Fundamentals of Direct-Ink-Writing

Direct-Ink-Writing (DIW) is an extrusion-based additive manufacturing method heavily utilized in meso- and micro-scales. In DIW, the liquid-phase “ink” is dispensed out of small nozzles under controlled flow rates and deposited along digitally defined paths to fabricate 3D structures layer-by-layer. Our research focuses on various key fundamental questions about the process:

1. What thermofludic mechanisms govern the flow and deposition of the inks?
2. How are these mechanisms determined by the material properties and process parameters such as printing speed, nozzle-substrate distance, flow rate etc.?
3. How do these mechanisms impact the printed part properties including their geometry, micro-structure, electrical and thermal conductivities and mechanical properties?
4. What are the key factors impacting process accuracy, resolution, repeatability and throughput and how can these factors be controlled?

We study the DIW of a wide variety of materials with drastically different properties leading to drastically different process mechanisms. We primarily focus on:

1. Polymer nanocomposites consisting of a polymer matrix and nanoparticles including carbon based ones such as carbon nanotubes, graphene flakes.
2. Hydrogels
3. Alloys and pure metals with melting points up to 700 degrees Celsius

See below videos demonstrating on DIW of different materials. For further details check out our recent publications below:

Freeze‐Printing of Liquid Metal Alloys for Manufacturing of 3D, Conductive, and Flexible Networks

Additive Manufacturing with Conductive, Viscoelastic Polymer Composites: Direct-Ink-Writing of Electrolytic and Anodic Poly (ethylene oxide) Composites

Prediction of steady-state freeze front position during 3D printing of microstructures