3D Printing on Droplets by Ultrasonic Levitation

Vat photopolymerization 3D printing creates structures by projecting patterns onto a photosensitive resin within a vat. However, the presence of resin vats limits the printing of multiscale multimaterial structures. In this context, a novel 3D printing process is presented in which a cured structure is produced from acoustically levitated droplets without a physical vat. This enables the printing process to achieve high flexibility in the printing orientation and material supply. In pursuit of the envisioned 3D acoustic levitation printing strategy, acoustic levitation technology was utilized to suspend a photosensitive resin. Objects with small features were successfully produced by projecting patterns onto levitated resin droplets. Transforming printing orientations allows the fabrication of multiscale structures. Levitating resin droplets on-demand enables the rapid replacement of materials, thereby realizing effortless multimaterial 3D printing. By exploiting the flexibility of printing on levitation resin droplets, the capability of 3D printing on existing objects was established. Finally, an interesting example was illustrated, in which an object integrating liquid, gas, and solid materials was fabricated using the proposed 3D printing strategy. The results show that 3D printing on levitated droplets is feasible for fabricating multiscale and multimaterial objects, which contributes to the development of new 3D printing methods and potential applications.