What is heat shrink tubing, its main types and characteristics

  • Dec 26, 2019

A necessary condition for proper functioning of the electrical cables is its reliable insulation. In the production process proper level to achieve this parameter producing enterprise using insulating sheets, which, however, accounts for greater or lesser length removed in installation.

Accordingly, the final stage of installation of sockets, and the connection of taps, and other recovery procedures becomes the insulation integrity. Classic means is deservedly considered the masking tape to complete this procedure. For all its positive qualities of the treated area did not differ good aesthetic parameters, and often receive much hyped. And the tape reel is often not convenient.

Heat-shrinkable tubing and function

Heat-shrinkable tubing, which is a valuable alternative insulating tape is formed as a short length of typically a few tens of millimeters tubular segment terpolymer.

The material used in the manufacture of this component is selected in such a way that it:

  • He possessed good electrical properties;
  • significantly shrank during heating;
  • demonstrated a radial contraction coefficient in the range of from 2 to 6 (by heating the tube diameter down to the specified number of times, which is clearly seen in Figure 1);
  • I had a minimum value of the axial compression.

For the manufacture of pipes used polyolefin polymers, elastomers, rubber, plastic PVC, polyester, fluoropolymers. Other materials are only involved in the nomination of special requirements.

Picture 1. Shrink tube before and after exposure to a heat flux
Picture 1. Shrink tube before and after exposure to a heat flux

Compression begins by the air stream heated by conventional mounting hairdryer.

Due to strong compression action directed to the protected area:

  • achieved certain improvement in the dielectric strength is reduced and the conductivity material;
  • cut off the access of oxygen, air and aggressive slurries to the protected surface, i.e. provided protection against corrosion;
  • provided some increase in the mechanical strength.

The latter two properties are enhanced further in the case of tubes with internal adhesive, which polymerizes during installation.

Advantages and disadvantages

The process of working with the tube is extremely simple. When it is used quite correctly adjust the air flow temperature and uniformly direct it to the insulated region.

With the tube can execute, for example, the branch wires as shown in Figure 2).

Figure 2. Performance of Heat-branch via
Figure 2. Performance of Heat-branch via

The tube is well in demand in a wide range of areas, which are not related to electrical engineering.

The tube is substantially greater than electrical tape durability because contains no drying glue, and because of its homogeneity is not prone to unwinding over time.

Moreover, if assembling the disposal of heat shrinkable tubes of different colors (an example is shown in Figure 3), they can be successfully used as a marking means.

Figure 3. Heat shrinkable tubes of different colors
Figure 3. Heat shrinkable tubes of different colors

Disadvantages-shrinking tubes are in fact a continuation of its merits and are as follows:

  • a one-time nature of this component;
  • a slightly higher price;
  • dependence on the availability of the mounting dryer.

For the rest of the handset can be considered equivalent to an insulating tape.

selection rules

A significant advantage of the shrink tube can be considered as the simplicity of its selection for specific tasks.

The selection algorithm is reduced to control the following three simple rules:

  • tube material is selected according to the operating region (along with the overall application tubes exist, e.g., benzostojkie tube).
  • after installation on the workstation value shrinkage tube should be in the range of from 20 to 80% of the values ​​of its parameters.
  • tube length is selected, taking into account its 10-percent reduction in dryer after processing.

Additionally controlled by appropriate temperature shrinkage heating instrument.

Features of supply and the tool used

Known termotrubok variety in appearance of the packaging:

  • gilzovidnye certain length with packing in plastic bags (usually 50 or 100 pieces);
  • buhtovaya delivery.

Sometimes as a criterion also drawn shape of the product in its original state: there are ordinary round in cross-section and the flattened tube. The round shape is typical for thick-walled tubes, thin-walled articles from the preform size reduction considerations generally produced flat. An example is shown in Figure 4.

Figure 4. Thin wall heat shrinkable tube in the bay
Figure 4. Thin wall heat shrinkable tube in the bay

To work required:

  • sharp scissors (primarily for cutting a desired length from the coils);
  • heat gun or Melt.

Note that if you have the skill pretty high quality precipitated tube can even ordinary lighter.