Microstructure development analysis of long-glass-fiber-reinforced polypropylene in injection molded spiral-flow

[Display omitted] •In this article, we compare the fiber characteristic results by Micro-CT scan, OM and High-Temperature Sintering.•The behavior of the glass fiber will be examined by setting various screw speed and back pressure and employing different melt paths.•Increasing back pressure and screw speed will decrease the fiber length but enhance the fiber orientation average to the flow direction.•The fiber orientation displays an asymmetrical layer hierarchy because of an imbalanced mold filling phenomenon and entrance effect. The research focuses on the fiber behavior following injection molding on a spiral-flow mold, particularly its fiber orientation behavior. The behavior of the glass fiber will be examined by altering key experiment settings, the screw speed and the back pressure, and employing different melt paths. The results show that the application of high back pressure and high screw speed decreased the fiber length but successfully increased the fiber orientation average to the flow direction. The design of the melt flow paths that employed here are showing imbalance mold filling phenomena that resulting asymmetric fiber orientation hierarchy. Meanwhile, with the combination of correct settings in the experimental parameters and the right choice of melt flow path can create a very high tensor value with more than 80% fibers aligned to the flow direction.