Material Drying
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PARA Mold Temperature Too Low, Insufficient Crystallization
Problembeschreibung
PARA products show poor surface appearance, increased moisture absorption, large creep tendency and abnormal shrinkage, concentrated in batches molded with low-temperature molds.
Ursachenanalyse
PARA is a semi-crystalline polymer with a glass transition temperature of 85°C; when mold temperature is below 120°C crystallinity is insufficient; the large amorphous region proportion increases moisture absorption; failure to reach maximum crystallinity leads to post-crystallization risk and performance defects.
Lösung
①Mold temperature must be at least 120°C, recommended 120~140°C; ②Use a temperature probe to measure the actual cavity surface temperature for verification; ③DSC analysis of crystallinity to confirm no 80~120°C exothermic peak; ④Evaluate scrapping of low-temperature mold batches.
Wichtigste Erkenntnis
PARA's 120°C mold temperature red line is determined by the 85°C Tg; the DSC post-crystallization peak is direct evidence of insufficient crystallization; mold temperature verification must be measured rather than the displayed value.
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