Strength limiting defects in additively manufactured ceramics

To optimize part design and the fabrication process of additively manufactured ceramics, it is of importance to accurately determine the functional and mechanical properties of a part. Regarding the mechanical properties, the strength of ceramics is governed by failure inducing defects. Therefore, understanding such defects is fundamental to ensure a high quality, reliability, and performance of any ceramic part. However, for manufacturing methods such as material extrusion, fabrication of a part is realized through a vastly different approach compared to vat-photopolymerization or other methods. Thus, every method introduces unique, process-related defects. While some of these defects occur in multiple manufacturing methods, they are often described and named differently. Thus far, no unified nomenclature and classification is available, which hinders comparison and increases misunderstanding. Therefore, the goal of this work is to assess and categorise the process-related defects in ceramic additive manufacturing, demonstrated for vat photopolymerization, material extrusion and material jetting.