Shrink labeling is fast becoming the go-to choice in the world of consumer product decoration. Employing automated shrink labeling using the correct shrink tunnels makes the packaging process fast, easy to manage and allows for a wide range of graphic design on the package. Shrink tunnels use heat to shrink the film around the package with little or no distortion. However, the quality of the packaging is only as good as the quality of the shrink tunnel itself. Here are some of the factors you need to keep in mind while deciding which shrink tunnel to buy:
Each of these three major types of tunnels has its most appropriate application. Dry heat is typically used for tamper evident neck bands. Infrared for tamper evident neck bands and sleeves, and a combination of the two for some graphically printed full sleeve labels. Steam is often used for full body shrink sleeve labels and typically provides distortion-free product appearance.
The temperature of the shrink tunnel needs to stay within a particular range and have a precise control system. If the temperature rises too far it can cause damage to the product itself. On the other hand, if the temperature is too low, the shrink labeling process will not be carried out completely and the labels will not conform to the product shape.
The tunnel must be capable of responding to the varying levels of thermal load during the stops and starts of normal production. A stream of product will pull heat from the tunnel and every product needs to be properly shrunk, regardless if it is the 1st or 101st. This is a function of the tunnel design and the PID settings in the temperature controller.
Good performance by a shrink tunnel is always a result of sound mechanical design. The heater specifications, materials used, fan velocity, ability to precisely control the volume and direction of the air, and tunnel size and length are all important to the tunnel performing according to expectations. The material of the tunnel should be such that it is able to regularly tolerate high temperatures. The size of the tunnel should be large enough to accommodate the range of packages and allow the sleeve to properly shrink on all sides of the package.
A good quality shrink tunnel will be able to efficiently recirculate its airflow, thus minimizing utility consumption. This will help save energy costs and minimize the machine's carbon footprint.
It is important that the conveyor through the tunnel is built for this purpose. A standard conveyor is not appropriate, particularly for a full sleeve application in which the tunnel is positioned directly on the chain. Its construction must be able to withstand the expansion and contraction of heating and cooling. The chain is typically made from a high temperature, low friction plastic. The wear strips on which the chain travels must not warp when heated. Make sure the conveyor you purchase in constructed for these requirements.
A shrink tunnel is a long-term investment, and needs to provide years of service to the factory in order to be worth the costs. Most shrink tunnels come with a one year guarantee, and should be useful for many years provided they are used properly.
The design of a shrink tunnel often plays as large a role as the film itself in the quality and appearance of the final package. Make sure to carefully examine the tunnel you are looking to buy before purchasing to see how well it performs according to the above-mentioned parameters. A properly designed and functioning shrink tunnel will ensure that not only are your products labeled properly, but also that the graphic design will come out as planned, providing the shelf pop you had intended to attract customers at the point of purchase on the store shelves.
© PDC International Corp. 2016
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