Blow Molding
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HDPE '2079851475616104457 container melt fracture
Problem Phenomenon
The parison surface is rough like sharkskin, and the container surface becomes rough accordingly.
Cause Analysis
Exit shear stress exceeds the critical value; low mold temperature and fast extrusion speed; more obvious when the regrind ratio is high.
Solution
①Change the extrusion pressure/speed; ②adjust the back pressure; ③reduce the regrind ratio; ④check the head heating band; ⑤increase the die temperature.
Key Takeaway
For rough parison, first adjust the pressure-temperature combination.
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