TW202039380A - Glass plate forming method - Google Patents

Abstract

The glass plate press-forming method of the invention comprises sandwiching a glass plate with two forming molds, forming the glass center portion of the glass plate by applying a first compressive force of 0.1 MPa or less in the mold clamping direction or without applying the compressive force, and forming the glass outer periphery portion by bringing a second compressive force to 0.1 to 10 MPa. Alternatively, the method includes applying the first compressive force of 0.1 MPa or less in the mold clamping direction from one of the pair of forming molds onto the glass plate, sandwiching the glass outer periphery portion of the glass plate between the pair of forming molds, delimiting, on the inner periphery side of the glass outer periphery portion, a space between the glass plate and the first forming mold disposed at the front end in the mold clamping direction, and supplying negative pressure to this space to cause the glass plate to be suctioned onto the first forming mold.

Description

The forming method of glass plate

The present invention relates to a method for forming glass plates.

Various methods have been used in which a glass material contained in a forming mold is heated, softened, and pressurized to produce a glass press molded product. For example, there has been proposed a forming apparatus that sequentially transports plate-shaped glass materials to heating, pressurizing, and cooling stages installed in a chamber, and continuously forming press-molded products on each stage (Patent Document 1).

In this type of forming device, the glass material is maintained at a heating temperature sufficient for processing the glass material by making the forming mold at a predetermined temperature during pressurization. In addition, the glass material after forming is cooled, solidified, and finally cooled to a temperature below 200°C at which the forming mold will not be oxidized. As described above, the glass material is accurately transferred to the shape of the forming mold when pressurized, and the formed shape is maintained by cooling and solidification, thereby becoming a press-formed product with high shape accuracy. Prior art literature Patent literature

Patent Document 1: International Publication No. 2013/103102

[The problem to be solved by the invention]

However, in the above-mentioned forming apparatus, as the forming shape of the glass material becomes more complicated or mass-produced, there is room for improvement in various aspects such as the productivity of the formed product, the quality of the shape, and the surface properties.

The purpose of the present invention is to provide a method for forming a glass sheet that can reduce equipment cost even if it is a formed product with a complicated shape, while at the same time forming a glass sheet with higher shape accuracy and higher productivity. [Technical means to solve the problem]

The present invention includes the following configurations. (1) A method for forming a glass plate, which is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above glass plate between a pair of forming dies; Using the above-mentioned forming mold, a first pressure of 0.1 MPa or less is applied in the clamping direction to the center of the glass on the inner side of the outer periphery of the glass plate, or no pressure is applied to the outer periphery of the center of the glass to the glass A second pressing force of 0.1-10 MPa different from the above-mentioned first pressing force is applied to the outer peripheral portion of the glass between the outer peripheral edges of the plates in the clamping direction, and the glass plate is press-formed. (2) A method for forming a glass plate, which is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above glass plate between a pair of forming dies; Apply a pressure of 0.1 MPa or less to the glass plate in the clamping direction from one of the above-mentioned pair of forming dies, and move the glass plate from the outer circumference of the glass central part on the inner side of the outer circumference to the outer circumference of the glass plate The ring-shaped outer periphery of the glass is sandwiched between the pair of forming dies, and the inner periphery of the outer periphery of the glass is divided between the first forming mold arranged in front of the clamping direction and the glass plate Out of space; and Negative pressure is supplied to the space defined between the glass plate and the first forming mold, so that the glass plate is attracted to the first forming mold. [Effects of Invention]

According to the present invention, even if it is a molded product with a complicated shape, the equipment cost can be reduced, and at the same time, it can be molded with higher shape accuracy and higher productivity.

Hereinafter, embodiments of the present invention will be described in detail. Here, specific examples of a forming apparatus and forming method for forming a glass plate into a shape with at least a part of a curved shape are presented for description, but the present invention may also be based on various manufacturing conditions such as the material used, the forming shape, and the size. Appropriately change the composition or sequence of the device.

In addition, in this specification, "~" indicating a numerical range is used to include the numerical values described before and after it as the lower limit and the upper limit.

＜Outline of glass plate forming steps＞ Fig. 1 is a schematic step diagram showing the steps of forming a glass plate into a curved shape. The glass plate forming apparatus 100 is sequentially arranged with a preheating platform 11, a forming platform 13, and a cooling platform 15, and further includes a loading part 19 for carrying the glass plate 17 before forming into the preheating platform 11, and forming from the cooling platform 15 The unloading part 21 after which the glass plate 17A is moved out.

In the preheating platform 11, the glass plate 17 carried in is heated to soften it. In the forming platform 13, the glass plate 17 heated and softened by the preheating platform 11 is subjected to press forming or the like to be formed into a desired shape. In the cooling platform 15, the glass plate 17 formed by the forming platform 13 is slowly cooled to a temperature at which deformation can be suppressed.

The glass plate 17 is carried in and out from the loading section 19 and the unloading section 21 with respect to each of the above-mentioned platforms. That is, the glass plate 17 before forming is placed on the lower mold (first forming mold) 23 in the loading section 19. The lower mold 23 on which the glass plate 17 is placed is transported to the preheating platform 11 and heated to a specific temperature in the preheating platform 11. The heated glass plate 17 and the lower mold 23 are transported to the forming platform 13 together.

In the forming platform 13, the glass plate 17 is sandwiched between the upper mold (second forming mold) 25 and the lower mold 23 mounted on the forming platform 13, and the mold is clamped. Thereby, the glass plate 17 is formed into a curved shape. After forming, the upper mold 25 and the lower mold 23 are separated, and the processed glass plate 17A remaining in the lower mold 23 and the lower mold 23 are conveyed to the cooling platform 15 together.

In the cooling platform 15, the heated glass plate 17A is slowly cooled. The slowly cooled glass plate 17A is taken out from the lower mold 23 in the unloading part 21 and carried out.

In the forming apparatus of this structure, in the forming platform 13, in addition to the pressure forming of the glass sheet 17 softened by heating with the lower mold 23 and the upper mold 25, the glass sheet is also combined according to the purpose. Bending due to its own weight (bending under its own weight), suction of the glass sheet to the forming surface of the forming mold (vacuum suction), and pressure bonding of the glass sheet to the forming surface of the forming mold (pressure forming). By selectively using such a plurality of pressure sources, it is possible to form a curved surface with high shape accuracy. Furthermore, regarding self-weight bending, as long as the glass plate 17 is placed on the lower mold 23 and heated, the glass plate 17 will be bent under its own weight, but it can be made controllable. For example, when there is almost no difference between the bending start temperature caused by the dead weight and the press forming temperature, and the influence of the dead weight bending caused by heating to the press temperature is small, the dead weight bending forming is not applied. On the other hand, when there is sufficient time for self-weight forming before and after pressing, gravity will affect the shape after forming, so self-weight bending is used. In this way, it is possible to control the dead weight bending forming according to the standby time and standby temperature before the press forming is performed.

The above-mentioned respective forming methods are the forming methods shown below. (1) The so-called pressure forming refers to the following method: a glass plate is set between a specific forming mold (lower mold, upper mold), and a pressure load is applied between the upper and lower forming molds while the glass sheet is softened. The glass plate is bent and attached to the forming mold to form a specific shape. (2) The so-called self-weight bending molding refers to the following method: after the plate glass is set on a specific forming mold, the glass plate is heated to soften it, and gravity is used to bend the glass plate to fit the mold to form a specific shape. shape. (3) The so-called vacuum forming means that the glass plate is set on a specific forming mold, for example, a fixed forming mold is set on the glass plate, and the periphery of the glass plate is sealed. After that, the closed space between the forming mold and the glass plate is reduced in pressure by a pump or the like, and differential pressure is applied to the front and back surfaces of the glass plate to form. (4) In the air pressure forming method, the glass plate is set on a specific forming mold, for example, a fixed forming mold is set on the glass plate, and the periphery of the glass plate is sealed. After that, compressed air is used to apply positive pressure to the upper surface of the glass plate, and differential pressure is applied to the front and back surfaces of the glass plate to form.

＜The glass material of the molded object＞ Regarding the glass plate as the molded body, for example, the thickness is 0.5 mm or more, preferably 0.7 mm or more. In addition, the thickness of the glass plate is 5 mm or less, preferably 3 mm or less, and more preferably 2 mm or less. As long as it is in this range, the final product can obtain strength that is not easy to break.

As the glass composition of the glass plate, it can be used: alkali-free glass, soda lime glass, soda lime silicate glass, aluminosilicate glass, borosilicate glass, lithium aluminosilicate glass, and borosilicate glass. In particular, if the glass forming device of this structure is used, it is excellent when aluminosilicate or aluminoborosilicate is used in the glass plate. These glass plates have high Young's modulus and high coefficient of expansion, and high thermal stress will be generated due to the heating of the glass plates. Therefore, the deviation from the desired buckling shape of the glass plate becomes large, and when the glass plate is further strengthened, the value of the compressive stress may be uneven. In the case of the glass forming device of this structure, by making the glass plate into the glass composition, even if it is a buckled shape, the shape deviation can be reduced, and the unevenness of the compression stress can be suppressed.

As a specific example of the glass composition, the following glass can be cited, that is, it contains 50 to 80% of SiO ₂ , 0.1 to 25% of Al ₂ O ₃ , and 3 to 30 in terms of the composition expressed in mole% based on oxide % Li ₂ O + Na ₂ O + K ₂ O, 0-25% MgO, 0-25% CaO and 0-5% ZrO ₂ , but there is no special limitation. More specifically, the following glass composition can be cited. Furthermore, for example, "containing 0-25% MgO" means that although MgO is not essential, it can contain up to 25%. The glass of (i) is contained in soda lime silicate glass, and the glass of (ii) and (iii) is contained in aluminosilicate glass. (v) The glass is contained in lithium aluminum silicate glass. (i) Containing 63-73% SiO ₂ , 0.1-5.2% Al ₂ O ₃ , 10-16% Na ₂ O, 0-1.5% of K ₂ O, 0～5% Li ₂ O, 5～13% MgO and 4～10% CaO glass. (ii) It contains 50～74% SiO ₂ , 1～10% Al ₂ O ₃ , 6～14% Na ₂ O, 3～11% based on the composition expressed by mole% based on oxide K ₂ O, 0～5% Li ₂ O, 2～15% MgO, 0～6% CaO and 0～5% ZrO ₂ , and the total content of SiO ₂ and Al ₂ O ₃ is 75% Below, the total content of Na ₂ O and K ₂ O is 12 to 25%, and the total content of MgO and CaO is 7 to 15% of glass. (iii) Containing 68～80% of SiO ₂ , 4～10% of Al ₂ O ₃ , 5～15% of Na ₂ O, 0～1% of K ₂ O, 0～5% Li ₂ O, 4～15% MgO and 0～1% ZrO ₂ glass. (iv) Containing 67-75% SiO ₂ , 0-4% Al ₂ O ₃ , 7-15% Na ₂ O, and 1-9% of Na ₂ O based on the composition expressed in mole% based on oxide K ₂ O, 0～5% Li ₂ O, 6～14% MgO and 0～1.5% ZrO ₂ , and the total content of SiO ₂ and Al ₂ O ₃ is 71～75%, Na ₂ O and The total content of K ₂ O is 12-20%. When CaO is contained, the content is less than 1% of glass. (v) Containing 56-73% SiO ₂ , 10-24% Al ₂ O ₃ , 0-6% B ₂ O ₃ , 0-6% based on the composition expressed by mole% based on oxide P ₂ O ₅ , 2～7% Li ₂ O, 3～11% Na ₂ O, 0～2% K ₂ O, 0～8% MgO, 0～2% CaO, 0～5 % SrO, 0～5% BaO, 0～5% ZnO, 0～2% TiO ₂ , 0～4% ZrO ₂ glass.

＜Constitution of forming device＞ Hereinafter, a configuration example of one of the aforementioned forming apparatuses will be described in detail. FIG. 2 is a schematic configuration diagram of the forming apparatus 100. Fig. 3 is a schematic plan view of the section of line III-III shown in Fig. 2 viewed from above. In the following description, sometimes the description is omitted or simplified by attaching the same symbols to members or parts that perform the same function. In addition, the aspect described in the drawing is modeled to make the description of this structure clear, and it is not accurately represented according to the size or scale of the actual product.

Regarding the forming apparatus 100 shown in FIG. 2, the direction from the left to the right in the horizontal direction is set as the conveying direction TD of the glass plate, and the preheating platform 11, the forming platform 13 and the cooling are arranged in order from the upstream side of the conveying direction TD. Platform 15. In addition, the preheating platform 11, the forming platform 13 and the cooling platform 15 are contained in the internal space of the chamber 27. The chamber 27 is flushed with an inert gas such as nitrogen, so as to reduce the gas concentration of the gas that has an adverse effect during glass forming.

The chamber 27 has a carry-in port 29 for carrying the glass plate and the lower mold 23 into the chamber 27 and a carry-out port 31 for carrying out the formed glass plate and the lower mold 23. The loading part 19 shown in FIG. 1 is connected to the carry-in port 29, and the unloading part 21 (illustration omitted) shown in FIG. 1 is connected to the export port 31 similarly. In addition, baffles (not shown) are provided at the carry-in port 29 and the carry-out port 31, and the gas atmosphere in the chamber 27 is maintained constant by closing the baffles except when the glass plate is moved in and out. A plurality of openings 101 are formed in the cavity 27, and a supporting shaft 37 described below is inserted into each opening 101. The support shaft 37 and the cavity 27 are sealed by a bellows structure not shown. The chamber 27 may be a semi-closed structure in which the inert gas is always supplied and the inside of the chamber 27 has a positive pressure in addition to the hermetic structure for sealing the inert gas.

The preheating platform 11 shown in FIG. 2 is arranged above the conveying surface of the glass plate with an upper heater (heating part for temperature increase) 35. The upper heater (heating part for temperature increase) 35 connects the glass plate and the lower mold 23 Heat to the desired heating temperature. The upper heater 35 is preferably configured to face the lower mold 23 and include a plurality of lamp heaters 36 supported by a fixed frame (not shown) as a heat source. As the lamp heater 36, for example, an infrared lamp heater can be used. Among the infrared lamp heaters, various well-known heaters, such as carbon lamps and halogen lamps, can be used, as long as they are heating elements capable of radiant heating.

FIG. 3 is a cross-sectional view of a plurality of lamp heaters 36. The lamp heater 36 has a heating wire 36A, which generates heat by energization, and a tube 36B such as quartz, which surrounds the heating wire 36A. The ceramic coating 40 is formed on the inner or outer circumferential surface of the pipe 36B so that the irradiation window 38 remains. The opening angle (central angle) θ of the irradiation window 38 centered on the heating wire 36A is based on the distance Ld from the center of the lamp heater 36 to the lower mold 23 as the heated body, and the arrangement pitch Lc of the lamp heater 36 It is decided that the lower mold 23 is equally irradiated with hot rays. Here, as an example, the opening angle θ is set to 60°.

In addition, the heating area of the upper heater 35 (the area where the lamp heaters 36 are arranged) is preferably wider than the outer edge of the horizontal plane of the lower mold 23. In this case, the entire lower mold 23 can be uniformly heated.

Above the upper heater 35, a water cooling plate 39 supported by the support shaft 37 is arranged. It is desirable to provide a reflective film on the surface of the water cooling plate 39 facing the upper heater 35. A cooling water flow path is formed in the water cooling plate 39 for circulating the cooling water supplied and discharged through the support shaft 37. The water-cooling plate 39 suppresses unnecessary heating of the surrounding members other than the lower mold 23 or the glass plate by the upper heater 35.

A heat dissipation plate 41 is arranged under the lower mold 23 with a gap therebetween. In addition, a lower heater (heating unit for temperature increase) 43 is arranged below the heat dissipation plate 41. The heat dissipation plate 41 includes a material with excellent thermal conductivity, so that the heat generated by the lower heater 43 is uniformly radiated and transferred to the lower mold 23. As the material of the heat sink 41, for example, tungsten carbide, carbon, cemented carbide, copper, iron, stainless steel, etc. can be used. The lower heater 43 can be a contact heating type platform heater or the like, but it can also be configured as a radiation heating type like the upper heater 35.

In addition, a water cooling plate 47 is arranged below the lower heater 43. The water-cooling plate 47 is supported by a support 45 fixed to the lower part of the cavity 27 to suppress unnecessary heating of the surrounding components by the lower heater 43 except for the heat dissipation plate 41 and the lower mold 23. The water cooling plate 47 has the same structure as the water cooling plate 39 described above, and cooling water is supplied and discharged from the support 45.

In the cooling platform 15, the gap between the lower mold 23 and the heat dissipation plate 41 is not particularly limited, but if it is too large, the heating efficiency is reduced, if it is too small, it is difficult to suppress the temperature deviation of the glass plate, so it is set as the lower limit of the gap , Set to 1 mm. In addition, the upper limit of the gap is set to 10 mm.

A heat-insulating case 51 is arranged so as to surround the outer periphery of the platform on the upper surface side of the lower mold 23 where the glass plate is placed, and the side of the upper heater 35, the water cooling plate 39, and the support shaft 37. The heat-insulating shell 51 covers the side of the glass plate placed on the lower mold 23 arranged in the platform.

The heat-insulating shell 51 can use, for example, a heat-insulating plate formed by sheet forming a material mainly composed of calcium silicate. In addition to this, for example, it may be a metal plate such as a stainless steel material. As shown in FIG. 4, the heat-insulating shell is preferably a shell that surrounds a wider area outside the outer periphery of the lower mold 23 and has a rectangular horizontal section. The heat-insulating shell 51 may also have a cover covering the upper part of the shell.

Moreover, in the forming platform 13 and the cooling platform 15, it is also preferable to configure the heat-insulating shells 53, 55 of the same structure. In order to improve the forming quality of the obtained glass plate, it is particularly important to reduce the temperature deviation of the glass plate in each platform. Therefore, it is preferable that all the platforms are equipped with a heat-insulating shell. According to this, the temperature distribution of the internal space covered by the heat insulating shells 51, 53, 55 can be made uniform. Furthermore, the outer side of the heat-insulating shells 51, 53, 55 is surrounded by the cavity 27, so it is not easy to generate heat inflow and outflow from the outside in the heat-insulating shells 51, 53, 55, and a more uniform Temperature Distribution. Thereby, the thermal efficiency is improved, the processing time in each platform can be shortened, and the temperature deviation of the glass plate in each platform can be reduced.

As shown in FIG. 4, lower molds 23 are respectively arranged in the preheating platform 11, the forming platform 13 and the cooling platform 15. In each lower mold 23, a pair of mold support rods 61 are respectively provided on the side surfaces 23a, 23b on both sides orthogonal to the conveying direction TD to protrude outward. Each mold support rod 61 is supported by mold conveyance parts 63A, 63B arranged on both sides with the lower mold 23 interposed therebetween. Regarding the mold conveying parts 63A and 63B, the detailed description of the mechanism is omitted, but the conveying mechanism of the walking beam method is used to convey a plurality of lower molds 23 arranged along each platform along the conveying direction TD .

FIG. 5 is a schematic explanatory diagram showing a case where the lower mold 23 is transported along the transport direction TD from the preheating platform 11 to the cooling platform 15. The mold conveying parts 63A and 63B support the mold supporting rods 61 protruding from each of the plurality of lower molds 23, and simultaneously convey the plurality of lower molds 23 from the preheating platform 11 to the forming platform 13 by the walking beam method. 13 is transported to the cooling platform 15. The displacement of the lower mold 23 in the upper and lower directions during this conveyance is performed within a range that does not interfere with the fixed side members such as the heat insulation casing 51, 53, 55 or the heat dissipation plate 41.

Next, the cooling platform 15 shown in FIG. 2 will be described. Above the lower mold 23 of the cooling platform 15, a heat dissipation plate 65, an upper heater (heating part for cooling) 67, and a water cooling plate 59, which are the same as the preheating platform 11, are arranged in this order. The heat sink 65 has the same structure as the heat sink 41 described above. The water cooling plate 59 is fixed to the upper part of the chamber 27, and is supported by a supporting shaft 71 in which a cooling water flow path is formed.

Below the lower mold 23 of the cooling platform 15, a heat dissipation plate 73, a lower heater (heating unit for cooling) 75, and a water cooling plate 77 are arranged in the same manner as the preheating platform 11. The water-cooling plate 77 is supported by a support 79 fixed to the lower part of the cavity 27, and unnecessary heating of the surrounding components except the heat dissipation plate 73 and the lower mold 23 by the lower heater 75 is suppressed. The water cooling plate 77 has the same structure as the water cooling plate 39 described above, and cooling water is supplied and discharged from the support 79.

It is also possible to make the lower mold 23 and the heat dissipation plate 65 of the cooling platform 15 and the lower mold 23 and the heat dissipation plate 73 closely contact, respectively, but the temperature distribution of the lower mold 23 can be made more uniform by providing a gap, which is preferable.

Next, the forming platform 13 shown in FIG. 2 will be described. FIG. 6 is an enlarged cross-sectional view of the forming platform 13. Above the lower mold 23 of the forming platform 13, an upper mold 25, a heat dissipation plate 81, an upper heater (heating portion for heat preservation) 83, a heat insulation plate 85 and a water cooling plate 87 are arranged in this order.

The upper mold 25 is connected to a plunger (not shown), and is supported to be able to move up and down between the molding position where the mold is clamped on the lower mold 23 and the retracted position above the molding position. The upper mold 25 is arranged at the retracted position during transportation of the lower mold 23, except during molding. In addition, a configuration may be adopted in which the upper mold 25 is fixed in the forming platform 13 and the lower mold 23 is lifted to lock the mold when the lower mold 23 is transported. In this case, the upper mold moving mechanism can be omitted, and the equipment cost can be reduced.

The water-cooling plate 87 is supported by a support shaft 89 fixed to the upper part of the chamber 27, and suppresses unnecessary heating of surrounding components by the upper heater 83 except for the upper mold 25 and the heat dissipation plate 81. The water cooling plate 87 has the same structure as the water cooling plate 39 described above, and cooling water is supplied and discharged from the support shaft 89.

For the heat insulation board 85, well-known heat insulation materials, such as ceramics, stainless steel, mold steel, and high speed steel, can be used, for example. In the case of using metal-based materials, it is preferable to apply CrN, TiN, TiAlN, etc. coating treatment to the surface. In addition, the surface of the heat insulating board 85 may have a rough surface structure. In this case, a small gap is formed between it and the water-cooled plate 39, and a higher heat insulation effect can be obtained.

Below the lower mold 23 of the forming platform 13, a heat dissipation plate 91, a lower heater (heating part for heat preservation) 93, a heat insulation plate 85 and a water cooling plate 97 are arranged in this order. The water-cooling plate 97 is supported by a support body 99 fixed to the lower part of the cavity 27 to suppress unnecessary heating of the surrounding components by the lower heater 93 except for the heat dissipation plate 91 and the lower mold 23. The water cooling plate 97 has the same structure as the water cooling plate 39 described above, and cooling water is supplied and discharged from the support 99.

The upper mold 25 of the forming platform 13 is mounted on a cylinder (not shown) that is driven in the vertical direction, and is supported to be able to move up and down by the drive of the cylinder. As the cylinders, air cylinders, hydraulic cylinders, servo cylinders using electric servo motors, etc. can be used.

The upper mold 25 of the forming platform 13 is in surface contact with the heat sink 81, and the heat from the upper heater 83 is evenly transferred to the upper mold 25. In addition, the lower mold 23 of the forming platform 3 faces the heat dissipation plate 91, and the heat from the lower heater 93 is evenly transferred to the lower mold 23. Furthermore, depending on molding conditions and the like, the upper mold 25 and the heat dissipation plate 81 and the lower mold and the heat dissipation plate 91 may be spaced apart.

FIG. 7 (A) is a cross-sectional view of the upper mold 25, and (B) is a cross-sectional view of the lower mold 23 including the forming surface 111. FIG. 8 is a rear view of the upper mold 25 when viewed from the direction B of (A) of FIG. 7. As shown in FIG. 7(A) and FIG. 8, the upper mold 25 has a ring-shaped protrusion 113 arranged at the rear in the clamping direction. The protrusion 113 is provided on the upper mold 25 corresponding to the outer edge of the molding surface 111 of the lower mold 23 so as to protrude toward the lower mold 23 shown in FIG. 7(B). The protruding portion 113 has an inclined surface 113a whose protrusion amount gradually increases from the outer periphery of the upper mold 25 toward the center. The molding surface 111 is set to a shape corresponding to the molding shape of the glass plate. That is, the inner side of the annular protrusion 113 shown in FIG. 8 becomes a bottomed groove 25a with a flat bottom surface.

The lower mold 23 shown in FIG. 7(B), which is arranged in front of the mold clamping direction, has a plurality of suction holes 115 for vacuum forming opened in the forming surface 111. The suction hole 115 is connected to a suction source such as a suction pump (not shown). Driven by the suction pump, the gas in the space between the lower mold 23 and the glass plate 17 is sucked at a specific time, so that the glass plate 17 is in close contact with the forming surface 111.

The lower mold 23 and the upper mold 25 may include materials such as carbon, stainless steel, ceramics, and cemented carbide. In particular, from the viewpoint of making the heat distribution uniform, it is preferable to use carbon.

In addition, the shape of the protrusion 113 of the upper mold 25 is not limited to this. The protrusion 113 may not form the bottomed groove 25a described above, but may make the protruding surface flat. 9 (A) is a cross-sectional view of the upper mold 25A of the modified example, and (B) is a cross-sectional view of the lower mold 23A including the molding surface 111A of the modified example.

The upper mold 25A of the modified example has a protrusion 113A protruding toward the lower mold 23B of the modified example. The protruding portion 113A is formed with an inclined surface 113a whose protruding amount gradually increases from the outer circumference of the upper mold 25A toward the center, and a flat top surface 113b is formed at the top. In addition, the lower mold 23A has a molding surface 111A having a shape corresponding to the molding shape of the glass plate, similarly to the lower mold 23 shown in FIG. 7(A). Moreover, a suction hole 115 is provided at a position where the curvature of the molding surface 111A becomes the maximum. In the case of this structure, the area of the ring shape in plan view that connects the inclined surface 111a corresponding to the inclined surface 113a of the upper mold 25A and the bottom surface 111b corresponding to the top surface 113b has the largest curvature. A plurality of suction holes 115 are provided in a manner of opening at least a part of the ring-shaped area.

The protrusion 113A of the upper mold 25A and the molding surface 111A of the lower mold 23A are in positions corresponding to each other, so that the curvature of the protrusion 113A is smaller than the curvature of the molding surface 111A. Accordingly, when the glass plate 17 is sandwiched between the inclined surfaces 111a and 113a, the contact area with the glass plate 17 becomes small, and the glass plate 17 is likely to be deformed or moved. Therefore, the glass plate 17 can be faithfully bonded to the molding surface 111A, and the shape accuracy can be improved.

Moreover, the upper heaters 35, 67, 83 and the lower heaters 43, 75, 93 in the preheating platform 11, forming platform 13, and cooling platform 15 shown in FIG. 2 are all connected to a temperature control unit not shown. , Are set to individual set temperature. The temperature control part uses control actions such as proportional control, PI (proportional-integral) control, PID (proportional-integral-derivative) control, etc., and realizes heating, heat preservation, and slow cooling in each platform .

In addition, the above-mentioned forming apparatus 100 sets the conveyance direction TD of the glass plate to the horizontal direction, but it may be a direction inclined with respect to the horizontal direction such as a vertical direction, for example. In this case, sometimes the lower mold 23 and the upper mold 25 are not arranged in the vertical direction, but the heating temperature of the glass plate can be adjusted to not excessively reduce the viscosity of the glass plate, and while suppressing the influence of gravity The mold 23 and the upper mold 25 are formed between.

＜Forming steps of glass plate＞ Next, a specific procedure for forming the glass plate 17 into a curved shape using the forming apparatus 100 having the above-mentioned structure and its function will be described.

The glass plate 17 before forming is placed on the lower mold 23 of the loading part 19 shown in FIG. 1 by a transfer device such as a robot arm (not shown), or an operator manually.

The lower mold 23 of the loading section 19 is conveyed to the preheating platform 11 while maintaining the state where the glass plate 17 is placed by the mold conveying sections 63A and 63B shown in FIG. 4. If the lower mold 23 is pre-heated to a temperature higher than normal temperature before placing the glass plate 17, the heating time in the preheating platform 11 can be shortened, which is preferable. For example, when the glass plate 17 is placed, the temperature of the lower mold 23 is preferably 300°C or higher, more preferably 500°C or higher.

(Preheating step) In the preheating platform 11 shown in FIG. 2, the upper heater 35 and the lower heater 43 are used to heat the glass plate 17 on the lower mold 23 until the target heating temperature (for example, 500°C to 700°C) is reached.

The temperature suitable for the press forming of the glass plate 17 differs according to the composition of the glass plate 17 itself, but if the temperature is too low, the glass plate 17 will not be sufficiently softened. Therefore, in the preheating stage 11, heating is preferably performed so as to be preferably equal to or higher than the glass transition point Tg of the glass plate 17, more preferably equal to or higher than Tg+40°C, and still more preferably equal to or higher than Tg+80°C. On the other hand, if the temperature of the glass plate 17 is too high, the glass plate 17 will soften excessively and become a state which is not suitable for maintaining a shape. Therefore, in the preheating stage 11, the glass plate 17 is heated to preferably become Tg+200°C or lower, more preferably Tg+150°C or lower, and more preferably Tg+120°C or lower.

In addition, from the same viewpoint as the above, in the preheating stage 11, heating is performed so that the viscosity of the glass plate 17 is preferably 5.22×10 ¹¹ Pa·s or more, and more preferably 1.97×10 ¹⁰ Pa·s. s or more, more preferably 1.81×10 ⁹ Pa·s or more. In addition, in the preheating platform 11, heating is performed so that the viscosity of the glass plate 17 is preferably 5.94×10 ⁶ Pa·s or less, more preferably 4.16×10 ⁷ Pa·s or less, and more preferably 1.65 ×10 ⁸ Pa·s or less.

From the viewpoint of the surface quality of the obtained glass plate molded product, it is preferable to uniformly heat the glass plate 17 in the preheating platform 11. That is, it is preferable to reduce the temperature deviation of the glass plate 17 being heated by the preheating platform 11. Specifically, the temperature deviation of the glass plate 17 being heated by the preheating platform 11 is preferably less than 30°C, more preferably less than 20°C, and more preferably less than 10°C.

In addition, the temperature distribution of the region of the lower mold 23 contacting the glass plate 17 during heating is preferably less than 30°C, more preferably less than 25°C, and still more preferably less than 20°C.

(Forming step) The glass plate 17 heated to the target heating temperature is conveyed to the forming platform 13 together with the lower mold 23. In the forming platform 13, an external force such as pressure is applied to the heated glass plate 17 in the clamping direction to form a desired shape.

In the forming platform 13, the upper mold 25 arranged at the retracted position is lowered, and the glass plate 17 is sandwiched between the lower mold 23 and the glass plate 17 to form the glass plate 17. The details of the forming process will be described in detail below. In the forming platform 13, the upper heater 83 and the lower heater 93 are used to keep the temperature of the glass plate 17 heated by the preheating platform 11 constant.

Regarding the temperature of the glass plate 17 in the forming stage 13, it is preferable to suppress the variation from the heating temperature in the preheating stage 11 to 20°C or less. Moreover, from the viewpoint of the surface quality of the obtained glass plate formed body, it is preferable to uniformly heat the glass plate 17 in the forming platform 13. Specifically, the temperature deviation of the glass plate 17 during forming by the forming platform 13 is preferably within 20°C.

After forming the glass plate 17, the upper mold 25 is raised and returned to the retracted position. Then, the lower mold 23 and the formed glass plate 17A are transported to the cooling platform 15 together.

(Cooling step) In the cooling platform 15, the set temperature of the upper heater 67 and the lower heater 75 is set to a temperature lower than the target heating temperature, and the glass plate 17A and the lower mold 23 are slowly cooled. In the cooling platform 15, the glass plate 17 is slowly cooled until the shape of the heated and formed glass plate 17A is stable.

In the cooling platform 15, while adjusting the heating temperature of the upper heater 67 and the lower heater 75, the glass plate 17A is slowly cooled. If the cooling rate in the cooling platform 15 is too fast, the glass plate 17A is likely to undergo deterioration or temperature deviation. Therefore, the cooling rate of the glass plate 17A in the cooling platform 15 is preferably set to 20°C within 30 s, more preferably 30°C, and still more preferably 40°C. In addition, the temperature distribution of the glass plate 17A during cooling is preferably set to 30°C or lower, more preferably 25°C or lower, and still more preferably 20°C or lower.

After the slow-cooled glass plate 17A is transported to the outside of the chamber 27, it is taken out by the unloading part 21 as shown in FIG. 1. In the unloading part 21, the glass plate 17A placed in a mold having a temperature of 300° or more, preferably 500°C or more, is formed and slowly cooled, and taken out from the mold surface. The taking out of the glass plate 17 can be carried out by a transfer device such as a robotic arm not shown, or can be carried out manually by an operator.

＜The homogenization effect of temperature distribution＞ The uniform temperature distribution of the above-mentioned glass plates 17, 17A is obtained by using the heat sealing effect obtained by the heat-insulating shells 51, 53, 55 and the cavity 27 outside the heat-insulating shells 51, 53, 55 The higher heat insulation effect with the outside, and the synergistic effect of the heaters obtained by the heat dissipation plates 41, 65, 73, 81, 91, etc. are realized. In addition, by using the radiant heating performed by the upper heater 35 of the preheating platform 11, the heat transfer heating from the lower heater 43, the heat transfer heating from the upper heater 83 and the lower heater 93 of the forming platform 13, and When the cooling platform is used, the upper heater 67 and the lower heater 75 perform radiant heating via the radiating plates 65 and 73, and each platform has a different heating mode. In addition, the upper heater and lower heater of each platform can be heated at individual set temperatures, enabling extremely precise temperature control.

By performing heating control for each platform and each heater individually, the temperature distribution of the glass plates 17, 17A can be uniformized to a higher degree. In addition, it is easy to make fine adjustments according to the part, and it is possible to accurately realize the heating treatment as designed. Furthermore, by covering the heating gas atmosphere with the heat-insulating shells 51, 53, 55 and the chamber 27, the outflow of heat to the outside is suppressed. As a result, the responsiveness of the heating control and the cooling control can be improved, and it can be uniformly and quickly Reach the desired temperature within time.

In addition, the mold conveying parts 63A and 63B are configured to convey the lower mold 23 by a walking beam method, so the moving speed between the platforms can be increased. Therefore, the heat loss due to heat dissipation between the platforms can be suppressed, and thereby the temperature distribution can also be uniformized.

Furthermore, depending on the molding conditions, the heat sink 41, 65, 73, 81, 91 may not be arranged, but by providing the heat sink, the temperature deviation of the glass plates 17, 17A in each stage can be suppressed to be small.

＜Details of forming steps＞ Next, the method of forming the glass plate 17 in the forming platform 13 and the structure of the forming mold will be described in detail.

First, the shape of the glass plate 17 used for forming is defined. FIG. 10 is a top view of the glass plate 17. The glass plate 17 has a glass central part 121 located further inside than the outer peripheral edge 17a of the glass shape, and a glass outer peripheral part 123 between the central part outer circumference 121a of the glass central part 121 and the outer peripheral edge 17a. Furthermore, in FIG. 10, the outer peripheral part 123 is hatched. In the forming step, at least a part of the glass central portion 121 is formed into a curved shape.

(First molding method) Figures 11A, 11B, and 11C are a step by step description of the outline of the case where the lower mold 23 and the upper mold 25 shown in (A) and (B) of Fig. 7 are brought close to each other to form the glass plate 17 Figure. As shown in FIG. 11A, a glass plate 17 is placed on the molding surface 111 of the lower mold 23 in a state of being in contact with the outer periphery 17 a of the glass plate 17. When the upper mold 25 is lowered toward the lower mold 23, the protrusion 113 of the upper mold 25 contacts the glass plate 17 placed on the lower mold 23.

The upper mold 25 has a part contacting the glass plate 17 and a part not contacting, and only the inclined surface 113 a of the protrusion 113 contacts the glass outer peripheral part 123 of the glass plate 17. Then, as shown in FIG. 11B, if the upper mold 25 is further lowered, the glass plate 17 is pressed into a convex shape toward the lower side due to the inclination of the inclined surface 113a of the protrusion 113. That is, the upper mold 25 can deform the glass plate 17 toward the lower mold 23 only by contacting the glass plate 17 in a ring shape. In addition, the glass plate 17 also bends downward due to its own weight, and deforms so as to follow the molding surface 111 of the lower mold 23.

Next, as shown in FIG. 11C, by supplying negative pressure from the suction hole 115, the glass plate 17 is vacuum sucked to the molding surface 111. Thereby, the glass plate 17 is in close contact with the molding surface 111, and the curved shape of the molding surface 111 is transferred to the glass plate 17. Therefore, the portion where the glass plate 17 and the molding surface 111 are difficult to be in close contact with only the press molding can be reliably adhered, and even a complicated shape that is difficult to be molded by only the press molding can be easily molded.

The position, number, size, etc. of the suction holes 115 are not particularly limited, but it is preferable to form the suction holes 115 in the part of the molding surface 111 that is not easy to contact the glass plate 17 by pressure molding alone. Moreover, the size of the suction hole 115 is preferably adjusted appropriately so that no trace of the suction hole 115 remains on the glass plate 17 or is not obvious even if it remains.

Generally, in the press forming of a glass plate, the glass plate is clamped so that the entire surface of the glass plate is in contact with the forming mold. Therefore, in order to ensure the surface quality of the obtained glass plate molded product, it is molded at a relatively low temperature. Therefore, it takes a relatively long time to deform the glass plate into the desired shape. Therefore, in the case of forming a complex shape, it is difficult to form in a low temperature region where the surface quality can be ensured. On the other hand, when the lower mold 23 and the upper mold 25 of the above-mentioned structure are used for molding, the upper mold 25 does not contact the glass central portion 121 of the glass plate 17. Therefore, even if it is formed at a relatively high temperature, it will not have adverse effects on the glass central portion 121 due to surface roughness caused by contact with the forming mold, and a glass plate formed product with excellent surface quality can be obtained. In this way, in the forming platform 13 of the present structure, forming can be performed at a relatively high temperature, so forming can be completed in a short time. That is, if the above-mentioned molding die is used, it is possible to obtain a glass plate molded product with excellent surface quality in a short time.

Furthermore, the lower mold 23 and the upper mold 25 of this structure are used to obtain a glass plate molded product in which the entire glass central portion 121 is bent at a fixed curvature, but the shapes of the lower mold 23 and the upper mold 25 are not Limited to the shape shown in the figure. The shapes of the lower mold 23 and the upper mold 25 can be appropriately changed according to the target shape to be molded.

In this configuration, the lower mold 23 and the upper mold 25 are combined pressure forming, vacuum forming, and gravity-based bending forming. However, depending on the material or forming conditions, only pressure forming other than vacuum forming and Forming by weight can also be formed.

(Second molding method) In the first forming method, three types of forming: press forming, vacuum forming, and self-weight bending forming are combined, but in the second forming method, pressure forming is further combined.

FIG. 12 is a process explanatory diagram showing the outline of the case where the glass plate 17 is formed by the second forming method. In this case, the molding die has the same configuration as the molding die of the first molding method except that the gas ejection hole 125 for pressure forming is formed inside the annular protrusion 113 of the upper die 25B.

The gas ejection hole 125 is usually provided in a portion of the upper mold 25B that is not in contact with the glass plate 17. The number and size of the gas ejection holes 125 are not particularly limited.

When using the lower mold 23 and the upper mold 25B of the above-mentioned configuration, and combined pressure forming and air forming, the protrusion 113 of the upper mold 25B is brought into contact with the glass outer peripheral portion 123 of the glass plate 17, and then the gas ejection hole 125 Spit out gas. Then, the glass plate 17 is pressed against the molding surface 111 of the lower mold 23. That is, the protrusion 113 is formed in a ring shape, and the contact with the glass plate 17 also becomes a ring shape. Therefore, a closed space 129 is formed between the molding surface 111 of the lower mold 23 and the glass plate 17. Gas is supplied to the enclosed space 129 so that the pressure in the enclosed space 129 becomes a positive pressure. Thereby, the glass plate 17 is pressed to the molding surface 111.

In addition, by performing the vacuum forming and the forming using gravity at the same time as the above-mentioned pressure forming, the glass plate 17 can be attached to the forming surface 111 more quickly and more reliably, and the amount of time until forming can be shortened. The time required. In this way, by combining at least any one of pressure forming, vacuum forming, air pressure forming, and self-weight bending forming, it is possible to easily realize the forming of a complicated shape and further shorten the forming time.

In addition, vacuum forming and pressure forming can be carried out at any time during the implementation of pressure forming. The order of execution can be either pressure forming, vacuum forming, and pressure forming, or pressure forming and pressure forming. The sequence of forming and vacuum forming. By performing pressure forming before vacuum forming and pressure forming, the positioning of the glass plate 17 with respect to the forming surface 111 can be performed more reliably.

In addition, by performing each molding at the same time, the adhesion between the glass plate 17 and the molding surface 111 can be further improved, and it is also easy to process the glass plate 17 in a shape that easily causes wrinkles.

(3rd molding method) Figures 13A, 13B, and 13C show step by step the modification of the lower mold 23A and the upper mold 25A shown in (A) and (B) of Fig. 9 to form the glass plate 17 Diagram showing outline steps. As shown in FIG. 13A, the glass plate 17 is placed on the molding surface 111A of the lower mold 23A in a state in contact with the outer periphery 17a of the glass plate 17. When the upper mold 25A is lowered toward the lower mold 23A, the top surface 113b of the protrusion 113A of the upper mold 25A contacts the glass plate 17 placed on the molding surface 111A of the lower mold 23A.

At this time, the top surface 113b of the upper mold 25A is in surface contact with the glass plate 17, so that the pressure on the glass plate 17 generated by the lowering of the upper mold 25A is dispersed. That is, it becomes a light touch state. Then, as shown in FIG. 13B, the upper mold 25 is further lowered, and the glass plate 17 is pressed into a downward convex shape with a light load (0.1 MPa or less) by the inclined surface 113a of the protrusion 113A. At this time, a gap 117 communicating with the suction hole 115 is formed between the bottom surface 111b of the lower mold 23A and the glass plate 17. In other words, the top surface 113b of the protruding portion 113A of the upper mold 25A and the bottom surface 111b of the molding surface 111A of the lower mold 23A are set to a shape that does not contact even if the mold is locked.

Next, as shown in FIG. 13C, by supplying a negative pressure into the gap 117 from the suction hole 115, the glass plate 17 is vacuum sucked to the molding surface 111A. Thereby, the glass plate 17 is in close contact with the molding surface 111A, and the curved shape of the molding surface 111A is transferred to the glass plate 17. Furthermore, in the process of advancing the molding process from FIG. 13B to FIG. 13C, the pressurizing pressure is preferably kept lower than the light load (0.1 MPa or less) in FIG. 13B.

By setting the suction hole 115 at the position where the curvature of the molding surface 111A of the lower mold 23A becomes the maximum, the gap 117 between the glass plate 17 and the molding surface 111A is gradually increased from the center side of the bottom surface 111b to the peripheral side The glass plate 17 disappears after being in close contact with the molding surface 111A. Then, finally, the curvature of the glass plate 17 in close contact with the molding surface 111A becomes the largest. In this way, the glass plate 17 is delivered to the bottom surface 111b of the molding surface 111A of the lower mold 23A from the state in which it abuts against the top surface 113b of the protrusion 113A in the upper mold 25A without a gap.

Furthermore, the glass outer periphery 123 is lightly pressurized between the inclined surface 113a of the upper mold 25A and the inclined surface 111a of the lower mold 23A. Therefore, the glass outer periphery is drawn by suction from the suction hole 115. 123 can be easily deformed toward the bottom surface 111b side. Therefore, the glass plate 17 is not locally constrained at the glass outer peripheral portion 123, but the whole of the glass plate 17 is attached with substantially equal pressure along the molding surface 111A.

According to this molding method, the operation of attaching the glass plate 17 to the molding surface 111A of the lower mold 23A to transfer the shape is substantially performed by vacuum suction. Therefore, a uniform pressure distribution is generated in the glass surface, so that the surface of the glass plate 17 is not caused to produce indentations or wrinkles caused by local mold contact caused by the pressure of the upper mold 25A, and high-quality Shaped. In addition, it is processed into a desired shape by vacuum suction, so even if it is a complicated shape that is difficult to be molded by only press molding, high-precision and high-quality molding can be performed.

(4th molding method) In the fourth forming method, pressure forming is further combined with the third forming method. FIG. 14 is a process explanatory diagram showing the outline of the case where the glass plate 17 is formed by the fourth forming method. In this case, the molding die has the same structure as the molding die of the third molding method except that the gas ejection hole 125 for pressure forming is formed inside the protrusion 113A of the upper die 25C.

As in the case of the second forming method described above, the opening of the gas ejection hole 125 is usually provided in the portion of the upper mold 25B that is not in contact with the glass plate 17. The number and size of the gas ejection holes 125 are not particularly limited.

When using the lower mold 23A and the upper mold 25C with the above-mentioned structure, and pressure forming and air forming are used together, the protrusion 113A of the upper mold 25C is brought into contact with the glass outer periphery 123 of the glass plate 17, and then the gas ejection hole 125 ejected gas. Then, the glass plate 17 is pressed against the molding surface 111A of the lower mold 23A. That is, the contact area between the protrusion 113A and the glass plate 17 becomes a ring shape, so a closed space 129 is formed between the molding surface 111A of the lower mold 23A and the glass plate 17. Gas is supplied to the enclosed space 129 so that the pressure in the enclosed space 129 becomes a positive pressure. Thereby, the glass plate 17 is pressed to 111A of molding surfaces.

The gas ejection from the gas ejection hole 125 can be performed after the vacuum adsorption of the glass plate 17 by the suction hole 115 or before the vacuum adsorption.

＜Configuration examples of other forming equipment＞ The aforementioned glass plate forming apparatus 100 may also be configured to include a plurality of preheating platforms 11 and cooling platforms 15 respectively. 15 is a schematic configuration diagram of a forming apparatus 200 provided with a plurality of preheating stages 11, a forming stage 13, and a plurality of cooling stages 15.

The preheating platform 11 is arranged at 4 positions (PH1～PH4) along the conveying direction TD of the lower mold 23, and the cooling platform 15 is arranged at 4 positions (C1～C4) along the conveying direction TD of the lower mold 23 . The forming platform 13 is provided at a position (PM1) between the preheating platform 11 and the cooling platform 15.

The PH1-PH4 system heating temperature of the preheating platform 11 is set to increase stepwise along the conveying direction TD. Thereby, the lower mold 23 and the glass plate 17 gradually increase in temperature as they are conveyed in the conveying direction TD, and are heated until they reach the target heating temperature as the molding temperature.

The C1-C4 system heating temperature of the cooling platform 15 is set to decrease stepwise along the conveying direction TD. Thereby, the lower mold 23 and the glass plate 17 are gradually lowered in temperature as they are conveyed in the conveying direction TD, and are gradually cooled from the target heating temperature.

16 is a graph showing an example of temperature changes of the lower mold 23 and the glass plate 17 in the preheating platform 11, the forming platform 13, and the cooling platform 15. The glass plate 17 supplied to the PH1 of the preheating platform 11 from the loading part 19 (LD) shown in FIG. 15 is placed in the lower mold 23 that has been heated to a specific temperature Tc in advance, and is heated from the room temperature T _RM . The lower mold 23 and the glass plate 17 increase in temperature as they are transported toward PH2, PH3, and PH4, and reach the target heating temperature T _PM as the forming temperature before being transported to the forming platform 13 (PM).

In the forming platform 13 (PM), the glass plate 17 is formed while being held at a fixed temperature of the target heating temperature T _PM .

After being formed, the temperature of the lower mold 23 and the glass plate 17A after forming are gradually decreased by being transported to C1 to C4 of the cooling platform 15. The glass plate 17A conveyed from C4 to the unloading part 21 (ULD) shown in FIG. 15 is naturally cooled.

In each platform of the preheating platform 11 and the cooling platform 15, each platform is used to perform temperature management so that the lower mold 23 and the glass plates 17, 17A uniformly become the set temperature. The greater the number of platforms, the greater the range of temperature changes. In addition, from the viewpoint of production gap time, it is better to reduce the number of platforms. The number of each platform can be appropriately set according to the size or processing shape of the glass plate to be processed. For example, in a situation where the size of the glass plate is large or when forming a complicated shape, in order to avoid sudden temperature changes, it is preferable to increase the number of the preheating platform 11 and the cooling platform 15.

Fig. 17 is a schematic view of a conventional forming apparatus as a reference example. In the previous forming apparatus, the lower mold 131 and the upper mold 135 are used to press the entire surface of the glass plate 17, and the heating temperature is set to be lower than the above-mentioned forming temperature (target setting temperature). Therefore, it is necessary to hold the glass plate 17 in a mold-locked state until the formed shape thereof becomes stable. As a result, the forming time T _PM2 becomes longer than the forming time T _PM1 shown in FIG. 16.

On the other hand, the forming device 200 of the present structure shown in FIG. 15 combines pressure forming, vacuum forming, pressure forming, and forming using gravity to form the glass plate 17, so that the heating temperature can be reduced. The temperature is set higher than the previous temperature, and the glass plate is closely attached to the forming surface of the forming mold by the synergistic effect of each forming, so that the forming shape is quickly stabilized. That is, the rebound of the glass plate is unlikely to occur. Thereby, the forming platform 13 only needs to have one platform, which can reduce equipment costs and increase productivity.

In addition, by heating the temperature of the lower mold 23 to a specific temperature Tc in advance, the time to reach the target set temperature can be further shortened, and the lead time can be shortened.

FIG. 18 is a schematic diagram of a molding apparatus 300 showing another configuration example of the molding apparatus 200 shown in FIG. 15. The forming apparatus 300 of this configuration includes a plurality of forming lines having a preheating stage 11, a forming stage 13, and a cooling stage 15 shown in FIG. 15. In FIG. 18, the forming apparatus 300 is shown with a configuration in which two lines of the first forming line 141 and the second forming line 143 are provided, but it may be provided with three or more lines.

The loading section 19 of the first molding line 141 of the molding device 300 is connected to the unloading section 21 of the second molding line 143, and the unloading section 21 of the first molding line 141 is connected to the loading section 19 of the second molding line 143. In addition, the lower molds 23 of the first molding line 141 and the lower molds 23 of the second molding line 143 are respectively used in common and circulate in each line.

According to this structure, by moving the lower mold 23 of the unloading section 21 conveyed to one molding line back to the loading section 19 of the other molding line, the temperature drop of the mold can be suppressed, and the molding apparatus 300 is always maintained during operation Above the specified temperature Tc. Therefore, the temperature change range of the lower mold 23 becomes smaller, and the temperature cycle burden on the lower mold 23 can be reduced. In addition, energy consumption for heating can be suppressed, and operating costs can be reduced.

Furthermore, compared with a configuration in which a plurality of molding lines are arranged in series, the installation space of the molding apparatus 200 can be reduced, thereby also reducing equipment costs.

＜Details of forming steps＞ Next, the preferable forming conditions in the forming step using the forming platform 13 will be described. In the forming apparatuses 100, 200, and 300 of this structure, it is preferable to form a glass plate based on the forming conditions shown below.

(Pressure conditions) In the press forming, different pressures are applied to the respective areas of the glass central part 121 and the glass outer peripheral part 123 of the glass plate 17 shown in FIG. 10, and the glass plate 17 is press-formed. Specifically, when vacuum forming and pressure forming are not performed, it is preferable that the pressure Pct applied to the glass central portion 121 is 0 to 0.1 MPa, and the pressure Peg applied to the glass outer peripheral portion 123 is 0.1 to 10 MPa.

When vacuum forming and pressure forming are not performed, pressure other than gravity does not act on the glass central part 121 of the glass plate 17. On the other hand, a pressure higher than that of the glass central portion 121 is applied to the glass outer peripheral portion 123 of the glass plate 17, and the glass plate 17 is fixed to the forming mold. Thereby, it is possible to perform stable press molding without positional deviation of the glass plate 17. In addition, the direction of the deformation of the glass plate 17 caused by press molding can be determined by the inclination direction and the angle of the protrusion 113 or the forming surface 111 (refer to (A), (B) of FIG. 7) in contact with the glass plate 17 ( Protruding downward or upward), the amount of deformation.

In the case of forming the glass sheet 17 by combining pressure forming and vacuum forming, it is preferable that the pressure Pct applied to the glass central part 121 by pressurization is 0 to 0.1 MPa, and the pressure Peg applied to the glass outer peripheral part 123 is 0.1～10 MPa. In addition, with regard to the total pressure applied to the glass plate 17 by pressure forming and vacuum forming, the pressure Peg of the glass outer peripheral portion 123 is higher than the pressure Pct of the glass central portion 121 (Peg>Pct).

Furthermore, when the glass sheet 17 is formed by pressure forming, vacuum forming, and pressure forming in combination, it is preferable that the pressure Pct applied to the glass central portion 121 by applying pressure is 0 to 0.1 MPa and applied to the outer periphery of the glass. The pressure Peg of the part 123 is 0.1 MPa～10 MPa. Furthermore, regarding the total pressure applied to the glass plate 17 by pressure forming, vacuum forming, and pressure forming, the pressure Peg of the glass outer peripheral portion 123 is higher than the pressure Pct of the glass central portion 121 (Peg>Pct). In this case, in addition to vacuum forming, pressure is applied to the glass center portion 121 by air pressure forming, and therefore, the pressure applied to the glass center portion is larger than when only pressure forming and vacuum forming are performed.

The above conditions may or may not include the bending effect produced by the self-weight forming before and after the press forming.

(Temperature of glass plate) When the glass plate 17 is formed into a desired shape, the lower limit of the temperature during forming is preferably 400°C, more preferably Tg+40°C, and even more preferably Tg+80°C. In addition, the upper limit of the temperature during molding is preferably 750°C, more preferably 680°C, and still more preferably 650°C.

By setting the forming temperature within the above range, the formed shape of the glass sheet 17 can be maintained in a short time, and the forming time can be shortened.

(Viscosity of the glass plate) When the glass plate 17 is formed into a desired shape, the viscosity of the glass plate 17 at the time of forming varies according to the type of material of the glass plate 17, etc., but from the viewpoint of formability In other words, it is preferably 1×10 ^-5 Pa·s or less.

In particular, ϕ (=∫(P/ρ)dt, [P: in-plane pressure, ρ: viscosity]), which is an index of formability, is preferably 1×10 ^{-8.7 at the} outer periphery of the glass plate. 1×10 ^2.5 , at the center of the glass, 1×10 ^-12 ～1×10 ^-0.5 eg.

(Dimensional accuracy of glass plate) According to the above-mentioned manufacturing apparatus and forming method, it is possible to obtain a glass plate formed body with excellent shape accuracy. As an evaluation index of the shape quality of the glass plate molded body, for example, the in-plane shape deviation obtained by comparing with the design shape (design surface) can be cited.

The so-called in-plane shape deviation means that when the normal line is set according to the design shape, the shape of the glass plate formed body is approximated by the surface in such a way that the absolute value of the distance between the normal line and the design surface becomes the smallest in the surface. The deviation value of the deviation between the normal direction of the surface after the curved surface is approximated and the design surface is defined as the in-plane shape deviation.

The in-plane shape deviation of the glass sheet forming system obtained by the manufacturing device and forming method of this configuration is preferably 0.6 mm or less, more preferably 0.4 mm or less. Example

Table 1 summarizes the forming conditions and forming results of the glass plates. Using the forming device shown in Figure 1, a glass plate (material: Dragontrail (registered trademark)) with a size of 100×50 mm (thickness t = 1.1 mm) is formed by the following forming methods, namely: bending only by its own weight, Full-surface press molding, press molding of edge press molding where only the outer periphery of the glass is pressurized, combined press molding, and vacuum molding.

Regarding the forming shape of the glass plate, set as Test Example 1 and 2 with a single radius of curvature shown in Figure 19(A); Test Example 3 in the S shape shown in Figure 19(B); Figure 19(B) C) Test example 4 of the J shape shown in Figure 19; Test example 5 of the saddle shape shown in (D) of Fig. 19. The radius of curvature R of Test Example 1 is 2000 mm, and the radius of curvature R0 of Test Example 2 is 800 mm. In addition, the radius of curvature of the S-shaped test example 3 is set in order from one end such that R1 is 2000 mm, R2 is 100 mm, and R3 is 2000 mm. The J-shaped test example 4 has a shape in which a curved surface with a radius of curvature R4 of 50 mm is connected from a flat shape. The saddle-shaped test example 5 has a convex surface with a curvature radius R5 of 800 mm and a concave surface with a curvature radius R6 of 2000 mm in a direction orthogonal to the convex surface.

In Test Examples 1 to 4, the pressure of the entire surface press molding was set to 0.1 MPa, and in Test Example 5, the pressure of the entire surface press molding was set to both of 0.1 MPa or less and a pressure exceeding 0.1 MPa And proceed. The molded body obtained by each molding method was evaluated in terms of the molding lead time, shape accuracy, and surface quality. The evaluation criteria are as follows. • Production interval time (time required for forming) ◎: Less than 30 s ○: more than 30 s and less than 100 s △: more than 100 s and less than 200 s ▲: more than 200 s and less than 500 s ×: 501 s or more

•Shape accuracy (deviation from the design shape) ◎: Less than 0.2 mm ○: 0.2 mm or more and less than 0.4 mm △: 0.4 mm or more and less than 0.6 mm ▲: 0.6 mm or more and less than 0.8 mm ×: 1.0 mm or more

• Surface quality (the number of defects counted by image processing) ◎: 0～5 ○: 6～10 △: 11～50 ▲: 51～100 ×: more than 101

[Table 1] Table 1 Shape of glass plate Self-weight bending Whole surface pressure forming Edge pressure forming Pressure below 0.1 MPa The pressure exceeds 0.1 MPa Pressure only Pressurization + Vacuum Test example 1 Single curve R2000 ×/○/○ ○/○/△ - ○/○/◎ ○/○/○ Test example 2 R800 ×/○/○ ○/○/△ - ○/○/◎ ○/○/○ Test example 3 S shape R2000-R100-R2000 ×/×/× ○/○/▲ - ×/×/× ○/○/○ Test example 4 J shape R∞-R50 ×/×/× ○/○/▲ - ×/×/× ○/○/○ Test Example 5 Saddle R800×R2000 ×/×/× ○/○/× ○/○/○ ×/×/× ○/○/× ※Production time/shape accuracy/surface quality

In the case of only self-weight bending and forming, none of the test examples could speed up the lead time. In the case of full-surface press molding, if the pressure is set to 0.1 MPa or less, the entire surface of the glass sheet will be in contact with the molding die, so the surface roughness of the glass surface after molding increases, and the surface quality decreases. However, in Test Example 5, if a pressure exceeding 0.1 MPa was applied, the noodle quality was improved.

In the case of applying pressure only by edge pressure forming, in the single-curved test examples 1 and 2, it was a result of good yield time, shape accuracy, and especially excellent noodle quality. However, in Test Examples 3, 4, and 5 where the forming shape is relatively complicated, the lead time, shape accuracy, and surface quality are all unacceptable (NG).

On the other hand, in the case of combining press forming and vacuum forming in edge press forming, good results were obtained in Test Examples 1 to 4, and in Test Example 5, the noodle quality was unacceptable. That is, in the case of the saddle shape of Test Example 5, if a pressure exceeding 0.1 MPa was applied by the entire surface press molding, good results were obtained.

The present invention is not limited by the above-mentioned embodiment. Combining the various components of the embodiment with each other, or modification and application by the industry based on the description of the specification and well-known technologies are also intended for the present invention and included in the scope of protection.

As described above, the following matters are disclosed in this specification. (1) A method for forming a glass plate, which is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above glass plate between a pair of forming dies; Using the above-mentioned forming mold, a first pressure of 0.1 MPa or less is applied in the clamping direction to the central part of the glass on the inner side of the outer periphery of the glass plate, and no pressure is applied to the outer circumference of the central part of the glass to the glass plate A second pressing force of 0.1-10 MPa different from the above-mentioned first pressing force is applied to the outer peripheral portion of the glass between the outer peripheries in the clamping direction, and the glass plate is press-formed. According to the method of forming the glass plate, the glass central portion and the outer peripheral portion of the glass plate can be press-formed with different pressures, thereby suppressing the degradation of the surface quality of the glass central portion with a low pressure.

(2) The method for forming a glass plate as described in (1), which has the steps of: supplying a negative pressure between the first forming mold arranged in front of the clamping direction and the glass plate to make the glass plate Adsorbed to the above-mentioned first forming die. According to this method of forming a glass plate, the glass plate can be adsorbed to the first forming mold by negative pressure, and the glass plate can be formed into a desired shape more reliably and at high speed.

(3) A method for forming a glass plate, which is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above glass plate between a pair of forming dies; Apply a pressure of 0.1 MPa or less to the glass plate in the clamping direction from one of the above-mentioned pair of forming dies, and push the glass plate from the outer circumference of the glass central part on the inner side of the outer circumference to the outer circumference of the glass plate The ring-shaped outer periphery of the glass is sandwiched between the pair of forming dies, and is defined on the inner periphery side of the outer periphery of the glass between the first forming mold arranged in front of the clamping direction and the glass plate Space; and Negative pressure is supplied to the space defined between the glass plate and the first forming mold, so that the glass plate is attracted to the first forming mold. According to this method of forming a glass plate, the operation of attaching the glass plate to the forming surface of the first forming mold to transfer the shape is substantially performed by vacuum suction. Therefore, it is possible to perform high-quality molding without generating impressions or wrinkles on the surface of the glass plate due to the pressurization of the second molding die. In addition, it is processed into a desired shape by vacuum suction, so even if it is a complicated shape that is difficult to be molded by only press molding, it can be molded with high precision and high quality.

(4) The method for forming a glass plate as described in (3), wherein at least a part of the part where the curvature of the forming surface of the first forming die for transferring the curved surface shape to the glass plate becomes the largest is provided with a drawing The suction hole supplies negative pressure to the space from the suction hole. According to the forming method of the glass plate, the gap between the glass plate and the forming surface gradually disappears toward the part where the curvature becomes the largest with the supply of negative pressure, and there is no gap between the glass plate and the forming surface. Close.

(5) The method for forming a glass sheet as described in (3) or (4), wherein the pair of forming dies is provided with a protrusion on either one, and the other is provided with a protrusion corresponding to the protrusion Concave shaped surface, and At a position where the protrusion corresponds to the molding surface, the curvature of the protrusion is smaller than the curvature of the molding surface. According to the method of forming the glass plate, when the glass plate is sandwiched between the inclined surface of the protrusion and the inclined surface of the forming surface, the contact area with the glass plate becomes small, and the glass plate is easily deformed or moved. Therefore, the glass plate can be faithfully bonded to the molding surface, and the shape accuracy can be improved.

(6) The method for forming a glass sheet as described in any one of (1) to (5), which has the steps of: supplying between the second forming mold arranged behind the clamping direction and the glass sheet With positive pressure, the glass plate is pressed to the first forming mold arranged in front of the clamping direction. According to this method of forming a glass plate, the glass center portion of the glass plate is pressed against the first forming mold, so that the glass plate can be formed into a desired shape more reliably and at high speed.

(7) The method for forming a glass plate as described in any one of (1) to (6), wherein the forming of the glass plate is by heating the glass plate so that the viscosity of the glass plate is 5.94×10 ⁶ Pa·s ~5.22×10 ¹¹ Pa·s. According to this method of forming a glass plate, by setting the glass plate to a viscosity with excellent formability, the adaptability to the forming mold becomes good, and it can be quickly formed into a desired shape.

(8) The glass sheet forming method described in any one of (1) to (7), wherein the in-plane shape deviation obtained by comparing the glass sheet forming system after forming the glass sheet with the designed shape is within 0.3 mm . According to the forming method of the glass plate, a glass plate formed body with high shape accuracy can be obtained.

This application is based on a Japanese patent application (Japanese Patent Application No. 2019-21562) filed on February 8, 2019, and its content is incorporated into this application by reference.

11: Warm up the platform 13: forming platform 15: cooling platform 17: glass plate 17A: Glass plate 17a: outer periphery 19: Loading department 21: Uninstallation Department 23: Lower mold (1st forming mold) 23A: Lower mold (1st forming mold) 25: Upper mold (2nd forming mold) 25A: Upper mold (second forming mold) 25B: Upper mold (second forming mold) 25C: Upper mold (second forming mold) 25a: Bottom groove 27: Chamber 29: move entrance 31: Export 35: Upper heater (heating part for temperature rise) 36: lamp heater 36A: Heating wire 36B: Pipe 37: Support shaft 38: Irradiation window 39: water cooling plate 40: ceramic coating 41: heat sink 43: Lower heater (heating part for temperature rise) 45: Support 47: water cooling plate 51: Insulated shell 53: Insulated shell 55: Insulated shell 61: Mould support rod 63A, 63B: Mould handling department 65: heat sink 67: Upper heater (heating part for heat preservation) 71: Support shaft 73: heat sink 75: Lower heater (heating part for heat preservation) 77: Water cooling plate 79: Support 81: heat sink 83: Upper heater (heating part for cooling) 85: heat insulation board 87: water cooling plate 89: Support axis 91: heat sink 93: Lower heater (heating part for cooling) 97: Water cooling plate 99: support body 100: forming device 101: opening 111: forming surface 111A: forming surface 111a: Inclined surface 111b: bottom surface 113: Inclined surface 113A: protrusion 113a: Inclined surface 113b: Top surface 115: suction hole 117: Gap 121: glass center 121a: Central outer periphery 123: glass periphery 125: gas ejection hole 129: Closed Space 131: Lower mold (1st forming mold) 135: Upper mold (2nd forming mold) 141: The first forming line (forming line) 143: The second forming line (forming line) 200: forming device 300: forming device

Fig. 1 is a schematic step diagram showing the steps of forming a glass plate into a curved shape. Fig. 2 is a schematic configuration diagram of the forming device. Figure 3 is a cross-sectional view of a plurality of lamp heaters. Fig. 4 is a schematic plan view of the section III-III shown in Fig. 2 viewed from above. Fig. 5 is a schematic explanatory diagram showing a case where the lower mold is transported along the transport direction from the preheating platform to the cooling platform. Figure 6 is an enlarged cross-sectional view of the forming platform. Figure 7 (A) is a cross-sectional view of the upper mold, and (B) is a cross-sectional view of the lower mold including the forming surface. Fig. 8 is a rear view of the upper mold from the direction B of Fig. 7 (A). Fig. 9 (A) is a cross-sectional view of the upper mold of the modified example, and (B) is a cross-sectional view of the lower mold including the forming surface of the modified example. Figure 10 is a top view of the glass plate. Fig. 11A is a schematic step explanatory diagram showing, step by step, the case where the lower mold and the upper mold shown in (A) and (B) of Fig. 7 are brought close to each other to form a glass plate. Fig. 11B is a schematic step explanatory diagram showing, step by step, the case where the lower mold and the upper mold shown in (A) and (B) of Fig. 7 are brought close to each other to form a glass plate. Fig. 11C is a schematic step explanatory diagram showing step by step the case where the lower mold and the upper mold shown in (A) and (B) of Fig. 7 are brought close to each other to form a glass plate. Fig. 12 is a process explanatory diagram showing an outline of a case where a glass plate is formed by the second forming method. FIG. 13A is a schematic step explanatory diagram showing step by step the case where the lower mold and the upper mold of the modified example shown in (A) and (B) of FIG. 9 are brought close to each other to form a glass plate. FIG. 13B is a schematic step explanatory diagram showing step by step the case where the lower mold and the upper mold of the modified example shown in (A) and (B) of FIG. 9 are brought close to each other to form a glass plate. FIG. 13C is a schematic step explanatory diagram showing step by step the case where the lower mold and the upper mold of the modified example shown in (A) and (B) of FIG. 9 are brought close to each other to form a glass plate. Fig. 14 is an explanatory diagram showing an outline of a case where a glass plate is formed by the fourth forming method. Figure 15 is a schematic configuration diagram of a forming device equipped with a plurality of preheating platforms, a forming platform, and a plurality of cooling platforms. Fig. 16 is a graph showing an example of temperature changes of the lower mold and the glass plate in the preheating platform, forming platform, and cooling platform. Fig. 17 is a schematic configuration diagram of a conventional forming apparatus as a reference example. FIG. 18 is a schematic configuration diagram of a molding device showing another configuration example of the molding device shown in FIG. 15. Figure 19 (A) shows the molding shape of Test Example 1 and 2, (B) shows the molding shape of Test Example 3, (C) shows the molding shape of Test Example 4, and (D) shows the shape of Test Example 5. A schematic cross-sectional view of the formed shape.

17: glass plate

17a: outer periphery

23: Lower mold (1st forming mold)

25B: Upper mold (second forming mold)

25a: Bottom groove

111: forming surface

113: Inclined surface

113a: Inclined surface

115: suction hole

121: glass center

123: glass periphery

125: gas ejection hole

129: Closed Space

Claims (8)

A method for forming a glass plate is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above-mentioned glass plate between a pair of forming dies; and Using the above-mentioned forming mold, a first pressure of 0.1 MPa or less is applied to the center of the glass on the inner side of the outer periphery of the glass plate in the clamping direction, and no pressure is applied to the outer periphery of the center of the glass to the glass plate. A second pressing force of 0.1-10 MPa different from the above-mentioned first pressing force is applied to the outer peripheral portion of the glass between the outer peripheries in the clamping direction, and the glass plate is press-formed. The method for forming a glass sheet according to claim 1, which has the steps of: supplying a negative pressure between the first forming mold arranged in front of the clamping direction and the glass sheet, so that the glass sheet is attracted to the first Forming mold. A method for forming a glass plate is to heat the glass plate and shape it into a desired shape, and has the following steps: Sandwich the above glass plate between a pair of forming dies; Apply a pressure of 0.1 MPa or less to the glass plate in the clamping direction from one of the above-mentioned pair of forming dies, and push the glass plate from the outer circumference of the glass central part on the inner side of the outer circumference to the outer circumference of the glass plate The ring-shaped outer periphery of the glass is sandwiched between the pair of forming dies, and on the inner periphery side of the outer periphery of the glass, it is divided between the first forming mold and the glass plate arranged in front of the clamping direction. Space; and Negative pressure is supplied to the space defined between the glass plate and the first forming mold, so that the glass plate is attracted to the first forming mold. The method for forming a glass plate according to claim 3, wherein a suction hole is provided in at least a part of the part where the curvature of the forming surface of the first forming mold for transferring the curved surface shape to the glass plate becomes the largest, and The suction hole supplies negative pressure to the above-mentioned space. The method for forming a glass sheet according to claim 3 or 4, wherein the pair of forming dies is provided with a protrusion on any one of them, and a concave forming surface corresponding to the protrusion on the other is provided, and At a position where the protrusion corresponds to the molding surface, the curvature of the protrusion is smaller than the curvature of the molding surface. The method for forming a glass plate according to any one of claims 1 to 5, which has the steps of: supplying a positive pressure between a second forming mold arranged behind the clamping direction and the glass plate, and pressing the glass plate It is pressed to the first forming die arranged in front of the above-mentioned clamping direction. The method for forming a glass plate according to any one of claims 1 to 6, wherein the forming of the glass plate is by heating the glass plate so that the viscosity of the glass plate is 5.94×10 ⁶ Pa·s～5.22×10 ¹¹ Pa· s and implementation. The method for forming a glass sheet according to any one of claims 1 to 7, wherein the in-plane shape deviation obtained by comparing the glass sheet forming system after forming the glass sheet with the design shape is within 0.3 mm.

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