Shrink Tunnels 101
Once the Sleeve is Applied, Whats Next?
Shrink tunnels play a crucial role in the shrink sleeve process. After a sleeve is applied by the shrink sleeve applicator, the product is moved down the conveyor to be shrunk by a steam, radiant, or electric shrink tunnel.
Shrink tunnels help to ensure that the product has a clean finish. To shrink the labels, shrink tunnels use a source of heat to conform the film to the container. Shrink tunnels use a variety of sources of heat including steam, electric, and radiant heat tunnels. Choosing the proper shrink tunnel depends on the desired heat source, the container shape and size, what type of sleeve is being applied, and the environment the tunnel will be in. It is important to pick the right shrink tunnel for your container to ensure a properly finished product.
Types of Heat
Steam tunnels use steam as the heat source to conform middle, full-body, and full body and cap shrink sleeves to the container. These tunnels are great for full sleeve applications because they offer uniform heat to shrink 360° around the container. This is ideal where high-quality, distortion-free graphics are important. When compared to other tunnels, steam tunnels run at a lower temperature around 180°-200°F. Steam tunnels often require a separate steam boiler in the production facility to provide the steam used in the tunnel. Some tunnels, including AFM’s WSN-GEN S steam tunnel, are designed with a built-in boiler and do not require an outside steam source.
Another type of shrink tunnel is an electric heat tunnel. These tunnels use heat that is produced by an electric heating element that is then circulated through the tunnel by air control fans to shrink the film to the container. Electric heat tunnels often have a compact design and can be wheeled up to an existing conveyor belt that is appropriate for the temperature the tunnel emits. Electric heat tunnels, such as AFM’s ES-200 Series tunnels, provide an ideal solution for shrinking shrink sleeve labels and tamper evident bands.
Radiant heat tunnels are used for shrinking tamper-evident bands and shrink sleeves by using electromagnetic infrared waves to shrink film. The heat is emitted by bulbs within the tunnel at a set temperature. These tunnels are great for simple and fast shrink applications like tamper bands and other low percentage shrink film. The GS Series radiant heat tunnels from AFM are designed to be compact and easy-to-operate additions to your existing shrink band applications. These tunnels can also be mounted right on top of existing conveyors as long as the conveyor is designed to withstand the high temperature the tunnel emits.
For more information on shrink sleeve tunnels, visit the equipment section of our website and view AFM’s full line of sleeving solutions. Still have questions about choosing a shrink tunnel? Contact us today, our knowledgeable packaging team is here to help!