Material Drying
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PCABS hydrolysis strength loss 50%
Fenómeno do problema
The impact strength of PC/ABS parts decreases by up to 50%, the performance after processing is far below the nominal value in the material manual, and tracing found insufficient drying.
Análise das causas
PC/ABS is highly hygroscopic, moisture triggers hydrolysis in the 220-260℃ melt, permanently breaking polymer chains; 0.02% residual moisture causes hydrolytic degradation; hydrolysis is irreversible, strength loss cannot be recovered.
Solução
①Dehumidifying dryer 100-110℃×3-4 hours; ②moisture content <0.02% verification; ③dew point -40℃ monitoring; ④never rely on pellet appearance to judge drying.
Conclusão principal
PCABS hydrolysis is the culprit of 50% strength loss; the 0.02% moisture content red line must be quantitatively verified; visual judgment of drying is a fatal error.; after confirming effectiveness, fix the parameters and practices into the work instruction to prevent recurrence
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