Processing Machinery
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Homopolymer polypropylene extruder screw design mismatch
Problem Phenomenon
Uneven product plasticization, low output or high energy consumption; the screw does not match raw material characteristics.
Screw design directly affects plasticizing quality, output, and energy consumption.
Cause Analysis
(1) Screw compression ratio does not match the density and melting characteristics of homopolymer polypropylene
(2) Insufficient screw L/D ratio, inadequate plasticizing section length
(3) Improper design of the transition section between screw tip and die head
(4) Screw mixing elements not suitable for this material
(5) Improper screw flight depth design
Solution
(1) Select a screw compression ratio suitable for homopolymer polypropylene, generally 2.5-4.0
(2) Screw L/D ratio at least 25:1, ensure full plasticization
(3) Optimize the transition section between screw tip and die head, eliminate stagnation zones
(4) Select appropriate 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; custom dedicated screws when necessary.
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