Maybe you are very familiar with shrink wrapping machine. Maybe you often use the shrink wrappers to package your products. But you maybe haven’t noticed they are difference between the shrink ovens of shrink wrapping machine. If you have paid enough attention to the shrink wrappers, you can find they are actually different models for using the different shrink film materials.
This shrink wrapping machine is using POF as the main packaging material, and sometimes it also could be contractable PVC film when the products are easy to get damaged by high temperature and need to lower the heating level of the shrink oven. This shrink oven has just the heat tunnel with circulation fans. The products go through this shrink tunnel then to be picked up to fill into cartons directly.
Then we see this one which is an Uline shrink oven. It’s very different from the upper one as we can see there are extra cooling fans at the end and a pair of press rollers installed at the exit of the shrink tunnel.
So why it’s different from the upper one? That’s because this shrink wrapper uses contractable PE film as the main packaging materials. The PE film is different from POF and PVC film, it has the lower shrinkage. Not easily to get the tightness within a short time. So, the use of the cooling fans are to help the shrank package to cool down rapidly to get the best shrinkage. Besides, a pair of side press rollers can make the surplus material to stick more neat and nice.
Actually, besides all these what we can see, there are more difference we can find if we take more time to study. We will find the shrink oven with cooling fans usually has its shrinking temperature set to 210 Celsius, much higher than the shrink oven without cooling fans which only set to 190 Celsius. That’s because the PE film requires much higher temperature to shrink than POF and PVC. And the shrink tunnel of PE film shrinking is often longer than shrink tunnel of POF and PVC film. Which definitely consumes much more energy.
Inside the shrink tunnel, the PE film model often has its conveyor rollers fixed and POF film model has its conveyor rollers with self rotation. That’s because the PE film can be sticky after heating up and could stick to the rollers if it’s self rotating. But the POF film can still remain its physical form during the heat shrinking process.