Injection overmolding of polymer-metal hybrid structures: A review

Polymer-metal hybrid (PMH) structures, also known as metal-polymer hybrid(MPH) structures, have received considerable attention from industry and acade-mia due to the societal need for developing strong, lightweight, and durablestructures for several applications in strategic areas, such as transportation,household appliances, energy, and biomedical devices. Injection overmolding isan advantageous technique for manufacturing PMH structures as it combinesautomation, a fast process, cost efficiency, and dimensional accuracy. This reviewpresents a comprehensive discussion of recent advances reported in the literatureconcerning PMH structures fabricated by direct-adhesion injection overmolding.Following a general introduction, the fundamentals of the injection overmoldingtechnique are presented. Next, the potential of some metal surface preparationmethods to ensure good adhesion, and thus outstanding mechanical performancein injection overmolded PMH structures is discussed. Correlations are then madebetween metal surface features, processing parameters, and the mechanicalstrength of injection overmolded polymer-metal joints. Some applications ofinjection overmolded PMH structures are explored, and, lastly, the main conclu-sions and prospects on the use of injection overmolding are presented.