The type of heat tunnel used is typically dictated by the type of shrink film being shrunk onto the pack. The two main types of film used are polyolefin and polythene and to get the best out of each shrink film a different specification of heat tunnel is recommended.
Shrink Heat Tunnels for Polyolefin Film
You would typically use Polyolefin shrink film for display packaging applications where the appearance of the product on the shelf is critical.
Our shrink tunnels for Polyolefin utilise an active rotation conveyor system, ensuring perfect under pack shrinking is achieved as the pack actually travels faster than they conveyor belt itself. Accurate temperature control is important for absolute consistency of presentation and so “solid state” temperature controllers are used as the most accurate and reliable method to achieve this. Energy efficiency is increasingly important and so all of our shrink heat tunnels have exceptional insulation allowing YPS to offer an industry leading, five year warranty on the heating elements on all of our tunnels.
Yorkshire Packaging Systems supply shrink tunnels with accurate air flow control to three sides with sliding vents ensuring the best presentation can be achieved with any pack using polyolefin shrink film. Our shrink tunnels are also complete with an automatic run down timer making it easier for the operator and extending the life of the heating elements.
Shrink Heat Tunnels for Polythene Film
Polythene shrink film is typically thicker and more durable and behaves differently in the shrinking process than polyolefin film and so requires more heat to shrink. In addition most packs shrink wrapped in polythene tend to be substantially heavier than packs shrink wrapped in polyolefin and so the specification of shrink tunnel reflects this.
For Polythene applications we always recommend a steel mesh belt complete with an under belt blower and an after pack cooler.
We use a steel mesh belt with side chains as this is better on heavy packs compared to the cheaper method of using just a friction drive at the end of the shrink tunnel. This is because whilst a friction drive is acceptable for a lot of packs, the belt over time will stretch and with heavier packs in particular this can lead to the need to change the belt.
Side chains prevent the belt ever stretching and provide a much more positive method of driving the belt.
The under belt blower simply blows cool air onto the belt whilst it completes its full cycle. This prevents a critical temperature being reached on the belt, so that there is no possibility of polythene sticking to the belt if it gets too hot.
Their variable speed control provides complete control of production speeds and the adjustable air flow system helps to achieve the best possible presentation. The double insulated curtains improving consistency and reducing running costs.
Finally the after pack blower cools the pack down immediately after it leaves the heat tunnel. This completes the shrinking process on polythene and ensures that the packs reach maximum handling strength in the shortest possible time. Polythene shrink film reaches full strength once it has cooled.
YPS have worked with ULMA Packaging a highly trusted, reliable shrink wrapping machine supplier for over 35 years and are also able to custom modify these machines alongside YPS built machines in order to create automated packaging systems specific for each customer’s needs or factory format.
- Accurate temperature control ensuring absolutely consistent end pack presentation.
- Variable speed control providing complete control of production speeds.
- Active rotation conveyor ensuring perfect under pack shrinking.
- Adjustable air flow system helping to achieve the best possible presentation.
- Double insulated curtains improving consistency and reducing running costs.
- Solid state relay temperature controllers for improved reliability and accuracy.