Basic Concept Of Blow Molding

Blow molding is the process of forming a molten tube (referred to as the parison or preform) of thermoplastic material (polymer or resin) and placing the parison or preform within a mold cavity and inflating the tube with compressed air, to take the shape of the cavity and cool the part before removing from the mold.

The basic concept of blow molding comes from the glassblowing process. As early as the 1880’s there was a patented method of extruding a Celluloid polymer into a parison and blow molding a part.

Early methods and materials to blow plastics into shapes were very crude and not suitable for mass production. It wasn't until the late 1930’s that the first commercial machines and products were developed for the manufacturing of blow molded bottles.

The major event that triggered and fueled the early years of commercial blow molding was the development of low and high density polyethylene suitable for blow molding and consumer packages. From this, there was an explosion of blow molded products and equipment in both Europe and North America.