Plastic Blow Moulding: PET Bottles and HDPE Drums

Hollow plastic is blown. A PET drinks bottle starts as an injection-moulded preform, a thick test tube with the finished screw neck; it is reheated, usually with infrared heaters, above its glass transition temperature, stretched by a core rod and blown with high-pressure air against a cold metal mould. Drums and jerrycans are extrusion blow moulded: a hot tube, the parison, is extruded, closed in the mould and blown out.