Additive Manufacturing (AM) encompasses a broad variety of fabrication techniques characterized by successive additions of mass and/or energy to a build domain. AM processes have been developed for a wide variety of feedstock materials, including metals, polymers, and ceramics. In the present work we study the AM of ceramics using the Direct Ink Writing (DIW) technique. We performed comparative studies between additively manufactured and conventionally manufactured test articles, in order to quantify the variations in output geometry and mechanical properties induced by the DIW process. Uniaxial tests are conducted using high-performance optical strain measurement techniques. In particular, it is shown that the DIW-produced specimens exhibit anisotropic shrinkage when fired, as well as a marked decrease in stiffness and ultimate strength. We conclude with a discussion of potential mechanisms which may be responsible for these property degradations, and introduce potential adaptations to the DIW AM process that may be effective in combating them.
Assessment of strain measurement techniques to characterise mechanical properties of structural steel