Leanne Friedrich (Assoc)

Leanne Friedrich (she/her) is a materials scientist working on embedded 3D printing of soft materials. Leanne earned a B.S. in materials science and engineering from Northwestern University in 2015. She earned a Ph.D. in materials from University of California Santa Barbara in 2020, developing methods to 3D print polymer matrix composites with controlled property gradients using direct ink writing with acoustophoresis. She joined NIST in 2020 as an NRC postdoc.

Embedded 3D printing is a fabrication technique wherein a nozzle extrudes continuous filaments into a support bath. Usually, the bath has a yield stress, so it fluidizes around the nozzle, allowing the nozzle to move, but it re-solidifies behind the nozzle, holding the printed part in place. Because the bath takes care of form holding, embedded 3D printing allows for inks that were previously not printable. Inks no longer need to be self-supporting and can have a low viscosity, making embedded 3D printing particularly useful for printing low-viscosity biomaterials and cell-containing inks. 

Leanne's work focuses on developing guidelines for material selection and printing parameter selection in embedded 3D printing. By examining how the rheology of the ink, rheology of the support, and surface tension influence defects in printed structures, we can achieve more reliable prints with better shape fidelity, mechanical integrity, and functional properties. Leanne uses computational fluid dynamics simulations in OpenFOAM to study the underlying physics of the printing process, and she uses in-situ imaging experiments to measure defects in printed structures.