Omnidirectional and Multi‐Material In Situ 3D Printing Using Acoustic Levitation

Abstract Additive manufacturing is critical in modern production with advanced applications across various domains. However, achieving omnidirectional printing that can adapt to varying substrate geometries is still a challenge. Moreover, multi‐material in situ printing without cross‐contamination presents another hurdle. In this study, an acoustophoretic 3D fabrication system capable of omnidirectional and multi‐material in situ 3D printing is reported using acoustic levitation. This system harnesses a phased array of transducers (PAT) to finely tune the ultrasonic field, generating acoustophoretic forces that levitate and transport objects in mid‐air. It allows omnidirectional in situ printing of materials onto complex substrates with diverse orientations in a contactless and voxel‐by‐voxel manner. It is capable of manipulating a broad spectrum of materials, including liquids with zero‐shear viscosities from 1 to 5,000,000 mPa·s, as well as solids. AcoustoFab has successfully printed structural, conductive, and biological materials in varying directions on complex substrates. Additionally, the contactless approach enables in situ printing safely on a delicate surface, as demonstrated by printing on a human hand. The flexibility and versatility of this approach demonstrate promising applications in areas ranging from biomedical engineering to industrial manufacturing.