JPWO2016098824A1 - Glass plate chamfering apparatus, glass plate chamfering method, and glass plate manufacturing method - Google Patents

Abstract

Provided are a glass plate chamfering device, a glass plate chamfering method, and a glass plate manufacturing method capable of improving the chamfering quality of a glass plate without increasing the number of grindstones. The grindstone (10) configured in a columnar shape is divided into at least two or more divided grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion (36) is set to that of the other divided grindstone portion (42). It is higher than the grinding ability. That is, a single grindstone (10) is provided with a plurality of performances, and the divided grindstone portions (36, 42) selected according to the performance are used for chamfering the glass plate (16). For example, when the first chamfering process is performed on the end surface (16A), the divided grindstone portion (36) is pressed against the end surface (16A) of the glass plate (16) and ground. Next, when performing a 2nd chamfering process, it grinds by pressing a division grindstone part (42) to the end surface (16A).

Description

  The present invention relates to a glass plate chamfering apparatus, a glass plate chamfering method, and a glass plate manufacturing method.

  A glass plate for FPD (Flat Panel Display) used for liquid crystal displays, plasma displays, etc. is a molding process for forming molten glass into a belt-like plate glass (also referred to as a glass ribbon). It is manufactured through a cutting step of cutting into a plate and a chamfering step of grinding and polishing the end face of the glass plate.

  Patent Document 1 discloses a chamfering device used in the chamfering step.

  The chamfering apparatus of Patent Document 1 transports a glass plate (workpiece) held by a holding unit to a position where a primary end surface grinding unit is installed by a transport mechanism, and performs grinding processing on both end surface portions. . Subsequently, a glass plate is conveyed to the position where the secondary end surface grinding part was installed, and the grinding process is performed about the both end surface part. Patent Document 1 also discloses that an end surface polishing portion is provided on the downstream side in the conveyance direction of the glass plate in order to perform mirror finishing on the end surface of the glass plate.

  On the other hand, the chamfering device described in Patent Document 2 includes a metal bond grindstone having a V-shaped groove for grinding on the outer peripheral surface and an elastic grindstone having a flat outer peripheral surface which is a polishing surface. According to the chamfering device of Patent Document 2, the end surface of the glass plate is ground by the V-shaped groove of the metal bond grindstone to form a chamfered surface on the end surface, and then the chamfered surface is formed by the flat outer peripheral surface of the elastic grindstone. Grind.

JP 2013-198974 A Japanese Patent Laid-Open No. 2001-9589

  By the way, recently, with the high definition of liquid crystal displays, quality requirements for fine dust (also referred to as particles) adhering to the surface of a glass plate have been increasing. That is, fine dust becomes a foreign substance when an element such as an electrode is formed on the surface of the glass plate.

  From this, it has been found that the fine cullet generated from the chamfered surface (end surface) of the glass plate also affects the quality of the glass plate, and therefore further improvement in the chamfering processing technology of the glass plate. It has been desired.

  In the conventional chamfering devices disclosed in Patent Documents 1 and 2, two grindstones are arranged on one end face of the glass plate, the end face is ground into a desired chamfered shape with the front stage grindstone, and the rear stage grindstone is used. The end face is polished.

  However, it has been difficult to reliably remove the relatively large chipping and cracks (chips) generated on the end face by the front-stage grindstone with only the rear-stage grindstone. That is, it has been difficult to process a chamfered surface into a mirror surface from which cullet does not generate dust with only a subsequent grindstone.

  As a result, the conventional chamfering apparatus has a problem that it is difficult to chamfer the liquid crystal display to the specifications accompanying the recent high definition.

  In addition, it is also conceivable to arrange four grindstones having different grinding capabilities, that is, grindstones having different performances, so that rough grinding, intermediate grinding, finishing and mirror finishing can be sequentially performed on the end face of the glass plate. However, this chamfering device is not preferable because the number of rotating devices increases by the increase in the number of grindstones, resulting in a complicated device configuration.

  This invention is made | formed in view of such a situation, The chamfering apparatus of the glass plate which can improve the chamfering quality of a glass plate, without increasing the number of grindstones, the chamfering method of a glass plate, and glass It aims at providing the manufacturing method of a board.

In order to achieve the above object, the glass plate chamfering apparatus of the present invention provides:
Whetstone,
Rotating means for rotating the grindstone about its central axis, and first moving means for relatively moving the grindstone and the glass plate along a first direction orthogonal to the end surface of the glass plate;
A second moving means for relatively reciprocating the grindstone and the glass plate along a second direction in which the end surface of the glass plate extends, and grinding the same end surface of the glass plate a plurality of times;
Third moving means for relatively moving the grindstone and the glass plate along a third direction orthogonal to the main surface of the glass plate and the second direction;
Control means for controlling the first moving means, the second moving means, and the third moving means;
It is characterized by providing.

In order to achieve the above object, the glass plate chamfering method of the present invention provides:
The grindstone is composed of upper and lower divided grindstone portions. After pressing one divided grindstone portion of the upper and lower divided grindstone portions against one end surface of the glass plate, the grindstone and the glass plate are A first grinding step of grinding the one end face by rotating the one end grindstone part about its central axis while relatively moving in one extending direction of the end face;
After pressing the other divided grindstone portion of the upper and lower divided grindstone portions of the grindstone against the one end surface of the glass plate, the grindstone and the glass plate are moved to the other extending direction of the one end surface or one of the one end surfaces. A second grinding step of relatively moving in the extending direction and rotating the other divided grindstone portion around its central axis to grind the same end surface;
It is characterized by providing.

  In order to achieve the above object, the method for producing a glass plate of the present invention comprises a melting step of obtaining a molten glass by heating a glass raw material, a forming step of obtaining a glass ribbon by forming the molten glass into a plate shape, and the glass A cutting step of cutting a ribbon to obtain a glass plate, and a chamfering step of chamfering the glass plate by a chamfering method of the glass plate.

  In one aspect of the glass plate chamfering apparatus of the present invention, the grindstone is composed of at least a first grindstone and a second grindstone, and the first grindstone and the second grindstone are configured in a column shape. Thus, it is preferable that the grinding ability of one of the divided grindstone parts is higher than the grinding ability of the other divided grindstone part.

One aspect of the chamfering method of the glass plate of the present invention is:
The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone and the second grindstone are configured in a cylindrical shape and divided into at least two divided grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion is divided. It is higher than the grinding ability of the other divided grindstone part,
After pressing one divided grindstone portion having a high grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are relatively opposed to one extending direction of the one end surface. A first chamfering step of grinding the one end face by rotating the first grindstone about its central axis,
After pressing one divided grindstone portion having a high grinding ability of the second grindstone against one end face of the glass plate, the second grindstone and the glass plate are relatively opposed to one extending direction of the one end face. A second chamfering step of grinding the one end face by rotating the second grindstone about its central axis,
After pressing the other divided grindstone part having a low grinding ability of the second grindstone against one end surface of the glass plate, the second grindstone and the glass plate are placed in the other extending direction of the one end surface. A third chamfering step of grinding the one end face by rotating the second grindstone around its central axis, and relatively moving the second grindstone;
After pressing the other divided grindstone portion having a low grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are placed in the other extending direction of the one end surface. A fourth chamfering step of grinding the one end face by rotating the first grindstone around its central axis while relatively moving;
It is preferable to provide.

  In one aspect of the glass plate chamfering apparatus of the present invention, the grindstone is composed of at least a first grindstone and a second grindstone, and the first grindstone is formed in a column shape and has at least 2 in the axial direction. The divided grindstone portion is divided into two or more divided grindstone portions, and the grindability of one of the divided grindstone portions is higher than the grindability of the divided divided grindstone portion, and the second grindstone is configured in a cylindrical shape and is the same It is preferable to have a grinding ability of

One aspect of the chamfering method of the glass plate of the present invention is:
The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone is formed in a cylindrical shape and is divided into at least two or more divided grindstone portions in the axial direction, and the grinding ability of one of the divided grindstone portions is that of the other divided grindstone portion. It is higher than the grinding ability,
The second grindstone is constituted by the grindstone having a cylindrical shape and the same grinding ability,
After pressing one divided grindstone portion having a high grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are relatively opposed to one extending direction of the one end surface. A first chamfering step of grinding the one end face by rotating the first grindstone about its central axis,
After the second grindstone is pressed against one end surface of the glass plate, the second grindstone and the glass plate are relatively moved in one extending direction of the one end surface, and the second A second chamfering step of grinding the one end face by rotating a grindstone about its central axis;
After the second grindstone is pressed against one end surface of the glass plate, the second grindstone and the glass plate are relatively moved in the other extending direction of the one end surface, and the second A third chamfering step of grinding the one end face by rotating the grindstone about the central axis;
After pressing the other divided grindstone portion having a low grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are placed in the other extending direction of the one end surface. A fourth chamfering step of grinding the one end face by rotating the first grindstone around its central axis while relatively moving;
It is preferable to provide.

  In one aspect of the glass plate chamfering apparatus of the present invention, it is preferable that the glass plate has a rectangular shape, and the grindstone is disposed so as to face two opposite end surfaces of the glass plate.

  In one aspect of the method for chamfering a glass plate of the present invention, it is preferable that the glass plate has a rectangular shape, and the grindstone is disposed so as to face two opposite end surfaces of the glass plate.

  A chamfering apparatus and a chamfering method according to the present invention include a first grinding step in which a grindstone is moved forward (1 pass) relative to one end surface of a glass plate to perform grinding, and one glass plate is ground. Grinding the same end face multiple times without increasing the number of grindstones in the second grinding process in which the grindstone is moved backward (2 Pass) relative to the end face in the other direction. It is characterized by chamfering. Also, by repeating the forward movement twice (from 1 Pass to 2 Pass), the same end face can be chamfered without increasing the number of grindstones.

  According to the grindstone of one aspect of the present invention, the grindstone configured in a columnar shape is divided into at least two or more divided grindstone portions in the axial direction, and the divided grindstone of one divided grindstone portion is used as the other divided grindstone. It is higher than the grinding ability of the part. That is, a single grindstone is provided with a plurality of performances, and a grindstone portion selected according to the performance is used for chamfering a glass plate. For example, when performing the 1st grinding process with respect to an end surface, it grinds by pressing one division grindstone part with high grinding capability to the end surface of a glass plate. Next, when performing the 2nd chamfering process, it grinds by pressing the other division grindstone part with low grinding ability to the end surface.

  As described above, in the present invention, one grindstone has two or more kinds of grinding ability. Therefore, as the grindstone, at least two of the first grindstone and the second grindstone are provided, each of the first grindstone and the second grindstone is divided in the axial direction, and a divided grindstone portion is provided. Rough grinding is performed at the divided grindstone part of the eye, intermediate grinding is performed at the second divided grindstone part, finishing is performed at the third divided grindstone part, and the fourth divided grindstone part is formed. Mirror processing can also be performed. Moreover, you may give four types of grinding ability to one grindstone. The first grindstone is divided into four in the axial direction, four divided grindstone portions are provided, rough grinding is performed with the first divided grindstone portion, and intermediate grinding is performed with the second divided grindstone portion. Processing may be performed, finishing may be performed at the third divided grindstone, and mirror processing may be performed at the fourth divided grindstone. If it does in this way, the 2nd whetstone is unnecessary. In other words, the technical idea of the present invention is that the chipping and cracks generated on the end face by the previous stage processing are gradually removed in a plurality of subsequent process steps, and the end face is processed into a mirror surface in the final process step. One grindstone is provided with a plurality of grindstones having different grinding capabilities.

  Thereby, according to the grindstone for glass plates of this invention, the chamfering quality of a glass plate can be improved, without increasing the number of grindstones.

  The “grinding ability” described in the specification and claims refers to the first grinding step, the second grinding step, the first chamfering step, the second chamfering step, and the third chamfering as described above. It means the grinding / polishing ability of the grindstone used in the process, the fourth chamfering process, etc., that is, the performance of the grindstone. As shown below, the grindstone can be broadly classified into a grindstone mainly composed of “grinding” and a grindstone mainly composed of “polishing”.

The grindstone mainly composed of “grinding” can be exemplified by a hard grindstone in which abrasive grains of diamond or CBN (Cubic Boron Nitride) are fixed with metal bonds. An electrodeposited diamond grindstone can also be exemplified. By changing the grain size of these grindstones, a plurality of types of grinding such as rough grinding and medium grinding can be performed.
A grindstone mainly composed of “polishing” is a grindstone such as diamond, green silicon carbide (GC), alumina (Al ₂ O ₃ ), pumice, or garnet fixed with a bond such as butyl rubber, natural rubber, or resin. A whetstone can be illustrated. Further, by changing the grain size of the abrasive grains and the type of bond, a plurality of types of polishing such as finishing and mirror finishing can be performed.

  Furthermore, the “columnar shape” that is the shape of the grindstone includes a disk shape and a cylindrical shape. In addition, those in which a ring-shaped groove is formed on the surface of the grindstone and those in which the surface is flat are also included in the “columnar shape”.

  In the conventional chamfering apparatus, the one end surface of the glass plate is chamfered at 1 Pass (forward movement) in the second direction. In one aspect of the present invention, after the completion of 1 Pass, the grindstone and the glass plate are thirdly processed. Is moved relatively in the direction of 2 and 2 Pass (return) in the second direction. Thereby, the 2nd chamfering process (namely, 2nd chamfering process) can be performed to the end surface of a glass plate.

  According to one aspect of the present invention, for example, in a form in which two grindstones are arranged on one end surface, one grindstone of the first grindstone first hitting one end surface is used as a grindstone for rough grinding, and the other grindstone Is a grindstone for mirror finishing. Then, one grindstone of the second grindstone that comes into contact with one end face is used as a medium grinding grindstone, and the other grindstone is used as a finishing grindstone.

  In this case, 1 pass processing is performed with one grindstone of the first grindstone and one grindstone of the second grindstone, and then the other grindstone of the second grindstone and the other grindstone of the first grindstone. 2Pass processing.

  As a result, in the present invention, the processing steps constituted by rough grinding and finishing in the conventional chamfering apparatus can be performed in the present invention without increasing the number of grindstones, rough grinding, medium grinding, finishing, and mirror finishing. It can be configured in four processing steps. For example, as described above, the above four steps can be performed by using two grindstones. Therefore, in this invention, chamfering quality can be improved significantly, without increasing the number of grindstones.

  Further, in a form in which two grindstones are arranged on one end face, one grindstone of the first grindstone first hitting the one end face is a grindstone for rough grinding, and the other grindstone is a grindstone for mirror finish. . Then, the grindstone of the second grindstone that comes next to one end face is used as a grindstone for medium grinding.

  In this case, 1 Pass processing is performed with one grindstone of the first grindstone and the second grindstone, and then 2 Pass processing is performed with the other grindstone of the second grindstone and the first grindstone.

  Furthermore, in the form in which two grindstones are arranged with respect to one end face, the first grindstone that first hits one end face is used as a grindstone for rough grinding. And let the 2nd grindstone which hits one end surface next be a grindstone for medium grinding.

  In this case, 1 Pass processing is performed with the first grindstone and the second grindstone, and then 2 Pass processing is performed with the second grindstone.

  In one aspect of the present invention, it is preferable that the glass plate has a rectangular shape, and the grindstone is disposed so as to face two opposite end surfaces of the glass plate.

  According to one aspect of the present invention, the four end surfaces of a rectangular glass plate can be efficiently chamfered by turning the glass plate 90 degrees with respect to the grindstone.

  According to the glass plate chamfering apparatus, the glass plate chamfering method, and the glass plate manufacturing method according to the present invention, the chamfering quality of the glass plate can be improved without increasing the number of grindstones.

The top view which shows schematic structure of the chamfering apparatus of the glass plate of embodiment to which the grindstone for glass plates of embodiment was applied. The principal part expansion perspective view which showed the up-and-down arrangement position of the grindstone in the forward movement of the arrow A direction of a glass plate The principal part expansion perspective view which showed the up-and-down arrangement position of the grindstone in the backward movement of the arrow B direction of a glass plate 4 (A), 4 (B), 4 (C), 4 (D), and 4 (E) show the state in which the end face of the glass plate is sequentially chamfered by each grindstone. Explanatory diagram shown in 5 (A), FIG. 5 (B), FIG. 5 (C), FIG. 5 (D), and FIG. 5 (E) are explanatory views showing the chamfering method by the chamfering apparatus of the embodiment continuously. 6 (A), 6 (B), 6 (C), 6 (D), 6 (E), and 6 (F) show other chamfering methods by the chamfering apparatus according to the embodiment. Explanatory diagram FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E are explanatory diagrams showing another chamfering method of the embodiment over time. FIG. 8A, FIG. 8B, FIG. 8C, FIG. 8D, and FIG. 8E are explanatory diagrams that show other chamfering methods of the embodiment over time.

  Hereinafter, preferred embodiments of a glass plate chamfering apparatus, a glass plate chamfering method, and a glass plate manufacturing method according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a first grindstone 10 (hereinafter, the first grindstone 10 is simply referred to as a grindstone 10) and a second grindstone 12 (hereinafter, the second grindstone 12 is simply referred to as a grindstone 12) according to an embodiment of the present invention. It is a top view which shows schematic structure of the chamfering apparatus 14 of the glass plate of embodiment provided with each pair. This chamfering device 14 is a device used in the chamfering step in the glass plate manufacturing method of the embodiment including a melting step, a molding step, a cutting step, and a chamfering step.

  Further, as the chamfering device 14, an apparatus for chamfering the four end surfaces 16 </ b> A to 16 </ b> D of the glass plate 16 for liquid crystal display having a thickness of 0.7 mm or less with the grindstones 10 and 12 is illustrated. The grindstones 10 and 12 will be described later.

  In addition, as a glass plate applicable to the chamfering apparatus 14, it is not limited to the glass plate 16 for liquid crystal displays. For example, other glass plates for FPD such as a glass plate for plasma display and a glass plate for LED display may be used, and general glass plates for solar cells, lighting, building materials, mirrors, etc. may be used. Moreover, the thickness of a glass plate is not limited to 0.7 mm or less, The thickness exceeding 0.7 mm may be sufficient. Furthermore, it is not limited to a glass plate, and the end face can be chamfered by the chamfering device 14 even if it is a plate made of metal or resin.

[Overall configuration of chamfering device 14]
The chamfering device 14 moves the surface plate 18 that sucks and holds the rectangular glass plate 16 and the surface plate 18 in the horizontal direction (second direction) in the direction of arrow A (that is, 1 Pass) and in the direction of arrow B. A moving device (that is, second moving means) 20 that moves (2 Pass) and grinds the same end faces 16A and 16B a plurality of times is provided. The chamfering device 14 according to the embodiment is a device that reciprocates the glass plate 16 with respect to the grindstones 10 and 12 that are fixedly arranged. However, the grindstones 10 and 12 and the glass plate 16 are connected to the end surface of the glass plate 16. Any device that reciprocally moves in the horizontal direction along the extending direction of 16A and 16B may be used.

  Further, the chamfering device 14 is pressed against the end surfaces 16A to 16D of the glass plate 16 to process the chamfered surfaces into end surfaces 16A to 16D, and a motor (rotation) for rotating the grindstones 10 and 12 at high speed. Means) 22 and 24. Two grindstones 10 and 12 are disposed on the opposing end surfaces 16A and 16B of the glass plate 16, but three or more grindstones may be disposed.

  Further, the chamfering device 14 is processed by the elevating devices (that is, third moving means) 26 and 28 that move the grindstones 10 and 12 in the vertical direction (third direction) together with the motors 22 and 24 and the grindstones 10 and 12. The nozzles 30 and 32 which inject a cooling liquid to a part, the control apparatus (control means) 34, etc. are provided. Moreover, while feeding the grindstones 10 and 12 against the end surface 16A of the glass plate 16 in the horizontal direction, feeding devices (that is, first moving means) 31 and 33 (see FIG. 2). In addition, although the chamfering apparatus 14 of embodiment is an apparatus which raises / lowers the grindstones 10 and 12 with respect to the glass plate 16, the grindstones 10 and 12 and the glass plate 16 are made into the main surface 16E of the glass plate 16 (FIG. 2). And a device that relatively moves up and down along the vertical direction orthogonal to the horizontal direction. Moreover, it is not limited to the apparatus which moves the grindstones 10 and 12 forward and backward by the feeding devices 31 and 33 with respect to the end face 16A, and any apparatus that relatively moves the end face 16A of the glass plate 16 and the grindstones 10 and 12 forward and backward. Good. The grinding allowance is set according to the feed amounts of the feeding devices 31 and 33. Further, the feed amount is controlled by the control device 34 based on the grinding ability and performance of the grindstones 10 and 12.

  The control device 34 controls the operations of the moving device 20, the rotation speed / rotation direction of the motors 22 and 24, the lifting devices 26 and 28, and the feeding devices 31 and 33. A method of controlling each operation by the control device 34 will be described later.

  FIG. 2 is an enlarged perspective view of a main part showing the vertical positions of the grindstones 10 and 12 during the forward movement of the glass plate 16 in the direction of arrow A.

  FIG. 3 is an enlarged perspective view of a main part showing the upper and lower arrangement positions of the grindstones 10 and 12 during the backward movement of the glass plate 16 in the arrow B direction.

  As shown in FIGS. 2 and 3, the grindstone 10 is rotationally driven by the motor 22 about the central axis 10 </ b> A. Further, when the motor 22 is controlled by the control device 34 (see FIG. 1), the rotation speed is controlled, and the forward and reverse rotation directions indicated by the arrow C in FIG. 2 and the arrow D in FIG. 3 are controlled. . In the embodiment, when the glass plate 16 is moved forward in the arrow A direction, the grindstone 10 is rotated in the arrow C direction opposite to the forward movement direction. Similarly, when the glass plate 16 is moved backward in the arrow B direction, the rotation direction is converted to the arrow D direction opposite to the backward movement direction. In addition, conversion of the rotation direction of the grindstone 10 is not essential. By not changing the rotation direction of the grindstone, the processing time can be shortened.

  Similarly, the grindstone 12 is rotationally driven by a motor 24 around the central axis 12A. Further, when the motor 24 is controlled by the control device 34 (see FIG. 1), the rotation speed is controlled, and the forward and reverse rotation directions indicated by the arrow C in FIG. 2 and the arrow D in FIG. 3 are controlled. . In the embodiment, when the glass plate 16 is moved forward in the arrow A direction, the grindstone 12 is rotated in the arrow C direction opposite to the forward movement direction. Similarly, when the glass plate 16 is moved backward in the arrow B direction, the rotation direction is converted to the arrow D direction opposite to the backward movement direction. In addition, conversion of the rotation direction of the grindstone 12 is not essential.

<Configuration of the first grindstone 10 and the second grindstone 12>
The grindstone 10 is divided into two grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion (the upper divided grindstone portion 36 in the illustrated example) is higher than the other divided grindstone portion (in the illustrated example upper portion). Is set to be higher than the grinding ability of the divided grindstone portion 42).

  Similarly, the grindstone 12 is divided into two divided grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion (upper divided grindstone portion 38) is the same as that of the other divided grindstone portion (lower divided grindstone portion 40). It is set higher than the grinding ability.

  In addition, the division | segmentation number of the grindstones 10 and 12 is not limited to two, You may divide | segment into three or more.

  The divided grindstone portions 36, 38, 40, and 42 of the embodiment perform rough grinding (that is, first chamfering step: first grinding step) on the end surfaces 16A and 16B by the reciprocating movement of the glass plate 16 described above. Medium grinding (ie, second chamfering step: first grinding step), finishing (ie, third chamfering step: second grinding step), and mirror finishing (ie, fourth chamfering step: first) Each grinding ability, that is, the performance is set so that the second grinding step) can be performed sequentially.

  Specifically, the divided grindstone portion 36 can perform rough grinding, the divided grindstone portion 38 can perform medium grinding, the divided grindstone portion 40 can perform finish processing, and the divided grindstone portion 42 can perform mirror surface machining. The performance is set as follows.

  4 (A) to 4 (E) are explanatory views showing the state in which the same end surface 16A of the glass plate 16 is sequentially chamfered by the divided grindstone portions 36, 38, 40, 42. is there.

  FIG. 4A shows the shape of the end face 16A of the glass plate 16 before chamfering. That is, the end surface 16A of the glass plate 16 is a cut surface that is cut in a cutting step preceding the chamfering step, and is formed in a direction orthogonal to the main surface 16E.

  FIG. 4B shows the shape of the end face 16A subjected to rough grinding by the divided grindstone portion 36, and an annular groove 36A having a U-shaped cross section (FIG. 2, FIG. 2), which is a grinding groove of the divided grindstone portion 36. (See FIG. 3). The roughness of the end face 16A after the rough grinding is rough, and chipping and cracks caused by the rough grinding are frequently generated on the surface.

  The cross-sectional shape of the annular groove 36A of the divided grindstone portion 36 shown in FIGS. 2 and 3 is not limited to the U shape, and may be a V shape or a concave shape. Further, the number of the annular grooves 36A may be one, but it is preferable to provide a plurality of annular grooves 36 at a predetermined interval in the axial direction of the divided grindstone portion 36 in order to omit the replacement work of the divided grindstone portion 36. Since the plurality of annular grooves 36A are provided in the divided grindstone portion 36, when the annular groove 36A in use reaches the end of its life, the lifting device 26 raises and lowers the divided grindstone portion 36 in the axial direction in units of the pitch of the annular grooves 36A. In this case, the end face 16A can be roughly ground using the new annular groove 36A without replacing the divided grindstone 36.

  FIG. 4C shows the shape of the end face 16 </ b> A that has been subjected to medium grinding by the divided grindstone 38. By pressing the surface of the divided grindstone portion 38 against the end face 16A, most of the chipping and cracks frequently generated in the rough grinding process are removed by polishing.

  FIG. 4D shows the shape of the end face 16 </ b> A that has been finished by the divided grindstone 40. By pressing the surface of the divided grindstone portion 40 against the end face 16A, chipping and cracks frequently generated in the rough grinding process are further polished and removed.

  FIG. 4E shows the shape of the end face 16 </ b> A that has been finished by the divided grindstone 42. By pressing the surface of the divided grindstone portion 42 against the end face 16A, chipping and cracks frequently generated in the rough grinding process are almost completely polished and removed, and the end face 16A is mirror-finished. That is, the end surface 16A is processed into a mirror surface that is assumed not to generate dust from the end surface 16A.

  Here, as the divided grindstone portions 36 and 38 that mainly perform “grinding”, a hard grindstone in which diamond or CBN abrasive grains are fixed by metal bonds can be exemplified. An electrodeposited diamond grindstone can also be exemplified. By setting the grain size of the abrasive grains of the divided grindstone 36 to, for example, 270 to 600, rough grinding can be performed by the divided grindstone 36. The grain size of the abrasive grains of the divided grindstone portion 36 is more preferably 325 to 500. By setting the grain size of the abrasive grains of the divided grindstone 38 to, for example, 400 to 1000, medium grinding can be performed by the divided grindstone 38. The grain size of the abrasive grains of the divided grindstone 38 is more preferably 420 to 600.

As the divided grindstone portions 40 and 42 that mainly perform “polishing”, grindstones such as diamond, CBN, green silicon carbide (GC), alumina (Al ₂ O ₃ ), pumice, or garnet are made of butyl rubber, natural rubber, Or the grindstone fixed with bonds, such as resin, can be illustrated. Moreover, the division grindstone part 40 performs finishing by setting the grain size of the abrasive grains of the divided grindstone part 40 to, for example, 270 to 800 and setting the grain size of the abrasive grains of the divided grindstone part 42 to, for example, 600 to 4000. Mirror surface processing can be performed by the divided grindstone portion 42.
The divided grindstone 38 is a grindstone in which a grindstone such as diamond, CBN, green silicon carbide (GC), alumina (Al ₂ O ₃ ), pumice, or garnet is fixed with a bond such as butyl rubber, natural rubber, or resin. In that case, medium grinding can be performed by setting the grain size of the abrasive grains of the divided grindstone portion 38 to, for example, No. 400-600.

[Operation of the chamfering device 14]
First, the grinding allowance by the grindstones 10 and 12 is set in the control device 34 of FIG. 1, and the forward speed and the backward speed of the surface plate 18 are set. At this time, on the basis of the conventional processing time at 1 Pass, the control device 34 for controlling the moving device 20 so that the processing time at 1 Pass and 2 Pass (reciprocating) of the embodiment and the conventional 1 Pass processing time are substantially equal. It is preferable to set the operation program. If it does in this way, the chamfering quality of the glass plate 16 can be improved in the time equivalent to the process by the conventional 1Pass. In this case, the grain size of the abrasive grains of the divided grindstone portion 36 is preferably 200 to 450, and the grain size of the abrasive grains of the divided grindstone portion 38 is preferably 350 to 500. Further, when performing machining with a short machining time, it is preferable to shorten the backward 2 Pass machining time rather than the forward 1 Pass machining time. When finishing-oriented machining is performed, it is preferable to make the backward 2 Pass machining time longer than the forward 1 Pass machining time. The forward 1 Pass machining time and the backward 2 Pass machining time may be set to be equal.

  Next, when the glass plate 16 is moved forward by the surface plate 18, the end surfaces 16A and 16B pass through the divided grindstone portions 36 and 38, and at the time of backward movement, the end surfaces 16A and 16B pass through the divided grindstone portions 40 and 42. An operation program of the control device 34 that controls the lifting devices 26 and 28 is set.

  Next, the motors 22 and 24 are controlled so that the grindstones 10 and 12 rotate in the direction of the arrow C when the glass plate 16 moves forward by the surface plate 18, and the grindstones 10 and 12 rotate in the direction of the arrow D when returning. An operation program for the control device 34 is set. As described above, the rotational direction of the grindstones 10 and 12 may be constant without conversion.

  The pre-setting work by the chamfering device 14 is thus completed.

  Next, the glass plate 16 cut in the cutting step is sucked and held on the suction surface on the upper surface of the surface plate 18. Thereafter, the control device 34 controls each member of the chamfering device 14 and starts chamfering of the end surfaces 16A and 16B of the glass plate 16.

  That is, the control device 34 controls the moving device 20 to move the glass plate 16 in the direction of arrow A in FIG. And the control apparatus 34 controls the motors 22 and 24, and rotates the grindstones 10 and 12 to the arrow C direction of FIG. And the control apparatus 34 controls the raising / lowering apparatuses 26 and 28, and adjusts the height of the grindstones 10 and 12 to the height which the end surface 16A passes the division | segmentation grindstone parts 36 and 38. FIG.

  5 (A) to 5 (E) are explanatory views showing the chamfering method by the chamfering device 14 over time.

  FIG. 5A shows a state in which the height of the grindstones 10 and 12 is adjusted to a height at which the end face 16A passes through the divided grindstone portions 36 and 38, and the glass plate 16 is moved forward in the arrow A direction. It is a schematic side view.

  Thereafter, the end surface 16A of the glass plate 16 is first subjected to rough grinding by the divided grindstone portion 36 by the forward movement of the glass plate 16 as shown in FIG. Medium grinding is performed by the grindstone 38. That is, a second chamfering process is performed.

  During rough grinding and medium grinding, coolant is sprayed from the nozzles 30 and 32 in FIG. 1 to the processing portion where the grindstones 10 and 12 and the end face 16A are in contact with each other. Thereby, since the said process part is cooled with the said cooling fluid, generation | occurrence | production of the burning, chipping, etc. which arise in the end surface 16A of the glass plate 16 can be reduced. Further, chipping generated on the boundary surfaces between the two main surfaces of the glass plate 16 and the end surfaces 16A and 16B can be reduced. An example of the coolant is pure water.

  As shown in FIG. 5C, when the intermediate grinding of the end face 16A is completed and the glass plate 16 is positioned at the end position of the forward movement, the control device 34 in FIG. Stop moving.

  Thereafter, as shown in FIG. 5C, the control device 34 controls the moving device 20 to move the glass plate 16 backward in the direction of arrow B by the surface plate 18. And the control apparatus 34 controls the motors 22 and 24, and rotates the grindstones 10 and 12 to the arrow D direction of FIG. 1 controls the elevating devices 26 and 28 to adjust the height of the grindstones 10 and 12 to a height at which the end surface 16A passes through the divided grindstone portions 40 and 42. That is, the grindstones 10 and 12 are moved up in the direction of arrow E in FIG.

  FIG. 5D is a schematic side view showing a state at the start of the backward movement.

  As shown in FIG. 5E, the returning glass plate 16 is finished by the end face 16A passing through the divided grindstone portion 40 (that is, subjected to a third chamfering step), and passes through the divided grindstone portion 42. As a result, mirror finishing is performed (that is, a fourth chamfering step is performed).

  In addition, you may chamfer the other opposing end surfaces 16C and 16D of the glass plate 16 with the grindstones 10 and 12 which are arrange | positioned in the back | latter stage of the grindstones 10 and 12 of FIG. That is, the glass plate 16 is rotated 90 degrees around the vertical line in the principal plane direction on the apparatus having the same mechanism as that in FIG. 1 disposed at the subsequent stage of FIG. 1, and the grindstone having the same performance as the grindstones 10 and 12 is used. The end faces 16C and 16D may be chamfered.

  Alternatively, after the glass plate 16 is moved in the B direction by the surface plate 18 and returned to the original position, the glass plate 16 is rotated by 90 degrees about the perpendicular in the main surface direction of the glass plate 16 by the surface plate 18. Then, while moving the glass plate 16 in the A direction by the surface plate 18, the pair of grindstones 10, 12 whose intervals are changed according to the length in the extending direction of the end surfaces 16 A, 16 B of the glass plate 16. The end faces 16C and 16D may be chamfered.

[Characteristics of the first grindstone 10 and the second grindstone 12]
The grindstone 10 (including the grindstone 12) of the embodiment is divided into at least two or more divided grindstone portions in the axial direction, and the grinding ability of the divided grindstone portion 36 is higher than the grinding ability of the divided grindstone portion 42. . That is, a single grindstone 10 has a plurality of performances, and a grindstone selected according to the performance is used for chamfering the glass plate 16.

  For example, when the first chamfering process is performed on the end surface 16A, the divided grindstone portion 36 having a high grinding ability is pressed against the end surface 16A of the glass plate 16 for processing. Next, when performing the 2nd chamfering process, it processes by pressing the division grindstone part 42 with low grinding ability to the end surface 16A.

  As described above, the present invention is characterized in that one grindstone 10 has two or more kinds of performance. Therefore, as the grindstone, at least two of the first grindstone and the second grindstone are provided, each of the first grindstone and the second grindstone is divided in the axial direction, and a divided grindstone portion is provided. Rough grinding is performed at the divided grindstone part of the eye, intermediate grinding is performed at the second divided grindstone part, finishing is performed at the third divided grindstone part, and the fourth divided grindstone part is formed. Mirror processing can also be performed. Moreover, you may give four types of grinding ability to one grindstone. The first grindstone is divided into four parts in the axial direction to provide four divided grindstone parts, rough grinding is performed with the first divided grindstone part, and intermediate grinding is performed with the second divided grindstone part. Processing may be performed, finishing may be performed at the third divided grindstone, and mirror processing may be performed at the fourth divided grindstone. If it does in this way, the 2nd whetstone is unnecessary.

  Thereby, according to the grindstone for glass plates of this invention, the chamfering quality of a glass plate can be improved, without increasing the number of grindstones.

[Characteristics of chamfering device 14]
While the moving device 20 moves the glass plate 16 in the direction of arrow A, the motor 22 rotates the divided grindstone portion 36 and presses the divided grindstone portion 36 against the end surface 16 </ b> A of the glass plate 16. Thereby, the first chamfering process can be performed on the end face 16A (that is, the first chamfering process). Next, the grindstone 10 is moved in the direction of arrow E (see FIG. 5C) by the lifting device 26 and the glass plate 16 is moved back in the direction of arrow B by the moving device 20, while the divided grindstone portion 42 is moved to the end face 16A. Press against. Thereby, the second chamfering process can be performed on the end face 16A (that is, the second chamfering process).

  Here, the conventional chamfering apparatus and the chamfering apparatus 14 of the embodiment will be compared.

  The conventional chamfering device is a device that chamfers the end surface 16A by causing the glass plate 16 to move 1 pass (forward movement) in the direction of arrow A with respect to the grindstone.

  On the other hand, the chamfering device 14 of the embodiment changes the height of the grindstone 10 after the end of 1 Pass, causes the glass plate 16 to pass 2 passes (that is, backward) in the direction of arrow B, and ends 16A of the glass plate 16. 2 is a device for performing a second chamfering process. Therefore, the chamfering method by the conventional chamfering apparatus and the chamfering method by the chamfering apparatus 14 of the embodiment are completely different.

[Other Embodiments of Chamfering Method]
6 (A) to 6 (F) are explanatory views showing other chamfering methods by the chamfering device 14 over time.

  As shown in FIGS. 6A to 6F, the grindstone 10 includes a divided grindstone portion 36 and a divided grindstone portion 40, and the grindstone 12 includes a divided grindstone portion 38 and a divided grindstone portion 42. It has been.

  FIG. 6A shows a state in which the height of the grindstones 10 and 12 is adjusted to a height at which the end face 16A passes through the divided grindstone portions 36 and 38, and the glass plate 16 is moved forward in the arrow A direction. It is a schematic side view.

  Thereafter, the end face 16A of the glass plate 16 is first subjected to rough grinding by the divided grindstone portion 36 by the forward movement of the glass plate 16 as shown in FIG. As the chamfering process 2, intermediate grinding is performed by the divided grindstone 38.

  As shown in FIG. 6C, when the intermediate grinding of the end face 16A is completed and the glass plate 16 is positioned at the end position of the forward movement, the control device 34 of FIG. Stop moving.

  Thereafter, the control device 34 controls the feeding devices 31 and 33 to retract the grindstones 10 and 12 from the contact position of the end surface 16A, and also controls the lifting devices 26 and 28 so that the end surface 16A has the divided grindstone portion 40. , 42 is adjusted to a height that passes through 42. That is, the grindstones 10 and 12 are moved up in the direction of arrow E in FIG. Then, the control device 34 controls the moving device 20 to move the glass plate 16 backward in the direction of arrow B by the surface plate 18, and is positioned at the end position of the backward movement of the glass plate 16 as shown in FIG. Let Thereafter, the control device 34 controls the feeding devices 31 and 33 to move the grindstones 10 and 12 forward to the contact position of the end surface 16A. The contact position refers to the grindstone diameter, the additional driving amount corresponding to the preceding grinding amount, and the grindstone depending on the bond type for each of the divided grindstone portions 36, 38, 40, 42 of the grindstone 10, 12. This is set based on the degree of wear and the amount of additional driving for each processing of one glass plate according to the degree of wear. Then, the control device 34 controls the moving device 20 to move the glass plate 16 forward again in the arrow A direction by the surface plate 18.

  As shown in FIG. 6 (F), the forwardly moving glass plate 16 is finished by the end surface 16A passing through the divided grindstone portion 40 (that is, subjected to the third chamfering step) and passes through the divided grindstone portion 42. As a result, mirror finishing is performed (that is, a fourth chamfering step is performed).

  FIG. 7A to FIG. 7E are explanatory diagrams showing other chamfering methods over time.

  As shown in FIGS. 7A to 7E, the grindstone 10 is provided with a divided grindstone portion 36 and a divided grindstone portion 42, and the grindstone 12 is provided with only the same divided grindstone portion 40. .

  FIG. 7A shows a state in which the height of the grindstones 10 and 12 is adjusted to a height at which the end surface 16A passes through the divided grindstone portions 36 and 40, and the glass plate 16 is moved forward in the arrow A direction. It is a schematic side view.

  Thereafter, the end face 16A of the glass plate 16 is first subjected to rough grinding by the divided grindstone portion 36 (ie, the first chamfering step is performed) by the continuous movement of the glass plate 16 as shown in FIG. 7B. After that, finishing is performed by the divided grindstone portion 40 (that is, a second chamfering step is performed). In this case, the grinding force of the divided grindstone 40 is weak.

  As shown in FIG. 7C, when finishing of the end face 16A is completed and the glass plate 16 is positioned at the end position of the forward movement, the control device 34 in FIG. 1 controls the moving device 20 to move the surface plate 18. Is temporarily stopped.

  Thereafter, the control device 34 controls the elevating devices 26 and 28 to adjust the height of the grindstones 10 and 12 to a height at which the end surface 16A passes through the divided grindstone portions 40 and 42. That is, the grindstones 10 and 12 are moved up in the direction of arrow E in FIG. Then, the control device 34 controls the moving device 20 to move the glass plate 16 back in the arrow B direction by the surface plate 18 as shown in FIG.

  As shown in FIG. 7E, the glass plate 16 that moves backward is subjected to the second finishing process (that is, the third chamfering step) when the end face 16A passes through the divided grindstone portion 40, and the divided grindstone portion 42 is obtained. Is mirror-finished (that is, a fourth chamfering step is performed).

  In this other chamfering method, the grinding force of the divided grindstone portion 40 at the time of forward movement is weak, but since it is ground by the divided grindstone portion 40 also at the time of backward movement, it is possible to carry out chamfering with the required roughness as a whole. .

  FIG. 8A to FIG. 8E are explanatory views showing other chamfering methods over time.

  As shown in FIGS. 8A to 8E, the grindstone 10 includes only the same divided grindstone portion 36, and the grindstone 12 includes the divided grindstone portion 38 and the divided grindstone portion 40.

  FIG. 8A shows a state in which the height of the grindstones 10 and 12 is adjusted to a height at which the end face 16A passes through the divided grindstone portions 36 and 38, and the glass plate 16 is moved forward in the direction of arrow A. It is a schematic side view.

  Thereafter, the end face 16A of the glass plate 16 is first subjected to rough grinding by the divided grindstone portion 36 (ie, the first chamfering step is performed) by the continuous movement of the glass plate 16 as shown in FIG. 8B. After that, the grinding is performed by the divided grindstone portion 38 (that is, the second chamfering process is performed).

  As shown in FIG. 8C, when the intermediate grinding of the end face 16A is completed and the glass plate 16 is positioned at the end position of the forward movement, the control device 34 in FIG. Stop moving.

  Thereafter, the control device 34 controls the feeding device 31 to retract the grindstone 10 from the contact position of the end surface 16A and also controls the lifting device 28 so that the end surface 16A passes through the divided grindstone portion 40. The height of the grindstone 12 is adjusted. That is, the grindstone 12 is moved upward in the direction of arrow E in FIG. Then, the control device 34 controls the moving device 20 to move the glass plate 16 back in the arrow B direction by the surface plate 18 as shown in FIG.

  As shown in FIG. 8 (E), the backward moving glass plate 16 is finished by the end face 16A passing through the divided grindstone portion 40 as a third chamfering step.

  In this other chamfering method, the mirror surface processing by the divided grindstone portion 42 is not performed. However, if the finishing processing equivalent to the mirror surface processing can be performed by increasing the particle size of the divided grindstone portion 40, the divided grindstone portion 42 is applied to the grindstone 10. It is not necessary to have.

[Characteristics of glass plate manufacturing method using chamfering device 14]
The manufacturing method of the glass plate of the embodiment of the present invention is as follows.
A melting step of heating the glass raw material to obtain molten glass;
A molding step for obtaining a glass ribbon by making the molten glass into a plate shape,
A cutting step of cutting the glass ribbon to obtain a glass plate;
A chamfering step of chamfering the glass plate by the chamfering method of the glass plate,
Have
In the melting step, silica sand and other glass raw materials are adjusted so as to have a desired glass composition, the raw materials are put into a melting furnace, and preferably heated to about 1400 ° C. to 1650 ° C. to obtain molten glass.
In the molding step, a glass ribbon is obtained by applying a float method, a fusion method or the like to form a molten glass into a plate shape. For example, in the float process, molten glass is flowed on a molten metal to obtain a glass ribbon.
In the cutting step, after the glass ribbon is slowly cooled, the glass ribbon is cut into a predetermined size to obtain a glass plate.
In the chamfering method, the glass plate is chamfered by the above-described chamfering method of the glass plate.
According to the glass plate manufacturing method of the present invention, the glass plate 16 with improved chamfering quality can be manufactured.

  Further, it is possible to cope with only the modification of the operation software of the control device 34 without making a major modification such as adding a grindstone rotating device, and the time and cost required for the modification can be greatly reduced.

  Further, by increasing the processing speed of the grindstones 10 and 12, it is possible to improve the chamfering processing quality without changing the processing tact, that is, without reducing the productivity of the glass plate 16.

  Furthermore, as another chamfering method, the chamfering method of the present invention can be applied to the chamfering method disclosed in Japanese Patent Laid-Open No. 2008-49449. That is, the first chamfering grindstone chamfers from approximately the center of one side to the other end of one side on one side of the glass plate, and the second chamfering grindstone from one end of the same side to the same side The chamfering apparatus and the chamfering method of the present invention can also be applied to the chamfering method disclosed in the above-mentioned publication, which is characterized in that chamfering is performed up to approximately the center of the above.

According to the glass plate chamfering apparatus, the glass plate chamfering method, and the glass plate manufacturing method according to the present invention, the chamfering quality of the glass plate can be improved without increasing the number of grindstones.
The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2014-257462 filed on Dec. 19, 2014 are incorporated herein as the disclosure of the present invention. .

  DESCRIPTION OF SYMBOLS 10, 12 ... Grinding stone, 14 ... Chamfering device, 16 ... Glass plate, 16A-16D ... End surface, 18 ... Surface plate, 20 ... Moving device, 22, 24 ... Motor, 26, 28 ... Lifting device, 30, 32 ... Nozzle , 31, 33 ... feed device, 34 ... control device, 36, 38, 40, 42 ... divided grindstone section.

Claims (9)

Whetstone,
Rotating means for rotating the grindstone about its central axis;
A first moving means for relatively moving the grindstone and the glass plate along a first direction orthogonal to an end surface of the glass plate;
A second moving means for relatively reciprocating the grindstone and the glass plate along a second direction in which the end surface of the glass plate extends, and grinding the same end surface of the glass plate a plurality of times;
Third moving means for relatively moving the grindstone and the glass plate along a third direction orthogonal to the main surface of the glass plate and the second direction;
Control means for controlling the first moving means, the second moving means, and the third moving means;
A chamfering device for a glass plate, comprising: The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone and the second grindstone are configured in a cylindrical shape and divided into at least two divided grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion is divided. The glass plate chamfering device according to claim 1, wherein the chamfering device has a higher grinding ability than the other divided grindstone. The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone is formed in a cylindrical shape and is divided into at least two or more divided grindstone portions in the axial direction, and the grinding ability of one of the divided grindstone portions is that of the other divided grindstone portion. Higher than grinding ability,
The glass plate chamfering apparatus according to claim 1, wherein the second grindstone is configured in a cylindrical shape and has the same grinding ability.   The said glass plate is a rectangular shape, The chamfering apparatus of the glass plate of Claim 1, 2, or 3 with which the said grindstone is arrange | positioned facing two opposing end surfaces of the said glass plate. The grindstone is composed of upper and lower divided grindstone portions. After pressing one divided grindstone portion of the upper and lower divided grindstone portions against one end surface of the glass plate, the grindstone and the glass plate are A first grinding step of grinding the one end face by rotating the one end grindstone part about its central axis while relatively moving in one extending direction of the end face;
After pressing the other divided grindstone portion of the upper and lower divided grindstone portions of the grindstone against the one end surface of the glass plate, the grindstone and the glass plate are moved to the other extending direction of the one end surface or one of the one end surfaces. A second grinding step of relatively moving in the extending direction and rotating the other divided grindstone portion around its central axis to grind the same end surface;
A method for chamfering a glass plate, comprising: The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone and the second grindstone are configured in a cylindrical shape and divided into at least two divided grindstone portions in the axial direction, and the grinding ability of one divided grindstone portion is divided. It is higher than the grinding ability of the other divided grindstone part,
After pressing one divided grindstone portion having a high grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are relatively opposed to one extending direction of the one end surface. A first chamfering step of grinding the one end face by rotating the first grindstone about its central axis,
After pressing one divided grindstone portion having a high grinding ability of the second grindstone against one end face of the glass plate, the second grindstone and the glass plate are relatively opposed to one extending direction of the one end face. A second chamfering step of grinding the one end face by rotating the second grindstone about its central axis,
After pressing the other divided grindstone part having a low grinding ability of the second grindstone against one end surface of the glass plate, the second grindstone and the glass plate are placed in the other extending direction of the one end surface. A third chamfering step of grinding the one end face by rotating the second grindstone around its central axis, and relatively moving the second grindstone;
After pressing the other divided grindstone portion having a low grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are placed in the other extending direction of the one end surface. A fourth chamfering step of grinding the one end face by rotating the first grindstone around its central axis while relatively moving;
A method for chamfering a glass plate, comprising: The grindstone is composed of at least a first grindstone and a second grindstone,
The first grindstone is formed in a cylindrical shape and is divided into at least two or more divided grindstone portions in the axial direction, and the grinding ability of one of the divided grindstone portions is that of the other divided grindstone portion. It is higher than the grinding ability,
The second grindstone is constituted by the grindstone having a cylindrical shape and the same grinding ability,
After pressing one divided grindstone portion having a high grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are relatively opposed to one extending direction of the one end surface. A first chamfering step of grinding the one end face by rotating the first grindstone about its central axis,
After the second grindstone is pressed against one end surface of the glass plate, the second grindstone and the glass plate are relatively moved in one extending direction of the one end surface, and the second A second chamfering step of grinding the one end face by rotating a grindstone about its central axis;
After the second grindstone is pressed against one end surface of the glass plate, the second grindstone and the glass plate are relatively moved in the other extending direction of the one end surface, and the second A third chamfering step of grinding the one end face by rotating the grindstone about the central axis;
After pressing the other divided grindstone portion having a low grinding ability of the first grindstone against one end surface of the glass plate, the first grindstone and the glass plate are placed in the other extending direction of the one end surface. A fourth chamfering step of grinding the one end face by rotating the first grindstone around its central axis while relatively moving;
A method for chamfering a glass plate, comprising:   The said glass plate is a rectangular shape, The chamfering method of the glass plate of any one of Claim 5 to 7 with which the said grindstone is arrange | positioned facing the two end surfaces which the said glass plate opposes. A melting step of heating the glass raw material to obtain molten glass;
A molding step for obtaining a glass ribbon by forming the molten glass into a plate shape; and
A cutting step of cutting the glass ribbon to obtain a glass plate;
A chamfering step of chamfering the glass plate by the chamfering method of the glass plate according to any one of claims 5 to 8,
The manufacturing method of the glass plate characterized by having.

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