Upflow mitigation strategy for nested printing

Embedded printing enables the fabrication of integrated and enveloped internal geometries. Upflow, a geometrical deviation resulting from nozzle-translation-induced hydrodynamics, may affect the printing accuracy during embedded printing, in particular, nested printing where multiple layers are disturbed simultaneously during embedded printing internally nested structures within pre-deposited yield-stress structures. For the first time, this study identifies and characterizes two distinct upflow patterns including the interfacial upflow between the depositing and enclosure matrices during nested printing. Furthermore, a four-step upflow mitigation strategy is proposed and evaluated, and its effectiveness is demonstrated in printing a brain limbic system with significantly improved printing fidelity.