Silica aerogels have ultra-low thermal conductivities and densities due to their porous nanostructures. Traditional aerogels can be produced in regular monolithic shapes, but forming more intricate shapes through subtractive manufacturing processes is limited due to the material's brittleness. Additive manufacturing is a solution for these issues, enabling the production of miniature-scale, high-fidelity silica aerogels for a large range of applications. 3D printing has been successfully used to fabricate aerogel structures using a silica aerogel ink. The process requires consistent and fast extrusion rates to produce quality products. A manual, low-cost experimental method was developed to measure ink extrusion rate as a function of the force applied to a syringe-based extrusion system. The results indicate that approximately 75 N of force is required with a 14-gauge needle and more than 85 N is required with an 18-gauge needle to achieve a 12 mm/s extrusion rate. Three analytical models were used to account for the ink's non-newtonian behavior and predict the forces necessary to replicate the 12 mm/s extrusion rate. All three models underpredicted the required forces measured experimentally. The various models ignore contraction effects and plunger friction as a function of velocity, requiring advancements to accurately predict extrusion rate in this printing system.
Acknowledgements: I would like to express my gratitude to Professor Anderson, Professor Carroll, the Student Research Grant Committee, Chris Tracy, and the Aerogel Research Group for their support and funding for this project.