JP6031998B2 - Glass plate forming method - Google Patents

Description

  The present invention relates to a method for forming a glass plate, and more particularly, to a method for forming a thin glass plate.

  As a method for forming a glass plate, a vertical rollout method is known (for example, Patent Document 1). In the vertical rollout method, a drawing roller is used, and molding is performed while drawing molten glass in a plate shape in the vertical direction. And plate-like glass pulled out in the vertical direction (hereinafter referred to as a glass plate) is gradually cooled while being conveyed downward, and then cut into a desired length.

  In the vertical rollout method, it is necessary to slowly cool and cut the glass plate while pulling it out in the vertical direction. For this reason, a shaping | molding apparatus becomes long in the vertical direction, and it is necessary to also raise the height of the building which installs a shaping | molding apparatus. Further, since the glass plate drawn downward is not fixed, it swings back and forth and right and left with respect to the vertical direction (conveying direction). Thin glass plates are particularly easy to swing. For this reason, there exists a problem which a glass plate wavy and the flatness of a glass plate becomes low.

  On the other hand, the molten glass is caused to flow out from an orifice having a rectangular cross section, and the molten glass is rolled into a plate shape by a pair of rollers downstream of the orifice, and the glass formed in the plate shape is inclined. A method of pulling out with an inclination has been proposed (see Patent Document 2). In this method, since it is not necessary to pull out the glass plate in the vertical direction, the length of the forming device in the vertical direction can be shortened.

JP-T-2004-523452 Japanese Patent Laid-Open No. 11-139837

  However, it has been confirmed by the present inventors that when a glass plate is formed by the roll-out method, irregularities are periodically generated in the glass plate in the drawing direction (forming direction) of the glass plate. Periodic unevenness was confirmed not only in the vertical rollout method but also in the method of pulling out the glass plate with an inclination in an oblique direction. Moreover, it has been confirmed by the inventors of the present application that the periodic unevenness appears more prominently as the glass plate is thinner. In addition, this periodic unevenness | corrugation differs also from the corrugation which arises by the shaking of the glass plate which generate | occur | produces in a vertical rollout method.

  When periodic irregularities occur in this way, the flatness of the glass plate decreases. For this reason, in order to remove periodic unevenness and improve the flatness of the glass plate, a process of heating the drawn glass plate again is required. As a result, the processes and facilities required for manufacturing the glass plate increase.

  An object of this invention is to provide the shaping | molding method of the glass plate which can obtain a glass plate with high flatness.

The method for forming a glass plate according to the present invention includes a step of flowing molten glass from a slit-shaped opening, and rolling the molten glass with first and second rolling rollers arranged to face each other, thereby forming a glass plate. And a step of inclining and conveying the glass plate toward the first rolling roller, the surface temperature of the first rolling roller being higher than the surface temperature of the second rolling roller, The glass plate is formed on the downstream side of the second rolling roller so that the contact area with the molten glass is wider on the first rolling roller side.

  According to the present invention, the step of flowing the molten glass from the slit-shaped opening and the first and second rolling rollers arranged to face each other when the molten glass is rolled to form a glass plate, The glass plate is formed on the downstream side of the second rolling roller so that the contact area with the molten glass is wider on the first rolling roller side. For this reason, it can suppress that a periodic unevenness | corrugation generate | occur | produces in a glass plate, and can obtain a glass plate with high flatness.

It is a side view of the shaping | molding apparatus of the glass plate which concerns on embodiment. It is a partial expanded side view of the shaping | molding apparatus of the glass plate which concerns on embodiment. It is a partially expanded side view of the shaping | molding apparatus of the glass plate which concerns on the comparative example of embodiment. It is a figure which shows the measurement result of the glass plate which concerns on an Example. It is a figure which shows the measurement result of the glass plate which concerns on a comparative example.

  Hereinafter, a method for forming a glass plate according to an embodiment will be described with reference to the drawings. In addition, this invention is suitable for shaping | molding of a thin glass plate (for example, plate | board thickness is 0.5 mm-2.5 mm).

(Embodiment)
FIG. 1 is a side view of a glass plate forming apparatus 100 according to an embodiment. As shown in FIG. 1, the glass plate forming apparatus 100 includes rolling rollers 110 </ b> A and 110 </ b> B, a drawing roller 120, a panel heater 130, an inclined conveyor 140, a cutting mechanism 150, a push-up mechanism 160, and a conveyor 170. Is provided.

  The rolling roller 110 is composed of a pair of rollers 110A (first rolling roller) and 110B (second rolling roller) arranged to face each other. The rolling roller 110 shapes the molten glass G supplied from the slit nozzle SN having a slit-shaped opening into a plate shape.

  The rolling roller 110 may have various functions. For example, you may make it use the rolling roller 110 by which the pattern for transcription | transfer (the lens for solar cells) was formed in the surface of roller 110A, 110B. A plurality of rolling rollers 110 may be arranged to form a multistage rolling roller. Further, a cullet discharging mechanism for discharging cullet generated when the glass G is formed may be provided immediately below the rolling roller 110.

  The stretching roller 120 is composed of a pair of rollers 120A and 120B arranged to face each other. The drawing roller 120 pulls out the glass plate T formed into a plate shape by the rolling roller 110. Here, the drawing roller 120 pulls out the glass plate T formed by the rolling roller 110 so that the glass plate T cannot sag.

  By pulling out from the rolling roller 110 so that the glass plate T does not sag, it is possible to form the glass plate T having a high degree of flatness with less warping and waviness. In order to make the temperature in the width direction of the glass plate T uniform, temperature adjusting means may be provided inside the stretching roller 120. As the temperature control means, for example, an electric heater may be provided, or a flow path for circulating a coolant (refrigerant) may be provided.

  The panel heater 130 is disposed so as to sandwich the glass plate T between the rolling roller 110 and the stretching roller 120. In the example shown in FIG. 1, six panel heaters 130 are provided above and below the glass plate T, respectively. The panel heater 130 can independently heat the glass plate T, and regulates the glass plate T to a desired temperature. Note that the number of the panel heaters 130 is not limited as long as the glass plate T can be adjusted to a desired temperature.

The inclined conveyor 140 is a conveyor constituted by a plurality of transfer rollers 141. It is preferable that the inclined conveyor 140 is inclined in a range of 30 ° to 60 ° with respect to the horizontal direction. That is, the inclination angle θ ₁ of the inclined conveyor 140 is preferably 30 ° or more and 60 ° or less. The inclination angle θ ₁ is an angle of the inclined conveyor 140 with respect to the horizontal plane P ₁ .

If the inclination angle θ ₁ of the inclined conveyor 140 is less than 30 °, the inclined conveyor 140 is excessively inclined, so that the glass plate T is bent sharply at the lower end of the rolling roller 110. For this reason, there exists a possibility that the flatness of the shape | molded glass plate T may become low. Further, when the inclination angle θ ₁ of the inclined conveyor 140 exceeds 60 °, the inclined conveyor 140 becomes longer in the vertical direction. For this reason, the advantage which inclines the inclination conveyor 140 will fade.

  In this embodiment, the conveyor which conveys the glass plate T is disposed at an angle, so that the lower surface of the glass plate T is conveyed in a state of being in contact with the conveying roller 141. For this reason, the glass plate T does not move back and forth and left and right with respect to the transport direction. As a result, the glass plate T can be stably conveyed. Moreover, the impact at the time of cutting the glass plate T by the cutting mechanism 150 is transmitted to the upstream side and does not adversely affect the forming of the glass plate T.

  Moreover, the height direction of the shaping | molding apparatus 100 of the glass plate T and the length of a horizontal (horizontal) direction can be suppressed. Furthermore, since the glass plate T after cutting can be prevented from falling, a mechanism for holding (catching) the glass plate T so as not to be impacted becomes unnecessary.

  The cutting mechanism 150 cuts the glass plate T in an inclined state. The cutting mechanism 150 includes a wheel cutter 151, a guide 152, a roller 153 provided with a protrusion 153 a (hereinafter referred to as a break roller 153), and a drive motor 154 that rotates the break roller 153.

  The wheel cutter 151 makes a crack on the back surface of the glass plate T at a predetermined interval. At this time, the wheel cutter 151 operates in an oblique direction with respect to the glass plate T. This is to break the glass plate T while conveying it at a predetermined speed. By setting the angle in consideration of the conveyance speed of the glass plate T and the operation speed of the wheel cutter 151, it is possible to make a crack in a direction perpendicular to the conveyance direction of the glass plate T.

  The guide 152 operates in synchronization with the operation of the wheel cutter 151 and presses the glass plate T from above. By using the guide 152 to press the glass plate T from above, the glass plate T can be surely broken.

  The break roller 153 is rotationally driven at a predetermined rotation (rpm) by the drive motor 154, impacts the broken glass plate T, breaks the glass plate T along the crack, and obtains a glass piece P.

  In addition, it is preferable to cut | disconnect the glass plate T within the temperature of 100 to 300 degreeC.

The push-up mechanism 160 is a metal plate that is fed out in the transport direction so that the glass plate T is easily broken. The tilt angle θ ₂ of the push-up mechanism 160 is smaller than the tilt angle θ ₁ of the transport mechanism 130. For this reason, the glass plate T conveyed by the conveyance mechanism 130 is sent out in the conveyance direction by the push-up mechanism 160 so that the tip portion is pushed up. For this reason, in the glass plate T, the inclination angle of the glass plate T on the tip side (front side with respect to the conveyance direction) from the crack is larger than the inclination angle of the glass plate T on the rear side (backward with respect to the conveyance direction) from the crack. It becomes small. The inclination angle θ ₂ is an angle of the push-up means 160 with respect to the horizontal plane P ₂ .

  That is, the push-up mechanism 160 sends out in the transport direction so as to widen the cracks entering the back surface of the glass plate T. As a result, the glass plate T is very easily broken. And the glass plate T can be reliably cracked by giving an impact to the glass plate T with the break roller 153 in the state which the crack which entered the back surface of the glass plate T has spread by the raising mechanism 160. FIG.

Note that the tilt angle θ ₂ of the push-up mechanism 160 is preferably in the range of 30 ° to 60 ° (however, the tilt angle θ ₂ of the push-up mechanism 160 is smaller than the tilt angle θ ₁ of the tilt conveyor 140). . Moreover, as long as it can endure the temperature of 100 degreeC-300 degreeC, you may use materials (ceramics and heat resistant resin) other than a metal for the raising mechanism 160. FIG.

  The conveyor 170 conveys the glass piece P discharged | emitted from the raising mechanism 160 to the slow cooling apparatus which is not shown in figure.

  Next, the molten glass G will be described more specifically. FIG. 2 is a partially enlarged view of the glass plate forming apparatus 100, specifically, an enlarged side view of a region including the rolling roller 110.

  As shown in FIG. 2, the molten glass G supplied from the slit nozzle SN is formed into a plate shape by a rolling roller 110. At the time of this shaping | molding, the molten glass G is shape | molded so that the contact area with the molten glass G (glass plate T) may become wide on the roller 110A (1st rolling roller) side in the downstream of the rolling roller 110. That is, the molten glass G is formed in a form slightly wound around the inclined roller 110A side of the glass plate T.

(First method)
Next, a method for forming the molten glass G in a form slightly wound around the one roller 110A side will be described. As a first method, the rotation speed (feeding speed) on the roller 110A side may be slower than the rotation speed (feeding speed) on the roller 110B side. By making the rotation speed on the roller 110A side slower than the rotation speed on the roller 110B side, the delivery speed of the molten glass G on the roller 110B side is increased.

  As a result, the molten glass G is molded in a form slightly wound around the inclined roller 110A side of the glass plate T. The rotation speed of the rollers 110A and 110B is preferably about 85 to 99, more preferably about 90 to 98, when the rotation speed of the roller 110B is 100.

  In this embodiment, since the size (diameter) of the roller 110A and the roller 110B is substantially the same, the rotation speed on the roller 110A side is slower than the rotation speed on the roller 110B side. When the diameters are different, the rotation speed of each of the rollers 110A and 110B is adjusted so that the speed (feeding speed) of the outer peripheral surface on the roller 110A side is slower than the speed (feeding speed) of the outer peripheral surface on the roller 110B side. .

When the diameters D of the rollers 110A and 110B are the same, if the rotation speed of the roller 110A is 95 when the rotation speed of the roller 110B is 100, the pulling angle θ ₃ (inclination angle θ ₃ ) of the glass plate T is assumed. Is about 45 ° with respect to the vertical direction. Also, when the rotational speed of the rollers 110A when the rotational speed of the rollers 110B and 100 is 90, the inclination angle theta ₃ of the glass plate T is about 60 °. Furthermore, when the rotation speed of the roller 110A is 85 when the rotation speed of the roller 110B is 100, the inclination angle θ ₃ of the glass plate T is about 90 °.

(Second method)
As a second method, the surface temperature on the roller 110B side may be lower than the surface temperature on the roller 110A side. By making the surface temperature on the roller 110B side lower than the surface temperature on the roller 110A side, the releasability of the molten glass G on the roller 110B side is improved. As a result, the molten glass G is molded in a form slightly wound around the inclined roller 110A side of the glass plate T.

  Further, in order to make the surface temperature on the roller 110B side lower than the surface temperature on the roller 110A side, a coolant (refrigerant) is circulated in each of the rollers 110A and 110B, and the flow rate of the refrigerant circulated to the roller 110A side is increased. May be. Moreover, an electric heater may be provided in each of the rollers 110A and 110B, and the current flowing to the roller 110B side may be increased.

  Further, a thermometer for measuring the surface temperature of each roller 110A, 110B is provided, and the flow rate and current value of the refrigerant circulated in each roller 110A, 110B are controlled based on the temperature measured by the thermometer. Good. The difference in surface temperature between the roller 110A and the roller 110B is preferably 10 ° or more.

  The first method and the second method described above may be combined.

(Cause of unevenness)
Next, in the conventional roll-out method, the cause of periodic irregularities occurring in the molded glass plate T will be considered. Each of the rollers 110A and 110B of the rolling roller 110 is connected to a motor, which is a power source, via a gear, but the period of unevenness generated on the glass plate T is substantially the same as the pitch of this gear. Moreover, the force required at the time of rolling tends to occur with a thin glass plate T having a large thickness. From the above, it is considered that a force that alternately presses the molten glass G is generated on each of the rollers 110 </ b> A and 110 </ b> B, and periodic unevenness is generated on the glass plate T. That is, it is estimated that the periodic unevenness of the glass plate T is caused by the backlash of the drive system gears of the rollers 110A and 110B.

  Further, when the rotation speeds of the rollers 110A and 110B are the same, the molten glass G formed into a plate shape passing between the rollers 110A and 110B is drawn out in the vertical direction and then bent toward the roller 110A. (See FIG. 3). For this reason, it is speculated that this also contributes to the periodic unevenness generated in the glass plate T (it is considered that wrinkles (unevenness) are generated by being bent halfway). Furthermore, it is considered that the glass plate T drawn out in the vertical direction alternately contacts the rollers 110A and 110B.

  From the above, it can be seen that the above-described first and second methods are effective in suppressing the occurrence of periodic irregularities in the glass plate T. That is, by forming the glass plate T so as to be slightly wound around the one roller 110A, a load is applied to the roller 110A rather than the roller 110B. As a result, the rotational torque of the rollers 110A and 110B is unlikely to fluctuate and gear backlash is less likely to occur. Moreover, since the surface of the glass plate T is flattened by the outer peripheral surface of the roller 110A by being pulled out along the outer peripheral surface of the roller 110A, the flatness of the glass plate T is further improved. In order to further improve the flatness of the glass plate T, after the glass plate T is formed into a plate shape, a re-warping process in which the glass is heated again or pressed while being heated may be separately provided.

  Furthermore, since the glass plate T is sent out in a state where the glass is wound, the glass plate T drawn in the vertical direction is not bent to the roller 110A side after being drawn out in the vertical direction. 110B is not alternately touched. For this reason, it can suppress effectively that a periodic unevenness | corrugation generate | occur | produces in the glass plate T. FIG.

Next, an Example is given and this invention is demonstrated in detail. In this example, a glass plate was formed using the glass plate forming apparatus 100 described with reference to FIGS. 1 and 2, and the unevenness of the glass plate was measured. The unevenness is measured by measuring the rotation speeds of the rollers 110A and 110B of the rolling roller 110 by setting the rotation speeds of the rollers 110A and 110B of the rolling roller 110 to 95: 100 (gear ratio 95%). Was performed on a glass plate (comparative example) when the ratio was 100: 100 (gear ratio 100%). The diameters of the rollers 110A and 110B are the same, and the drawing angle θ ₃ (tilt angle θ ₃ ) of the glass plate is about 45 ° with respect to the vertical direction. The molded glass plate had a width (direction perpendicular to the molding direction (longitudinal direction)) of 300 mm and a plate thickness of 1.2 mm. Moreover, the plate | board thickness of the glass plate was substantially the same in all the measurement points in the Example and the comparative example.

  FIG. 4 is a diagram showing the measurement results of the unevenness of the example. FIG. 5 is a diagram showing the measurement results of the unevenness of the comparative example. 4 and 5, the vertical axis represents the displacement (μm) in the height direction (plate thickness direction) of the glass plate (from the reference height), and the horizontal axis represents the glass plate from the reference point (measurement start point). The distance (mm) in the molding direction (longitudinal direction) is taken. In addition, the measurement results of the unevenness are shown at the center in the direction orthogonal to the molding direction and at three locations 60 mm away from the center in the end direction. In addition, the measurement of the unevenness | corrugation (displacement amount) of an Example and a comparative example was performed by 1 mm pitch with respect to the shaping | molding direction (longitudinal direction) of a glass plate.

  From the measurement results, it can be seen that in the embodiment shown in FIG. 4, the height displacement is about 70 μm in height difference, and no periodic unevenness is generated. On the other hand, in the comparative example shown in FIG. 5, it is understood that the displacement in the height direction is about 500 μm in height difference, and irregularities having a period of about 20 mm are generated in the measurement length direction. In addition, since the unevenness | corrugation which has generate | occur | produced in the Example is not a periodic unevenness | corrugation, it is thought that it is based on the curvature and plate | board thickness deviation of a glass plate.

  Moreover, since the unevenness | corrugation generation | occurrence | production tendency of the center and the edge part side of a comparative example is the same, and the unevenness | corrugation tendency is the same in the width direction of shaping | molding, the unevenness | corrugation which has generate | occur | produced in the glass plate is in a glass plate forming process It is thought that it is caused.

  From the above, the rotation speed on the roller 110A side is made slower than the rotation speed on the roller 110B side, that is, the contact area with the molten glass G is widened on the roller 110A side on the downstream side of the rolling roller 110. It was found that the unevenness (displacement amount) of the glass plate to be formed can be suppressed by forming the glass plate.

  The glass plate molding method of the present invention can obtain a glass plate with high flatness, and is suitable for molding a thin glass plate, particularly a glass plate having a thickness of 0.5 mm to 2.5 mm.

  DESCRIPTION OF SYMBOLS 100 ... Molding apparatus 110 ... Rolling roller, 110A, 110B ... Roller, 120 ... Stretching roller, 120A, 120B ... Roller, 130 ... Panel heater, 140 ... Inclined conveyor, 141 ... Roller for conveyance, 150 ... Cutting mechanism, 151 ... Wheel cutter, 152 ... guide, 153 ... break roller.

Claims (4)

A process of flowing molten glass from the slit-shaped opening;
Rolling the molten glass with first and second rolling rollers arranged to face each other, and forming a glass plate;
A step of transporting the glass plate inclined toward the first rolling roller, and
With
The surface temperature of the first rolling roller is higher than the surface temperature of the second rolling roller;
A method for forming a glass plate, wherein the glass plate is formed such that a contact area with the molten glass is widened on the downstream side of the first and second rolling rollers on the first rolling roller side. .   The method for forming a glass sheet according to claim 1, wherein a speed of the outer peripheral surface of the first rolling roller is slower than a speed of the outer peripheral surface of the second rolling roller. In the step of transporting the glass plate inclined to the first rolling roller side,
The method for forming a glass sheet according to claim 1 or 2 , wherein the glass sheet is conveyed using an inclined conveyor that is inclined in a range of 30 ° to 60 ° with respect to the horizontal direction . The thickness of the said glass plate exists in the range of 0.5 mm-2.5 mm, The shaping | molding method of the glass plate of any one of Claim 1 thru | or 3 characterized by the above-mentioned.

Images