Liquid-solid co-printing of multi-material 3D fluidic devices via material jetting

Multi-material material jetting additive manufacturing processes deposit micro-scale droplets of different model and support materials to build three-dimensional (3D) parts layer by layer. Recent efforts have demonstrated that liquids can act as support materials, which can be easily purged from micro/milli-channels, and as working fluids, which permanently remain in a structure, yet the lack of a detailed understanding of the print process and mechanism has limited widespread applications of liquid printing. In this study, an all in one gomulti-material print process, herein termed liquid-solid co-printing in which non photo-curable and photo-curable liquid droplets are simultaneous deposited, is extensively characterized. The mechanism of liquid-solid co-printing is explained via experimental high speed imaging and computational fluid dynamic (CFD) studies. This work shows that a liquid's surface tension can support jetted photopolymer micro-droplets which photo-polymerize on the liquid surface to form a solid layer of material. Design rules for liquid-solid co-printing of micro/milli-fluidic devices are presented as well as case studies of planar, 3D, and multi-material micro/mesofluidic structures such as mixers, droplet generators, highly branching structures, and an integrated one-way flap valve. We envision the liquid-solid co-printing process as a key new capability in additive manufacturing to enable simple and rapid fabrication of 3D, integrated print-in-place multi-material fluidic circuits and hydraulic structures with applications including micro/mesofluidic circuits, electrochemical transistors, lab-on-a-chip devices, and robotics.

Automated summary

This study extensively characterizes a liquid-solid co-printing process in multi-material material jetting additive manufacturing. The mechanism of this process is explained through experimental high speed imaging and computational fluid dynamic studies. Design rules for liquid-solid co-printing of micro/mesofluidic devices are presented, and case studies of various structures are shown. The liquid-solid co-printing process is considered a key new capability in additive manufacturing for the simple and rapid fabrication of integrated multi-material fluidic circuits and hydraulic structures.