Abstract
The sandwich injection molding technique can be adopted in a wide range of engineering applications. In this study, plate samples with holes were molded by using the sandwich injection molding technique, and the effects of the injection velocity of the core material and the viscosity ratio of the skin/core materials on the weld line generated in the region just behind the hole were examined. The results clearly showed that the lower viscosity and the higher injection velocity of the core material result in the thicker core layer, and that the depth of the V-notch of the weld line decreased with this. This suggests that generation of the weld lines in sandwich injection moldings, which is due to combination of two flow fronts of the skin material, is also affected by the flow behavior of the core material.
