Processing Machinery
2 views
Random copolymer polypropylene pipe special material (Nordic standard） extruded products inner wall roughness
Problem Phenomenon
The inner wall of the pipe or profile is rough and uneven, with visible stripes or particles.
A rough inner wall affects pipe fluid resistance and hygienic performance, and may breed bacteria in water supply pipes.
Cause Analysis
（1）The mandrel temperature is too low, the melt undergoes stick-slip flow on the mandrel surface\
（2）The mandrel surface finish is insufficient or worn\
（3）Compressed air pressure insufficient (during internal pressure sizing)\
（4）Melt temperature too low, flowability poor\
（5）Screw plasticization insufficient, unmelted particles in the melt
Solution
（1）Appropriately increase the mandrel temperature, matching the die temperature (200-220°C range)\
（2）Polish the mandrel surface to Ra≤0.2μm, chrome plating if necessary\
（3）Check the compressed air system, ensure stable pressure\
（4）Appropriately increase the barrel temperature to a reasonable value within the 200-220°C range\
（5）Optimize screw design and speed, ensure full plasticization
Key Takeaway
Inner wall roughness is caused by low mandrel temperature or poor surface condition, and needs to be solved from temperature control and mold maintenance.
Was this helpful?
0 people found this helpful
Thank you for your feedback!