Zhe Shu

Additive manufacturing (AM), so‐called 3D printing, has reshaped manufacturing technologies with attractive alternatives to the traditional centralized, subtractive‐based mass production. Further functionalities like multimaterial AM (MMAM) are essential for mainstream manufacturing. With MMAM of electrical traces, the traditional printed circuit board can be transformed to freeform 3D electronics using the entire volumetric space. Although research groups attempt MMAM for freeform 3D electronics, achieving easy integration of the electrical traces with high conductance into dielectric substrates in a streamlined and simplified process remains challenging. Herein, an in‐house developed printer, named Synkròtima, is demonstrated for one‐stop printing of 3D dielectric parts with fully embedded and structured conductive features via drop‐on‐demand printing of molten metal for the first time. Printed traces show 12 times lower electrical resistance of at 230 μm linewidth than the lines from conductive inks. Printed traces with 100 μm dot spacing reveal exemplary shape fidelity with a standard deviation of only 7 μm. Quantitative estimation of adhesion of metal traces to dielectric reveals a mean shear‐off force of 7.20 N which is half of what is obtained for reflow soldered electronics. Demonstrators with embedded functional electrical circuits, directly interconnected components, and 3D out‐of‐plane metal structures are printed via Synkròtima.