The integration of additive manufacturing direct writing technologies with injection molding provides an innovative way to integrate functional features into plastic components. The flexibility of the 3D printing technology combined with the large scale injection molding capabilities can allow mass-manufacturing of custom molded interconnected devices (MID). In this study, an ink-dispensing system is used to deposit conductive ink particles directly on an injection mold surface. After curing, the ink-based printed electronic is transferred to the plastic part exploiting the high temperature and pressure of a thermoplastic polymer melt. The conductive traces transfer and interlocks with the plastic system due to the creation of a strong plastic/ink interface. The hybrid process chain exploits surface interactions and plastic shrinkage to manufacture functional plastic parts. The prototype process chain is here proposed and validated considering geometrical integrity of the structures and mechanical properties of the functional plastic systems. The adhesion at the polymer/ink interface is analyzed, considering the mold topography, its surface energy, and melt polymer contact angle.