Shrink wrapping is nothing but the covering (wrapping) of a product with a thin plastic film (plain or printed). After covering the product, film is then sealed together to form a loose bag around the product. Further, that bag is shrunk tightly with the help of a heat sealer or with a heat shrink tunnel.
Shrink wrapper process comprises of two stages:
• Enfolding the pack in shrink wrap either partially or totally and….
• Heating the shrink wraps film to activate the material’s non-stretched molecular chains into stretchable material so that it can be formed into the desired shape.
The process of shrink wrap is further divided into two types –
1) Transit: Transit packaging is the cheapest packaging of all. But, the benefit it offers, last for longer duration.
a) Polyethylene is the material exclusively used, which offers appropriate strength at a lower price.
b) Transit packaging is mostly used in the pack cans, bottles or cartons for distribution.
c) The gear used, comprises of a sheath or packaged sealer working in aggregation with a shrink tunnel.
d) 2 rolls of material produce a sleeve of shrink wrap film around the pack that is further processed over the tunnel.
e) Normally, these open sleeves don’t have any drawbacks in regards to the pack veracity, even though an alteration can be done to the tunnel whereby an effort is made to have the hole closed via surplus, hardened film.
f) The processing of polyethylene is distinguished when the shrink wrap film reaches the melt state, after that it is left to cool down, which offers additional shrink.
Now, you can understand that tunnels actually require precise cooling devices if higher output speeds are required. You can get to know more about shrink wrapping from various web sources.
2) Display: Display packaging is used for gift wrap and wallpaper roll falls. The process is totally similar, though both the sealer and tunnel will be changed to facilitate individual rolls.
In the end, automation is applied to the seal head along with packed support. Usually, it is termed as semi-automation. To fasten the functioning of the sealer head, solenoid or a pneumatic ram is used.