Processing Machinery
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Screw design mismatch of polyolefin plastomer extruders
Problem Phenomenon
The product is plasticized unevenly, the output is low or the energy consumption is high, and the screw does not match the characteristics of the raw material.
The screw design directly affects the plasticization quality, output, and energy consumption.
Cause Analysis
（1）The screw compression ratio does not match the density and melting characteristics of the polyolefin plastomer
（2）The screw L/D ratio is insufficient and the plasticizing section length is not enough
（3）The design of the transition section between the screw head 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 polyolefin plastomers, generally 2.5-4.0
（2）The screw L/D ratio is at least 25:1 to ensure sufficient plasticization
（3）Optimize the transition section between the screw head and the die head to eliminate stagnation zones
（4）Select suitable mixing elements (pins, barriers, etc.) according to the material characteristics
（5）Ask professional screw designers to optimize the flight parameters according to the material characteristics
Key Takeaway
The screw design needs to match the material characteristics and product requirements, and a dedicated screw should be customized when necessary.
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