Injection blow moulding

Process:   Hot air is blown into a pre-formed tube, known as a parison, of semi-molten plastic.  Under pressure from the blown air, the parison expands, like a balloon, to fill the cavity formed by a two-part, usually metal, mould.  The tube is injection moulded allowing a thread for a lid or some other detail to be formed.  Textures can be formed on the mould walls.

Introduced:   1881 for use with cellulose nitrate

Plastics:   Commonly high density polyethylene and polyethylene terephthalate

Marks:   An injection gate – see injection moulding.

Tooling cost:   Relatively high

Production volume:   High

Uses:   Hollow articles, usually with openings of smaller diameter than the body, such as bottles or containers.