阅读说明：本技术 修整工具 (Dressing tool ) 是由 星川裕俊 于 2020-04-09 设计创作，主要内容包括：提供修整工具,其能够适当地判断修整板是否磨损至使用界限的厚度。该修整工具对呈环状排列在磨削磨轮的一个面侧的多个磨削磨具进行修整,其中,该修整工具具有：修整部,其对磨削磨具进行修整；以及支承部,其对修整部的背面侧进行支承,在修整部的背面侧设置有凹部,该凹部未到达修整部的位于与背面相反的一侧的正面,并且该凹部的深度与修整部的使用界限的厚度对应。(Provided is a dressing tool capable of appropriately judging whether a dressing plate is worn to the thickness of a use limit. The dressing tool dresses a plurality of grinding stones annularly arranged on one surface side of a grinding wheel, wherein the dressing tool comprises: a dressing section that dresses the grinding wheel; and a support portion that supports the back surface side of the finishing portion, wherein a recess is provided on the back surface side of the finishing portion, the recess does not reach the front surface of the finishing portion on the side opposite to the back surface, and the depth of the recess corresponds to the thickness of the use limit of the finishing portion.)

1. A dressing tool for dressing a plurality of grinding stones annularly arranged on one surface side of a grinding wheel,

the dressing tool has:

a dressing section for dressing the grinding wheel; and

a support portion for supporting the back side of the dressing portion,

a concave portion is provided on the back surface side of the dressing portion, the concave portion does not reach the front surface of the dressing portion on the side opposite to the back surface, and the depth of the concave portion corresponds to the thickness of the use limit of the dressing portion.

2. The dressing tool of claim 1,

the recessed portion of the dressing portion is provided linearly when the dressing portion is viewed from the rear surface side.

3. The dressing tool of claim 1,

when the dressing portion is viewed from the rear surface side, the concave portion of the dressing portion is provided on the outer peripheral side of the center of the dressing portion.

4. The dressing tool of claim 1,

the recessed portion of the dressing portion is provided in a ring shape when the dressing portion is viewed from the back surface side.

5. The dressing tool of any one of claims 1 to 4,

the recess of the trimming portion includes a 1 st recess having a 1 st depth and a 2 nd recess having a 2 nd depth deeper than the 1 st depth.

6. The dressing tool of claim 5,

the 1 st recess overlaps the 2 nd recess in the depth direction of the recess.

Technical Field

The present invention relates to a dressing tool for dressing an abrasive tool for grinding a grinding wheel.

Background

As a processing method in the case of dividing a wafer having a plurality of devices formed on the front surface side into chips corresponding to the respective devices, for example, the following methods are mentioned: after the back surface side of the wafer is ground, the wafer is cut by a cutting tool and divided.

The grinding of the wafer is performed, for example, by a grinding apparatus to which a grinding wheel having a grinding wheel (grinding wheel) for grinding is attached. The wafer is held by a holding table of a grinding apparatus, and a rotating grinding wheel is pressed against a surface to be processed of the wafer to grind the wafer (see, for example, patent document 1).

The grinding wheel is formed by, for example, mixing abrasive grains such as diamond and cBN (cubic boron nitride) with a bonding material such as ceramics or resin and sintering the mixture. When a wafer is ground by this grinding wheel, a large number of abrasive grains protruding from the front surface (i.e., a grinding surface) of the grinding wheel each act as a cutting edge, and scrape a surface to be processed of the wafer.

As the grinding progresses, the grinding stone is worn away, and new abrasive grains gradually appear on the front surface of the grinding stone in contact with the surface to be processed of the wafer. This action (referred to as a self-sharpening action or the like) suppresses a reduction in grinding performance due to the dropping, clogging, dulling or the like of abrasive grains, and realizes a good cutting work.

However, the abrasive grains of the unused grinding stones do not protrude properly from the front surfaces of the grinding stones, and the grinding surfaces of the grinding stones also vary in height. Therefore, before grinding the wafer, the following dressing process is performed: by sharpening the grinding wheel with a dressing plate, the bonding material covering the abrasive grains is partially removed and the abrasive grains are appropriately projected from the front surface of the grinding wheel (see, for example, patent document 2).

The trimming plate is formed to have a thickness of, for example, about 1mm to 5mm, and a support plate made of resin is fixed to the back surface side thereof with an adhesive or the like. The dressing plate is worn out by the sharpening process of the grinding wheel, and is replaced when the dressing plate becomes thinner to a predetermined thickness. For example, the replacement timing of the trimming plate is judged by visually checking the thickness of the trimming plate.

Patent document 1: japanese patent laid-open No. 2000-288881

Patent document 2: japanese laid-open patent publication No. 2009-142906

However, the above-described methods such as visual observation do not necessarily allow the timing of replacement of the trimming plate to be appropriately determined. If the support plate is ground by the grinding wheel without replacement by using a dressing plate having a thickness that has been worn to the limit of use, the grinding wheel may be damaged.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dressing tool capable of appropriately determining whether or not a dressing plate has worn to a thickness of a use limit.

According to one aspect of the present invention, there is provided a dressing tool for dressing a plurality of grinding stones annularly arranged on one surface side of a grinding wheel, wherein the dressing tool comprises: a dressing section for dressing the grinding wheel; and a support portion that supports a back surface side of the dressing portion, wherein a recess is provided on the back surface side of the dressing portion, the recess does not reach a front surface of the dressing portion on a side opposite to the back surface, and a depth of the recess corresponds to a thickness of a usage limit of the dressing portion.

Preferably, the recessed portion of the dressing portion is provided linearly when the dressing portion is viewed from the rear surface side. Preferably, when the dressing portion is viewed from the rear surface side, the concave portion of the dressing portion is provided on the outer peripheral side of the center of the dressing portion.

Preferably, the recessed portion of the dressing portion is provided in a ring shape when the dressing portion is viewed from the rear surface side. Preferably, the recess of the trimming portion includes a 1 st recess having a 1 st depth and a 2 nd recess having a 2 nd depth deeper than the 1 st depth. Preferably, the 1 st recess and the 2 nd recess overlap in a depth direction of the recess.

A dressing tool according to one embodiment of the present invention includes: a dressing section that dresses the grinding wheel; and a support portion that supports the back surface side of the dressing portion. A recess is provided on the back side of the dressing section, the recess does not reach the front side of the dressing section, and the depth corresponds to the thickness of the use limit of the dressing section.

Since the dressing portion (dressing plate) is worn away by the sharpening process of the grinding wheel and becomes thinner to a predetermined thickness, the recess appears on the front surface side of the dressing portion, and thus the thickness of the dressing portion worn to the use limit can be visually determined. Therefore, the timing at which the dresser reaches the use limit can be appropriately determined.

Drawings

Fig. 1 (a) is a perspective view of the dressing tool of embodiment 1, and fig. 1 (B) is a sectional view taken along line a-a of the dressing tool of embodiment 1.

Fig. 2 is a side view showing a use state of the dressing tool.

Fig. 3 is a cross-sectional view a-a of the dressing tool reaching the use limit.

Fig. 4 (a) is a perspective view of the dressing tool of embodiment 2, and fig. 4 (B) is a B-B sectional view of the dressing tool of embodiment 2.

Fig. 5 (a) is a perspective view of the dressing tool of embodiment 3, and fig. 5 (B) is a C-C sectional view of the dressing tool of embodiment 3.

Fig. 6 (a) is a perspective view of the dressing tool of embodiment 4, and fig. 6 (B) is a D-D sectional view of the dressing tool of embodiment 4.

Fig. 7 (a) is a sectional view a-a of the dressing tool of modification 1 of embodiment 1, fig. 7 (B) is a sectional view B-B of the dressing tool of modification 1 of embodiment 2, fig. 7 (C) is a sectional view C-C of the dressing tool of modification 1 of embodiment 3, and fig. 7 (D) is a sectional view D-D of the dressing tool of modification 1 of embodiment 4.

Fig. 8 (a) is a sectional view a-a of the dressing tool of modification 2 of embodiment 1, fig. 8 (B) is a sectional view B-B of the dressing tool of modification 2 of embodiment 2, fig. 8 (C) is a sectional view C-C of the dressing tool of modification 2 of embodiment 3, and fig. 8 (D) is a sectional view D-D of the dressing tool of modification 2 of embodiment 4.

Description of the reference symbols

2: a dressing tool; 4: trimming the plate; 4 a: a front side; 4 b: a back side; 6: a support plate; 6 a: a front side; 6 b: a back side; 8. 8a, 8b, 8 c: a recess; 8-1, 8a-1, 8b-1, 8 c-1: 1 st recess; 8-2, 8a-2, 8b-2, 8 c-2: a 2 nd recess; 8-3, 8a-3, 8b-3, 8 c-3: a 3 rd recess; 12: a grinding device; 14: a main shaft; 16: a spindle housing; 18: grinding the grinding wheel; 20: a grinding wheel mounting seat; 22: a rotation mechanism; 24: a grinding wheel base station; 26: grinding the grinding tool; 28: a holding table; 28 a: a front side; d 1: depth 1; d 2: a 2 nd depth; r: a radius; and (2) O: a center.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 (a) is a perspective view of a dressing tool 2 according to embodiment 1, and fig. 1 (B) is a sectional view of the dressing tool 2 according to embodiment 1 taken along a line a-a.

As shown in fig. 1 a, the dresser 2 of embodiment 1 includes a dresser plate (dresser portion) 4 formed in a flat disc shape. The shape of the trimming plate 4 is not limited to a disk shape. The shape of the trimming plate 4 may be a rectangular plate shape.

A front surface 6a of a support plate (support portion) 6 for supporting the trimming plate 4 is bonded to the rear surface 4b of the trimming plate 4. The support plate 6 is formed in a disk shape having a larger diameter than the trimming plate 4 so as to support the entire trimming plate 4. The support plate 6 is formed of, for example, resin.

The dressing plate 4 is formed using a mixed material in which abrasive grains such as white corundum (WA) and Green Carbon (GC) are mixed with a bonding material such as ceramics and resin, for example. However, the bonding material and the abrasive grains constituting the dressing plate 4 are changed depending on the structure of the grinding stone 26 (see fig. 2) and the like.

The finishing plate 4 has a thickness of, for example, 3mm to 5 mm. A recess 8 is provided on the rear surface 4b side of the trimming plate 4. The recess 8 is a hole formed by a substantially cylindrical space, and as shown in the cross section a-a in fig. 1 (B), the recess 8 is provided at a substantially central portion on the rear surface 4B side of the trimming plate 4.

The section a-a in fig. 1 (B) is a cross-sectional plane obtained by cutting the trimming plate 4 and the support plate 6 through a plane perpendicular to the front surface 4a and passing through the center of the circular front surface 4a (i.e., the surface located on the opposite side of the rear surface 4B) of the trimming plate 4.

The recess 8 is formed from the back surface 4b to a predetermined depth not reaching the front surface 4 a. The depth of the recess 8 is adjusted in such a manner that the recess 8 appears on the front surface 4a side of the trimming plate 4 when the trimming plate 4 is worn to the thickness of the use limit (i.e., in such a manner as to correspond to the thickness of the use limit of the trimming plate 4).

For example, when the thickness of the use limit of the trimming plate 4 is set to 400 μm, the depth of the recess 8 is adjusted to 400 μm from the rear surface 4 b. However, the thickness of the use limit of the trimming plate 4 and the depth of the recess 8 are not limited to 400 μm, and may be set to various values.

The dressing plate 4 is worn away by the sharpening process of the grinding stone 26, and when thinned to a prescribed thickness, the recess 8 appears on the front surface of the dressing plate 4. Therefore, the operator can visually determine whether or not the dressing plate 4 is worn to the thickness of the use limit, and can therefore appropriately determine when the dressing tool 2 reaches the use limit.

The above-described finishing plate 4 can be manufactured by a manufacturing method similar to a conventional manufacturing method of a finishing plate. For example, the above-mentioned mixed material is first molded to form a flat disk-shaped molded body. In the molding, a hole corresponding to the recess 8 is formed in the center of the circular one surface of the molded body. Then, the molded body is sintered, whereby the trimming plate 4 having the concave portion 8 can be manufactured.

Further, a hole corresponding to the concave portion 8 may be formed in the sintered body without forming a hole corresponding to the concave portion 8 in the molded body. For example, after the mixed material is molded into a flat disk shape, the molded body is sintered. Then, the disc-shaped sintered body is cut to form the concave portion 8. Thereby, the trimming plate 4 having the recess 8 can be manufactured.

Next, a dressing process of the grinding stone 26 using the dressing tool 2 of embodiment 1 will be described. Fig. 2 is a side view showing a use state of the dressing tool 2. As shown in fig. 2, the grinding apparatus 12 used in the dressing step includes a cylindrical spindle housing 16 that rotatably supports the spindle 14.

The spindle housing 16 is attached to a support column (not shown) of the grinding apparatus 12 via a moving mechanism (not shown) and moves in the vertical direction. A grinding wheel mounting seat 20 for mounting the grinding wheel 18 is fixed to the lower end side of the main shaft 14.

A rotation mechanism 22 including a motor and the like is connected to the upper end side of the main shaft 14. A grinding wheel 18 is attached to the grinding wheel attachment seat 20, and the grinding wheel 18 is rotated by a rotational force transmitted from a rotating mechanism 22.

The grinding wheel 18 has a cylindrical wheel base 24 made of a metal material such as aluminum or stainless steel. One surface of the grinding wheel base 24 on the opposite side to the grinding wheel attachment seat 20 is formed in an annular shape, and a plurality of grinding stones 26 are fixed along the circumferential direction of the annular one surface. That is, a plurality of grindstones 26 are annularly arranged on one surface side of the grinding wheel base 24.

A holding table 28 is provided below the grinding wheel mounting base 20. The holding table 28 is coupled to a driving mechanism (not shown) such as a motor, and rotates about a rotation axis parallel to the axial direction of the spindle 14.

The front surface 28a of the holding table 28 serves as a holding surface for sucking and holding a workpiece such as a wafer. A negative pressure of a suction source (not shown) such as an ejector is applied to the holding surface through a flow path (not shown) formed inside the holding table 28, and a suction force for sucking the workpiece is generated.

In a state where the back surface 6b side of the support plate 6 is attracted to the holding table 28, the grinding wheel 18 and the holding table 28 are rotated, and the spindle housing 16 is lowered. When the lowering amount of the spindle case 16 is adjusted so that the grinding wheel 26 is pressed against the front surface 4a of the dressing plate 4, the grinding wheel 26 is dressed by the dressing plate 4.

Fig. 3 is a cross-sectional view a-a of the dressing tool 2 up to the limit of use. When the finishing plate 4 is worn by the dressing of the grinding stone 26 described above, the finishing plate 4 becomes gradually thinner. When the finishing plate 4 is worn to the thickness of the use limit, the recess 8 appears on the front face 4a side of the finishing plate 4.

As described above, the dressing tool 2 according to embodiment 1 is provided with the recess 8 having a depth corresponding to the thickness of the use limit of the dressing plate 4. Therefore, it is possible to determine whether or not the finishing plate 4 is worn to the thickness of the use limit, based on whether or not the recess 8 is present on the front surface 4a side of the finishing plate 4.

For example, when recognizing whether or not the recessed portion 8 is present on the front surface 4a side, the operator observes the front surface 4a side of the stationary trimming plate 4 conveyed to the magazine since the trimming tool 2 is conveyed from the holding table 28 to the magazine (not shown) after the trimming process is completed. This allows the operator to recognize whether or not the recess 8 is present on the front surface 4a side.

The operator may observe the front surface 4a side of the dressing plate 4 in a state where the dressing tool 2 is held by the holding table 28 and rotated (i.e., during the dressing process). In this way, even if the rotating trimming plate 4 is visually checked, it can be recognized whether or not the recess 8 is present on the front surface 4a side.

The main body for identifying whether or not the recess 8 is present on the front surface 4a side is not necessarily limited to the operator. For example, whether or not the recess 8 is present on the front surface 4a side may be automatically recognized by a determination device having a camera for photographing the front surface 4a side and a determination section such as a CPU for determining whether or not the recess 8 is present on the front surface 4a side based on an image photographed by the camera.

However, the shape of the recess 8 may be variously modified. The recess 8 of the trimming plate 4 of embodiment 1 is a substantially cylindrical hole, but the shape of the recess 8 is not limited to a cylindrical hole.

Fig. 4 (a) is a perspective view of the dressing tool 2 of embodiment 2, and fig. 4 (B) is a cross-sectional view of the dressing tool 2 of embodiment 2 taken along line B-B. As shown in fig. 4 (a) and 4 (B), a recess 8a is provided on the rear surface 4B side of the trimming plate 4 according to embodiment 2. The concave portion 8a is a linear groove having a length portion in the radial direction of the dressing plate 4.

More specifically, when the finishing plate 4 is viewed from the rear surface 4b side, the recess 8a is formed in a linear shape passing through the center of the circular rear surface 4b, and the length of the recess 8a in the longitudinal direction is formed to be substantially the same as the diameter of the circular rear surface 4 b. However, the concave portion 8a may be formed in a straight line not passing through the center O of the rear surface 4b when viewed from the rear surface 4 b.

The recess 8a is formed from the back surface 4b to a predetermined depth not reaching the front surface 4 a. The depth of the concave portion 8a is adjusted in such a manner that the concave portion 8a appears on the front surface 4a side of the trimming plate 4 in contact with the grinding stone 26 when the trimming plate 4 is worn to the thickness of the use limit.

Therefore, in embodiment 2, the worker or the like can determine whether or not the finishing plate 4 is worn to the thickness of the use limit based on whether or not the recess 8 is present on the front surface 4a side of the finishing plate 4.

Further, since the concave portion 8a is formed in a straight line passing through the center O, the concave portion 8a can be seen on the entire front surface 4a side when the trimming plate 4 is rotated. In contrast, when the center position of the recess 8 is set at the center O as in embodiment 1, the recess 8 is visually recognized as a circular point on the front surface 4a when the dressing plate 4 is rotated.

In this way, in embodiment 2, when the recess 8a appears on the front surface 4a side in the case where the trimming plate 4 is rotated, the recess 8a can be observed in a wider range than in embodiment 1, and therefore whether or not the recess 8a appears on the front surface 4a side can be recognized more easily than in embodiment 1.

Fig. 5 (a) is a perspective view of the dressing tool 2 of embodiment 3, and fig. 5 (B) is a C-C sectional view of the dressing tool 2 of embodiment 3. As shown in fig. 5 (a) and 5 (B), a recess 8B is provided on the rear surface 4B side of the trimming plate 4 according to embodiment 3. When the trimming plate 4 is viewed from the rear surface 4b side, the recess 8b is a substantially cylindrical hole provided at a position located more outward than the center of the circular rear surface 4 b.

The center position of the concave portion 8b of embodiment 3 is located at a distance of 7r/8 from the center O (r is the radius of the back surface 4 b). The center of the concave portion 8b on the back surface 4b may be located outside the position at a distance of r/2 from the center O or may be located at a distance of 3r/4 from the center O.

The recess 8b is formed from the back surface 4b to a predetermined depth not reaching the front surface 4 a. The depth of the recess 8b is also adjusted in such a manner that the recess 8b appears on the front surface 4a side of the trimming plate 4 when the trimming plate 4 is worn to the thickness of the use limit. Therefore, in embodiment 3, it is also possible to determine whether or not the finishing plate 4 is worn to the thickness of the use limit, based on whether or not the recess 8b is present on the front surface 4a side of the finishing plate 4.

Since the center position of the concave portion 8b is provided outside the center O of the back surface 4b, the concave portion 8b is visually recognized as a circular locus on the front surface 4a side when the dressing plate 4 is rotated. In contrast, when the center position of the recess 8 is set at the center O as in embodiment 1, the recess 8 is visually recognized as a circular point on the front surface 4a when the dressing plate 4 is rotated.

In this way, in embodiment 3, when the recess 8b appears on the front surface 4a side in the case where the trimming plate 4 is rotated, the recess 8b can be observed in a wider range than in embodiment 1, and therefore whether or not the recess 8b appears on the front surface 4a side can be recognized more easily than in embodiment 1.

Fig. 6 (a) is a perspective view of the dressing tool 2 of embodiment 4, and fig. 6 (B) is a D-D sectional view of the dressing tool 2 of embodiment 4. As shown in fig. 6 (a) and 6 (B), the trimming plate 4 of embodiment 4 has an annular recess 8c, and the annular recess 8c has a diameter smaller than that of the trimming plate 4.

When the trimming plate 4 is viewed from the rear surface 4b side, the recessed portion 8c is an annular groove provided on the outer circumferential side of the center of the circular rear surface 4 b. The concave portion 8c is circular when viewed from the back surface 4b side, but may not necessarily be a perfect circle. The recess 8c is also formed from the rear surface 4b to a predetermined depth not reaching the front surface 4 a.

The depth of the concave portion 8c is adjusted in such a manner that the concave portion 8c appears on the front surface 4a side of the trimming plate 4 in contact with the grinding stone 26 when the trimming plate 4 is worn to the thickness of the use limit. Therefore, in embodiment 4, it is also possible to determine whether or not the finishing plate 4 is worn to the thickness of the use limit, based on whether or not the recess 8c is present on the front surface 4a side of the finishing plate 4.

In embodiment 4, the recessed portion 8c is provided in a ring shape, and therefore, even if any region in the circumferential direction on the recessed portion 8c is partially thinned, it is possible to identify whether or not the recessed portion 8c is present on the front surface 4a side. Further, when the trimming plate 4 is rotated, if the recess 8c appears on the front surface 4a side, the recess 8c can be seen in a wider range than in embodiment 1, and therefore, the visibility and the like of the recess 8c are easier than those of the recess 8 in embodiment 1.

However, the recesses 8, 8a, 8b, and 8c of the trimming plate 4 in the above-described embodiments 1 to 4 are each constituted by an independent recess. However, the recesses 8, 8a, 8b, and 8c of the trimming plate 4 may be respectively constituted by two independent recesses.

Fig. 7 (a) is a cross-sectional view of the dresser 2 of modification 1 of embodiment 1. The trimming plate 4 of modification 1 of embodiment 1 has the 1 st recess 8-1 and the 2 nd recess 8-2 in the center portion on the rear surface 4b side. The 1 st recess 8-1 and the 2 nd recess 8-2 are each a substantially cylindrical hole formed separately from each other.

The 1 st recess 8-1 is formed from the rear surface 4b to a position of the 1 st depth d1, and the 2 nd recess 8-2 is formed from the rear surface 4b to a position deeper than the 1 st depth d1 (i.e., closer to the front surface 4a) and not reaching the 2 nd depth d2 of the front surface 4a from the rear surface 4 b.

The 2 nd depth d2 is deeper than the 1 st depth d1, so when the front face 4a side is worn, the 2 nd concave portion 8-2 appears on the front face 4a side first than the 1 st concave portion 8-1. Therefore, the 2 nd recessed portion 8-2 appearing on the front surface 4a side can be used as a warning display indicating that the thickness of the finishing plate 4 is close to the thickness of the use limit.

In contrast, the depth of the 1 st concave portion 8-1 is adjusted so that the 1 st concave portion 8-1 appears on the front surface 4a side of the dressing plate 4 in contact with the grinding stone 26 when the dressing plate 4 is worn to the thickness of the use limit. That is, the 1 st recess 8-1 appearing on the front surface 4a side shows the thickness of the dressing plate 4 worn to the limit of use, as in embodiment 1.

As described above, in modification 1 of embodiment 1, the information on the usage limit can be displayed in two stages. The operator or the like can recognize that the thickness of the finishing plate 4 is close to the use limit thickness when the 2 nd recessed portion 8-2 appears on the front surface 4a side, and can recognize that the finishing plate 4 is worn to the use limit thickness when the 1 st recessed portion 8-1 appears on the front surface 4a side.

Therefore, the operator can take measures to prepare the preparatory dressing tool 2 and the like at the timing when the 2 nd recess 8-2 appears on the front surface 4a side. In addition, by replacing the dressing tool 2 with a new dressing tool 2 at the timing when the 1 st recess 8-1 appears on the front surface 4a side, damage or the like of the grinding stone 26 can be more reliably prevented.

Fig. 7 (B) is a B-B cross-sectional view of the dresser 2 of modification 1 of embodiment 2. The trimming plate 4 of modification 1 of embodiment 2 has the 1 st recess 8a-1 and the 2 nd recess 8 a-2.

When the trimming plate 4 is viewed from the rear surface 4b side, the 1 st recessed portion 8a-1 and the 2 nd recessed portion 8a-2 are formed as linear recessed portions parallel to each other and are formed separately from each other.

More specifically, the 1 st recessed portion 8a-1 and the 2 nd recessed portion 8a-2 are linear grooves each having a length portion in a direction parallel to the radial direction of the dressing plate 4. The 1 st recessed portion 8a-1 is a linear groove passing through the center O on the rear surface 4B side of the trimming plate 4, and the 2 nd recessed portion 8a-2 (shown by a broken line in fig. 7B) is a linear groove arranged in parallel with the 1 st recessed portion 8a-1 and not passing through the center O.

The 1 st recess 8a-1 is formed from the rear surface 4b to a position of the 1 st depth d1, and the 2 nd recess 8a-2 is formed from the rear surface 4b to a position deeper than the 1 st depth d1 (i.e., closer to the front surface 4a) and not reaching the 2 nd depth d2 of the front surface 4a from the rear surface 4 b.

In the 1 st modification of the 2 nd embodiment, the operator or the like can recognize that the thickness of the finishing plate 4 is close to the use limit thickness when the 2 nd recess 8a-2 appears on the front surface 4a side, and can recognize that the finishing plate 4 is worn to the use limit thickness when the 1 st recess 8a-1 appears on the front surface 4a side.

Fig. 7 (C) is a sectional view of the dresser 2 of the 1 st modification of embodiment 3. The trimming plate 4 of the 1 st modification of the 3 rd embodiment has the 1 st recess 8b-1 and the 2 nd recess 8 b-2. The 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 are each a substantially cylindrical hole provided on the outer circumferential side of the center O of the back surface 4b of the dressing plate 4.

When the trimming plate 4 is viewed from the rear surface 4b side, the 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 are provided at different positions in the radial direction of the circular rear surface 4 b. Specifically, the center of the 1 st recess 8b-1 on the back surface 4b is located at a distance of r/2 from the center O.

In contrast, the center of the 2 nd concave portion 8b-2 on the back surface 4b is located at a distance of 7r/8 from the center O. The 2 nd concave portion 8b-2 is disposed on the opposite side of the 1 st concave portion 8-1 with respect to the center O, but the disposition of the 2 nd concave portion 8b-2 is not limited to this example. The 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 may be disposed at two positions at an arbitrary distance from the center O, as long as the distances from the center O are different.

The 1 st recess 8b-1 is formed from the back surface 4b to a position of the 1 st depth d 1. In contrast, the 2 nd recessed portion 8b-2 is formed from the rear surface 4b to a position deeper than the 1 st depth d1 (i.e., closer to the front surface 4a) and not reaching the 2 nd depth d2 of the front surface 4a from the rear surface 4 b.

In the 1 st modification of the 3 rd embodiment, in the case where the 2 nd concave portion 8b-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the use limit thickness, and in the case where the 1 st concave portion 8b-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn to the use limit thickness.

Fig. 7 (D) is a sectional view of the dresser 2 according to modification 1 of embodiment 4. The trimming plate 4 of the 1 st modification of the 4 th embodiment has the 1 st recessed portion 8c-1 and the 2 nd recessed portion 8c-2, which are annular when viewed from the rear surface 4b side.

When the trimming plate 4 is viewed from the rear surface 4b side, the 1 st recessed portion 8c-1 and the 2 nd recessed portion 8c-2 are annular grooves provided on the outer peripheral side of the center of the circular rear surface 4 b. The 1 st recess 8c-1 has a 1 st diameter smaller than the diameter of the trimming plate 4. In contrast, the 2 nd recess 8c-2 has a 2 nd diameter larger than the 1 st recess 8c-1 and smaller than the diameter of the trimming plate 4.

The 1 st recessed portion 8c-1 is provided on the inner side of the 2 nd recessed portion 8c-2, but when the 1 st diameter is larger than the 2 nd diameter, the 1 st recessed portion 8c-1 may be provided on the outer side of the 2 nd recessed portion 8 c-2. In addition, the 1 st recessed portion 8c-1 and the 2 nd recessed portion 8c-2 may not necessarily be a perfect circle, respectively, in the case of being viewed from the back surface 4b side.

The 1 st recessed portion 8c-1 is formed from the rear surface 4b to a position of the 1 st depth d1, and the 2 nd recessed portion 8c-2 is formed from the rear surface 4b to a position deeper than the 1 st depth d1 (i.e., closer to the front surface 4a) and not reaching the 2 nd depth d2 of the front surface 4a from the rear surface 4 b.

In the 1 st modification of the 4 th embodiment, in the case where the 2 nd concave portion 8c-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the thickness of the use limit, and in the case where the 1 st concave portion 8c-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn down to the thickness of the use limit.

The trimming plate 4 of the 1 st modification of the 1 st embodiment described above is provided with the 1 st recessed portion 8-1 and the 2 nd recessed portion 8-2 independently of each other, but a 3 rd recessed portion 8-3 connecting the 1 st recessed portion 8-1 and the 2 nd recessed portion 8-2 described above may be provided in the depth direction of the 1 st recessed portion 8-1. That is, the 1 st recess 8-1 and the 2 nd recess 8-2 may completely or partially overlap in the depth direction of the 1 st recess 8-1.

Fig. 8 (a) is a sectional view taken along line a-a of the dresser 2 according to modification 2 of embodiment 1. The trimming plate 4 of modification 2 of embodiment 1 has a 3 rd recess 8-3 in the center portion on the rear surface 4b side.

The 3 rd recess 8-3 is constituted by the 1 st recess 8-1 and the 2 nd recess 8-2 described above. The 1 st recess 8-1 is a substantially cylindrical hole having a 1 st depth d 1. On the other hand, the 2 nd recessed portion 8-2 is arranged substantially at the center of the 1 st recessed portion 8-1 as viewed from the rear surface 4b side, and the 2 nd recessed portion 8-2 has a 2 nd depth d2 deeper than the 1 st depth d1 from the rear surface 4b and is a substantially cylindrical hole having a diameter smaller than the 1 st recessed portion 8-1.

The 2 nd recessed portion 8-2 does not need to be arranged substantially at the center of the 1 st recessed portion 8-1 as viewed from the rear surface 4b side. The 2 nd recessed part 8-2 may be disposed at any position as long as it is located in the 1 st recessed part 8-1 as viewed from the rear surface 4b side.

In the 2 nd modification of the 1 st embodiment, in the case where the 2 nd concave portion 8-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the thickness of the use limit, and in the case where the 1 st concave portion 8-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn down to the thickness of the use limit.

Fig. 8 (B) is a B-B cross-sectional view of the dresser 2 of modification 2 of embodiment 2. The dressing plate 4 of modification 2 of embodiment 2 has linear 3 rd recessed portions 8a-3 having a length portion in the radial direction of the dressing plate 4. The 3 rd recessed portion 8a-3 is formed in a straight line shape having a length portion in the radial direction of the trimming plate 4 passing through the center O on the rear surface 4b side.

The 3 rd recess 8a-3 is also constituted by the 1 st recess 8a-1 and the 2 nd recess 8a-2 described above. The 1 st recessed portion 8a-1 is a linear groove having the 1 st depth d 1. On the other hand, the 2 nd recessed portion 8a-2 is a linear groove having a 2 nd depth d2 deeper than the 1 st depth d1 and having a width (i.e., a length in a direction perpendicular to the longitudinal direction of the 1 st recessed portion 8 a-1) smaller than the 1 st recessed portion 8a-1, which is arranged substantially in the center of the 1 st recessed portion 8a-1 as viewed from the rear surface 4b side.

In the 2 nd modification of the 2 nd embodiment, in the case where the 2 nd concave portion 8a-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the thickness of the use limit, and in the case where the 1 st concave portion 8a-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn down to the thickness of the use limit.

The 2 nd recessed portion 8a-2 does not need to be arranged substantially at the center of the 1 st recessed portion 8a-1 as viewed from the rear surface 4b side. The 2 nd recessed part 8a-2 may be disposed at any position as long as it is located in the 1 st recessed part 8a-1 as viewed from the rear surface 4b side.

Fig. 8 (C) is a C-C sectional view of the dresser 2 of the 2 nd modification of embodiment 3. The trimming plate 4 of modification 2 of embodiment 3 has the 3 rd recessed portion 8b-3 at a position on the outer peripheral side of the center O on the rear surface 4b side. The 3 rd recessed portion 8b-3 is constituted by the 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 described above.

The 1 st recess 8b-1 is a substantially cylindrical hole having a 1 st depth d 1. On the other hand, the 2 nd recessed portion 8b-2 is a substantially columnar hole having a 2 nd depth d2 deeper than the 1 st depth d1 and a diameter smaller than the 1 st recessed portion 8b-1, which is arranged substantially at the center of the 1 st recessed portion 8b-1 as viewed from the rear surface 4b side.

The 1 st and 2 nd recesses 8b-1 and 8b-2 on the back surface 4b are arranged at the same position outside the center O. In this example, the center of each of the 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 is arranged at a distance of 7r/8 from the center O.

However, the center positions of the 1 st recessed portion 8b-1 and the 2 nd recessed portion 8b-2 are not limited to the positions 7r/8 from the center O, and may be arranged at the positions r/2 from the center O and 3r/4 from the center O.

In the 2 nd modification of the 3 rd embodiment, in the case where the 2 nd concave portion 8b-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the thickness of the use limit, and in the case where the 1 st concave portion 8b-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn down to the thickness of the use limit.

The 2 nd recessed portion 8b-2 does not need to be arranged substantially at the center of the 1 st recessed portion 8b-1 as viewed from the rear surface 4b side. The 2 nd recessed portion 8b-2 may be disposed at any position as long as it is located in the 1 st recessed portion 8b-1 as viewed from the rear surface 4b side.

Fig. 8 (D) is a D-D cross-sectional view of the dresser 2 of modification 2 of embodiment 4. The trimming plate 4 of modification 2 of embodiment 4 has a 3 rd recess 8c-3 formed annularly on the rear surface 4b side. The 3 rd recessed portion 8c-3 is constituted by the 1 st recessed portion 8c-1 and the 2 nd recessed portion 8c-2, which are annular, respectively.

The 1 st recess 8c-1 is an annular groove having a 1 st depth d 1. On the other hand, the 2 nd recessed portion 8c-2 is an annular groove having a 2 nd depth d2 deeper than the 1 st depth d1 and a width smaller than the width in the radial direction of the 1 st recessed portion 8c-1, which is arranged at a position overlapping the 1 st recessed portion 8c-1 as viewed from the rear surface 4b side.

The 2 nd recessed portion 8c-2 is disposed at a position intermediate between the inner diameter and the outer diameter of the 1 st recessed portion 8c-1 as viewed from the rear surface 4b side, but the disposition of the 2 nd recessed portion 8c-2 is not limited to this example. The 2 nd recessed part 8c-2 may be disposed at any position as long as it is located in the 1 st recessed part 8c-1 as viewed from the rear surface 4b side.

In the 2 nd modification of embodiment 4, in the case where the 2 nd concave portion 8c-2 appears on the front surface 4a side, it can be recognized that the thickness of the finishing plate 4 is close to the thickness of the use limit, and in the case where the 1 st concave portion 8c-1 appears on the front surface 4a side, it can be recognized that the finishing plate 4 is worn to the thickness of the use limit.

In addition, the structure, method, and the like of the above embodiments may be modified and implemented as appropriate without departing from the scope of the object of the present invention. For example, the shape of the recess 8 is not limited to a cylindrical shape, a linear shape, an annular shape, or the like, and may be a lattice shape or a polygonal shape.

Further, characters, symbols, or the like for attracting the attention of an operator or the like may be written or attached to the position of the region corresponding to the recess 8 or the like on the front surface 6a of the support plate 6. For example, characters such as "dangerous", "stop", "End", "Life End" are described in the region corresponding to the recess 8 and the like on the front surface 6a of the support plate 6, and when the recess 8 and the like appear on the front surface 4a side, the operator can visually recognize the characters such as "dangerous".

The dressing tool 2 may be used for dressing the grinding stone 26, or for sharpening the grinding stone 26. In the shaping use of the grinding stone 26, the dressing plate 4 containing abrasive grains having a relatively large size may be used, and in the sharpening use of the grinding stone 26, the dressing plate 4 containing abrasive grains having a relatively small size may be used.