Mold Gate System and Volume Expansion of Microcellular Foaming Technology.

Abstract

Microcellular technology is an advanced foaming technique which uses inert gas as a foaming agent and brings many merits such as improved impact strength and toughness. Microcellular foaming was developed as a batch process but unfortunately, the time required for foaming is too long. Extrusion and injection molding are under development so that microcellular foaming may be profitably used in industry. In our research, we designed a controllable ratio of flow length to cavity thickness Lit mold for microcellular foaming and measured volume expansion as a function of Lit. We obtained uniformly distributed microcells about 30 pm in size and observed 30.1% volume expansion for Lit=20. Volume expansion data are necessary for designing a mold system that is proper for microcellular foam moldng.