One stage vs. two stage machinery

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PET Resin
Preform molding
Preform design
Preform Animation
Blow Molding
Bottle Design
Reheat stretch blow machinery
Single stage machinery
One stage vs. two stage machinery

PET bottles are made by Injection and Stretch Blow Molding. The two steps can be integrated in one machine, or they can be performed in separate pieces of equipment.

In the two-stage process, the preforms are molded in a dedicated injection molding system which produces fully-cooled preforms. These preforms can then be stored, shipped, and even sold, before being blow molded in a different machine. The blow molding machine unscrambles the preforms, reheats them with infrared radiation, and conditions them before blow molding.

In the one-stage process, the injection molded preforms are sent directly to the blow molding station integrated in the same machine, before they are fully cooled. The preforms are blow molded with little or no reheating or conditioning. There is a wide range of capabilities in one-stage systems. Generally, these systems have lower outputs than a reheat blow machine, but cost much less than two separate machines.

The decision which process to choose is often not an obvious one. Container volumes, technical difficulty, preform availability, capital costs, as well as other factors need to be carefully weighed to choose the right process for your application. Our team of experts can guide through the decision process!