Effect of Glass Bead Content and Diameter on Shrinkage and Warpage of Injection-Molded PA6

A simple technique has been introduced to evaluate the shrinkage and warpage behavior of injection molded products. Using the shrinkage values measured on specific locations of the specimen, three deformation factors have been defined to characterize the warpage behavior of the materials examined. Experiments were carried out to determine these properties of injection molded polyamide 6 (PA6) composites with solid glass bead (GB) contents of 10, 20, 30, 40 wt% and diameters of 11, 85, 156, 203 mu m. It was concluded that the flow directional shrinkages can principally be described by the change in the bead content and diameter; it was proven that the increase in bead content and in bead diameter induces a reduction in flow directional shrinkage. The rising bead content and diameter increased the deformation factor, defined by the shrinkage differences caused by the pressure drop. It was pointed out that the ideal bead content can be determined in the function of bead diameter. POLYM. ENG. SCL, 49:2218-2224, 2009. (C) 2009 Society of Plastics Engineers