Processing Machinery
9 views
Screw Design Mismatch of Polypropylene Extruder
Problem Phenomenon
The product is plasticized unevenly, the output is low or the energy consumption is high, and the screw does not match the raw material characteristics.
The 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 polypropylene
(2) The screw length-to-diameter ratio is insufficient, and the plasticizing section length is not enough
(3) The transition section between the screw tip and the die head is designed improperly
(4) The screw mixing elements are not suitable for this material
(5) The screw flight depth is designed improperly
Solution
(1) Select a screw compression ratio suitable for polypropylene, generally 2.5-4.0
(2) The screw length-to-diameter ratio is at least 25:1 to ensure full plasticization
(3) Optimize the transition section between the screw tip and the die head to eliminate stagnant material areas
(4) Select suitable mixing elements (pins, barriers, etc.) according to the material characteristics
(5) Ask professional screw designers to optimize the thread parameters according to the material characteristics
Key Takeaway
The screw design needs to match the material characteristics and product requirements, and a special screw needs to be customized when necessary.
Was this helpful?
0 people found this helpful
Thank you for your feedback!