Overmolding - An integrated design approach for dimensional accuracy and strength of structural parts

Overmolding of thermoplastic composites is a technology in which a thermoplastic composite is thermoformed and subsequently injection overmolded. Although the feasibility of the process is increasingly demonstrated, it is acknowledged that there is a lack of proper design tools that can be used for a right-the-first-time design strategy. A model was proposed for the prediction of the bond strength between a solid polymer or composite insert and an injected polymer. A test method was developed to validate this bond strength under tensile and shear loading conditions. An experimental method was developed for the analysis of warpage and spring-forward in single curved, overmolded geometries. A thermo-elastic model was experimentally validated, finding good correlation between the measured and predicted spring-forward.