JPH0328137A - Method for forming glass vessel having flat face - Google Patents

Abstract

PURPOSE:To improve the flatness of a face of a glass vessel by sucking air through small holes of a female mold to suck and fix the molded article to the female mold before releasing the molded glass article from a male mold and thereafter releasing the male mold from the molded article. CONSTITUTION:A male mold 1 for forming the upper face and a female mold 2 for forming the lower face are heated at about 550 deg.C. Each mold has a number of small holes having diameter of <=100mum. A prescribed amount of a glass gob heated at about 1000 deg.C is supplied to the female mold 2 and pressed with the male mold 1 to form a molded article having a thickness of about 5-10mm. The space in the mold is evacuated to about 3.3X10<4>Pa through a suction port 6. The male mold 1 for forming the upper face is moved upward, the pressure in the space is returned to atmospheric pressure through the suction port 6 and the molded article is released from the mold after cooling. Unevenness caused by the small holes is unnoticeable on the central flat face of the obtained molded article and the glass vessel having a flat face free from warpage can be produced by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming glass containers from molten glass gobs, and in particular to forming glass containers with a wide flat surface used in image display devices. It is about the method.

[Conventional technology]

Conventionally, in press molding of glass products, a molten glass gob is first supplied to a concave molding mold, and then a convex molding mold is pressed against the glass gob from above to mold a glass container of a predetermined shape.

[Problem to be solved by the invention]

However, in the conventional technology, when the molding convex mold is removed from the molded body after the glass gob is press-molded, the molded body does not separate from the molded convex mold and is lifted up, resulting in a large flat surface. When molding a glass container having such a shape, there is a problem in that the flat surface of the glass container is warped. For example, it has been difficult to shape a glass container having a flat surface with a radius of curvature of about 3.6 m or more.

The present invention solves the above-mentioned problems, that is, provides a method suitable for forming a glass container having a large radius of curvature and a large flat surface.

[Means to solve the problem]

The present invention is a method for forming a glass container having a flat cross-sectional shape by pressing a glass gob fed into a concave molding mold with a flat lower bottom part by a convex molding mold having a flat upper bottom part. Prior to separating the upper molding convex from the molded body, the lower This is a method for molding a glass container, in which a molded body is suctioned and fixed to the concave molding mold, and then the upper molding convex mold is removed from the molded body.

The size of the micropores provided through the concave mold for lower molding must be 100 μm or less in diameter. In other words, in order to mold a glass container with a wall thickness of 5 to 1 (1 + 1), it is necessary to raise the temperature of the glass gob to a high temperature to reduce the viscosity, and to prevent the formation of minute irregularities on the surface of the molded product. It is necessary that the diameter of the micropores be 100 μm or less.

Furthermore, before the upper molding convex mold is pulled out from the molded body, the molded body is fixed to the lower molding concave mold by suction, and the molded body is provided so as to penetrate through the upper molding convex mold. Blowing out gas onto the surface of the molded body through a plurality of micropores with a diameter of 100 μm or less, and separating the upper molding convex from the molded body, prevents the molded body from sticking to the upper molding convex. This is more preferable in order to reliably prevent the flat surface of the molded body from being lifted and deformed.

[For production]

By vacuuming the micro holes provided through the lower molding concave mold and sucking the molded product, the molded product is fixed in the lower molding concave mold without creating minute irregularities on the surface of the molded product. be done. This prevents the molded object from lifting up when the convex molding mold is removed from the molded object.

Furthermore, before the upper molding convex mold is separated from the molded body, gas is blown out onto the molded body surface from the micro holes provided through the upper molding convex mold, so that the molded body surface and the molding convex mold are separated from each other. By creating a positive pressure state in the space between the molded body and the surface, it is possible to reliably prevent the molded body from being lifted up when the upper molding convex mold is removed from the molded body.

〔Example〕

This will be explained below based on examples.

FIG. 1 is a perspective view of an example of a glass container molded by the method of the present invention, and FIGS. 2 and 3 are schematic cross-sectional views of a mold used for carrying out the present invention.

1 is a convex mold for upper molding, 2 is a concave mold for lower molding, 3 and 4 are microscopic holes provided through, 5 is a suction port, 6 is an air supply port, and 7 and 8 are molds 1 for molding, respectively. .2 shaft connected to a lifting device (not shown).

Example 1 As shown in FIG. 2, an upper molding convex mold l provided with a large number of micropores each having a diameter of 100 μm was used.

The convex mold 1 for upper molding and the concave mold 2 for lower molding are heated to 550°C, a predetermined amount of the glass gob heated to 1000°C is supplied to the concave mold 2 for lower molding, and then the convex mold 1 for upper molding is used to heat the glass gob. was pressed to obtain a molded body with a wall thickness of 5 mm. Thereafter, the pressure inside the suction port 6 was reduced to approximately 3.3XlO'Pa using an external vacuum bomb (not shown). The upper mold 1 was moved upward to return the inside of the suction port 6 to atmospheric pressure, and the molded body was cooled and taken out. No unevenness due to micropores was observed on the central flat surface of the obtained glass container, and no warpage was observed on the flat surface.

Example 2 As shown in FIG. 3, an upper molding convex mold 2l was used in which fine holes with a diameter of 100 μm were provided at positions corresponding to the side wall portion and the peripheral portion of the flat surface of the molded body. The convex mold 21 for upper molding and the concave mold 2 for lower molding are heated to 530°C and heated to 95°C.
A predetermined amount of the glass gob heated to 0° C. is supplied into the lower molding concave mold 2, and then the glass gob is pressed with the upper molding convex mold 2l to form a molded body with a wall thickness of 5 mm as shown in FIG. I got it.

Thereafter, the pressure inside the suction port 6 was reduced to approximately 3.3×10'Pa using an external vacuum pump (not shown). While the molded body is suctioned and fixed to the lower molding concave mold 2, a small amount of air is momentarily discharged from the air supply port 5 through the narrow hole 3 between the molded body and the upper molding convex mold 21, and then Convex mold for upper molding 2L
was moved upward and away.

Then, the inside of the suction port 6 was returned to atmospheric pressure, and the molded product was cooled and removed from the lower molding concave mold 2l.

The obtained glass container had a flat surface in the center as shown in FIG. 1, and no unevenness due to micropores was observed on the flat surface, and no warpage was observed.

Comparative Example A glass container was molded using a mold having the same shape as the mold used in Example 1, with no micropores in either the convex mold for the upper mold or the concave mold for the lower mold. A predetermined amount of the glass gob at 950° C. was supplied to the lower molding concave mold, and then the glass gob was pressed with the upper molding convex mold to obtain a molded body having a wall thickness of 5 mm. After that, the upper mold was moved upward, but part of the molded product was lifted up. After cooling the molded product, it was removed from the lower mold, and the flat part of the resulting glass container was examined. Warpage occurred in a part of the central flat surface, making it impossible to obtain a flat surface over the entire area.

〔Effect of the invention〕

According to the present invention, a glass container having a wide flat surface can be formed directly from a molten glass gob without causing defects such as minute irregularities or warping on the flat surface.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a glass container molded by the method of the present invention, and FIGS. 2 and 3 are schematic cross-sectional views of a mold used for carrying out the present invention. ■, 21... Convex mold for upper molding, 2... Concave mold for lower molding, 3.4... Fine hole, 5... Suction port, 6... Air supply port. Figure 1 Figure 2 [ 'W43 Figure ■. 2. 3. 4. 6. Display of the case Patent application No. 1-162424 Name of the invention Person who amends the molding method of glass containers with a flat surface Relationship to the case Patent applicant address 3-5-11 Doshomachi, Chuo-ku, Osaka Name
(400) Tatsuji Nakajima, Representative of Nippon Sheet Glass Co., Ltd.

Claims (1)

[Claims] 1) A glass gob supplied to a concave molding mold with a flat lower bottom is pressed by a convex molding mold with a flat upper bottom so that the glass gob has a concave cross-sectional shape and a flat surface. In the method for molding a glass container, prior to separating the convex molding mold from the molded object, the molding is performed by reducing the pressure in a plurality of micropores with a diameter of 100 μm or less provided through the concave molding mold. A method for molding a glass container, which comprises sucking and fixing a body to the concave mold, and then removing the convex mold from the mold. 2) After absorbing and fixing the molded body in the concave mold for molding, gas is blown out onto the surface of the molded body from a plurality of micropores with a diameter of 100 μm or less provided through the convex mold for molding, and then the molding The method according to claim 1, wherein the convex mold is separated from the molded body.