The blow moulding process consists of moulding a thermoplastic into a hollow product. A tube of thermoplastic material is expanded by the injection of pressurized air and cooled through the walls of the mould. There are two main types of blow moulding: Extrusion-Injection in extrusion, a hollow tube is extruded. It is then positioned in a mould, compressed air is injected, and through contact with the walls of the mould the shaped thermoplastic cools and solidifies to the desired shape. It is a continuous or semi-continuous extrusion process. In the blow moulding injection process, it is necessary to use a preform, obtained by extruding or injecting conventional moulds from plastics and then blow moulding. In conclusion, blow moulding is a low pressure process, in which some components such as