Production & Quality
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Unreasonable die head flow channel design of polyolefin plastomer extruders
Problem Phenomenon
The flow velocity of each part of the extrudate is uneven, and the cross-sectional dimension deviation of the product is large.
The die head flow channel design directly affects the uniformity and quality of the extrudate.
Cause Analysis
（1）The die head flow channel distribution is unreasonable, and the flow path lengths of each part are unequal
（2）The die land length is insufficient
（3）There are dead corners in the flow channel, and the material stagnates and degrades
（4）The flow channel surface finish is insufficient
（5）The die head heating is uneven
Solution
（1）Optimize the flow channel design, using a coat-hanger or manifold distributor to ensure equal flow path lengths
（2）Increase the die land length to stabilize the melt flow
（3）Eliminate dead corners in the flow channel, with all corners transitioned by arcs
（4）Polish the flow channel surface to Ra≤0.2μm
（5）Optimize the die head heating ring arrangement to ensure uniform temperature
Key Takeaway
The die head flow channel design needs to ensure uniform melt distribution and no stagnation, and the die head should be redesigned when necessary.
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