A method to create internal geometries within injection molded parts using water soluble polyvinyl alcohol (PVOH) inserts

In this study, we experimented with using water soluble (PVOH) patterns, to create internal geometries within injection molded parts. By overmolding sacrificial PVOH patterns with a thermoplastic shell and subsequently dissolving the inserts, diverse internal features were fabricated with traditional injection molding equipment. Metrological study performed on the components has shown that precise control of the internal dimensions is possible over a wide range of processing temperatures and conditions. White light interferometry analysis conducted on the surfaces of the PVOH patterns and shell materials show that the process is capable of replicating micro-scale features and decorations onto the internal surface of the molded components. It is suggested that in the modern global market, companies differentiate on the basis of innovation and speed of development. This process can help develop and mass-manufacture, complex parts with internal geometries and undercut features faster and more economically than the industrial alternatives.