JPS6033770B2 - Thin glass forming equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thin glass forming apparatus.

Conventionally, thin glass sheets up to about one rib have been formed by a vertical drawing method, and glass sheets even thinner than this have been manufactured by polishing.

Recently, in the field of electronic materials such as panel glass for display devices and IC boards, there has been a demand for thin glass plates with a yield of 0.1 to 0.8, rather than expensive polished glass plates. It is expected that mass production technology for thin glass plates with fire-shaped surfaces will be established. On the other hand, one of the precision molding methods for glass is the glass reshaping method (Glassredra method).
wprocess) or pre-format
A preform attenuation method is known (Proceedings of the 7th International Glass Conference, Brussels, June 28-7, 1965).
March 3, pp. 77-1 to 77-8).

In this method, a glass preform with an elongated shape (
preform), for example, a tube, a square bar, or a rod-shaped body with a complicated cross-sectional shape, is supported at one end and fed into a heating furnace at a slow speed, so that the preform is heated to a temperature above the softening point of glass where it can be deformed. By holding the pre-formed body and pulling the edge of the pre-formed body, the glass can be stretched while maintaining a similar cross-sectional shape, and an elongated re-formed body having a cross-sectional shape with high dimensional accuracy can be obtained.

In this case, the ratio of the tensile speed to the feeding speed of the preform into the heating furnace determines the elongation rate of the thickness of the glass, that is, the reduction rate of the cross-sectional dimension. In the conventional preform attenuation method as described above, the thickness and the middle are reduced in almost similar shapes, so in this process, for example, to obtain a low rib bond-like glass plate with a thickness of 0.5 willow. There are 5
Approximately 100 mm when using a material glass plate (preformed body) with a side thickness of
The inside of the shipboard is required, and therefore a large-area heating device is required. In addition, in the conventional preform attenuation method, in order to avoid bending of the glass plate due to the influence of gravity, the glass plate is not stretched horizontally but vertically downward. This was inconvenient for secondary processing such as cutting, transporting, and surface treatment of glass plates. SUMMARY OF THE INVENTION The object of the present invention is to provide an apparatus for forming thin glass which does not have the above-mentioned disadvantages. The object of the present invention is to: A heating chamber equipped with a heater inside to heat the raw glass plate to a temperature at which it can be deformed; Located upstream of the heating chamber, the raw glass plate is fed into the heating chamber at a predetermined feeding speed. A thin glass forming device comprising a feeding means; a stretching device located downstream of the heating chamber that stretches the glass plate in the heating chamber at a drawing speed higher than the feeding speed to reduce the thickness of the glass plate. Leave it behind.
This is achieved by providing a holding means in the heating chamber including a plurality of rotating rolls that grip and rotate both ends of the glass plate to suppress reduction in the glass plate.

The holding means includes a pair of rotating rolls that grip the glass plate from both sides of the end of the glass plate, a rotating shaft rod that supports the rotating rolls, and a drive device that rotates the rotating shaft rod in the advancing direction of the glass sheet. Consisting of The rotating roll is made of a material that does not adhere to high-temperature glass, and is attached to the tip of the rotating shaft so that it can rotate freely. Next, the present invention will be explained with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the molding device of the present invention, and FIG.
The figure shows a plan view of the device, and FIG. 3 shows a sectional view taken in the middle direction of the device.

In the figure, 1 is a raw glass plate, 2 is a glass plate in the process of thinning in a heating chamber, and 3 is a product glass plate made into a thin plate.

The raw glass plate 1 may be formed by a well-known plate glass forming process, such as a float process, a Colburn process, a vertical pulling process, or a roll forming process, cooled, and cut to a certain size, or may be formed by It may be continuous or bong-shaped glass that has been slowly cooled or cooled to some extent.

The raw glass plate 1 is sandwiched between a pair of feed rolls 11 disposed on both the upper and lower surfaces thereof, and is advanced horizontally at a constant speed into a heating chamber generally designated by the number 12 and extending in the horizontal direction. entered.

The heating chamber 12 is divided into a preheating zone 13 as the glass plate progresses.
, a main heating zone 14 and a gradual cooling zone 15, which are divided by partitions 16 and 17.

In the preheating zone 13, the lower surface of the raw glass plate 1 is supported by support rolls 18 and sent to the main heating zone 14. The inside of the preheating zone is maintained at a predetermined temperature by a heater 19 provided along the inner wall of the refractory material that constitutes the upper and lower structures of the heating chamber, and the material glass plate is preheated to a predetermined temperature.
Prevents thermal damage due to distortion when delivered to the main heating zone. In the main heating zone 14, the glass plate is heated by the heater 20' to a temperature higher than its softening point, and is stretched by a tension force applied by a tension roll (described later) provided at the exit of the heating chamber 12, so that the thickness of the glass plate is reduced. Decrease.

The glass plate 2, which is in the process of thinning, is rolled on rotating rolls 21 whose both ends are paired up and down in order to suppress the reduction in thickness.
gripped by a group of The rotating roll 21 is attached to the tip of a rotating shaft rod 22 so as to be freely rotatable, and the rear end of the rotating shaft rod 22 is connected to a drive motor 23 by a chain 24. As shown in FIG. 3, the rotating shaft 22' of the lower rotating roll 21' is connected to the rotating shaft 22 of the upper rotating roll 21 and the gear 2 provided on each wheel.
5 and 25' and are rotated at the same speed. The material of the rotating roll must be heat resistant, oxidation resistant, and not welded to high-temperature glass, and must also have low friction with the heat-resistant steel rotating shaft. Non-oxide ceramics such as silicon are suitable.

It is preferable that the shape of the rotating roll is as small as possible to the extent that it does not interfere with the heating of the glass plate due to its shadow, and as an example, as shown in Figure 4a, the outer diameter is 7~
It has a cylindrical shape with 2 proboscis and 5 to 2 proboscis.

It may be circular as shown in FIG. 4b, or it may be shaped like a Soroban bead as shown in c. The surface of the rotating roll that comes into contact with the glass may be roughened or knurled. In the main heating zone 14, the rotating rolls form several groups and grip both ends of the glass plate 2.

In this example, as the glass progresses, three pairs of rotating rolls in the first group and four pairs each in the 0th and 0th plate groups are arranged symmetrically on one side. The rotational speed of the rotating shaft rod in each group is the same. The reason for dividing into groups in this way is that as the thickness of the glass plate decreases as the glass plate progresses, the number of revolutions of the rotating shaft rod increases. This is because if the circumferential speed of the rotating roll is slower than the speed of the glass plate, resistance will occur between the glass and the roll that prevents the glass from flowing continuously, causing the glass to accumulate in clumps. As explained earlier, the rotating roll is attached to the rotating shaft so that it can rotate freely, so there is no need to match the circumferential speed of each rotating shaft to the speed of the glass. , in each group, the rotation of the rotating shaft is adjusted to the maximum speed of the glass within that group.Since there is no resistance other than a slight dynamic friction between the rotating roll and the rotating shaft, each rotating roll in each group rotates at the same circumferential speed as the glass speed.The rotating shaft rods are usually arranged at right angles to the advancing direction of the glass plate, but the rotating shaft rods of the first, second, and mth groups rotate. is arranged at an angle of up to 30° in the direction of glass travel, and applies force to the glass plate in the direction of expanding the inside of the glass plate, thereby more effectively suppressing reduction in the inside of the glass plate. be able to.

The glass plate whose thickness has been reduced to a predetermined thickness in the main heating zone enters the slow cooling zone 15, where it is gradually cooled to a predetermined temperature while being conveyed by support rolls 26.

Reference numeral 27 indicates a heater in the lining zone.

A tension roll 28 is provided at the exit of the heating chamber, which pinches the glass plate 3 from above and below, and pulls the glass plate at a speed that is a predetermined multiple of the rotational speed of the feed roll 11. Next, an example of molding will be described.

The glass plate is sent into the heating chamber at a constant speed.

The glass plate is heated to about 5300C by about 1/3 of the preheating zone.
The temperature is increased to about 6300C at the end of the heating zone.

Next, it enters the main heating zone and is heated to the temperature required for molding. The temperature required for forming varies depending on the glass composition.
In the case of soda-lime glass, it is 660-800 oo, and in the case of borosilicate glass, it is 720-830 qo. The rotating roll is arranged in the main heating zone. The rotating roll is
It is made of a nitrided element and grips the glass plate from above and below within about four skins from the edge of the glass plate, thereby suppressing reduction in the inside of the glass plate. In the child heating zone, heaters made of nichrome wire coils are uniformly distributed over the entire surface.

As an example, the power distribution is 1 to 2.5 W/ground. The central part of the main heating zone is heated by a nichrome wire coil heater with a power distribution of 3 to 5 W/ground, and 6
Up to the first position, the power distribution is 5 to 7 W/, which is higher in density than the central part, to compensate for the influence of the shadow of the rotating roll, and at the same time raise the glass temperature by 5 to 1 pi compared to the central part.

A thin plate was formed using a borosilicate glass plate (trade name: Pyrex J) with a thickness of 5.5 mm and 244 ribs under the following two conditions as the raw glass plate.

(1) (2) Feeding.

-no fin belly 1.8 Kaya 1.8 skin 12.0 Kaya 24.0 Kaya Thinning ratio 6.7 13.3 Heating chamber temperature First half of preheating zone 520℃ 520
℃〃 Second half 630℃ 6300C main heating zone 745℃ 780℃ slow cooling zone
3000C 300℃ rotating roll angle
Uri oo Speed of group 1 16 minutes 16 minutes Speed of group □ 28 minutes 28 minutes Speed of group m 43 minutes / minute 43 minutes Product plate thickness
1. Kasa 50〃 0 Utamakura 50 Buddha valid board
110 no. 11 sail planks. warp
50 French or less 50 or less In addition, if a rotating roll is not used, the plate thickness from the above material glass plate]. In order to obtain a thin board of 1 willow, the inside of the board should be approximately 50 sides, and the board thickness should be 0.5
In the case of 5 ribs, the board size will be approximately 25 sides, but by using a rotating roll corresponding to the border stretcher according to the present invention, the effective product board size can be increased to about 2 to 4 times.

Brief Description of the Drawings Fig. 1 is a longitudinal sectional view of the molding device of the present invention;
The figure is a plan view of the device, FIG. 3 is a sectional view of the inside of the device, and FIG. 4 shows three examples of rotating rolls.

1... Raw glass plate, 2... Glass plate in the process of thickness reduction, 3.
...Product glass plate, 11...Feed roll, 12...
Heating chamber, 13... Preheating zone, 14... Main heating zone, 15... Slow cooling zone, 16, 17... Partition, 18
…support.

Roll, 19... Heater, 20... Heater, 21... Rotating roll, 22... Rotating shaft birch, 23... Drive motor, 24... Chain, 25, 25'... Gear, 26...・
Support roll, 27... Gradient roll, 28... Tension ○1're. Hair style uneven hair 4 figure hair style hair 2 figure

Claims (1)

[Claims] 1. A heating chamber equipped with a heater inside to heat the raw glass plate to a temperature at which it can be deformed; located upstream of the heating chamber, the raw glass plate is fed into the heating chamber at a predetermined feeding speed. Feeding means: A thin glass forming apparatus comprising a stretching means located downstream of the heating chamber and stretching the glass plate in the heating chamber at a drawing speed higher than the feeding speed to reduce the thickness of the glass plate. A thin glass sheet, characterized in that the heating chamber is provided with a width maintaining means comprising a plurality of pairs of rotating rolls that grip and rotate both ends of the glass sheet, thereby suppressing a decrease in the width of the glass sheet. molding equipment. 2. The width maintaining means includes a rotating roll made of a ceramic material that does not adhere to glass, a rotating shaft that supports the rotating roll at its tip, and a shaft drive that rotates the rotating shaft in the direction of movement of the glass plate. 2. The device according to claim 1, wherein the rotating roll is mounted so as to be freely rotatable at the tip of the rotating shaft.