Material Drying
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Rough inner and outer walls of polyolefin plastomer pipes
Problem Phenomenon
The inner or outer wall surface of the pipe is rough, with visible stripes or particles.
Rough pipe walls increase fluid resistance and affect conveying efficiency, and may affect hygienic performance in water supply pipes.
Cause Analysis
（1）The die or mandrel temperature is too low and the melt surface is rough
（2）The surface finish of the die or mandrel is insufficient
（3）The sizing sleeve is worn or the surface is rough
（4）The melt temperature is too low and the flowability is poor
（5）The compressed air has a large water content, affecting the inner wall
Solution
（1）Appropriately raise the die and mandrel temperatures to the higher value within the range of 180-230°C
（2）Polish the die and mandrel to Ra≤0.2μm, with chrome plating treatment
（3）Check the sizing sleeve; replace it if worn or rough
（4）Appropriately raise the barrel temperature to a reasonable value within the range of 180-230°C
（5）Add a drying and filtering device to the compressed air
Key Takeaway
Rough pipe walls are caused by low mold temperature or poor surface condition, and need to be solved from temperature control and mold maintenance.
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