J70.00002. Printing direction dependent microstructures in direct ink writing
Presented by: Leanne Friedrich
Direct ink writing (DIW) can be combined with external fields to enable deposition of composite filaments with designed microstructures. Using acoustophoresis, we establish a narrow distribution of microparticles at the center of a direct write nozzle. In low-viscosity shear thinning inks, the particle distribution shifts and widens after deposition depending on the printing direction. We use particle image velocimetry and digital image analysis to characterize the flow field and particle distributions in the printed filament as a function of printing direction. We propose an analytical model for diagnosing sources of printing direction-dependent flows and particle distributions. Sources include anisotropy of the particle distribution in the nozzle, an asymmetric inertial disturbed zone near the nozzle, reshaping of a fluid-like square filament, rotation of a solid-like square filament, and printer calibration. Using the model, we propose strategies for mitigating or amplifying direction-dependent microstructures obtained via direct ink writing. The analytical model can also be adapted to similar direct-write applications to diagnose sources of direction dependence of printed microstructures.
- Leanne Friedrich
- Matthew Begley