Estimation of the foaming temperature of mold-opening foam injection molding process

Abstract

In recent years, the mold-opening foam injection molding technology has received great attention as a breakthrough technology for the production of low density and open-cell foams of three-dimensional geometries. Despite the earlier studies, there has been little investigation on the control of the foaming temperature of this foam manufacturing process. To help understand the mechanisms behind this technology, this paper presents a numerical approach to simulate the cooling of the polymer/gas mixture inside the mold cavity, and thereby, estimating the foaming temperature of this manufacturing process. The temperature of the material inside the mold cavity prior to the mold-opening foam expansion process was mathematically modeled and resolved using finite difference approximation. Iteration considerations to the exothermic crystallization phenomenon for semi-crystalline polymers were also presented with reference to the non-isothermal crystallization characteristics from the differential scanning calorimetry (DSC) analysis. The numerically simulated results were shown to agree with the results obtained from a set of mold-opening foam injection molding experiments.