4D printing of molded interconnect device

4D printing represents a progressive extension of 3D printing technology, enabling shape transformation over time. To establish the pragmatic utility of 4D printing, we have developed an efficient 4D printing method using a fast-filament fabrication (FFF) type 3D printer and a single thermoplastic polymer. This methodology entails the deliberate introduction of anisotropy within the printing trajectories, thereby inducing a bending deformation in response to thermal stimuli. The developed 4D printing was used to fabricate a molded interconnect device (MID) featuring a curved shape. A flat MID keypad was designed to encompass conductive circuits within a nonconductive polymer substrate. The flat MID keypad frame was then additively manufactured by embedding conductive circuits during the printing process, according to programmed printing paths. A curved fixture was designed to guide thermal deformation in alignment with the desired curvature. The proposed 4D printing technology with constrained shape transformation facilitated the realization of a curved MID keypad, distinguished by improved dimensional fidelity and replication consistency.