Direct Freeform Laser Fabrication of Multimaterials for 3D Electronics

In the past decade, direct laser fabrication (DLF) has been witnessed an exponential growth in various applications. Among them, one prominent field is sensor and electronics. Despite much progress, the mainstream application of DLF is restricted to planar fabrication capability. In this talk, we will discuss our recent progress in bringing such a capability in the conventional 2D plane to 3D free space. The first technological advance is to develop a 5-axis laser processing platform. With the two additional two degrees of freedom, the laser beam can be focused on any arbitrary surfaces for freeform laser induction (FLI) of representative laser induced graphene (LIG), metals, and metal oxides as high-performance sensing or/and electrode materials in 3D conformable electronics. To make a new stride based on this success, recently, we developed a freeform multimaterial assembly platform (FMAP) by integrating 3D printing (fused deposition modeling (FDM), direct ink writing (DIW)) with the FLI technique. 3D printing performs the 3D structural material assembly, while the FLI can fabricate and pattern the functional materials in predesigned positions of the 3D structures by synergistical, programmed system actuation. By this platform, crossbar LED circuit, touchpad for human-machine interaction, multiple sensors, sensor-enveloped springs, electromagnets, force feedback manipulators, and microfluidic reactors with embedded heating elements were fabricated to demonstrate the versatility and effectiveness of the technique.