Heat shrink products like heat shrink tubes, heat shrink boots, heat shrink end-caps etc are an indispensable part of any industrial application. Heat shrink tube as the name suggests is a plastic tube that shrinks on application of heat. The extent of its shrinkage depends on the shrink ratio which can be anything from a 2:1 to a 6:1. A 2:1 ratio means that shrinkage occurs to the extent of 50% of its original diameter which means that a one inch diameter will shrink to half an inch and so on. Let us know a few more details of this versatile item.

How is it Made?

The typical process involves exposing the tube to intense radiation due to which it gets expanded to a bigger size. What you purchase from the market is the expanded tubing. This tubing can remember its original diameter and shrinks to that original size on application of heat.

How Do You Choose the Right Tubing?

The tubing is made from a number of materials depending upon the requirement of the application. The most popularly used material is polyolefin unless some customization is required. It is essential that you choose the right heat shrink tubing and for this a number of factors have to be considered which are:

Shrink ratio: Large objects will need tubing with high shrink ratio. This will allow the object to be sufficiently covered and snugly fitted over with the tubing on application of heat. It is recommended to choose a tubing size which will not surpass 40% of heat shrink ratio. Longitudinal shrinkage also occurs and this factor too must be kept in mind.

Sleeve diameter: Ensure that the ultimate shrink diameter is lesser than the item to be covered as only then the sleeve will fit snugly around the object.

Wall thickness: A thick wall will offer extra protection against abrasion or environmental factors and have greater capability to combat the wear and tear of the application. However, if this requirement is not important then a thin-walled product is good enough.

Stiffness: The tubes will come with varied flexibility levels. You need to choose rightly depending upon your requirement.

Sealing: If you want an effective sealing pick tubing that can tolerate even unusual contaminants. The shrinkage percentage should be limited to about 75% of maximum. Some heat shrink tubing are equipped with adhesive layer on the insides for applications requiring maximum sealing.

Shrink temperature: The shrink temperature advocated for tubing made of polyolefin substances is about 90 degree C though high shrink temperatures of 250 degree C are obtained with PTFE materials.

Shelf life: The shelf life of the tubing varies anything from one month to 20 plus years and is determined by the material type. This is based on standards specified by regulatory bodies in this context. The tubing can be tested again to check if it meets the specifications and the shelf life prolonged to 50% of the original life.

Other considerations: Other basic considerations of operating temperature range, voltage and special considerations like oil and chemical resistance etc have to be borne in mind before you make the choice of the heat shrink tubes.

Summarizing

Keep all the above factors in mind and you will get a product that best fits your requirement.