In stretch blow moulding PET bottles can be manufactured by using two production techniques: The single-stage (Injection Stretch Blow Moulding) and two stage processes (Reheat Stretch Blow Moulding).
Injection Stretch Blow Moulding
In the single-stage process the preform is injection moulded from PET resin in the same machine which will stretch and inflate it to form a finished bottle. Two distinct production stages are incorporated in one machine, with the preform being transferred from one stage to the other while still warm.
Typical machines used for this production method are the Nissei ASB and the Aoki single stage machines, which can both be found at our Injection Stretch Blow Moulding equipment section:
Reheat Stretch Blow Moulding
In the two-stage process the preform is injection moulded on one machine (Preform Injection Moulding Machine ie. Husky, SIG, Netstal, Arburg, among others), and is then transferred to the second stage machine, the Reheat Stretch Blow Moulding machine. This transference can be from the Preform Supplier or through in-house production.
Typical manufacturers/brands of Reheat Stretch Blow Moulding Machines are Sidel, SIG, ADS, SIPA, SMI, Kosme or Krones among others).
Because the stretch blow moulding part of the two stage process is much faster than the injection moulding of the preforms it is possible to achieve very high outputs from two stage systems, provided that sufficient preforms are available, compared to single stage systems.
Currently output of a Reheat Stretch Blow Moulding machine is 1,000 bottles/cavity up to 1,800 bottles/cavity depending on the age of the machine.
The rate of production of injection moulded preforms is dependent on the number of cavities in the mould tool as well as cycle time. Cycle time depends on the preform wall thickness, preform neck finish and the cooling time required.
The customer choosing to operate his business by using the two stage process can enjoy the option of either injection moulding his own preforms or of purchasing them from an outside supplier. Buying preforms offers the flexibility of changing types, weights etc. without having to spend time changing over costly injection moulds. The customer is able to select the most suitable preform to produce the bottle he requires. The specification of the preform to be used will be dictated by a number of different factors in the overall production process and markets being served. These factors include not only the bottle size and contents, but how it is to be filled, the type of closure to be used and the shelf life required.
At IPR we have a wide choice of preforms available for customers to choose from. If you are interested in purchasing preforms we suggest you contact us by email at email@example.com and let us know your requirements or you can visit our sister website www.capsandpreforms.com.