In the beginning, before we get to know about PET blow molding machines, we should have a brief overview of PET material: PET material is usually used for injection molding to shape plastic containers, such as mineral water bottles, cola bottles, juice bottles, etc. Properties of PET material: The material’s transparency reaches over 90%, giving transparency to the resulting containers, excellent surface gloss, and a glassy appearance. Good odor and pressure for the gas stored inside. Excellent resistance to chemicals, as PET is resistant to almost all organic drugs. High degree of cleanliness. Does not emit toxic gases when burned. Excellent strength properties, which can be enhanced by biaxial stretching. Single-stage bottle blowing machine: The single-stage injection molding machine ASB-150 for manufacturing new dual-axis PET bottles was unveiled in December 1975. All single-stage injection blow mold machines derived from the original Stretch Blow design are referred to as classic single-stage machines, as the concept has been extended for a long time to include other PET developments. The classic design of the single-stage machine is highly versatile, as the same basic design of the machine can be used to produce a variety of containers of all shapes and sizes.

In the new developments of the machine, it now produces preforms continuously. To achieve this, the machine continuously picks up a PET tube, heats and seals one end, then heats the other end and forms a thread finish by blowing. This process had a faster production rate than single-stage injection machines, at a rate of 12,000 bottles per hour for 8 and 16 cavity molds. Previously, during the production process, the produced bottles could have multiple layers of materials involved in the production process, but this has been surpassed by injection molding where the cavity increased to 32 and beyond. Additionally, the quality of the injection molded neck is considered better through the addition of some modifications such as ventilation holes. Furthermore, the IM technology is available in many machine manufacturing companies, providing customers with greater technical and commercial options. Two-stage machines are equipped with six blow molds and produce around 4,000 bottles per hour. Later, the development of the mold and cooling led to an increase in production to 6,000 bottles per hour.

The PET processing includes two stages:

Molding

Blowing bottles using stretch blow molding machines

Due to being more flexible than single-step processing, it is widely accepted in the plastic packaging market.

You can choose to make preforms only or blow bottles only if you want one of them specifically.

It is popular and widely favored in the plastic packaging market because it is more flexible than single-step processing, and you can choose to make preforms only or blow bottles in a customized manner.

Integrated two-stage blow molding machine

In the integrated two-stage approach, the preform is formed through traditional injection molding methods (with the optimal number of cavities to match the desired outputs) and then, while still hot, transferred to a separate blowing machine with the optimal number of blow molds to match the desired outputs. This was the first “integrated” approach to making PET bottles.

Source: https://www.oberk.com/packaging-crash-course/pet-blow-moulding-machines