The glass bottle blow molding process

The blow molding process for glass bottles is a method where thermoplastic resin is extruded or injected to form a tubular plastic preform. The preform, softened, is placed in a mold, then expanded and pressed against the mold's inner wall using compressed air. After cooling and shaping, the mold is removed, leaving a hollow product. Initially used for forming glass bottles, this technique now encompasses extrusion blow molding and injection blow molding, ranking as the third-largest molding method globally after extrusion and injection molding and one of the fastest-growing methods.

In the production of glass bottles, raw material pre-processing is the initial step, involving crushing of raw materials (such as quartz sand, soda ash, limestone, feldspar, etc.) to powder form, drying of damp materials, and iron removal from iron-containing materials to ensure glass quality. Subsequently, the preparation of batch materials and the melting process occur, where glass batch materials are heated in a tank furnace or pot furnace to form molten glass.

Controlling the blowing air pressure is crucial in the blow molding process. To address potential issues during blow molding, an automatic control solution for blowing air pressure has been proposed, allowing for rapid and precise control of blowing air pressure according to a set curve, significantly improving production efficiency and product yield. Additionally, environmental factors such as temperature and humidity affect bottle capacity, with higher temperatures and humidity resulting in greater shrinkage of bottle capacity.

This process involves multiple steps and technical details, from raw material pre-processing to final product molding, each requiring precise control to ensure product quality. Adoption of advanced technologies and equipment, such as fully automated blowing air pressure control schemes, can effectively enhance production efficiency and product quality, meeting the market demand for high-quality glass bottles.