Injection overmolding of polymer-metal hybrid structures: A review

Abstract

Polymer-metal hybrid (PMH) structures, also known as metal-polymer hybrid (MPH) structures, have received considerable attention from industry and academia due to the societal need for developing strong, lightweight, and durable structures for several applications in strategic areas, such as transportation, household appliances, energy, and biomedical devices. Injection overmolding is an advantageous technique for manufacturing PMH structures as it combines automation, a fast process, cost efficiency, and dimensional accuracy. This review presents a comprehensive discussion of recent advances reported in the literature concerning PMH structures fabricated by direct-adhesion injection overmolding. Following a general introduction, the fundamentals of the injection overmolding technique are presented. Next, the potential of some metal surface preparation methods to ensure good adhesion, and thus outstanding mechanical performance in injection overmolded PMH structures is discussed. Correlations are then made between metal surface features, processing parameters, and the mechanical strength of injection overmolded polymer-metal joints. Some applications of injection overmolded PMH structures are explored, and, lastly, the main conclusions and prospects on the use of injection overmolding are presented.