Quantitative study of the dimensional stability of injection molded parts using conventional and microcellular injection molding and microcellular co-injection molding

This research investigated the effects of processing conditions on the dimensional stability in terms of shrinkage and warpage (S&W) behavior of a box-shaped polypropylene part using conventional injection molding, microcellular injection molding, and microcellular co-injection molding. Design of experiments (DOE) was used to analyze significant main and two-factor interactions. Results indicate that a large reduction in S&W can be achieved when using microcellular injection molding and microcellular co-injection molding. This paper also presents the effect of process conditions on the filling pattern and microstructure of various injection molded parts, as well as the spatial distribution of the microcellular core in microcellular co-injection molded parts.