Sarah Sortedahl

Exploring the Influence of Flaw Populations on the Mechanical Behavior of Ceramics Formed through Lithography-based Additive Manufacturing

BIO:

Sarah is a PhD student in the Materials Science program at Colorado School of Mines. Her research involves studying the stereolithographic additive manufacturing technique of ceramic materials. Sarah is involved with the Colorado Center for Advanced Ceramics where she is a lab manager and is on the planning committee for the annual student conference. In May 2017, Sarah completed her B.S. in Materials Science with a Geology minor at the University of Wisconsin – Eau Claire. She has previous research experience investigating the mechanical properties of superconducting ceramic materials. In her spare time, she enjoys the Colorado outdoors through skiing and climbing. She has her American Institute for Avalanche Research and Education Level 1 certification. She boulders and lead climbs outside with the goal of branching into trad climbing.

ABSTRACT:

Of the many different emerging solid freeform fabrication avenues to create intricate geometries of ceramic parts, stereolithography is one of the best techniques to create high resolution parts with relatively large part volumes and reasonable print times. The printer used in this study is the Lithoz CeraFab 7500 which uses the stereolithographic technique. This printer uses a digital light projector to cure a photopolymer ceramic slurry layer by layer to create a green body. The mechanical performance of the parts made through this layered manufacturing technique is not well characterized. In this study, the mechanical properties of parts created under different printing conditions will be evaluated such as print orientation, support structure geometry, layer thickness, and presence of a backlight layer. The flexural strength of samples will be tested on alumina bars in accordance to the ASTM 1161-18 standard. From this data, Weibull statistics will be generated. In addition, the fracture toughness will be measured. Later, mechanical tests will be utilized that integrate a more complex test geometry. It is important to fully characterize mechanical properties through traditional bars. However, simple shaped parts will not be created through printing as other ceramic processing techniques are better understood and more economical. The mechanical property data generated in this study will help with part design for ceramic additive manufacturing.