Learn more about tempered glass

Tempered glass production process includes: batching, melting, forming, annealing and other processes. 

The introduction is as follows:

1. Proportioning: according to the designed material list, all kinds of raw materials are weighed and mixed evenly in a mixing machine. The main raw materials of glass are: quartz sand, limestone, feldspar, soda ash, boric acid, etc.

2. The raw material will be heated uniformly without bubbles. This is a very complex physical and chemical reaction process. Glass is melted in a furnace. There are mainly two types of Furnaces: one is crucible furnace, in which the glass material is stored in the crucible and heated outside the crucible.

3. Forming is to transform molten glass into solid products with fixed shape. Glass forming must be carried out in a certain temperature range. This is a cooling process. The glass first changes from viscous liquid to plastic state, and then to brittle solid state. Forming methods can be divided into artificial forming and mechanical forming——

A. Artificial forming. There are——

(1) Blowing, with a nickel chromium alloy blowing pipe, pick a group of glass in the mold while rotating and blowing. It is mainly used to form glass bubbles, bottles, balls, etc.

(2) Drawing: after blowing into bubbles, another worker sticks it with a top plate. Two people blow and pull. It is mainly used to make glass tubes or rods.

(3) Press, pick a ball of glass, cut it with scissors, drop it into the die, and then press it with the punch. It is mainly used to form cups and plates.

(4) Free forming, after picking materials, directly make crafts with pliers, scissors, tweezers and other tools.

B. Mechanical forming. Because of the high labor intensity, high temperature and poor conditions of artificial forming, most of them have been replaced by mechanical forming. In addition to pressing, blowing and drawing, there are——

(1) Calendering method is used to produce thick plate glass, engraved glass, wire glass, etc.

(2) Casting method, production of optical glass.

(3) Centrifugal casting method is used to manufacture large diameter glass tubes, utensils and large capacity reaction pots. This is to inject the glass melt into the high-speed rotating mold. Due to centrifugal force, the glass clings to the mold wall, and the rotation continues until the glass hardens.

(4) sintering process is used to produce foam glass. It is to add foaming agent into glass powder and heat it in a metal mold with a cover. During the heating process, the glass forms many closed bubbles, which is a good heat insulation and sound insulation material.

4. Annealing. During the forming process, the glass undergoes intense temperature and shape changes, which leave thermal stress in the glass. This thermal stress will reduce the strength and thermal stability of glass products. If it is cooled directly, it is likely to rupture during cooling or during storage, transportation and use.