Comparing the Compatibility of 3D Printer Inks of Contrasting Rheology

• Rita Wilson, Physics, University of Delaware

• Alexandra Bayles, , University of Delaware

3D printing is a useful tool for producing highly customizable parts at a low cost. The resolution of traditional 3D printers are limited by their nozzle size where the smallest features are at minimum the nozzle diameter. Advective assembly nozzles seek to overcome this bottleneck by building complex patterns within the nozzle using laminar flow patterning.  While these new nozzles show promising results for a few model systems, the breadth of inks that can be printed and patterned with these nozzles is poorly understood. Additionally, advective assembly nozzles have the capacity to use multiple inks at a time, meaning inks are required to both be compatible with the nozzle and each other.  This project seeks to provide the rheological parameters required for inks to be compatible with advective assembly nozzles. In order to test how rheological parameters affect compatibility, inks’ rheologies are measured using a flow sweep to mimic the behavior of inks during extrusion. Inks of contrasting rheology are then extruded through an advective assembly nozzle and compared with prints obtained from the same nozzle using matching rheology inks. This process provides a baseline to compare prints to and quantify the variation in print fidelity caused by mismatched rheology. It also provides insight into how different flow operations are affected by rheology. For example, rotational flow operations are more sensitive to mismatched rheology than additions. Understanding how fluid characteristics affect the integrity of the print is vital in making adjective assembly more accessible and developing inks that are compatible with advective assembly nozzles.