Method of Forming Glass Containers

Due to the characteristics of glass: its viscosity changes with temperature and there is no definite melting point. The forming and setting process is continuous, which makes glass containers have a variety of forming methods, which is an important characteristic that distinguishes glass from other materials.

The main forming methods of glass containers are blow molding, pressing, drawing, pouring, sintering, etc.

From the artificial or mechanical molding, it can be divided into manual molding and mechanical molding.

1. Artificial molding

Before the invention of forming machines, they were all formed manually. Manual molding mainly includes: manual blowing, free molding, manual pressing, manual drawing.

(1) Manual blowing: The main tools for manual blowing are hollow blowing rods and carbon lining molds.

The main processes of manual blowing are: picking, blowing small bubbles, blowing, and processing.

(2) Free forming: No molds are used, glass products are made with some special tools, which are mainly used for the production of artworks.

(3) Manual drawing: Manual drawing mainly refers to the forming method of drawing glass tube (or glass rod), which is produced from the blowing method.

The main process is similar to the blowing method, namely picking, rolling, making foam, and drawing the tube. Under constant blowing, the glass tube is drawn at a certain speed.

(4) Manual pressing: It is an older forming method, in fact it is a semi-mechanical forming method. It is operated manually from picking, cutting to pressing, demoulding, etc.

2. Mechanical molding

Before all mechanized molding is realized, glass containers are still semi-mechanized molding. At that time, the main methods for forming hollow products: the press-blow method and the blow-blow method have been invented. Initially, the picking of the glass, the opening and closing of the model, the transfer of the prototype and the product were manual operations. Other processes are carried out mechanically.

Later, the forming table was developed into a rotary table, and the rotary table was manually operated by a motor. In addition to picking materials, model opening, closing, and prototype transfer are gradually replaced by machinery.