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Heat shrink tube is not an important device in circuit design, but it plays a role of protecting the circuit and important devices in the circuit. But only by selecting the heat shrink tube according to the appropriate size, can the circuit protection be realized to the greatest extent. In this article, I will introduce the basic parameters of heat shrinkable tubes for everyone.

1.Inner diameter

We know that the cross-section of the casing is cylindrical, and the inner diameter is the size of the inner diameter of the pipe wall, that is, the distance between the inner walls. We usually use the letter Φ to indicate the diameter of Φ in engineering. Then followed by a number, indicating the value of the inner diameter. If the unit is not written by default, it is MM millimeters, such as Φ6.

2.Wall thickness

The second parameter wall thickness refers to the thickness of the pipe wall, and the inner diameter reflects the size of the pipe. What does this wall thickness mean? Intuitively speaking, it is the thickness of a thing, so what does thickness affect? We know that the role of heat shrink tube is insulation protection, so thickness affects the size of insulation protection. We all know that clothes are thick, so it is cold and warm The effect is greater, and the ability of the thinner clothes to protect against cold is small, so the wall thickness of the heat shrinkable tube affects its protection ability. Therefore, the thicker the heat shrinkable tube, the better its mechanical protection ability.

3. Shrinkage

The heat shrinkable tube will shrink when heated, and only the things that shrink will have this parameter. Sometimes the shrinkage ratio is also called the heat shrinkage ratio, heat shrinkage ratio, etc. It refers to the diameter of the heat shrinkable tube at room temperature, such as Φ6 , The diameter after heating shrinkage, such as Φ3, then what we call the shrinkage ratio is the ratio of the inner diameter of the heat shrinkable tube before shrinking to the inner diameter of the shrinking, that is, 6/3 = 2/1, this 2: 1 It is the shrinkage rate of the sleeve. The shrinkage rate reflects the shrinkage capacity of the heat shrinkable sleeve. The higher the shrinkage ratio, the finer the heat shrinkable sleeve is after fully shrinking. If the heat shrinkable tube is Φ6 before shrinking and Φ2 after shrinking, it is only two millimeters in size, then its shrinkage is 6: 2, which is 3: 1.

If it is 1.5mm after shrinkage, then the shrinkage rate is 4: 1, and the common heat shrinkable tube shrinkage rate is 2: 1, 3: 1, 4: 1; when it comes to shrinkage, we will continue to talk about the wall Thick, just like cowhide tendons, it will become thinner when it is stretched, and the wall thickness will be thicker after shrinking. After the same heat shrinkable tube shrinks, the wall thickness will also increase. For heat shrinkable tubes, it is more important. The wall thickness refers to the wall thickness of the heat shrinkable tube after shrinking, because the shrinkage is such a state that our heat shrinkable tube plays a protective role under true heavy working condition. The shrinkage rate of the heat shrinkable tube refers to the shrinkage rate in the radial direction, because in principle for the heat shrinkable tube, theoretically it is not allowed to change longitudinally.

4, shrinking temperature

On the surface, it is the temperature at which the heat shrinkable tube starts to shrink and reflect. We take the heat-shrinkable tube to start heating. When the heat-shrinkable tube starts a certain reaction, the temperature just begins to reflect the shrinkage. Our general PE heat-shrinkable tube starts with a shrinkage temperature of 84 ° C, and it starts to shrink.

5, final shrinking temperature

It refers to the temperature at the end of shrinking, which can make the heat shrinkable tube reach the temperature of full shrinkage. For example, our heat shrinkable tube is heated to 84 ° C. It is not like cowhide bands. I just need to hold it to a large size. Jin immediately bounced back completely and returned to the original state. And our heat shrinkable sleeve is not like this. When it is heated to 84 ℃, it will not immediately change back to its original shape like cowhide tendon. Our heat shrinkable tube shrinking is a gradual process. We heat the heat shrinkable tube to 84. ℃, it just reflects the shrinkage. It can't make the heat shrinkable tube shrink completely. We must continue heating and heat it to the final shrinking temperature. If it is 120 ℃, it can shrink completely.

6.Working temperature

This temperature is an important parameter throughout the heat shrinkable tube. The working temperature is sometimes referred to as the rated temperature, which refers to the normal and continuous working temperature of the casing. The first two temperatures refer to the temperature at which the heat shrinkable tube can shrink and reflect. , Let's take the Φ6 heat shrinkable tube as an example.

Heat the heat shrinkable tube slowly with a hot air gun. When the temperature starts to reach 84 ° C, the heat shrinkable tube starts to shrink and reflect, and then slowly shrinks to Φ5, Φ4. When the temperature reaches 120 ° C, the heat shrinkable tube completely shrinks to Φ3. , Shrink tightly on the object, and then the process of heating is over, and then install this part of the heat shrink tube to the air conditioner, etc., to perform normal work, its normal working environment, such as our set The normal working temperature of the tube is -55 ° C to 125 ° C, because we know that many times the product will be sold to various places, some places are relatively cold, and some places are hot, then it has a certain scope of application. Our The nominal product temperature indicates that it can be used normally at this temperature. Once it exceeds the normal use temperature, it may not guarantee the life and may not work normally. The normal temperature we are talking about here is that the heat shrinkable tube can play Insulation protection, beyond this temperature may not be able to play a role.

7, color

Needless to say, the color of the heat shrinkable tube is conventional.

This article gives a comprehensive introduction to the seven basic knowledge parameters of heat shrinkable tubes. Before choosing a heat shrinkable tube, it may take a few minutes to read the text in order to further understand the parameters, specifications, dimensions, etc. of the heat shrinkable tube, which is convenient for us Design according to the actual design situation.