The Effect of Injection Molding Conditions on the Morphology of Polymer Structural Foams

This study investigates the relations between processing conditions and morphology of injection molded structural foams. The samples were produced by adjusting five process parameters (blowing agent concentration, mold temperature, melt temperature, injection pressure, and back pressure) at four different levels. The experiments were based on the design of experiments (DOE) analysis with a Taguchi method, and the results were used to determine the optimum conditions to produce high quality foams in terms of low skin thickness, small cell sizes, and narrow cell size distribution combined with low foam density and high cell density. The conclusions revealed that blowing agent concentration and injection pressure were the most influential factors. Using the optimum conditions predicted from the DOE, a validation test was performed and confirmed the results. POLYM. ENG. SCI., 49:949-959, 2009. (C) 2009 Society of Plastics Engineers