KR102403487B1 - A glass plate and the manufacturing method of a glass plate - Google Patents

Abstract

The glass plate 1 which concerns on this invention is the glass plate 1 in the state to which predetermined processing was performed with respect to the end surface 2, The arithmetic mean wave Wa of the end surface 2 is 2.7 micrometers or more.

Description

A glass plate and the manufacturing method of a glass plate

This invention relates to a glass plate and the manufacturing method of a glass plate.

In recent years, the improvement request|requirement with respect to the manufacturing efficiency of the glass substrate used for the said display etc. is increasing so that the improvement request with respect to the production efficiency of a liquid crystal display etc. may be met. Here, in manufacture of a glass substrate, cutting out one sheet or a plurality of glass substrates from a large glass original plate (molding original plate) is performed. Thereby, it is making it possible to acquire the glass substrate of a desired dimension.

On the other hand, since the end surface of the glass substrate cut out from a glass original plate becomes a cut surface or a snap-cut surface normally, a micro flaw (defect) exists in many cases. If there is a scratch on the end surface of the glass substrate, cracks or the like will occur from the scratch. In order to prevent this, grinding processing (rough polishing processing) and polishing processing (treatment polishing processing) are performed on the end surface of the glass substrate (for example, , refer to Patent Document 1).

International publication WO2013/187400

By the way, in the production process of a liquid crystal display, various processes performed with respect to a glass substrate, such as a film-forming process, an exposure process, and an etching process, exist. At this time, a glass substrate is positioned by making a positioning pin contact an end surface, for example. However, some glass powder may generate|occur|produce from an end surface by the contact of an end surface and a positioning pin, and there arises a possibility of adhering to the main surface (flat surface with the largest area) of a glass plate by this. Since adhesion of glass powder causes film-forming defect, and also disconnection defect, it is necessary to avoid generation|occurrence|production of this kind of glass powder as much as possible.

With respect to the end surface, for example, when grinding using the above-mentioned grindstone is given, the end surface after processing is flattened. However, when the positioning pin is made of rubber or plastic having a hardness of about 60 degrees and the positioning pin is elastically deformed, the end surface after processing is too flattened, so that the contact area between the positioning pin and the end surface increases. As a result, there existed a problem that glass powder became easy to generate|occur|produce.

In view of the above circumstances, it is a technical problem to be solved by the present invention to prevent generation of glass powder from the end face as much as possible by forming a predetermined micro wave on the end face of the glass plate.

The solution of the said subject is achieved by the glass plate which concerns on this invention. That is, this glass plate is a glass plate in a state in which predetermined processing has been performed with respect to the end face, and it can be characterized by having an arithmetic mean wave Wa of 2.7 μm or more.

As described above, in the present invention, the minimum value to be satisfied by the value of the arithmetic mean wave Wa is stipulated by focusing on the arithmetic mean wave Wa of the end face. In the case of an end face having such a shape, for example, when a positioning member such as a pin contacts the end face of a glass plate during each manufacturing process or transport between processes of a glass plate or a product containing a glass plate as an element, the end face has a micro wave ( Since it is mainly in contact with the ridge of the locating member, the contact area with the positioning member can be reduced. Thereby, it becomes possible to suppress generation|occurrence|production of a glass powder.

Moreover, in the glass plate which concerns on this invention, 5.0 micrometers or more may be sufficient as average height Wc of an end surface.

In this way, by defining the average height Wc of the end face, the difference in elevation between the peak and the curved portion of the minute wave of the end surface becomes large, and it becomes difficult to contact the positioning member with the curved portion of the minute wave. Thereby, the contact area with a positioning member can further be reduced, and it becomes possible to suppress generation|occurrence|production of glass powder more effectively.

Moreover, in the glass plate which concerns on this invention, 2000 micrometers or more may be sufficient as the average length (Wsm) of an end surface.

In this way, by defining the average length (Wsm) of the end surface, the period of the minute wave becomes longer. For this reason, since the number of the peaks of a micro wave contacting a positioning member decreases, the contact area with a positioning member can further be reduced, and it becomes possible to suppress generation|occurrence|production of glass powder more effectively.

Moreover, in the glass plate which concerns on this invention, the skewness Wsk of an end surface may be larger than 0.

In this way, by defining the skewness Wsk of the end face, the shape of the micro wave can be indirectly defined. That is, when the skewness Wsk takes a positive value, the peaks of the minute waves tend to have a sharp shape. Therefore, by specifying the skewness Wsk to be 0 or more, the contact area between the positioning member and the ridge of the minute wave that the end face has can be reduced. Thereby, the contact area with a positioning member can further be reduced, and it becomes possible to suppress generation|occurrence|production of glass powder more effectively.

Further, the glass plate according to the present invention may satisfy the relationship of the following formula (1) when A [mm] is one period of the minute wave appearing on the end surface and B [mm] is the difference in elevation between the ridge and the curved part.

[Number 1]

The above regulation is made by paying attention to the relationship between the shape of the minute wave appearing on the end surface of the glass plate and the contact state of the positioning pin. That is, when the end face of the glass plate is processed with a whetstone capable of shaft rotation, as shown in FIG. 3 , minute waves 3 having a longer period of irregularities than roughness curves such as surface roughness Ra appear on the end face 2. . This micro wave 3 appears, for example, in the same order as the wave curve of the arithmetic mean wave Wa, and the concave-convex shape (the shape of the peak 4 and the curved part 5) follows the outer shape of the grindstone. There are many that form an approximately arc shape. Therefore, for example, in the case where the microwave 3 in which the positioning pin 6 of radius r [mm] forms a substantially arc shape is in contact with the neighboring peaks 4 and 4, the following Equation 2 Insofar as the relationship defined by is satisfied, the positioning pin 6 does not come into contact with the curved portion 5 of the micro wave 3 . In addition, the variable B in Equation 2 is the height difference [mm] between the peak 4 and the curved part 5, and the variable C is the midpoint P2 between the contact points P1 and P1 of the positioning pin 6 and the peak 4 ) to the center point P3 of the positioning pin 6 [mm].

[Number 2]

Here, the relationship represented by Equation 3 is established between the radius r, the period A, and the distance C of the positioning pin 6 . In addition, the variable A in Equation 3 is the distance [mm] between the peaks 4 and 4 adjacent to the micro wave 3 .

[Number 3]

By transforming Equation 3, the distance C is expressed as a function of the radius r and the period A as in Equation 4.

[Number 4]

By substituting Equation 4 into Equation 2 and rearranging Equation 5, Equation 5 is obtained.

[Number 5]

Here, when the representative size of the outer diameter dimension (double of the radius r) of the positioning pin 6 is 400 mm, for example, Formula 1 is obtained.

In this way, by making the micro wave into an optimal shape in consideration of the specific contact form with the positioning pin, the situation in which the positioning pin comes into contact with the curved portion of the micro wave can be prevented as much as possible. Therefore, it becomes possible to suppress generation|occurrence|production of glass powder more effectively.

Moreover, the solution of the said subject is achieved also by the manufacturing method of the glass plate which concerns on this invention. That is, this manufacturing method is a manufacturing method of a glass plate provided with the end surface processing process which gives predetermined processing to the end surface by relatively moving along the end surface while making the rotating processing tool contact the end surface of a glass plate, Comprising: Arithmetic of an end surface It can be characterized by the point that a predetermined processing is performed with a grindstone on the end surface so that the average wave Wa is 2.7 μm or more.

In the present invention, paying attention to the arithmetic mean wave (Wa) of the end face, predetermined machining is performed with a machining tool rotating with respect to the end face so that the value of this arithmetic mean wave (Wa) becomes a value to be satisfied. According to this method, similarly to the glass plate according to the present invention, when a positioning member such as a pin is in contact with the end face of the glass plate during each manufacturing process or inter-process transport of a glass plate or a product containing a glass plate as an element, the end face has Since the peaks of the minute waves mainly contact, the contact area with the positioning member can be reduced. Thereby, it becomes possible to suppress generation|occurrence|production of a glass powder.

(Effects of the Invention)

As explained above, according to this invention, it becomes possible to prevent generation|occurrence|production of glass powder from an end surface as much as possible by forming a predetermined micro wave in the end surface of a glass plate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view of the end surface processing apparatus of the glass plate which concerns on one Embodiment of this invention.
It is a principal part side view of the grindstone rotation system shown in FIG.
It is a figure for demonstrating the contact form in the wave curve order of the end surface of a glass plate, and a positioning pin.
It is a figure which shows the contact form in the wave curve order of the end surface of the glass plate which concerns on another form, and a positioning pin.
It is a figure which shows the contact form in the wave curve order of the end surface of the glass plate which concerns on this invention, and a positioning pin.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described with reference to FIGS. First, the outline|summary of the end surface processing apparatus used for the manufacturing method which concerns on this embodiment is demonstrated based on FIG.1 and FIG.2.

As shown in FIG. 1 and FIG. 2, the end surface processing apparatus 10 gives predetermined processing to the end surface 2 of the glass plate 1, The motor which rotationally drives the grindstones 11 and 12 as an end surface processing part. (13) and a spindle (14) are mainly provided. The spindle 14 is connected to the motor 13 . In this embodiment, the motor 13 and the spindle 14 have a common rotation axis Y. In addition, the spindle 14 may be connected to the main shaft of the motor 13 via a belt or the like.

The end surface processing apparatus 10 of such a structure may be provided with the apparatus which controls the pressing force of the grindstones 11 and 12 as described in patent document 1. Alternatively, the end surface processing apparatus 10 may be a system in which the positions of the grinding stones 11 and 12 during processing are made constant. Alternatively, an end surface processing apparatus 10 other than these methods may be used.

The grindstones 11 and 12 are attached to the spindle 14 via the flange 20 for grindstone attachment, as shown in FIG. In detail, the fitting holes 21 are provided in the grindstones 11 and 12, and the fitting convex part 22 is formed in the flange 20 for grindstone attachment. By fitting the fitting convex portion 22 of the flange 20 for attaching the grindstone to the fitting hole 21 of the grindstones 11 and 12, the grindstones 11 and 12 are connected to the flange 20 for attaching the grindstone, and at the same time, the flange for attaching the grindstone. Positioning including centering of whetstones 11 and 12 with respect to 20 is made.

Moreover, the fitting recessed part 23 is formed in the flange 20 for grindstone attachment on the side opposite to the fitting convex part 22. As shown in FIG. The fitting concave portion 23 has a tapered shape, and is capable of tapering fitting with the tip portion 24 of the spindle 14 having the same tapered shape. Therefore, for example, after preparing the subassembly 25 of the grinding stones 11 and 12 and the flange 20 for attaching the grindstone, which will be described later, the subassembly 25 is attached to the tip portion 24 of the spindle 14 automatically. Centering and positioning with respect to the spindle (14) of the grindstones (11, 12) is made.

In addition, in this embodiment, with respect to the end surface 2 of the glass plate 1, two types of processing (here, grinding processing which has the main purpose of chamfering of the end surface 2, and the minute unevenness|corrugation of the end surface 2 are evenly In order to carry out abrasive processing whose main purpose is to do this, corresponding whetstones 11 and 12, respectively, can be used. That is, the particle size of the abrasive grains in the 2nd grindstone 12 for grinding|polishing is the same as or larger than the grain size of the abrasive grains in the 1st grindstone 11 for grinding. The particle size of the abrasive grains in the first grindstone 11 for grinding can be, for example, #100 to #1000, and the grain size of the abrasive grains in the second grindstone 12 for grinding is, for example, #200. You can do it with ~#2000. In addition, the diameters of the grindstones 11 and 12 are 100-200 mm, for example.

The glass plate 1 has a rectangular plate shape, as shown in FIG. 1, for example. It is preferable that they are, for example, 0.05 mm - 10 mm, and, as for the thickness dimension of the glass plate 1, it is more preferable that they are 0.2 mm - 0.7 mm. Of course, the glass plate 1 to which this invention is applicable is not limited to the said form. For example, this invention is applicable also to the glass plate of the glass plate which has a shape other than a rectangle (for example, polygons other than a rectangle), and a thickness dimension deviates from 0.05 mm - 10 mm.

It is preferable that the main surface (surface and back surface) of the glass 1 is in a state to be polished, that is, in a molded state without being subjected to processing by a whetstone or the like and without abrasive marks. Moreover, it is preferable that it is 10 nm or less, and, as for arithmetic mean roughness Ra (JIS R 1683:2014) of the main surface of the glass 1, it is more preferable that it is 2 nm or less.

The glass plate 1 can be moved relative to the grindstones 11 and 12 in a predetermined transfer direction (X). In addition, in FIG. 1, although the glass plate 1 moves in the conveying direction X, and shows the case where the grindstones 11 and 12 are fixed, of course, the glass plate 1 is fixed and the grindstones 11 and 12 are transported You may move in the direction opposite to (X). In addition, at this time, either one of the glass plate 1 and the grindstones 11 and 12 may move, the other may be fixed, and both may move.

In addition, although the rotation direction of the grindstones 11 and 12 is arbitrary, for example, it is good to determine the rotation direction of each grindstone 11 and 12 so that it may rotate in the direction opposite to the conveyance direction X of the glass plate 1. Referring to FIG. 1 , it is preferable to set the rotation direction of each of the grinding stones 11 and 12 so that the upper grinding stones 11 and 12 rotate counterclockwise, and the lower grinding stones 11 and 12 rotate clockwise.

Then, an example of the manufacturing method of the glass substrate at the time of using the edge surface processing apparatus 10 mentioned above is demonstrated.

That is, in the manufacturing method according to this embodiment, while the rotating grindstones 11 and 12 are brought into contact with the end surface 2 of the glass plate 1, the grinding stones 11 and 12 are relatively moved along the end surface 2, The end face machining step of subjecting the end face 2 to a predetermined process by cutting is provided. This manufacturing method may further comprise the process of preparing the glass plate 1 (glass plate preparation process). In the process of preparing the glass plate 1, a shaping|molding original plate is obtained by the down-draw method called the overflow down-draw method, the float method, etc., for example, and the glass plate 1 is cut out from the shaping|molding original plate. Inspection, packing, etc. of the glass plate 1 are performed after processing of the end surface 2 as needed. The overflow down-draw method in the process of preparing the glass plate 1 from a viewpoint of making the main surface (surface and back surface) of the glass 1 into a roughened surface and making the arithmetic mean roughness Ra into 10 nm or less It is preferable to use

In the process of giving a predetermined processing to the end surface 2 of the glass plate 1 (end surface processing process), the grinding stones 11 and 12 and the subassembly 25 of the grinding wheel attachment flange 20 are subjected to a predetermined static vibration and dynamic balance. A sub-assembly preparation step S1 prepared so as to become In addition, in the process of giving predetermined processing to the end surface 2 of the glass plate 1, the end surface processing is performed so that the arithmetic mean wave Wa of the end surface 2 in after an end surface processing may become 2.7 micrometers or more.

(S1) Sub-assembly preparation process

In this process, the subassembly 25 of the grindstones 11 and 12 and the flange 20 for mounting a grindstone is prepared so that a dynamic balance may become more than a predetermined value, for example, 60 g*mm or more. In addition, the dynamic balance can be measured using a predetermined dynamic balance measuring device.

In addition, at this time, the individual dynamic balance of the grindstones 11 and 12 and the flange 20 for grindstone attachment in particular is not questioned. As long as the dynamic balance of the subassembly 25 is 60 g·mm or more, it is possible to use the whetstones 11 and 12 and the flange 20 for attaching the whetstone which exhibit an arbitrary dynamic balance.

(S2) End surface machining process

In this process, the subassembly 25 prepared in the preparatory process S1 is attached to the spindle 14 (refer FIG. 2) of the end surface processing apparatus 10 shown in FIG. 1, for example, The end surface 2 of the glass plate 1 ) is subjected to the predetermined end surface processing (grinding processing and polishing processing).

Here, in an example of the wave curve of the end surface 2' of the glass plate 1' obtained when the dynamic balance uses the subassembly 25 whose dynamic balance is 10 g*mm in FIG. 4, in FIG. 5, a dynamic balance is 80 g* An example of the wave curve of the end surface 2 of the glass plate 1 obtained when the subassembly 25 of mm is used is shown, respectively. All of these glass plates 1 and 1' have a rectangular shape of 2250 mm x 2500 mm, and have a thickness of 0.5 mm. The end surface processing was performed using the end surface processing apparatus 10 shown in FIG. 1 with respect to the end surface of the long side of the glass plates 1 and 1'. In end surface processing, one set of the 1st grindstones 11 for grinding was arrange|positioned, and one set of the 2nd grindstones 12 for grinding|polishing was arrange|positioned. The dynamic balance of the whetstones 11 and 12 and the subassembly 25 of the whetstone attachment flange 20 was the same in all (the 1st grindstone 11 for grinding, and the 2nd grindstone 12 for grinding|polishing).

As shown in Fig. 4, when the subassembly 25 having a dynamic balance of 10 g·mm is used, in the wave curve of the obtained end surface 2', the height difference between the peak 4' and the curved part 5' is very small. Wave 3' was appearing. In this case, the arithmetic mean wave Wa of the end face 2' was 2.5 μm, the average height Wc was 5 μm, and the average length Wsm was 2500 μm.

On the other hand, when the subassembly 25 having a dynamic balance of 80 g·mm is used, the obtained wave curve of the end surface 2 has a substantially circular arc shape along the outer shape of the grindstones 11 and 12 as shown in FIG. 5 . A brightly reflected smile wave (3) appeared. In this case, the arithmetic mean wave Wa of the end face 2 was 2.8 μm, the average height Wc was 10 μm, and the average length Wsm was 4000 μm. Also, the skewness Wsk of the end face 2 was greater than zero.

Therefore, when the contact state between these end surfaces 2 and 2' and the positioning pin 6 having a circular cross-sectional shape, for example, is considered, for example, the micro wave 3' shown in Fig. 4 is the curved portion 5 '), in the case of the micro wave 3 shown in FIG. 5, that is, the micro wave 3 according to the present invention, with respect to the high probability of contacting the positioning pin 6 in the ridge 4 of the positioning pin ( 6) with high probability.

At this time, from the viewpoint of reducing the contact area with the positioning pin 6 as much as possible, each parameter indicating the shape and size of the micro wave 3 (period A, peak 4 and curved portion 5) It is preferable that the elevation difference (B)) satisfies the relation of Equation 1 above.

In addition, when the arithmetic mean wave Wa of the end face 2 is 2.7 μm or more, the average height Wc of the end face 2 is 5.0 μm or more, the average length Wsm is 2000 μm or more, and the skewness Wsk) is preferably a value exceeding 0.

In this way, in the present invention, paying attention to the arithmetic mean wave (Wa) of the end surface (2), the grindstone (11, 12), a predetermined end surface processing (grinding processing, polishing processing) by rotational contact was performed. In the case of the end face 2 having such a shape, for example, the positioning pin 6 or the like during each manufacturing process or transfer between processes of the glass plate 1 or a product (liquid crystal display, etc.) containing the glass plate 1 as an element. When the positioning member contacts the end face 2 of the glass plate 1, the peak 4 of the micro wave 3 of the end face 2 mainly contacts. For this reason, the contact area of the end surface 2 of the glass plate 1, and a positioning member can be reduced, and it becomes possible to suppress generation|occurrence|production of glass powder.

In addition, in consideration of the specific contact form with the positioning pin 6, by making the micro wave 3 of the end face 2 into a shape that satisfies the relationship of Equation 1, the positioning pin 6 is a micro wave (3) The situation in contact with the curved portion 5 of the can be prevented as much as possible. Therefore, it becomes possible to suppress generation|occurrence|production of glass powder more effectively.

From the viewpoint of further reducing the contact area between the end face 2 of the glass plate 1 and the positioning member, the arithmetic mean wave Wa of the end face 2 is preferably 3.0 µm or more. It is preferable that it is 5.0 micrometers or more, and, as for the average height Wc of the end surface 2 from a similar viewpoint, it is more preferable that it is 15 micrometers or more. Moreover, it is preferable that it is 2000 micrometers or more, and, as for the average length Wsm of the end surface 2, it is more preferable that it is 2500 micrometers or more.

On the other hand, if the contact area between the end face 2 of the glass plate 1 and the positioning member is too small, excessive stress is generated in the ridge 4 of the micro wave 3 of the end face 2 and the glass plate 1 There is a risk of getting hurt. For this reason, it is preferable that the arithmetic mean wave Wa of the end surface 2 is 4.0 micrometers or less. Moreover, it is preferable that the average height Wc of the end surface 2 is 20 micrometers or less. It is preferable that the average length (Wsm) of the end surface 2 is 6000 micrometers or less.

In the present invention, the arithmetic mean wave (Wa), the mean height (Wc), and the mean length (Wsm) of the end face 2 are measured in accordance with JIS B 0601:2013. In addition, in the measurement of the arithmetic mean wave (Wa), the average height (Wc), and the average length (Wsm), with respect to the end surface of a glass plate, it measures at 10 places with the same space|interval along one side of a glass plate. The arithmetic mean wave Wa shall use the average value of the measurement results of 10 locations, and the average height Wc and the average length Wsm shall use the minimum value of the measurement results of 10 locations.

In addition, in the present invention, one period (A) in the micro wave is assumed to use the average length (Wsm) measured by the above method, and the height difference (B) between the peak and the curved portion is measured by the above method. It is assumed that the average height (Wc) is used.

As mentioned above, although one Embodiment of this invention was described, of course, the glass plate which concerns on this invention and its manufacturing method are not limited to this form, It is possible to take various forms within the scope of this invention.

For example, in the above embodiment, using the subassembly 25 of the grindstones 11 and 12 and the flange 20 for attaching the grindstone whose dynamic balance is equal to or greater than a predetermined value, for example, 60 g·mm or more, Fig. 1 and The case of obtaining the glass plate 1 in which the arithmetic mean wave Wa of the end surface 2 becomes 2.7 micrometers or more was exemplified by performing the end surface processing shown in FIG. 2, but of course the end surface processing method which concerns on this invention is limited to this doesn't happen For example, even by performing the above-described end surface machining in a state in which a predetermined vibration is added to the grindstones 11 and 12 by means other than dynamic balance adjustment, the arithmetic mean wave Wa of the end surface 2 is 2.7 µm. The glass plate 1 used as the ideal can be obtained. Alternatively, the glass plate 1 having an arithmetic mean wave Wa of 2.7 µm or more can be obtained even by performing the above-described end surface processing in a state in which a predetermined vibration is added to the glass plate 1 .

In addition, in the said embodiment, while arranging two sets of whetstones 11 and 12 in opposing positions with the glass plate 1 interposed therebetween, two types (two sets) of whetstones 11 and 12 having different grain sizes. Although the case where they are arranged side by side in the conveying direction has been exemplified, it is of course possible to take other arrangement forms. For example, it is also possible to arrange|position 2 sets or 3 sets or more of the grindstone 11 for grinding and the grindstone 12 for grinding, respectively. In addition, for the end face 2 after the end face processing, as long as the required quality including the shape can be ensured, for example, it is possible to arrange one set or multiple sets of whetstones 11 and 12 having one type of shape. do.

In addition, in the above description, the case where the present invention is applied to a case where a predetermined end surface processing is performed on the end surface 2 by rotational contact of the whetstones 11 and 12 has been exemplified, but the end surface processing method according to the present invention includes this not limited Any end surface processing method as long as predetermined processing is performed on the end surface 2 by relatively moving the rotating processing tool along the end surface 2 while contacting the end surface 2 of the glass plate 1 It is possible to hire

In addition, further speaking, the glass plate which concerns on this invention is not limited to what is based on the said end surface processing method. As long as the arithmetic mean wave Wa of the end face 2 is 2.7 μm or more, it is possible to obtain the glass plate according to the present invention by applying any end face processing method.

Claims (6)

A glass plate in a state in which a predetermined processing has been performed with respect to the end surface,
A glass plate having an arithmetic mean wave (Wa) of the end surface of 2.7 µm or more and 4.0 µm or less. The method of claim 1,
A glass plate having an average height (Wc) of 5.0 μm or more of the end surface. 3. The method of claim 1 or 2,
A glass plate having an average length (Wsm) of the end surface of 2000 μm or more. 3. The method of claim 1 or 2,
A glass plate having a skewness (Wsk) of the end surface greater than zero. 3. The method of claim 1 or 2,
A glass plate that satisfies the relationship of the following formula (1) when A [mm] is one period in the minute wave appearing on the end surface, and B [mm] is the difference between the elevations of the peaks and the curved parts.
[Number 1]

A method of manufacturing a glass plate comprising an end surface processing step of performing a predetermined processing on the end surface by relatively moving the rotating processing tool along the end surface while contacting the end surface of the glass plate,
In the end surface processing step, the arithmetic mean wave (Wa) of the end surface is 2.7 µm or more and 4.0 µm or less, and the end surface is subjected to the predetermined processing by a whetstone as the processing tool. Way.

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