Overview

Injection stretch blow moulding is used for the production of high quality containers.

The Process
The process is divided in to four:
 
Injection
Molten polymer flows into the injection cavity via the hot runner block, to produce the desired shape of the PREFORM with a mandrel (the core pin) producing the inner diameter and the injection cavity the outer. After a set time the injection moulds and core pins part and the preform held in a neck carrier is rotated 90º.

Stretching and Blowing
Once conditioned to the correct temperature the preform is ready for STRETCHING and BLOWING to the finished shape. Once the preform is within the BLOWMOULD area the moulds close, a stretch rod is introduced to stretch the preform longitudinally and using two levels of air pressure, the preform is blown circumferentially.

Discharge
After a set time for cooling the moulds open and the preform is removed via drop chutes or robotics. In practice the four stages are carried out concurrently using a revolving carousel of moulds.