This process is made in one single machine and one single station, but is compounded by two steps, in difference with blow injection preform is manufactured
and it can be storage, transported and blown in a different machine. In this process since the preform is injected until it is blown the process is not
interrupted at anytime.
This process is very common in plastic containers for pharmaceutical and cosmetic industries, because it is a more advanced technology.
1. In this technique the fused material is injected trough one or many holes on the first mold.
2. Getting an empty form denominated “preform”.
3. It gets cold until reaches a temperature which the material is still moldable and it is closed into semi molds which bring form to the plastic container.
4. Pressurized air is blown and material is stretched..
5. When material touches the mold it gets cold acquiring its definitive shape.
6. In this last phase, bottle is expelled.
Therefore, this technology has two main stages:
1. In the first one, the neck of the bottle and weight are done.
2. On the second one the plastic container is stretched and then blown (it is bioriented), determining its final aspect.
There are also machines that add a conditioning stage. They regulate temperature on simultaneous zones of the preform and act over the material stretching.
Advantages of Bioriented process over conventional process:
Weight and volume precision in the container are excellent. Once the injection pressure is regulated there are no considerable variations on these parameters.
The neck of the containers is an injected piece, because of this; there are not important variations on neck’s dimensions, assuring under control tolerance ranges.
Stretching and blowing processes, bring the plastic container and its PET molecules into two directions. This improves considerably its mechanic characteristics: Rigidness, compression resistance, etc.
Comparing conventional technology wall thickness is lower and therefore weight is lower too, we get better plastic containers with better mechanic characteristics.
Biorientation also improves material distribution along the container, improving its optical properties like shine and transparency.
Biorientation improves pass resistance to gas and steam.
In this technology there are not fins, either cutting wastes.
