Injection Molding
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Poor PEI Melt Flowability
Problem Phenomenon
In '2079851475616104452 of PEI complex structures or thin-walled parts, incomplete filling and internal stress concentration occur, and the high-viscosity melt has large flow resistance.
Cause Analysis
PEI's melting temperature is as high as 340~380℃, far higher than ordinary engineering plastics, and the melt viscosity is still relatively high; poor flowability makes filling of complex and thin-walled structures difficult; it places high requirements on the '2079851475616104452 machine heating system and mold temperature control.
Solution
①High-pressure filling with injection pressure of 80~120MPa; ②runner with circular cross-section and diameter ≥6mm; ③use hot runner or fan gate for the gate to reduce shear heat; ④switch to a high-flow grade when necessary.
Key Takeaway
PEI's high viscosity requires dual guarantees of pressure and runner structure; 80~120MPa is the supplier's guidance range; high-flow grades are a material-level solution.
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