Rapid Heating of Mold: Effect of Uneven Filling Temperature on Part Morphology and Molecular Orientation

Abstract

Mold temperature is the key parameter in determining the morphology of molded parts. Uneven temperature distribution could induce significant effects on part performances. In such cases, uneven temperature is induced to analyze the morphology developed in the molded specimens. The technology used for controlling mold temperature during the process is crucial to maintain the short processing time. This paper proposed a strategy for controlling mold temperature during the process, avoiding a significant increase in processing time. A thin electrical heater is designed and adapted below the cavity surface, allowing for the increase of the cavity surface temperature soon after the mold closure, and the fast decrease of the mold temperature soon after the filling. The effect of several heating powers and heating durations on the molecular orientation was analyzed and exploited considering the temperature and flow field realized during the process.

Morphology Distribution in Injection Molded Parts

“…The kind of semicrystalline structures formed during injection molding of non-nucleated iPP depends on the local crystallization conditions (temperature and flow field experienced by the polymer chains). This determines the overall performance of the parts [8][9][10]. Thus, tailoring the morphological structure development during injection molding would imply tailoring the final part properties.…”