Modeling and measuring the bonding strength of overmolded polymer parts

Overmolding a polymer onto a polymer substrate is a versatile plastic processing technique already widely used in industry and has a high potential to customize mass-produced polymer parts. Even though the industry is ready for this technology, there are still no engineering calculation methods to predict the strength of overmolded parts. None of the available engineering software packages contains the modeling of bonding strength between a polymer substrate and an overmolded element of the same material. This is because the complexity and interdisciplinary nature of bonding and the lack of a unified adhesion theory. In this study, we developed a unique modeling method that can accurately predict the bonding strength of the interface formed between a substrate and an overmolded element for acrylonitrile butadiene styrene (ABS). The method combines the analytical modeling of reptation, the numerical modeling of overmolding, the modeling of tensile tests, and the verification of the obtained modeling results with the tested ones. Our method has an average accuracy of over 90%. •A novel method to predict bonding strength in overmolded polymer parts is developed.•The method combines analytical modeling, numerical modeling, and modeling of tensile tests.•The accuracy of the method is 99%, compared to commonly used averaging methods.•The method correctly handles uneven temperature distribution during injection molding.