Matters needing attention in using heat shrinkable tube

Heat shrinkable tube is a blend polymer composed of rubber and plastic, with irradiation or chemical method to make the linear molecular chain of the polymer into a network structure, with "memory effect", after heating expansion, rapid cooling finalize the design, heated to a certain temperature in use, you can shrink to the size before expansion.

If there is a mistake in the selection of heat shrinkable tube in the last link, then the heat shrinkable tube can not achieve the protection effect of the cable well, and it is likely to have a bad effect on the whole circuit.

Consideration 1 - Selecting type mistake

The heat shrinkable tube has different heat shrinkable rate. The specification of the heat shrinkable tube is generally the product of the maximum inner diameter allowed after the heat shrinkable tube is shrunk by the heat shrinkable tube.

For example, the maximum allowable inner diameter after shrinkage is 2mm (that is, the inner diameter after shrinkage ≤2), the shrinkage ratio is 2, then the specification of the heat shrinkable tube is: φ4; If the shrinkage ratio is 3, then the specification of the heat shrinkable tube is: φ6.

So in the selection, we must comply with the principle of Inner Diameter > the wrapped object before shrinkage, Inner Diameter < the wrapped object after shrinkage.

Consideration 2 - The edge of the wrapped object is too sharp

When the heat shrinkable tube is cut, the incision is uneven or the grinding is not smooth, which will lead to the cracking of the heat shrinkable tube in the process of use. 

Consideration 3 - The heating temperature is much higher than the shrinkage temperature

Common tools for heating shrinkable tubes are: Lighters, Heat Guns, Special Ovens.

Lighter is a convenient and common heating tool for us, but the external flame temperature of the flame is as high as 1000 degrees, which is far greater than the shrinkage temperature of the heat shrinkable tube. Therefore, when using the lighter for heating, we must pay attention to moving back and forth so that the heat shrinkable tube is uniformly heated as a whole, so as to prevent burning the heat shrinkable tube or making the shape of the heat shrinkable tube deformed.

The heat gun is a professional heating tool, but the temperature of the commonly used heat gun can also be as high as 400℃. The heat gun is not likely to burn the heat shrinkable tube, but it is still necessary to keep moving the heat gun back and forth to heat the heat shrinkable tube as a whole to ensure the uniform contraction of the heat shrinkable tube.