Blow Moulding

Blow moulding is used to form hollow enclosed components where there are two basic types of technology: extrusion blow moulding and injection blow moulding. In extrusion blow moulding a parison or tube is created by extrusion. A mould is then closed around the parison and the product is blown to the form of the mould with compressed air. In injection blow moulding two moulds are utilized. A mandrel or blowing stick is positioned in the first mould, and the thermoplastics material is then injected into the mould flowing around the mandrel to create a tube. This is then transferred to the second mould where air is introduced to expand it to the shape of the mould. A variation on this method is stretch blow moulding by which the material is biaxially oriented to form stronger products. This process is notably
used for the manufacture of PET bottles.

There are more than 1,300 blow moulders in Europe and AMI publishes several directories that identify the companies which carry out this
technique.