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Effects of processing conditions on birefringence development in injection molded parts. II. Experimental measurement
Author(s) -
Chen Yung Cheng,
Chen ChaoHsun,
Chen Shia Chung
Publication year - 1996
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/(sici)1097-0126(199608)40:4<251::aid-pi547>3.0.co;2-l
Subject(s) - birefringence , photoelasticity , materials science , mold , viscoelasticity , molding (decorative) , composite material , optics , engineering drawing , engineering , solid mechanics , physics
The birefringence of injection molded parts was measured using a digital photoelasticity system, which combines a digital image analysis technique and the half‐fringe photoelasticity (HFP) method The effects of processing conditions, including melt temperature, mold temperature, filling time and packing pressure, on the birefringence development in the molded parts were investigated. It was found that temperature and pressure are the two dominant factors that determine the birefringence development in the parts during the molding process. Frozen‐in birefringence of the molded parts decreases with increasing melt temperature, mold temperature and injection speed. Birefringence of the parts also increases with increased packing pressure, especially around the gate area. Numerical simulations using the Leonov viscoelastic fluid model predict similar dependence of birefringence of parts on processing conditions. Simulated results are also consistent with measured values.