A study on the mechanical property and 3D fiber distribution in injection molded glass fiber reinforced PA66

Polyamide66 (PA66) is being widely used for automobile part and other applications. In many cases, PA66 is reinforced with glass fiber to enhance its mechanical properties. In this study, the mechanical properties and glass fiber distributions in injection molded part have been investigated for glass fiber reinforced PA66. Two shapes of glass fibers, circular and flat, were used for the glass fiber reinforced PA66. X-ray microtomography (micro-CT) was used to observe the glass fiber distributions in the PA66 composites. Micro-CT photos were taken in three directions to observe the three-dimensional glass fiber distributions in the injection molded specimens. Investigation of the mechanical properties in relation to the glass fiber orientation revealed that the orientation of the fibers enhanced the mechanical properties. Glass fibers with smaller diameters resulted in better mechanical properties. Circular glass fiber reinforced PA66 exhibited better mechanical properties than flat glass fiber reinforced PA66. The skin layer showed that the glass fibers strongly orientated to the flow direction while glass fibers in the core layer orientated perpendicular to the flow direction because of fountain flows. Glass fibers in the core layer also oriented to the width direction of the flow. Consequently, glass fibers in this core region oriented three dimensionally. Full three-dimensional model of glass fiber orientation was proposed in this paper.