg1 is defined by the angle formed by the first groove inclined surface 21A at the end of the groove 24 and the second groove inclined surface 22A at the end of the groove 24. The second groove included angle θg2 is defined by the angle formed by the first groove inclined surface 21A at the center of the groove 24 and the second groove inclined surface 22A at the center of the groove 24.

Additionally, the first groove included angle θg1 and the second groove included angle θg2 can be arbitrarily changed. In one example, the second groove included angle θg2 may be equal to the included angle θr or may be smaller than the included angle θr.

(Example)

In order to evaluate the performance of the scribing wheel 1, the scribing wheel of Example 1 and Example 2 and the scribing wheel of Comparative Example 1 and Comparative Example 2 were used to evaluate the relationship between scribing load and penetration amount. Confirmed. Additionally, the penetration amount represents the ratio of the depth of the vertical crack to the thickness of the brittle material substrate in percentage (%).

For each of the scribing wheels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the included angle difference (θd) at the measurement position was measured every 2.5㎛ based on the starting position of the groove 24. did. Specifically, the position corresponding to line segment A to line segment H in FIG. 3 is set as the measurement position. Line segment A is a position 5 μm away from the starting position of the groove 24 toward the ridge portion 23, and line segment B is a position 2.5 μm away from the starting position of the groove 24 toward the tip 25. Line segment A and line segment B are both line segments that pass through the ridge portion 23. Line segment C is the starting position of the groove 24, line segment D is a position 2.5㎛ away from the starting position of the groove 24 toward the groove 24, and line segment E is from the starting position of the groove 24 toward the groove 24. The line segment F is 7.5 ㎛ away from the starting position of the groove 24, and the line segment G is 10.0 ㎛ away from the starting position of the groove 24, Line segment H is a position 12.5 μm away from the starting position of the groove 24 toward the groove 24. Line segments C to H are all line segments that pass through the outer edge of the groove 24. Figure 6 is a graph showing the relationship between line segment A, which is the measurement position in the scribing wheel of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, and the included angle difference (θd) between line segments B to line segments H. am.

In addition, the scribing wheels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 each had an outer diameter (ϕ) of 2 mm, an included angle (θr) of 120°, a number of grooves of 150, and a groove depth (H ) of 5.5㎛ was used. The specific groove shapes of the scribing wheels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 will be described using FIG. 6.

Figure 6 shows the included angle difference (θd) of each measurement point in the scribing wheel of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, based on the included angle (θr) of the position of line segment A. This is a graph that represents At the position of line segment C to line segment E, the included angle difference (θd) of the scribing wheels of Examples 1 and 2 becomes a negative value, while the included angle difference of the scribing wheels of Comparative Examples 1 and 2 (θd) becomes a positive value. In detail, at the position of the line segment C, the groove included angle θg of the scribing wheel in Example 1 is about 3° smaller than the included angle θr, and the groove included angle θg of the scribing wheel in Example 2 is the included angle ( It is about 2.5° smaller than θr). The groove included angle θg of the scribing wheel of Comparative Example 1 is about 0.2° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 0.1° larger than the included angle θr. At the position of line segment D, the groove included angle θg of the scribing wheel of Example 1 is about 5.5° smaller than the included angle θr, and the groove included angle θg of the scribing wheel of Example 2 is less than the included angle θr. It is about 4.5° smaller. In the scribing wheels of Examples 1 and 2, the groove included angle θg becomes smallest with respect to the included angle θr at the position of line segment D. In addition, the groove included angle θg of the scribing wheel of Comparative Example 1 is about 1° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 0.8° larger than the included angle θr. big. At the position of line segment E, the groove included angle θg of the scribing wheel of Example 1 is about 0.5° smaller than the included angle θr, and the groove included angle θg of the scribing wheel of Example 2 is less than the included angle θr. It is about 1° smaller. The groove included angle θg of the scribing wheel of Comparative Example 1 is about 3° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 3.5° larger than the included angle θr.

At the position of the line segment F, the included angle difference (θd) of the scribing wheel of Example 2 becomes a negative value, while the included angle difference (θd) of the scribing wheels of Example 1, Comparative Example 1, and Comparative Example 2 becomes a positive value. In detail, at the position of the line segment F, the groove included angle θg of the scribing wheel in Example 1 is about 0.1° larger than the included angle θr, and the groove included angle θg of the scribing wheel in Example 2 is the included angle ( It is about 1° smaller than θr). The groove included angle θg of the scribing wheel of Comparative Example 1 is about 8° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 7.5° larger than the included angle θr.

At the position of the line segment G, the included angle difference (θd) of the scribing wheel of Example 2 is a negative value, while the included angle difference (θd) of the scribing wheels of Comparative Examples 1 and 2 is a positive value. do. Also, the included angle difference (θd) of the scribing wheel of Example 1 is 0°. In detail, the groove included angle θg of the scribing wheel of Example 2 is about 0.2° smaller than the included angle θr. The groove included angle θg of the scribing wheel of Comparative Example 1 is about 8° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 10° larger than the included angle θr.

At the position of the line segment H, the included angle difference θd of the scribing wheels of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 becomes a positive value. The groove included angle θg of the scribing wheel of Example 1 is about 2° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Example 2 is about 1° larger than the included angle θr, The groove included angle θg of the scribing wheel of Comparative Example 1 is about 9° larger than the included angle θr, and the groove included angle θg of the scribing wheel of Comparative Example 2 is about 8° larger than the included angle θr.

Additionally, the groove included angle θg, which is the included angle in the groove 24, can be calculated as follows using, for example, a laser microscope. That is, the laser microscope measures the distance between the laser microscope and the scribing wheel (1) by irradiating a laser in the radial direction of the scribing wheel (1), thereby forming a groove ( 24) Acquire the profile. And the groove included angle θg can be calculated from the respective profiles of the first groove inclined surface 21A and the second groove inclined surface 22A of the acquired groove 24. In this example, KEYENCE's VK-X100 was used as a laser microscope.

In the relationship between scribe load and penetration amount, the penetration amount was measured when the scribe load was changed to 0.09 MPa, 0.10 MPa, 0.11 MPa, 0.13 MPa, 0.15 MPa, 0.17 MPa, 0.19 MPa, 0.21 MPa, and 0.23 MPa.

As shown in Figure 7, when the scribing load is 0.09 MPa, the penetration amount of the scribing wheel of Example 1 is about 75%, the penetration amount of the scribing wheel of Example 2 is about 76%, and the penetration amount of the scribing wheel of Example 1 is about 76%. The penetration amount of the scribing wheel is about 64%, and the penetration amount of the scribing wheel in Comparative Example 2 is about 66%. When the scribing load is 0.10 MPa, the penetration amount of the scribing wheel of Example 1 and Example 2 is about 78%, the penetration amount of the scribing wheel of Comparative Example 1 is about 60%, and the penetration amount of the scribing wheel of Comparative Example 2 is about 60%. The penetration of the Bing wheel is about 74%. When the scribing load is 0.11 MPa, the penetration amount of the scribing wheel of Example 1 is about 82%, the penetration amount of the scribing wheel of Example 2 is about 81%, and the penetration amount of the scribing wheel of Comparative Example 1 is It is about 77%, and the penetration amount of the scribing wheel in Comparative Example 2 is about 74%. When the scribing load is 0.13 MPa, the penetration amount of the scribing wheel of Examples 1 and 2 is about 84%, the penetration amount of the scribing wheel of Comparative Example 1 is about 79%, and the penetration amount of the scribing wheel of Comparative Example 2 is about 79%. The penetration of the wheel is approximately 77%. When the scribing load is 0.15 MPa, the penetration amount of the scribing wheels of Examples 1 and 2 is about 86%, the penetration amount of the scribing wheel of Comparative Example 1 is about 81%, and the penetration amount of the scribing wheel of Comparative Example 2 is about 81%. The penetration of the wheel is approximately 83%. When the scribing load is 0.17 MPa, the penetration amount of the scribing wheels of Examples 1 and 2 is about 87%, and the penetration amount of the scribing wheels of Comparative Examples 1 and 2 is about 85%. When the scribing load is 0.19 MPa, the penetration amount of the scribing wheels of Examples 1, 2, and Comparative Examples 2 is about 90%, and the penetration amount of the scribing wheel of Comparative Example 1 is about 86%. When the scribing load is 0.21 MPa, the penetration amount of the scribing wheel of Example 1 is about 92% and the penetration amount of the scribing wheel of Example 2 is about 93%, and the penetration amount of the scribing wheel of Example 1 and Comparative Example 2 is about 93%. The penetration of the wheel is approximately 90%. When the scribing load is 0.23 MPa, the penetration amount of the scribing wheels of Examples 1 and 2 is about 95%, and the penetration amount of the scribing wheels of Comparative Examples 1 and 2 is about 93%.

As shown in Figure 7, it was confirmed that the penetration amount of the scribing wheels of Examples 1 and 2 was 5 to 10% greater than that of the scribing wheels of Comparative Examples 1 and 2. In particular, it was confirmed that in the range of low scribing load, the amount of penetration by the scribing wheels of Examples 1 and 2 was significantly larger than that of the scribing wheels of Comparative Examples 1 and 2.

According to this embodiment, the following effects can be obtained.

(1) As the groove included angle θg is smaller than the included angle θr, the penetration amount of the brittle material substrate increases. As a result, the brittle material substrate can be easily divided. In addition, since the scribing load for obtaining the desired vertical crack depth can be reduced, the occurrence of defects when scribing brittle material substrates, such as overtaking due to an increase in the scribing load, can be suppressed.

(2) When the end of the groove 24 contacts the brittle material substrate, vertical cracks are more likely to be formed than when the central portion of the groove 24 contacts the brittle material substrate. Additionally, when the groove included angle θg is small, stress that expands vertical cracks is more likely to occur compared to when the groove included angle θg is large. Therefore, in this embodiment, the first groove included angle θg1 is made smaller than the second groove included angle θg2. As a result, the stress that expands the vertical crack can be effectively increased, and thus the amount of penetration can be further increased.

(variation example)

The description of the above embodiments is illustrative of the form that the scribing wheel according to the present invention can take, and is not intended to limit the form. The scribing wheel according to the present invention may, for example, take the form of a combination of a modification of the above embodiment shown below and at least two modifications that do not contradict each other. In the following modified examples, parts that are common to the form in the above embodiment are given the same reference numerals as those in the above embodiment and their description is omitted.

· The groove 24 may be provided so that the groove included angle θg gradually decreases as it moves from the end of the groove 24 of the scribing wheel 1 to the center of the groove 24. Even with this configuration, the effects of the above embodiment can be obtained.

· At the end of the groove 24, the groove 24 may be provided so that the groove included angle θg gradually decreases as it moves from the starting point (the position of the line segment C in FIG. 3) to the position of the line segment E in FIG. 3. Even with this configuration, the effects of the above embodiment can be obtained.

· The groove included angle θg of the groove 24 other than the end of the groove 24 may be equal to or greater than the included angle θr. That is, only the first groove included angle θg1 at the end of the groove 24 may be formed to be smaller than the included angle θr. Even with this configuration, the effects of the above embodiment can be obtained.

· The shape of the groove 24 in the depth direction can be arbitrarily changed. In one example, the groove 24 may have a shape whose bottom includes a flat portion.

· The shape of the tip of the knife (20) can be arbitrarily changed. In one example, the position of the ridge portion 23 in the thickness direction DT may be different from the position of the center of the scribing wheel 1 in the thickness direction DT.

1 Scribing wheel
10 Main body
20 Blade tip
21 1st slope
22 Second slope
23 Ridge
24 home
θr included angle
θg groove included angle
θg1 1st groove included angle
θg2 2nd groove included angle
DC circumferential direction

Claims (5)

A scribing wheel having a blade tip formed on the outer periphery,
The tip portion includes a plurality of grooves formed at intervals in the circumferential direction and a ridge portion formed between the grooves adjacent to each other in the circumferential direction,
The groove includes a portion with a smaller included angle than the ridge portion,
The groove includes a portion whose depth increases from an end of the groove in the circumferential direction toward the center of the groove,
The end of the groove ranges from 10% to 30% on one side of the width of the groove in the circumferential direction from the starting point of the groove,
A scribing wheel wherein the included angle of the end portion of the groove is smaller than the included angle of the ridge portion and is smaller than the included angle of the central portion of the groove. delete delete delete According to claim 1,
A scribing wheel wherein the included angle of the central portion of the groove is greater than or equal to the included angle of the ridge portion.

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