Blow Moulding (or moulding) is a manufacturing process for forming and joining together
hollow plastic parts. It is also used for forming glass bottles or other hollow shapes.
In general, there are three main types of blow Moulding: extrusion blow Moulding, injection
blow Moulding, and injection stretch blow Moulding.
The blow Moulding process begins with softening plastic, by heating, and forming it into
a parison or, in the case of injection and injection stretch blow Moulding (ISB), a preform.
The parison is a tube-like piece of plastic with a hole in one end through which compressed
air can pass.
The parison is then clamped into a mold and air is blown into it. The air pressure then
pushes the plastic out to match the mold. Once the plastic has cooled and hardened the
mold opens and the part is ejected. Water channels within the mold assist cooling.