Processing Machinery
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Random copolymer polypropylene pipe special material (Nordic standard） extruder screw design mismatch
Problem Phenomenon
The product is unevenly plasticized, output is low or energy consumption is high, and the screw does not match the raw material characteristics.
Screw design directly affects plasticization quality, output and energy consumption.
Cause Analysis
（1）The screw compression ratio does not match the density and melting characteristics of the random copolymer polypropylene pipe special material (Nordic standard）\
（2）The screw L/D ratio is insufficient, the plasticizing section length is not enough\
（3）The design of the transition section between the screw tip and the die head is improper\
（4）The screw mixing elements are not suitable for this material\
（5）The screw flight depth design is improper
Solution
（1）Select a screw compression ratio suitable for the random copolymer polypropylene pipe special material (Nordic standard）, generally 2.5-4.0\
（2）Screw L/D ratio at least 25:1, ensure full plasticization\
（3）Optimize the transition section between the screw tip and the die head, eliminate stagnant material zones\
（4）Select suitable mixing elements according to material characteristics (pins, barriers, etc.)\
（5）Ask professional screw designers to optimize flight parameters according to material characteristics
Key Takeaway
Screw design needs to match material characteristics and product requirements; if necessary, customize a dedicated screw.
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