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Twelve quality problems and solutions of PE pipe

November 25,2021

Unexpected quality problems often occur during the production of PE pipes, usually due to problems with equipment or raw materials. The following will introduce the common PE pipe quality problems, as well as the causes and solutions of the quality problems.

1、Corrugation on the surface of the pipe

Cause: 1 Insufficient cooling
      2 seal ring size is not appropriate, the formation of vibration phenomenon.
Solution: Increase the water intake of the sizing sleeve or increase the distance between the mouth touch and the sizing sleeve. Check whether the vacuum tank seal ring size is small, if small, replace or appropriately reduce the first section vacuum tank vacuum, increase the second section vacuum tank vacuum.

2、Surface pitting (mainly on the inner wall)

Reason: 1 raw materials contain impurities
        2 mouth touch and core touch between the inner wall cleaning is not clean
        3 local temperature is too high, resulting in aging.
Solution: 1 check the raw materials 2 clean up or transition for a period of time 3 check the temperature sensor

3、Surface cratering

Reason: 1 raw material tide, bubble rupture
        2 sizing set of uneven water.
Solution: 1 raw material drying
          2 adjust the amount of water or replace the sizing sleeve

4、Surface Bright Spot

Cause: Insufficient water in the sizing sleeve.
Solution: Increase the water volume of the sizing sleeve or replace the sizing sleeve with a large volume of water

5、Inner and outer wall axial roughness

Cause: The moisture content of raw materials is too high.
Solution: Raw material drying treatment

6、The surface is not shiny

Cause: Melt temperature is not suitable or raw materials have problems
Solution: Adjust the melt temperature or replace the raw material

7、External surface scratches

Cause: Sizing sleeve, support plate or seal ring with sand and gravel
Solution: Clean the sleeve, support plate or seal ring

8、External surface waterline

Cause: The sizing sleeve is partially blocked by the water eye, causing the individual water eye to have too much water.
Solution: Clean the sizing sleeve

9、Internal wall grooves (mostly found in thick-walled tubes)

Cause: The wall thickness is too thick, and the melt is difficult to cool, producing flow.
Solution: Try a central cooling system to reduce the temperature of the mouth touch and core touch.

10、Uneven pipe wall thickness

Causes: 1) Loose bolts of mouth or core touch, improper adjustment of mouth touch gap.
        2) Uneven temperature of mouth or core touch, resulting in inconsistent material flow.
        3)The sizing sleeve and the mouth touch are not centered, and the spiral diversion shuttle or screen is blocked.
Solution: 1) Tighten the bolts or adjust the gap between the mouth touch
          2) Check the heating ring and temperature sensor
          3) Adjust the sizing sleeve and mouth touching the center of the folded diversion shuttle or screen.

11、Low elongation at break

Reason: 1 bad plasticization of raw materials
        2 orientation increase, cleanliness increase
Solution: 1 adjust the process temperature to strengthen the plasticizing effect
          2Increase the distance between the mouth touch and the sizing sleeve.

12、Large ellipticity

Cause: Gravity effect
Solution: Add the correction device

PE pipe manufacturers must establish a strict raw material supplier evaluation process to select the right raw materials and handle them appropriately according to their testing. The production of high quality PE pressure pipe is highly dependent on the comprehensive output capability of the equipment and the pipe manufacturer must fully investigate and demonstrate the equipment selection in order to choose the most cost effective equipment. The pipe manufacturer should establish strict operating and process procedures and strengthen the process and control to achieve both quality control and reasonable cost reduction. The process setting of pressure pipe and the solution of quality problems during production requires a lot of production experience, which requires manufacturers to accumulate a lot of raw data, analyze and summarize it, and guide the production to achieve a steady improvement of product quality.

Contact:Michelle Jiang/Andrew Shan
Mail:[email protected]/[email protected]
Phone/Whatsup/Wechat:+86 18851210802/ +86 188 5120 1053

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