Physics Colloquium: “Photopolymer Additive Manufacturing from NIST to Mines: Novel Voxel & Sub-Voxel-Scale Characterization Throughout All Major Stages of the Printing Process”

Callie Higgins

NIST

Abstract: Vat photopolymerization is a powerful additive manufacturing technique that address many applications ranging from personalized medicine to large-scale manufacturing. Unfortunately, these printing processes introduce micrometer-scale anisotropic inhomogeneities due to the resin absorptivity, diffusivity, reaction kinetics, and swelling during the requisite photoexposure. Previously, it has not been possible to characterize high-resolution mechanical heterogeneity as it develops during the printing process. By combining vat photopolymerization additive manufacturing with atomic force microscopy (AFM) in a hybrid instrument, heterogeneity of a single, in situ printed voxel is not only characterized and quantified for the first time, but also an as-printed modulus-informed corrective algorithm is applied to fabricate homogeneous voxels. Our results demonstrate the complex properties of printed voxels at all relevant stages of the printing process including in resin and after post-processing (both after rinse and after secondary cure). This instrument and voxel-correction now equips researchers with the tools to develop rich insight into not only resin development, but into the entire photopolymer 3D printing process.

Biography: Dr. Callie Higgins is a Materials Research Engineer at the National Institute of Standards and Technology (NIST) in Boulder working to drive innovation in the PAM industry by enabling unprecedented high-resolution, mechanically-precise vat photopolymerization via fundamental understanding informed by novel voxel and sub-voxel-scale characterization throughout all major stages of the printing process. She graduated with her PhD from CU Boulder’s Department of Electrical Engineering with specialties in optics and material science where she characterized the fundamental properties of photopatterned hydrogels for use in regenerative medicine. Outside of the lab, she loves to adventure around Colorado skiing, hiking, and picnicking with her husband, friends, and family.

Unless otherwise specified, all lectures will take place in CoorsTek 140/150, located at 1523 Illinois Street, Golden, CO