Capturing variability in injection molding with short fiber polymer composites

Applications of fiber filled thermoplastic injection molded parts are increasing. The need to predict and quantify the variability in these parts grows with the demand. In this work variability of the fiber orientation is captured through the Folgar-Tucker orientation tensor and variability in anisotropy is captured through the ratio of the first two diagonal terms of the fully anisotropic stiffness matrix. The largest influences on the variability of these two parameters are determined to be the mold temperature, the melt temperature, and the temperature of the heater rods in the mold. Models to predict the response of the parameters over a range of input variability are developed.