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Dynamic local temperature control in micro‐injection molding: Effects on poly(lactic acid) morphology
Author(s) -
De Meo Annarita,
De Santis Felice,
Pantani Roberto
Publication year - 2018
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.24784
Subject(s) - materials science , mold , thermoplastic , composite material , molding (decorative) , crystallinity , microinjection , temperature control , polycarbonate , annealing (glass) , injection molding machine , polymer , resistive touchscreen , mechanical engineering , medicine , electrical engineering , engineering , endocrinology
Microinjection molding is one of the most efficient processes for wide‐scale production of thermoplastic polymer microparts. The injection molding process with a cold mold suffers from drawbacks, that is, the premature solidification, caused by the small thickness and large temperature difference between the surface of the mold and the incoming polymer. In this work, an original and versatile system to dynamically control the local temperature of the cavity surfaces in microinjection molding was developed. The system was used to investigate the effects of rapid variations of the temperature of a 200 μm thick cavity on the reachable flow length and study the morphology of microinjection molded parts of poly(lactic acid). For the rapid mold temperature control, electrical resistive thin components are located very near the surface of the impression to change the temperature by some tens of degrees per second. This study also demonstrates that the system is able to influence the final morphology of the part with a semicrystalline thermoplastic material. Changing the annealing time and temperature, the effects on the morphology of the part, in the mold and immediately after the injection, were investigated by microscopy analysis and X‐ray diffraction. POLYM. ENG. SCI., 58:586–591, 2018. © 2017 Society of Plastics Engineers