RU2487089C1 - Method of bending glass sheet - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: prior to heating, glass workpiece is arranged above die and some 4-12 mm from its top surface. Glass workpiece is heated to be bent thereafter. Note here that bending is performed over the entire surface of workpiece simultaneously. After glass workpiece is curved as required, its is cooled.

EFFECT: better optical properties, decreased defects.

3 ex

Description

The invention relates to the building materials industry, in particular to the manufacture of bent glass, and can be used in the glass industry to produce bent large-sized glass products with a cylindrical curvature of the surface with a deflection arrow equal to the radius of curvature (half cylinders), used, for example, as glazing elements for fireplaces .

A known method of bending sheet glass, including heating the glass and rolling molding elements according to US patent No. 3929441, CL. 65-106, publ. 12/30/1975

The disadvantage of the analogue is that it provides for forced bending with elements of the matrix and punch. In this regard, it is impossible to obtain glassware without mechanical damage and optical distortion of their surfaces. In addition, using an analogue, it is almost impossible to obtain large-sized glassware with a cylindrical curvature of the surface with a deflection arrow equal to the radius of curvature (half cylinders).

Closest to the invention is a method of bending sheet glass, comprising heating the glass and rolling in the forming elements from the middle of the sheet to its edges according to USSR author's certificate No. 793949, IPC ⁷ C03B 23/03, publ. 01/07/1981

The disadvantage of the prototype is that during its implementation using forming elements in contact with the entire upper surface of the glass, while the forming elements locally act on the glass surface along the line of their contact, which, ultimately, leads to mechanical damage and optical distortion of both surfaces obtained glassware, since the run-in is carried out between two forming elements, namely between a convex shape and rolls. This disadvantage is most significant when obtaining large-sized glassware, which does not allow their use as optical elements of various objects. In addition, the glass is heated in a horizontal furnace when the glass is moved on the rolls, which leads to mechanical damage to the lower surface of the glass, especially at the final stage of heating, when the glass is heated to its softening temperature.

The objective of the invention is to obtain large glassware with a cylindrical curvature of the surface with an arrow of deflection equal to the radius of curvature (half cylinders), with improved optical performance and with less mechanical defects compared with the prototype.

To achieve the objective of the invention, a method for bending sheet glass, including heating the glass workpiece and bending it in a convex form, characterized in that before heating the glass workpiece is placed over the mold at a distance of 4-12 mm from its upper part, and bending is carried out over the entire glass work surface at the same time.

Placing the glass workpiece before it is heated above the mold at a distance of 4-12 mm from its upper part allows the entire heating process to be carried out up to the glass softening temperature without any contact between both glass workpiece surfaces and solid elements. The range of 4-12 mm is determined in each case and depends on the geometric parameters of the glass. The bending of the glass workpiece over the entire surface at the same time, for example, by applying a load to the edges of the glass workpiece, eliminates any contact of the upper surface of the glass workpiece with solid elements and reduces damage to its lower surface, since the workpiece is equally distributed and there is no local mechanical effect.

The method is carried out in the following sequence. glass workpieces with predetermined geometric dimensions are symmetrically placed above the mold located in the electric furnace, at a distance of 4-12 mm from the top of the mold. Carry out the glass work to the softening temperature of the glass. Next, the glass workpiece is bent over the entire surface simultaneously by loading the edge parts of the glass workpiece. After the glass workpiece has adopted the specified curvature of the forming surface of the mold, the glass workpiece is cooled to a temperature of 50 ± 10 ° C. Then, the bent glass workpiece is transferred to the cold glass processing section to obtain glassware.

Example 1. It is necessary to obtain glassware with a thickness of 6 ± 0.5 mm with a cylindrical radius of curvature R = 405 mm and with an arrow of deflection equal to R = 405 mm, the width of the product is 610 mm.

A convex metal mold with a radius of curvature of 405 mm and glass workpiece 6 mm thick and with dimensions of 610 × 1272 mm are used.

The glass blank is placed symmetrically relative to its upper part at a distance of 4 mm above the mold, while the mold is located in an electric furnace. Carry out the glass work to the softening temperature of the glass. The time of heating the glass to the softening temperature of the glass is determined by the sagging of the glass to a distance of 4 mm and contacting the glass with the upper part of the mold using a known device according to USSR author's certificate No. 734150, IPC ⁷ S03B 23/02, publ. 01/21/1980. Further, the glass workpiece is bent over the entire surface at the same time by loading the edge parts of the glass work using a known device according to the USSR copyright certificate No. 743955, IPC ⁷ C03B 23/02, publ. 06/30/1980, after the glass-workpiece has adopted the specified curvature of the forming surface of the mold, inertial cooling of the electric furnace to a temperature of 50 ± 10 ° C is carried out. Then, the bent glass workpiece is transferred to the cold glass processing section to obtain glassware.

Example 2. It is necessary to obtain glassware with a thickness of 6 ± 0.5 mm with a cylindrical radius of curvature R = 495 mm and with an arrow of deflection equal to R = 495 mm, the width of the product is 650 mm.

A convex metal mold with a radius of curvature of 495 mm and glass workpiece with a thickness of 6 mm and with dimensions of 650 × 1554 mm are used.

The glass blank is placed symmetrically relative to its upper part at a distance of 8 mm above the mold, while the mold is located in an electric furnace.

Further operations of heating, bending and cooling the glass is carried out in the same manner and in the same sequence as described in example 1.

Example 3. It is necessary to obtain glassware with a thickness of 6 ± 0.5 mm with a cylindrical surface curvature R = 585 mm, the product width is 690 mm.

A convex metal mold with a radius of curvature of 585 mm and glass workpiece with a thickness of 6 mm and with dimensions of 690 × 2167 mm are used.

Glass workpiece is placed above the mold symmetrically relative to its upper part at a distance of 12 mm, while the mold is located in an electric furnace.

The subsequent operations of heating, bending and cooling the glass work is carried out as described in example 1.

Oversized glassware obtained in examples 1-3, are better in comparison with the prototype optical performance and the absence of mechanical damage to its surfaces, which allows them to be used as optical elements for glazing fireplaces.

Information sources

1. US patent No. 3929441, CL 65-106, publ. 12/30/1975

2. USSR author's certificate No. 734150, IPC ⁷ C03B 23/02, publ. 01/21/1980

3. USSR Author's Certificate No. 743955, IPC ⁷ C03B 23/02, publ. 06/30/1980

4. Copyright certificate of the USSR No. 793949, IPC ⁷ C03B 23/03, publ. 01/07/1981 - Prototype.

Claims (1)

A method of bending sheet glass, including heating the glass blank and bending it in a convex shape, characterized in that before heating the glass billet is placed above the mold at a distance of 4-12 mm from its upper part, and the bending is carried out over the entire surface of the glass billet at the same time.