Experimental Study on Filling Stage of Microcellular Injection Molding Process

Abstract

An experimental research work was carried out to produce microcellular foam in an injection molding process. Microcellular foams are identified by a porous structure containing cells on the order of 10 μm in size. In this work, a conventional molding system was modified and a gas injection module was devised and integrated to the system. The experiments were carried out to attain the suitable processing windows with main emphasis on the cell growth stage (or foam expansion) via variation of shot size. While obtaining a sound microstructure, the results indicated that, in microcellular injection molding process, cell formation and growth depend strongly on the shot size. Further, it was found that a single phase solution of gas-polymer system is resulted with regulating a high shot size. Finally a foaming characteristics diagram is introduced for (microcellular) foaming process.