Robocasting Additive Manufacturing of Titanium and Titanium Alloys: A Review

Robocasting, also known as Direct Ink Writing, is emerging as an additive manufacturing technology for titanium and its alloys. It is a material extrusion method that deposits a suspension of titanium particles (ink) to fabricate structures designed in silico. The structures are made of unbounded titanium particles and require sintering to become a continuous mechanically stable solid. The removal of the binder is a very important operation performed before sintering to satisfy the chemical, mechanical, and metallurgical specifications of the titanium standards. Currently, relatively small porous titanium structures have been fabricated by robocasting, mainly for bone repair applications but also for catalyst supports. Progress in the robocasting of titanium and its alloys is modest but promising, offering opportunities with significant impact in advanced titanium applications. This review presents the state of the art of robocasting of titanium metallic materials, as well as discusses the mechanical properties and current applications of manufactured parts. The review also provides an overview of current challenges and limitations and offers guidelines for the new directions that future research and technology development can take in the field.