Production technology of glass bottles

- Nov 05, 2018-

Now, glass is becoming more and more popular among consumers. There are not only polished glass, hot-melt glass, painted glass and other decorative glass, but also various functional glass, such as soundproof and noise-reducing adhesive glass. Insulating glass and insulating fire proof glass, etc. This article will introduce glass bottle production technology and glass bottle types to help you broaden your knowledge.

How is the glass made? Glass production process includes: batching, melting, forming, annealing and other processes. They are as follows:

  1. Ingredients, according to the design of the square sheet, weighing all kinds of raw materials in a mixer mixing evenly. The main raw materials of glass are: quartz sand, limestone, feldspar, soda, boric acid and so on.

  2. By melting, the raw materials are heated at high temperature to form a uniform, bubble-free glass solution. This is a very complex physical, chemical process. The melting of glass takes place in the furnace. There are two main types of furnace: one is a crucible kiln, glass in the crucible, heating outside the crucible. A small crucible kiln contains only one crucible and can be as large as 20 crucible. Crucible kiln is a gap production, only optical glass and color glass using crucible kiln production. The other is a pool kiln in which the glass is melted and the open fire is heated at the top of the glass surface. The melting temperature of glass is mostly at 1300 ~ 1600 ℃. Most of them are heated by flame and a few by electric current, which are called electric furnaces. Nowadays, the kilns are produced continuously, the small kilns can be several meters, and the big ones can be as large as 400 meters.

  3. Forming is the transformation of molten glass into a solid product with a fixed shape. The forming process must be within a certain temperature range, which is a cooling process. The glass changes from viscous liquid to plastic state and then to brittle solid state. Forming methods can be divided into two categories: manual forming and mechanical forming.

    a. Artificial forming. There are (1) blowing, with a nickel-chromium alloy blowing tube, pick a glass in the mold while blowing. Mainly used for forming glass bubbles, bottles, balls (for scratching glasses), etc. (2) drawing, after blowing into small bubbles, another worker adheres to it with a top disk, and the two are mainly used to make glass tubes or rods by blowing and pulling. (3) pressing, picking up a piece of glass, Cut it with scissors and drop it into the die and press it with the punch. Mainly used for forming cups, plates, etc. (4) Free forming, pick after the use of pliers, scissors, tweezers and other tools made directly into arts and crafts.

    b. Mechanical forming Due to high labor intensity, high temperature and poor conditions, most of manual forming has been replaced by mechanical forming. In addition to pressing, blowing and drawing, mechanical forming has (1) calendering, which is used to produce thick flat glass, carved glass, intercalated wire glass, etc. (2) casting, producing optical glass. (3) centrifugal casting, Used to manufacture large-diameter glass tubes, utensils and large-capacity reaction pots. The glass melt is injected into the high speed rotating mold. Because of centrifugal force, the glass is pressed to the mold wall, and the rotation continues until the glass harms. (4) Sintering method is used to produce foam glass. It is to add foaming agent in the glass powder, heat in the metal mould with cover, the glass forms a lot of closed bubble in the process of heating, this is a kind of very good heat insulation, soundproof material. In addition, the forming of flat glass has vertical drawing method, flat drawing method and float method. Floatation is a method that allows liquid glass to float on the surface of molten metal (tin) to form flat glass. Its main advantages are high quality (smooth, smooth), fast drawing speed and large output.

  4.  After annealing, the glass is subjected to intense changes in temperature and shape, which leave thermal stress in the glass. This thermal stress reduces the strength and thermal stability of glass products. If cooled directly, it is likely to rupture during cooling or later storage, transportation and use (commonly referred to as cold burst of glass). In order to eliminate the phenomenon of cold explosion, glass products must be annealed after forming. Annealing is holding or cooling slowly for a period of time in a certain temperature range to eliminate or reduce the thermal stress in the glass to the allowable value.

    In addition, some glass products can be stiffened to increase their strength. It includes: physical hardening (quenching) for thicker glass, tabletop glass, automobile windshield, etc., and chemical stiffening (ion exchange) for watch surface glazing, aviation glass, etc. The principle of stiffening is to create compressive stress on the glass surface to increase its strength.