The process set out in steps
PET Power uses a technology called ISBM for the bulk of its range. This stands for Injection Stretch Blow Moulding. The machinery is equipped for single-stage technology, which means that one and the same machine makes the preform and the final form (jar/bottle). This method is highly suited to both small and large production runs. The entire production process is optimally controlled in this way. With this method, the manufacture of bottles and jars proceeds in three steps.
Step 1: To the preform
The raw material, the PET granulate, is dried. Then it goes via a screw-shaped cylinder from the drier to the machine. During this transport the granulate grains are strongly heated, as a result of which they turn into liquid PET. In the case of normal PET, the transparent clarity occurs in this phase. Colours are now added to obtain coloured material. The liquid PET is subsequently injected into the first mould, the so-called preform mould. Here the neck of the bottle or jar receives its precise size in one go and the jar or bottle as a whole the correct weight.
Step 2: To the end form
The preform remains attached to the neck that has just been injected to a high degree of precision and then proceeds via a turntable to the next stage. In the case of some machines, this is a stage for conditioning the preform in order to, for example, further improve the temperature profile. In the case of other machines, the preform proceeds directly to the blowing phase. The blow-mould gives the preform its final shape by stretching the workable part under the neck and blowing it out. Stretching takes place by means of a stretching pin, which pushes the material to the base. Due to the blowing the PET shapes against the wall of the blow-mould, as a result of which all kinds of forms and motifs may occur.
Step 3: To the end product
The product now goes to the last machine stage. Here the extractor unit places the bottle or jar on a conveyor belt, where a check is carried out. This is the last check before the packaging phase. This may be a visual inspection, a leakage test and possibly additional supervision by camera. The method depends on the nature of the product. After this, packaging takes place according to the agreed specifications. The machines apply codes for storage and despatch.
There are other methods of making PET bottles and jars, such as the two-stage method, which is frequently used for mass production. Actually this operates according to the same steps described above, but on two different machines, which could even be at different locations. This method has pros and cons; PET Power will provide information on request. The same applies to other methods, such as the extrusion of PETG and other materials for example.
A brief instructive film is available to customers for better insight into the production processes.
Perhaps it is even better to watch how things work with your own eyes. For information on the film or a guided tour, or for specific questions, please send an e-mail to info[at]petpower.eu.