What is a PET preform?


A PET preform is the first stage in the production of a PET container. PET needs to be heated and stretched to make it strong and flexible. The first part of the production process for a PET bottle or jar is to injection mould a “test tube” like part, called a preform. The neck of the preform remains the same but the body of the preform is heated and stretched inside a mould to form the container shape. This normally occurs at a later date on a reheat blow moulding machine.


How to make PET preforms?


There are two ways of producing PET preform/bottle: one-stage “hot preform” method and two-stage “cold preform” method.


The One-Step method — from PET granule to finished bottle — all processes are completed within one integrated machine. This means the injection-molded preform is taken off from the injection cavity while still hot enough to be stretch blown to form the bottle. No extra heating is required, and since PET preforms are freshly molded every time, there is no risk of surface damage during storage or transportation. Besides, there are many other advantages such as energy saving for reheating is not required; high productivity as cooling and reheating are not necessary; no pollution as human hand is out of reach. One-Step method is highly suited to small and medium scale production lines.


The Two-Stage method refers to the injection stretch blow molding process which is composed of an injection molding machine for making the PET preforms and a reheat blow molding machine to reheat the cooled preforms and blow the bottles. The preform is injection molded on the first, then reheated and blown on the second. The requirement for a preform heating system means the two-stage process has a lower thermal efficiency but a perfect neck finish and economical resin usage. This method is most suited for PET bottle production on medium & large-scale.


Now, have you had a basic understanding in PET preform? If you are interested in or need further details about PET preform and other PET products, welcome to visit the website of Living Fountain – the professional trigger sprayers and plastic bottles manufacturer. Feel free to contact us!


Article Source: http://www.esterform.com/technology/pet-faqs.aspx


Article Source: http://www.preformmold.com/mold-faq/how_to_make_pet_preform.htm