Blow moulding is a process used together with either extrusion or injection moulding. Blow moulding is accomplished in two steps:
- Creating a tube of molten plastic, called a parison (the same term as used in glass-blowing)
- Inflating the tube to the desired final shape.
Blow moulding only uses thermoplastics. Stiffer and stronger materials are often used so that the walls of the product can be thinner.