Production Process

At Graham Packaging Plastics Ltd we produce:
– PET and PP containers using the Injection Stretch Blow Moulding “single stage” method
– PET containers using the “2-stage method” – Injection Moulding the preform then Stretch Blow Moulding to create the final product

Single stage – Granular resin is plasticized then injection moulded to form a preform, this is only partially cooled, the retained heat is used to ensure the preform is still flexible. The preform is then stretched and blown into the final container shape. All this takes place on one machine.

Two stage – Granular resin is plasticized and injection moulded to form a preform, the preform is then brought down to ambient temperature and stored for later use. When required the preforms are fed into a second machine which reheats the preforms to the correct temperature, the preforms are then stretched and blown. Two machines are required, but output from this method is much faster.

1.5 stage, this manufacturing method is a combination of the one stage and the two stage process, only one machine is used but the techniques of two stage processing are employed.

Graham Packaging are also the world leader on extrusion blown HDPE which is also available, contact us for more information.

Let our specialists help you to choose the correct manufacturing method for your next key project.