Additive manufacturing (AM) has gained significant attention due to its ability to drive technological development as a sustainable, flexible, and customizable manufacturing scheme. Among the various AM techniques, direct ink writing (DIW) has emerged as the most versatile 3D printing technique for the broadest range of materials. DIW allows printing of practically any material, as long as the precursor ink can be engineered to demonstrate appropriate rheological behavior. This technique acts as a unique pathway to introduce design freedom, multifunctionality, and stability simultaneously into its printed structures.
I wrote a review article, as a co-first author, titled Direct Ink Writing: A 3D Printing Technology for Diverse Materials and it is published in Wiley's Advanced Materials.
In this work, a comprehensive review of DIW of complex 3D structures from various materials, including polymers, ceramics, glass, cement, graphene, metals, and their combinations through multimaterial printing is presented. The review begins with an overview of the fundamentals of ink rheology, followed by an in-depth discussion of the various methods to tailor the ink for DIW of different classes of materials. Then, the diverse applications of DIW ranging from electronics to food to biomedical industries are discussed. Finally, the current challenges and limitations of this technique are highlighted, followed by its prospects as a guideline toward possible futuristic innovations.
DIW technology and ink rheology. a) Schematic process illustration of DIW. The technique has garnered significant attention because of its ability to process the widest range of materials in fabricating complex multifunctional 3D structures. Inset shows one of the first experimental structures developed by Cesarano in Sandia National Laboratory. Inset: Reproduced with permission.[8] Copyright 1997, Taylor & Francis. The structure was an aluminum oxide “Thunderbird” made of 20 layers and sintered “crack-free” to 96% of theoretical density. b) Schematic showing the ideal rheological response (storage modulus (G′)/loss modulus (G″) vs shear rate (σ)) of a printable ink and pressure-induced flow for a conventional ink that has bulk non-Newtonian properties. Reproduced with permission.[6] Copyright 2020, Wiley-VCH. c) Recent trend in the number of publications on DIW. Datafrom Web of Science (December 2021).