Material Drying
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Rough inner and outer walls of polyolefin plastomer pipes (Variant: Enhanced Measures)
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.
In particular, additional attention is needed on the original basis; this problem is more prominent and requires focused attention.
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
（6）On the original basis, additional attention is needed: fluctuations in process parameters or changes in equipment status have aggravated this problem
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
（6）And strengthen process monitoring; on the original basis, additional attention is needed to pay special attention to parameter stability
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.
Targeted preventive measures need to be taken in different production scenarios.
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