Abstract: In response to the challenges of process complexity, unstable interlayer electrical connections, and difficulties in achieving high-density integration of electronic components in existing manufacturing methods for multilayer flexible and stretchable electronics, a novel integrated manufacturing approach is proposed. This method is based on multi-material 3D printing and collaborative use of multiple nozzles. Through experimental comparisons and results analysis, the study unveils the significant influence and patterns of key printing process parameters, including printing speed, printing pressure, printing platform temperature, and nozzle diameter, on the thickness of dielectric material layers, intra-layer conductors, interlayer interconnect wire width, and overall printing quality. Consequently, an optimal range for printing parameters is identified, ensuring the direct formation of interlayer interconnect wires with a vertical printing height of up to 13 mm, thereby achieving stable electrical connections among multiple layers of circuits. Utilizing the proposed method, a rational multilayer circuit layout, and optimized process parameters, flexible PDMS dielectric material and high-stretchability nanosilver ink conductive material were employed to print multilayer flexible circuits with varying integration densities. The demonstrated performance showcases that this method provides a novel multi-material integrated manufacturing solution for multilayer flexible and stretchable electronic circuits.

Key words: multi-layer flexible and stretchable electronics, multi-material 3D printing, integrated manufacturing, vertically interconnected wires