One of the essential links of the PE pipe production line is how to use the sizing device correctly. The PE pipe melt parison leaving the machine head must be cooled and solidified in order to transmit the traction force and be formed into a PE pipe. In order to obtain the correct geometry, dimensions and perfect surface smoothness of the pipe, a sizing device should be used.

There are two kinds of PE pipe sizing methods: inner diameter sizing method and outer diameter sizing method.

The so-called inner diameter sizing method is that the sizing device controls the inner diameter and roundness of the PE pipe, so that the melt tube blank is wrapped tightly around the outer surface of the sizing sleeve to cool and harden.

The outer diameter setting method is that the sizing device controls the outer diameter and roundness of the pipe. Since ISO standards, European standards and my country's national standards are based on the outer diameter of the PE pipe specification series, in general, the production of PE pipes adopts the outer diameter setting process, and the inner diameter setting is only used in some special cases. The OD setting process can generally be divided into two categories: pressure setting and vacuum setting.

Compared to pressure setting. Vacuum outer diameter setting has the following advantages:

1. The guide tube is simple and fast, and the waste is less;

2. Air flows freely in the PE pipe during vacuum setting; the cooling effect of the inner wall of the pipe is good;

3. It can better control the dimensional tolerance;

4. The tube blank is in a plasticized state at the exit of the machine head, and there is almost no deformation;

5. The internal stress of the PE pipe is small;

6. There is no danger of being torn by the screw plug;

7. It will not stop production due to wear and tear of screw plugs;

8. The die of the die and the vacuum setting device are separated, because the temperature can be controlled separately.

What is a sizing sleeve? Special sizing sleeve for PE pipe, sizing sleeve is the most common sizing element. The sizing sleeve is tubular and made of brass, beryllium copper or aluminum. Although aluminum has good heat transfer performance, it is easily damaged. Some sizing sleeves are made by first forming a number of rings from flakes or fast materials, and then forming a tube, but most sizing sleeves are machined from tubular material.