Method for manufacturing a glass sheet

Abstract

A method for manufacturing a glass sheet includes a grinding process (P1) in which an end surface (1a) of a glass sheet (1) is processed using a grinding stone (2), and a lapping process (P2) in which the end surface (1a) of the glass sheet (1) processed by the grinding stone (2) is processed using a lapping stone (3). In the grinding process (P1), processing is performed in a brittle mode, and in the lapping process (P2), processing is performed mainly in a ductile mode.

Description

Technical Field

[0001] This invention relates to a method for manufacturing glass plates. Background Technology

[0002] It is customary in the glass plate manufacturing process to include a grinding process that uses a grinding stone to process the end face of the glass plate, and a polishing process that uses a grinding stone to process the end face after processing by the grinding stone (see Patent Document 1). In the grinding process, the end face of the glass plate is cut to perform chamfering, and in the polishing process, a finishing process is performed to smooth the end face.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-40073 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Glass plates are used as substrates for displays such as liquid crystal displays (LCDs) and organic EL displays. In recent years, there has been a demand for developing displays with higher resolution, which requires further improvement in the quality of the glass plate's end faces. Specifically, this includes requirements for low dust generation to further suppress glass dust, chemical resistance to prevent corrosion from etching solutions, and high strength to prevent cracking starting from the end face.

[0008] In view of the above, the technical problem that needs to be solved is to improve the end face quality of the glass plate during manufacturing.

[0009] Solution for solving the problem

[0010] A method for manufacturing a first glass plate to solve the above-mentioned problems includes: a grinding step, in which the end face of the glass plate is processed using a grinding stone; and a polishing step, in which the end face of the glass plate processed by the grinding stone is processed using a polishing stone. The method for manufacturing the glass plate is characterized in that the grinding step is performed in a brittle mode, and the polishing step is performed mainly in a ductile mode.

[0011] Here, "majorly processed in an extensibility pattern" means that more than 50% of the length of the end face of the object being processed (the length along the processing direction) is processed in an extensibility pattern (the same applies below).

[0012] In this method, the grinding process, which is a finishing step for the end face of the glass plate, primarily employs a ductile mode for processing. Based on this ductile mode, residual cracks on the processed end face can be minimized. Therefore, the end face after the grinding process exhibits low dust generation, resistance to etching solutions and corrosion, and high strength to prevent cracking originating from the end face. In other words, the end face quality of the glass plate is improved.

[0013] The manufacturing method of the second glass plate is based on the manufacturing method of the first glass plate described above, and is configured as follows: in the grinding process and the polishing process, cooling medium is supplied to the processing part on the periphery of the grinding stone and the polishing stone, respectively; in the polishing process, the amount of cooling medium supplied is reduced compared with the grinding process.

[0014] The results of experiments conducted by the inventors showed that when supplying cooling medium to the processing portion around the grinding stone, reducing the supply amount in the grinding process compared to the polishing process makes it easier to exhibit a ductile pattern in the grinding process. Therefore, by reducing the supply amount of cooling medium as described above, it is easier to stably perform processing based on the ductile pattern in the grinding process.

[0015] The manufacturing method for the third glass plate is based on the manufacturing method for the second glass plate described above, with the following scheme: water is used as the cooling medium. Furthermore, the manufacturing method for the fourth glass plate is based on the manufacturing method for the third glass plate, with the following scheme: water is supplied from a grinding nozzle and a grinding nozzle, respectively, during the grinding and polishing processes. During the grinding process, the flow rate of water flowing from the grinding nozzle is set to 15 L / min to 25 L / min, and during the polishing process, the flow rate of water flowing from the polishing nozzle is set to 0 L / min to 15 L / min.

[0016] According to the aforementioned method for manufacturing the third glass plate, by using water as a cooling medium, the aforementioned effect of improving the end-face quality of the glass plate can be achieved easily and at low cost. Furthermore, according to the aforementioned method for manufacturing the fourth glass plate, by adjusting the water flow rate to the aforementioned flow rate, it is further advantageous in that the ductility pattern is more easily manifested during the grinding process.

[0017] The manufacturing method of the fifth glass plate is based on any one of the manufacturing methods of the first to fourth glass plates described above, and is set as follows: In the grinding process, the relative moving speed between the grinding stone and the end face of the glass plate is set to 20 m / min or more.

[0018] One challenge in processing based on the ductility mode is that the relative movement speed (processing speed) between the grinding stone and the end face of the glass plate tends to be low. However, if the supply of cooling medium (water) is reduced in the grinding process compared to the grinding process, as described above, processing based on the ductility mode at a high relative movement speed of 20 m / min or higher can be achieved.

[0019] The manufacturing method of the sixth glass plate is based on any one of the manufacturing methods of the first to fifth glass plates described above, and is set as follows: In the grinding process, the value of G calculated according to the following [Mathematical Formula 1] is set to be less than 0.1.

[0020] [Mathematical Expression 1]

[0021]

[0022] m: The number of different types of abrasive grains contained in the grinding stone.

[0023] n k The number of abrasive grains of type k (calculated according to [Mathematical Formula 2] below).

[0024] r k The average abrasive radius [mm] for the k-th type of abrasive grain.

[0025] A k Abrasive type coefficient for the k-th abrasive grain

[0026] D: Diameter of the grinding stone [mm]

[0027] B: Regarding the binder coefficient of the binder used in grinding stones

[0028] Here, the abrasive type coefficient A k The value is set as follows, depending on the type of abrasive grain.

[0029] Diamond: 8000

[0030] Cubic boron nitride: 4700

[0031] Silicon carbide: 2500

[0032] Alumina: 2100

[0033] Here, the value of the binder coefficient B is set as follows, depending on the type of binder.

[0034] Metal: 3000

[0035] Resin: 30

[0036] Elastomer: 1

[0037] [Mathematical Expression 2]

[0038]

[0039] c k Regarding the abrasive grain ratio [vol%] of the k-th type of abrasive grain.

[0040] If the value of G calculated according to [Mathematical Formula 1] is less than 0.1, then the effect of improving the end face quality of the glass plate can be further enjoyed appropriately.

[0041] Here, we will explain [Mathematical Formula 1] above. The value of G is an indicator of the ability of the grinding stone to cut the end face of the glass plate. If we expand [Mathematical Formula 1] above, it will be as shown in [Mathematical Formula 3] below.

[0042] [Mathematical Expression 3]

[0043]

[0044] Regarding the above [Mathematical Expression 3], the denominator "n1+n2+…+n m "This represents the total number of abrasive grains contained in the grinding stone." (n1 + n2 + ... + n) m The larger the value of "", the greater the contact area, the smaller the force from each abrasive grain to the end face of the glass plate, and therefore the lower the ability of the grinding stone to cut the end face.

[0045] The coefficient "2 / 3" in the molecule is based on the fact that the amount of abrasive grains protruding from the binder in the grinding stone is generally considered to be 1 / 3 of the diameter of the abrasive grains.

[0046] The "A" of the molecule k "(k = 1, 2, ..., m)" is a coefficient set based on the Knoop hardness of the abrasive grains used in the grinding stone. The "r" in the molecule... k A k (k=1、2、…、m)” is obtained considering the following: the larger the abrasive grain size, the greater the amount of glass removed from the end face of the glass plate; in addition, the harder the abrasive grain, the more it can withstand the workpiece (glass) and be removed.

[0047] The "n" of a molecule k / n1+n2+…+n m "(k=1、2、…、m)" represents the proportion of the kth type of abrasive grain among all the abrasive grains contained in the grinding stone.

[0048] The denominator "√D" is obtained by taking into account the influence of the diameter of the grinding stone. The larger the diameter, the longer the contact length between the grinding stone and the end face of the glass plate during grinding, and the more abrasive grains touch the end face at one time. Therefore, the grinding stone has a lower ability to cut the end face.

[0049] The "B" in the molecule is a coefficient related to the binder used in the grinding stone, taking into account the influence of the binder's elastic modulus. The smaller the value of "B", the more the abrasive grains sink, the more uniform the amount of protrusion of each abrasive grain from the binder, the smaller the force of the load on the end face of the glass plate from each abrasive grain, and therefore the lower the grinding stone's ability to cut the end face.

[0050] The manufacturing method for the seventh glass plate is based on the manufacturing method for the sixth glass plate described above, and is configured as follows: In the grinding process, the product of the value of G calculated according to [Mathematical Formula 1] and the value of P calculated according to [Mathematical Formula 4] below satisfies 1.0 × 10⁻⁶. -9 ≤G×P≤1.0×10 -6 The relationship.

[0051] [Mathematical Expression 4]

[0052]

[0053] v: Relative moving speed between the grinding stone and the end face of the glass plate (processing speed) [m / min]

[0054] V: Circumferential speed of the grinding stone [m / min]

[0055] L: Water flow rate supplied to the grinding stone [L / min]

[0056] F: The pressing force [N] exerted by the grinding stone on the end face of the glass plate.

[0057] If the values ​​of G×P satisfy the above relationship, it is further advantageous in terms of making it easier to exhibit the ductility pattern in the grinding process, and further preferred in terms of improving the end face quality of the glass plate.

[0058] The manufacturing method of the eighth glass plate is based on any one of the manufacturing methods of the first to seventh glass plates described above, and is configured as follows: the temperature of the grinding point in the grinding process is higher than the temperature of the grinding point in the grinding process.

[0059] The results of experiments conducted by the inventors showed that if the temperature of the grinding point in the grinding process is higher than the temperature of the grinding point in the grinding process, a ductile pattern is more likely to appear in the grinding process. Therefore, if the temperature of the grinding point is higher than that of the grinding point as described above, it is easier to stably perform processing based on the ductile pattern in the grinding process.

[0060] A method for manufacturing a ninth glass plate to solve the above-mentioned problems includes: a grinding step, in which the end face of the glass plate is processed using a grinding stone; and a polishing step, in which the end face of the glass plate processed by the grinding stone is processed using a polishing stone. The method for manufacturing the glass plate is characterized in that, in the grinding step and the polishing step, a cooling medium is supplied to the processing portion on the periphery of the grinding stone and the polishing stone, respectively, and in the polishing step, the amount of cooling medium supplied is reduced compared to the grinding step.

[0061] In this method, when supplying cooling medium to the processing portion around the grinding stone, the supply amount is reduced compared to the grinding process. Therefore, even without reducing processing efficiency (processing speed) during the grinding process, the ductility pattern is easily observed. Based on the ductility pattern, residual cracks on the processed end face can be minimized. Consequently, the end face after the grinding process exhibits low dust generation, resistance to etching solutions, and high strength to prevent cracking originating from the end face. In other words, the end face quality of the glass plate can be improved.

[0062] Invention Effects

[0063] According to the glass plate manufacturing method of the present invention, the end face quality of the glass plate can be improved during the manufacturing process. Attached Figure Description

[0064] Figure 1 It is a top view that schematically shows the grinding and polishing processes included in the manufacturing method of the glass plate.

[0065] Figure 2 It is a diagram used to illustrate the ductility mode and the brittle mode.

[0066] Figure 3a This is a top view showing the grinding process included in the manufacturing method of the glass plate.

[0067] Figure 3b This is a top view showing the grinding process included in the manufacturing method of the glass plate.

[0068] Figure 4 This diagram shows the state in which the end face has been etched, for Comparative Example 3.

[0069] Figure 5 This is a diagram showing the state in Example 5 where the end face has been etched. Detailed Implementation

[0070] Hereinafter, the manufacturing method of the glass plate according to the embodiment will be described with reference to the accompanying drawings. It should be noted that the X, Y, and Z directions shown in the drawings referred to in the description of the embodiment are mutually orthogonal directions.

[0071] like Figure 1 As shown, this manufacturing method includes: a grinding step P1, in which the end face 1a of the glass plate 1 is processed using a grinding stone 2; and a polishing step P2, in which the end face 1a processed by the grinding stone 2 is processed using a polishing stone 3. In this manufacturing method, the end face 1a is processed in a brittle mode in the grinding step P1, and the end face 1a is processed mainly in a ductile mode in the polishing step P2.

[0072] Here, we will explain the ductile mode and the brittle mode.

[0073] When glass is ground (polished) using a grinding stone, the processed surface (end face 1a in this embodiment) becomes either transparent or opaque. In the ductile mode, the processed surface becomes transparent, and in the brittle mode, the processed surface becomes opaque.

[0074] like Figure 2 As shown, during periods when the pressure of the grinding stone pressed against the glass is sufficiently low, the glass slips on the surface of the grinding stone. However, when the pressure becomes sufficiently high, the glass is ground (grinded) using the grinding stone. Processing at a pressure greater than the initial pressure used to begin this grinding (grinding) is a ductile mode.

[0075] For example, the determination of whether it is a brittle or ductile mode can be performed as follows. First, the arithmetic mean height Sa of the end face of glass plate 1 is measured. The arithmetic mean height Sa can be measured, for example, using a Keyence VHX-8000 microscope. If Sa is 0.20 μm or more, it is a brittle mode; if Sa is less than 0.20 μm, it is a ductile mode.

[0076] In this embodiment, grinding process P1 and polishing process P2 are performed on the two end faces 1a, 1a extending along the X direction of a rectangular glass plate 1 that is set in a flat position. However, it is not limited to this. As a variation of this embodiment, the shape of the glass plate 1 that is the object of performing the two processes P1 and P2 may also be a shape other than a rectangle.

[0077] Glass plate 1 is a glass plate cut to a specified size after being formed by methods such as float glass, overflow drawing, slot drawing, and redrawing. Both end faces 1a and 1a' of glass plate 1 are cut surfaces. The thickness of glass plate 1 is, for example, 0.1 mm to 10 mm. Glass plate 1 is used as a substrate for displays such as liquid crystal displays and organic EL displays. Of course, besides glass for displays, glass plate 1 can also be used in applications such as solar cells and various lighting applications.

[0078] In this embodiment, to process the two end faces 1a, 1a of the glass plate 1, grinding stones 2 and grinding stones 3 are arranged in pairs, clamping the glass plate 1 in the Y direction. The two end faces 1a, 1a are processed while the pairs of grinding stones 2 and grinding stones 3 move relative to the glass plate 1, which is fixed on a platform (not shown), in the T direction parallel to the X direction. However, this is not a limitation. Since only the two grinding stones 2 and 3 need to move relative to the glass plate 1, it is also possible to perform two processes P1 and P2 by fixing the two grinding stones 2 and 3 and moving the glass plate 1, contrary to this embodiment. Alternatively, the two processes P1 and P2 can be performed simultaneously by moving the two grinding stones 2 and 3 relative to the glass plate 1 in both directions. The rotation direction of the two grinding stones 2 and 3 is counterclockwise when viewed from the Z direction. Of course, the rotation direction of the two grinding stones 2 and 3 can also be clockwise.

[0079] The grinding stone 2 is used to chamfer the end face 1a of the glass plate 1. On the other hand, the polishing stone 3 is used for finishing work to smooth the end face 1a, and it processes the end face 1a while pressing it with a constant pressure. It should be noted that, as a variation of this embodiment, the grinding stone 2 can also process the end face 1a while pressing it with a constant pressure. Here, "pressure" refers to a force acting parallel to the Y direction, expressed in [N].

[0080] In this embodiment, a grinding stone with a G value of 0.1 or higher calculated according to [Mathematical Formula 1] is used as the grinding stone 2, and a grinding stone with a G value less than 0.1 is used as the abrasive stone 3. However, regarding the abrasive stone 3, in order to avoid excessively insufficient ability to cut the end face 1a of the glass plate 1, the value of G is preferably 1.0 × 10⁻⁶. -5 above.

[0081] The grinding stone 2 is preferably a metal-bonded grinding stone that uses a metal bonding material (metal binder) as the bonding material (binder) for the abrasive grains. The metal used as the bonding material is preferably one metal selected from iron, copper, cobalt, nickel, tungsten, etc., or a mixture of two or more metals, and is particularly preferred to be a metal containing iron. The abrasive grains bonded to the grinding stone 2 are preferably diamond abrasive grains, with a grit size preferably #200 to 600. However, the type of binder, the type of abrasive grains, and the grit size in the grinding stone 2 can be any binder, abrasive grain, or grit size, as long as the value of G in [Mathematical Formula 1] is 0.1 or higher.

[0082] The grinding stone 3 is preferably a resin-bonded grinding stone that uses a resin-bonded material (resin binder) as the binder for the abrasive particles. Thermosetting resin is preferred as the resin binder. Specifically, phenolic resin, epoxy resin, polyimide resin, and polyurethane resin can be used as the resin binder. The abrasive particles bonded to the grinding stone 3 can be one selected from diamond abrasive particles, cubic boron nitride abrasive particles, silicon carbide abrasive particles, and alumina abrasive particles, or a mixture of two or more types. The particle size is preferably #320 to 1000. However, the type of binder, the type of abrasive particles, and the particle size in the grinding stone 3 can be any binder, abrasive particle, and particle size, as long as the value of G in [Mathematical Formula 1] is less than 0.1. Furthermore, the grinding stone 3 can be a different type of grinding stone from the grinding stone 2, or it can be the same type of grinding stone.

[0083] Figure 3a The grinding process P1 is shown. Figure 3b The grinding process P2 is shown. As can be understood from the two figures, the grinding process P1 and the polishing process P2 share commonalities in their execution. The commonalities between the grinding process P1 and the polishing process P2 will be explained below.

[0084] In the grinding process P1 and the polishing process P2, water 4, serving as a cooling medium, is supplied to the processing portions 2a and 3a on the periphery of the grinding stone 2 and the polishing stone 3, respectively. Grooves (not shown) for processing the end face 1a of the glass plate 1 are formed in multiple stages above and below the processing portions 2a and 3a of the two grinding stones 2 and 3. One of these multi-stage grooves is pressed against the end face 1a to process the end face 1a. It should be noted that in this embodiment, water 4 is used as the cooling medium, but air, microbubbles, nanobubbles, coolants, etc., can also be used as the cooling medium.

[0085] Water 4 is supplied from the grinding nozzle 5 and the polishing nozzle 6 to the processing section 2a of the grinding stone 2 and the processing section 3a of the polishing stone 3, respectively. Figure 1 (Illustrations of nozzles 5 and 6 are omitted). The grinding nozzle 5 and the polishing nozzle 6 each have first nozzles 7 and 8 and second nozzles 9 and 10. It should be noted that the grinding nozzle 5 and the polishing nozzle 6 move along the X direction in conjunction with the movement of the grinding stone 2 and the polishing stone 3, respectively.

[0086] The first nozzles 7 and 8 are positioned in the same vertical (Z-direction) direction as the glass plate 1, and water 4 is supplied from the rear side of the two grinding stones 2 and 3 in the rotation direction, pointing towards the grinding point 2x and the polishing point 3x. The grinding point 2x refers to the part where the processing part 2a of the grinding stone 2 contacts the end face 1a of the glass plate 1 to process the end face 1a, and the polishing point 3x refers to the part where the processing part 3a of the polishing stone 3 contacts the end face 1a to process the end face 1a. It should be noted that, as a variation of this embodiment, water 4 can also be supplied from the front side in the rotation direction of the two grinding stones 2 and 3. The water 4 from the first nozzles 7 and 8 is supplied to reduce the friction between the two grinding stones 2 and 3 and the end face 1a, or to prevent overheating of the two grinding stones 2 and 3 and the end face 1a caused by friction.

[0087] The second nozzles 9 and 10 are arranged opposite the grinding stone 2 and the polishing stone 3 in the Y direction. The second nozzles 9 and 10 supply jets of water 4 from the glass plate 1 side toward the grinding stone 2 side and the polishing stone 3 side. The water 4 from the second nozzles 9 and 10 is supplied for purposes such as removing glass powder generated in the grinding process P1 and the polishing process P2 from the glass plate 1, the grinding stone 2, and the polishing stone 3. It should be noted that the second nozzles 9 and 10 are not essential for the grinding process nozzle 5 and the polishing process nozzle 6; only the first nozzles 7 and 8 may be present.

[0088] The differences between grinding process P1 and lapping process P2 will be explained below.

[0089] In the grinding process P2, the supply of water 4 is reduced compared to the grinding process P1. That is, the flow rate of water 4 from the grinding process nozzles 6 (first nozzle 8 and second nozzle 10) (equivalent to L in [Mathematical Formula 4] above) is less than the flow rate of water 4 from the grinding process nozzles 5 (first nozzle 7 and second nozzle 9). Specifically, the flow rate of water 4 from the first nozzle 8 is less than that from the first nozzle 7, and the flow rate of water 4 from the second nozzle 10 is less than that from the second nozzle 9. However, this is not a limitation; as long as the flow rate of water 4 from the grinding process nozzle 6 is less than the flow rate of water 4 from the grinding process nozzle 5, the relationship between the flow rates of the first nozzle 7 and the first nozzle 8, and the relationship between the flow rates of the second nozzle 9 and the second nozzle 10, can be arbitrary.

[0090] Here, the flow rate of water 4 flowing from the grinding nozzle 6 is preferably set to 75% or less based on the flow rate of water 4 flowing from the grinding nozzle 5. It should be noted that a flow rate of 50% or less is more preferred, and a flow rate of 25% or less is even more preferred. In this embodiment, in the grinding process P1, the flow rate of water flowing from the grinding nozzle 5 is set to 15 L / min to 25 L / min. On the other hand, in the grinding process P2, the flow rate of water flowing from the grinding nozzle 6 is set to 0 L / min to 15 L / min. That is, in the grinding process P2, it may not be necessary to supply water 4 to the processing section 3a of the grinding stone 3. If water 4 is not supplied in the grinding process P2, the grinding nozzle 6 may not be provided.

[0091] In this manufacturing method, based on the aforementioned water flow rate relationship, the temperature of grinding point 3x in the grinding step P2 is made higher than the temperature of grinding point 2x in the grinding step P1. Furthermore, based on the aforementioned water flow rate relationship, a ductility pattern easily emerges in the grinding step P2, making it easier and more stable to perform the processing of the end face 1a of the glass plate 1 based on the ductility pattern. It should be noted that in this manufacturing method, compared to setting the water supply rate of 4 to be equal between the grinding step P1 and the grinding step P2, even when using coarser abrasive grains in the grinding stone 3, the ductility pattern is easily manifested. Moreover, since coarser abrasive grains can be used, it is also possible to achieve a longer lifespan for the grinding stone 3, reduce grinding unevenness, and increase processing speed.

[0092] The following describes the implementation conditions for grinding process P2, which are not covered in the previous descriptions.

[0093] In the grinding process P2, the relative moving speed (processing speed) between the grinding stone 3 and the end face 1a of the glass plate 1 is set to 20 m / min or more. It should be noted that the relative moving speed is preferably 25 m / min or more, and more preferably 30 m / min or more. In this embodiment, since the end face 1a is processed while the grinding stone 3 moves relative to the fixed glass plate 1, the aforementioned relative moving speed and... Figure 3b The moving speed v of the grinding stone 3 shown is the same.

[0094] Furthermore, in the grinding process P2, the circumferential speed of the grinding stone 3 is set to V, the flow rate of water 4 supplied to the grinding stone 3 (in this embodiment, it is equal to the flow rate of water 4 flowing from the grinding process nozzle 6) is set to L, and the pressing force of the grinding stone 3 pressing end face 1a is set to F. The value of P is calculated according to the aforementioned [Mathematical Formula 4]. Furthermore, the product of the value of P and the value of G calculated according to the aforementioned [Mathematical Formula 1] (G×P) is set to satisfy 1.0×10⁻⁶. -9 ≤G×P≤1.0×10-6 The relationship. It should be noted that the value of G×P is more preferably set to satisfy 5.0×10. -8 ≤G×P≤1.0×10 -6 The relationship is further preferably set to satisfy 3.0 × 10 -7 ≤G×P≤1.0×10 -6 The relationship.

[0095] Here, variations of the above-described embodiment can also be applied. In the above-described embodiment, only one grinding stone 2 and one polishing stone 3 are used in the grinding process P1 and the polishing process P2, respectively, but multiple grinding stones 2 and multiple polishing stones 3 can also be used. In this case, the end face 1a of the glass plate 1 is processed in a brittle mode using each grinding stone 2, and the end face 1a is processed mainly in a ductile mode using each polishing stone 3. In this case, it is preferable to reduce the amount of water 4 supplied to each polishing stone 3 compared to the amount of water 4 supplied to each grinding stone 2.

[0096] Example

[0097] After the end face of a glass plate was machined in a brittle mode using a grinding stone as a grinding process, the quality of the machined end face was compared between (a) the case where the end face was machined in a brittle mode using a grinding stone as a polishing process (comparative example) and (b) the case where the end face was machined in a ductile mode using a grinding stone as a polishing process (exemplary example). It should be noted that in the comparative example, the flow rate of water supplied to the grinding stone in the grinding process was set to be equal to the flow rate of water supplied to the grinding stone in the polishing process, while in the exemplary example, the flow rate of water supplied to the grinding stone in the polishing process was set to be less than the flow rate of water supplied to the grinding stone in the grinding process.

[0098] In Comparative Example 1 and Examples 1 and 2, the grinding stone under the conditions described below was used in common. Type of abrasive: Diamond (abrasive type coefficient A1 = 8000).

[0099] Abrasive grain size: #1500 (average abrasive grain radius r1 = 0.005 mm)

[0100] Abrasive particle ratio c1: 25 [vol%]

[0101] The diameter D of the grinding stone is 200 mm.

[0102] Type of binder: Phenolic resin (resin binder, binder coefficient B = 30)

[0103] In Comparative Example 1 and Examples 1 and 2, the processing conditions were set as described below.

[0104] [Comparative Example 1]

[0105] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0106] The grinding stone's circumferential speed V: 2000 m / min

[0107] The pressing force F applied by the grinding stone to the end face of the glass plate: 20 [N]

[0108] The water flow rate L supplied to the grinding stone is 15 [L / min].

[0109] The value of G×P: 1.33×10 -6

[0110] [Example 1]

[0111] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 10 m / min

[0112] The grinding stone's circumferential speed V: 2000 m / min

[0113] The pressing force F applied by the grinding stone to the end face of the glass plate: 20 [N]

[0114] The water flow rate L supplied to the grinding stone is 15 [L / min].

[0115] The value of G×P: 4.44×10 -7

[0116] It should be noted that the water supply to the grinding stone is 25L / min.

[0117] [Example 2]

[0118] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0119] The grinding stone's circumferential speed V: 2000 m / min

[0120] The pressing force F applied by the grinding stone to the end face of the glass plate: 20 [N]

[0121] The water flow rate L supplied to the grinding stone is 5 [L / min].

[0122] The value of G×P: 4.44×10 -7

[0123] It should be noted that the water supply to the grinding stone is 25L / min.

[0124] Unlike Comparative Example 1, high end-face quality (low dust generation, chemical resistance, and high strength) was obtained in Examples 1 and 2. Furthermore, in Example 2, high end-face quality was also achieved despite the same processing speed as Comparative Example 1. This is presumably because, in Example 2, in addition to the water flow rate supplied to the grinding stone during the grinding process being less than that during the grinding process, the water flow rate L was also reduced compared to Comparative Example 1.

[0125] In Comparative Example 2 and Examples 3 and 4, the grinding stones under the conditions described below were used in common. Type of abrasive (Type 1): Diamond (abrasive type coefficient A1 = 8000)

[0126] Abrasive grain size (Type 1): #600 (average abrasive grain radius r1 = 0.0125 mm)

[0127] Abrasive particle ratio (type 1) c1: 15 [vol%]

[0128] Type of abrasive (Type 2): Silicon carbide (Abrasive type coefficient A2 = 2500)

[0129] Abrasive grain size (type 2): #400 (average abrasive grain radius r2 = 0.01875 mm)

[0130] Abrasive grain ratio (type 2) c2: 15 [vol%]

[0131] The diameter D of the grinding stone is 200 mm.

[0132] Type of binder: Polyurethane rubber (elastomer, binder coefficient B = 1)

[0133] In Comparative Example 2 and Examples 3 and 4, the processing conditions were set as described below.

[0134] [Comparative Example 2]

[0135] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0136] The grinding stone's circumferential speed V: 2000 m / min

[0137] The pressing force F applied by the grinding stone to the end face of the glass plate is 30 [N].

[0138] The water flow rate L supplied to the grinding stone is 15 [L / min].

[0139] The value of G×P: 1.31×10 -6

[0140] [Example 3]

[0141] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 3 [m / min]

[0142] The grinding stone's circumferential speed V: 2000 m / min

[0143] The pressing force F applied by the grinding stone to the end face of the glass plate is 30 [N].

[0144] The water flow rate L supplied to the grinding stone is 15 [L / min].

[0145] The value of G×P: 1.31×10 -7

[0146] It should be noted that the water supply to the grinding stone is 25L / min.

[0147] [Example 4]

[0148] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0149] The grinding stone's circumferential speed V: 2000 m / min

[0150] The pressing force F applied by the grinding stone to the end face of the glass plate is 30 [N].

[0151] The water flow rate L supplied to the grinding stone is 2 [L / min].

[0152] The value of G×P: 1.74×10 -7

[0153] It should be noted that the water supply to the grinding stone is 25L / min.

[0154] Unlike Comparative Example 2, high end-face quality was obtained in Examples 3 and 4. Furthermore, in Example 4, high end-face quality was also achieved despite the same processing speed as Comparative Example 2. This is presumably because, in Example 4, in addition to the water flow rate supplied to the grinding stone in the grinding process being less than the water flow rate supplied to the grinding stone in the grinding process, the water flow rate L was also reduced compared to Comparative Example 2. Moreover, based on the results of Examples 3 and 4, it can be seen that in Example 4, with a relatively lower water flow rate L, high-speed processing can be achieved compared to Example 3, with a relatively higher water flow rate L.

[0155] In Comparative Example 3 and Example 5, the grinding stone under the conditions described below was used in common.

[0156] Abrasive type: Silicon carbide (abrasive type coefficient A1 = 2500)

[0157] Abrasive grain size: #400 (average abrasive grain radius r1 = 0.01875 mm)

[0158] Abrasive particle ratio c1: 50 [vol%]

[0159] The diameter D of the grinding stone is 200 mm.

[0160] Type of binder: Elastomer (binding coefficient B = 1)

[0161] In Comparative Example 3 and Example 5, the processing conditions were set as described below.

[0162] [Comparative Example 3]

[0163] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0164] The grinding stone's circumferential speed V: 2000 m / min

[0165] The pressing force F applied by the grinding stone to the end face of the glass plate is 15 [N].

[0166] The water flow rate L supplied to the grinding stone is 15 [L / min].

[0167] The value of G×P: 1.83×10 -6

[0168] [Example 5]

[0169] The relative moving speed v (processing speed) between the grinding stone and the end face of the glass plate: 30 m / min

[0170] The grinding stone's circumferential speed V: 2000 m / min

[0171] The pressing force F applied by the grinding stone to the end face of the glass plate is 15 [N].

[0172] The water flow rate L supplied to the grinding stone is 4 [L / min].

[0173] The value of G×P: 4.88×10 -7

[0174] It should be noted that the water supply to the grinding stone is 25L / min.

[0175] Unlike Comparative Example 3, high end-face quality was obtained in Example 5. Here, for Comparative Example 3 and Example 5, the etched state of the processed end face is described in detail. Figure 4 as well as Figure 5As shown in the figures, compared to Comparative Example 3, corrosion of the end face can be prevented in Example 5. Furthermore, in Example 5, although the processing speed is the same as in Comparative Example 3, a high end face quality can still be obtained. This is presumably because, in Example 5, in addition to the water flow rate supplied to the grinding stone in the grinding process being less than the water flow rate supplied to the grinding stone in the grinding process, the water flow rate L is also reduced compared to Comparative Example 3.

[0176] Explanation of reference numerals in the attached figures

[0177] 1. Glass plate

[0178] 1a end face

[0179] 2. Grinding stone

[0180] 2a Machining Department

[0181] 3. Grinding stone

[0182] 3a Machining Department

[0183] 4 Water

[0184] 5. Grinding nozzle

[0185] 6. Grinding process nozzle

[0186] D diameter

[0187] F Pressing pressure

[0188] P1 Grinding process

[0189] P2 Grinding process

[0190] v Movement speed (relative movement speed)

[0191] V-cycle speed.

Claims

1. A method for manufacturing a glass plate, comprising: The grinding process involves using grinding stones to process the end face of the glass plate; And a grinding process, in which the end face of the glass plate after processing by the grinding stone is processed. The method for manufacturing the glass plate is characterized in that, In the grinding process, the machining is performed in a brittle mode where the arithmetic mean height Sa of the machined end face is 0.20 μm or more. The grinding process is mainly carried out in a ductile mode where the arithmetic mean height Sa of the processed end face is less than 0.20 μm. In the grinding process, the value of G calculated according to the following [Mathematical Formula 1] is set to be less than 0.

1. [Mathematical Formula 1] m: The number of different types of abrasive grains contained in the grinding stone. n k The number of abrasive grains for the k-th type (calculated according to [Mathematical Formula 2] below). r k The average abrasive radius [mm] for the k-th type of abrasive grain. A k Abrasive type coefficient for the k-th abrasive grain D: Diameter of the grinding stone [mm] B: Regarding the binder coefficient of the binder used in grinding stones Here, the abrasive type coefficient A k The value is set according to the type of abrasive grain as follows: Diamond: 8000 Cubic boron nitride: 4700 Silicon carbide: 2500 Alumina: 2100 Here, the value of the binder coefficient B is set according to the type of binder as follows: Metal: 3000 Resin: 30 Elastomer: 1 [Mathematical Formula 2] c k : Abrasive fraction [vol%] for the k-th type of abrasive grain.

2. The method for manufacturing a glass plate according to claim 1, characterized in that, In the grinding and polishing processes, cooling media are supplied to the machining portions around the grinding stone and the polishing stone, respectively. In the grinding process, the amount of cooling medium supplied is reduced compared to the grinding process.

3. The method for manufacturing a glass plate according to claim 2, characterized in that, Water is used as the cooling medium.

4. The method for manufacturing a glass plate according to claim 3, characterized in that, In the grinding process and the polishing process, water is supplied from the nozzle for the grinding process and the nozzle for the polishing process, respectively. In the grinding process, the flow rate of the water flowing from the nozzle in the grinding process is set to 15L / min to 25L / min. In the grinding process, the flow rate of the water flowing from the nozzle in the grinding process is set to 0L / min to 15L / min.

5. The method for manufacturing a glass plate according to claim 3 or 4, characterized in that, In the grinding process, the relative moving speed between the grinding stone and the end face of the glass plate is set to 20 m / min or more.

6. The method for manufacturing a glass plate according to any one of claims 1 to 4, characterized in that, In the grinding process, the product of the value of G calculated according to [Mathematical Formula 1] above and the value of P calculated according to [Mathematical Formula 3] below satisfies 1.0 × 10⁻⁶. -9 ≤G×P≤1.0×10 -6 Relationship, [Mathematical Formula 3] v: Relative moving speed between the grinding stone and the end face of the glass plate (processing speed) [m / min] V: Circumferential speed of the grinding stone [m / min] L: Water flow rate supplied to the grinding stone [L / min] F: The pressing force [N] exerted by the grinding stone on the end face of the glass plate.

7. The method for manufacturing a glass plate according to any one of claims 1 to 4, characterized in that, The temperature of the grinding point in the grinding process is higher than the temperature of the grinding point in the grinding process.

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