New Metal–Plastic Hybrid Additive Manufacturing for Precise Fabrication of Arbitrary Metal Patterns on External and Even Internal Surfaces of 3D Plastic Structures

Constructing precise metal patterns on complex three-dimensional (3D) plastic parts allows the fabrication of functional devices for advanced applications. However, it is currently expensive and requires complex processes. This study demonstrates a process for the fabrication of 3D metal-plastic composite structures with arbitrarily complex shapes. A light-cured resin is modified to prepare the active precursor allowing subsequent electroless plating (ELP). A multimaterial digital light processing 3D printer was newly developed to fabricate the parts containing regions made of either standard resin or active precursor nested within each other. Selective 3D ELP processing of such parts provided various metal-plastic composite parts having complicated hollow structures with specific topological relationships with the resolution of 40 μm. Using this technique, 3D devices that cannot be manufactured by traditional methods are possible, and metal patterns can be produced inside plastic parts as a means of further miniaturizing electronics. The proposed method can also generate metal coatings exhibiting improved adhesion of metal to substrate. Finally, several sensors composed of different functional materials and specific metal patterns were designed and fabricated. The present results demonstrate the viability of the proposed method and suggest potential applications in the fields of 3D electronics, wearable devices, and sensors.