Extrusion & Post
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Spiral Marks in PEEK Extrusion
Problem Phenomenon
Spiral flow marks rotating with the screw appear in the core of PEEK extruded rods, with annular texture visible in the cross-section, affecting the uniformity of subsequent machining performance of the rod.
Cause Analysis
After leaving the screw, the melt still retains a rotational flow component and is shaped in the die before being fully stabilized; the die land length is insufficient or lacks a flow-splitting and stabilizing structure, so the rotational texture is carried into the product.
Solution
①Install a breaker plate and screen pack assembly to break up the rotational flow; ②Extend the die land length to stabilize melt flow; ③Thoroughly clean the screw and barrel to remove accumulated material that disturbs flow; ④Appropriately reduce the screw speed.
Key Takeaway
PEEK rod spiral marks originate from the melt's rotational flow not being stabilized; a breaker plate and an extended land are the standard solutions; the influence of screw cleanliness on flow stability cannot be ignored.
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