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Unexpected quality problems often occur during the production process of PE pipes, usually due to equipment or raw material problems. Below, Qingdao Shunyide Plastic Industry Co., Ltd. has compiled several common quality problems of PE pipes, as well as the causes and solutions for these problems, for your reference.

1、 Ripples appear on the surface of the pipe

Reason: 1. Insufficient cooling; 2. The size of the sealing ring is not appropriate, causing vibration.

Solution: Increase the water intake of the fixed diameter sleeve or increase the distance between the mouth and the fixed diameter sleeve. Check if the size of the vacuum tank sealing ring is small. If it is small, replace or appropriately reduce the vacuum degree of the first section of the vacuum tank, and increase the vacuum degree of the second section of the vacuum tank.

2、 Surface pitting (mainly on the inner wall)

Reason: 1. Impurities are present in the raw materials; 2. The inner wall between the mouth touch and the core touch is not cleaned thoroughly; 3. Local high temperature leads to aging.

Solution: 1. Check the raw materials; 2. Clean up or transition for a period of time; 3. Check temperature sensor

3、 Surface pits

Reason: 1. Wet raw materials and burst bubbles; 2. Uneven water volume in the fixed diameter sleeve.

Solution: 1. Drying of raw materials; 2. Adjust the water volume or replace the fixed diameter sleeve

4、 Surface bright spots

Reason: Insufficient water volume in the sizing sleeve.

Solution: Increase the water volume of the sizing sleeve or replace it with a larger one

5、 Axial roughness of inner and outer walls

Reason: The moisture content of the raw materials is too high.

Solution: Raw material drying treatment

6、 Surface not shiny

Reason: Improper melt temperature or issues with raw materials

Solution: Adjust the melt temperature or replace the raw materials

7、 Scratches on the outer surface

Reason: Sand and gravel are attached to the fixed diameter sleeve, support plate or sealing ring

Solution: Clean the fixed diameter sleeve, support plate or sealing ring

8、 Outer surface waterline

Reason: Local water holes in the fixed diameter sleeve are blocked, causing excessive water flow in some water holes.

Solution: Clean the calibrating sleeve

9、 Inner wall grooves (often found in thick walled pipes)

Reason: The wall thickness is too thick, making it difficult for the melt to cool and generate flow.

Solution: Try the central cooling system and reduce the temperature of the mouth and core touch.

10、 Uneven wall thickness of pipes

Reason: 1. Loose bolts in the mouth or core touch, and improper adjustment of the gap between the mouth and touch; 2. Uneven temperature in the mouth or core, resulting in inconsistent material flow; 3. The fixed diameter sleeve is not aligned with the mouth, and the spiral diversion shuttle or screen mesh is blocked.

Solution: 1. Tighten the bolts or adjust the gap between the mouth and touch; 2. Check the heating coil and temperature sensor; 3. Adjust the diameter sleeve and mouth to center the folding shuttle or screen.

11、 Low elongation at break

Reason: 1. Poor raw material homogenization; 2. Increased orientation and cleanliness

Solution: 1. Adjust the process temperature to enhance the plasticization effect; 2. Increase the distance between the mouth touch and the fixed diameter sleeve.

12、 Large ellipticity

Reason: Gravity effect

Solution: Add a calibration device

PE pipe manufacturers can only achieve the goal of controlling the quality of pipes while reasonably reducing production costs by establishing strict operating and process procedures, and strengthening process and control efforts.