Investigations on influence of core block driving method in in-mold pressing molding on characteristics of thick wall injection molded products

In polymer injection molding, injection compression moiding is applied to actively control the melt pressure in the mold cavity during molding process. The authors have developed an in-mold pressing molding method based on thick wall injection molding to prevent voids inside molded products. In this paper, we investigated the influence of the core block driving method during in-mold pressing molding on the flow behavior of glass fiber reinforced polyamide 66, on the following; generation of voids inside molded products, glass fiber orientation, appearance and surface roughness of molded products, and tensile strength. The results show that the core back using core block is effective for improving the appearance and surface properties of molded products, and that the compressive force generated by the core block improves the strength of molded products. © 2020 Japan Society for Precision Engineering. All rights reserved.