From Granulate to Preform and Bottle

Have you ever wondered how PET bottles are produced? Few consumers actually know where PET bottles come from and how they are made. Come and join us, one of the leading Austrian producers, on the way through the production process

Two steps to success

The production of PET bottles is a split process that requires diligence as well as careful quality control. As a first step, the PET granulate becomes the preform using state-of-the-art injection molding machines. The second step produces the final PET bottles using a stretch blow molder.

The first step consists of predrying, injection molding and cooling.

The PET preforms are produced in our production premises in Reichersdorf using state-of-the-art injection molding machines. After the granulate has been delivered, it is stored in silo facilities until it is needed. There it is protected from rain and solar radiation. When production starts, the granulate is transported to the drying unit of the machine through a pipe system. There it stays between 6 to 8 hours and is heated up by dry air (dew point – 30°C) until a temperature of 170°C is reached. As soon as the material has fallen below a certain moisture content, it can be further processed. After the pre-drying phase, the actual production starts.

Injection Molding
The pre-dried granulate is fed to the injection molding machine through another pipe system. There it is heated until a temperature of 280°C is reached. This heating process is important as it enables the material to become a homogenous mixture in the first place. Only then it can be further processed to become a PET preform. The plasticized material is injected into a preform tool, which is cooled with 6°C cold water. In this process, between 32 and 96 preforms are produced in every cycle, depending on which tool is used.

The cooling process of the preforms is highly important already during the injection molding phase as this prevents the preform from crystallization. If the preforms cool down too slowly, they turn milky and cannot be further processed. After one cycle is completed, the preforms are taken off the injection molding tool and further cooled down in a cooling station before getting packaged and being made ready for transport.

From the preform to the bottle

The majority of our customers independently execute the production step from the PET preform to the bottle. However, for customers that do not have the possibility or necessary facilities to do so, we offer to take over this step and inflate the bottles using our own stretch blow machine. State-of-the-art engineering combined with decades of development guarantee a high quality end product.

How does a PET preform turn into the actual bottle?

First, the PET preforms are heated up again until a temperature of 110°C is reached. Once this temperature is reached, the preform is handed over into a negative shape that holds the design of the actual bottle. Through clean and cool compressed air, the heated up preform is lengthened and widened until it fully fills the negative shape. This process simultaneously cools the preform. After the stretch blow molding, the PET bottles are transported to the palletizer using an air conveyer segment, where they are stacked and foiled.

Logistics: The right preform/bottle at the right time

The PET preforms- and bottles are produced individually for every one of our customers and only on demand. Hence we try to plan the production process as closely as possible to the delivery date to allow just-in-time delivery, which further allows our warehouse facilities to be used as efficiently and effectively as possible.

Quality Management: Security and Perfection

A continuously high product quality is especially essential in the food industry. In order to provide our customers with state-of-the-art, high quality products at all times, controlling already starts with continuously and carefully reviewing the delivered virgin raisin.
Moreover, the ongoing production also needs to be controlled steadily. As our machinery operates day and night, the PET preforms and bottles need to be checked frequently. Therefore our special educated employees work in the field of quality assurance in order to live up to our own claim.
In addition to the ongoing production we deliberately confront ourselves with an annual audit carried out by an external institute. Since the year 2012, we have been certified according to the strict regulations of the quality certificate FSSC 22000 (Food Safety Sytem Certification). Furthermore we rank among the establishing members of the “Gütergemeinschaft PET Verpackung” and have received the RAL Certificate for some of our products.