Session: 03-01-01: Annual Conference-Wide Symposium on Additive Manufacturing

Paper Number: 146012

146012 - Additive Manufacturing of Thermally Curable Fiber-Reinforced Polymer Composites 

Additive manufacturing (AM) has recently been transformed into a robust manufacturing paradigm for rapid, cost-effective, and reliable manufacturing of fiber-reinforced thermoset polymer composites. Among various AM techniques, direct ink writing (DIW) technique offers exceptional ability for constructing scalable 3D composite structures with a high resolution and rapid production rates. In the conventional DIW technique, composite parts are created by thermal post-curing of a thermoset resin ink in an oven at elevated temperatures to obtain a highly crosslinked polymer network. The long and energy-intensive curing processes, often required for curing the monomer, limits the applications of this approach to layer-by-layer printing of simple 2D geometries. In addition, the conventional approach is not suitable for creating large structures, as with increasing the number of layers the uncured material in the earliest deposited layers reaches a flow state, resulting in loss of print fidelity or even collapse of printed parts.  
Alternative in-situ curing approaches during the printing process are promising for high-rate and scalable AM of thermoset polymer composites. To date, a few AM techniques based on in-situ curing have been developed using UV-curable thermoset resins; however, these techniques are not yet applicable for creating structural components due to the poor mechanical performance of the matrix polymers as well as partial curing of the resin in the presence of light absorbing reinforcements. In this work, we present a novel technique that can realize fast and energy-efficient fabrication of high-performance polymer composites using a high-performance, thermoresponsive thermoset resin system. Our technique involves feeding resin inks filled with discontinuous carbon fibers (CF) or continuous carbon fiber reinforcements impregnated with the resin from the nozzle of a printing robot and directing a thermal stimulus toward the extruded material. The thermal stimulus is configured to rapidly and locally heat up the composite material and instantaneously rigidize the as-extruded material. Using our novel printing technique, we demonstrate AM of tall composite structures using conventional layer-by-layer printing strategy, which is hard to achieve using existing techniques. In addition, instantaneous and localized curing of the thermoset matrix resin allows for manufacturing freeform structures (in-the-air printing), eliminating the need for support materials and tooling.

Presenting Author: Mostafa Yourdkhani Colorado State University

Presenting Author Biography: Dr. Mostafa Yourdkhani is an assistant professor in the Department of Mechanical Engineering and a core faculty member in the School of Advanced Materials Discovery at Colorado State University (CSU). Prior to joining CSU, he was a postdoctoral research associate at the Beckman Institute for Advanced Science and Technology and a lecturer in the Department of Aerospace Engineering at the University of Illinois at Urbana-Champaign. He received his Ph.D. in Mechanical Engineering from McGill University on processing of advanced composite and nanocomposite materials. Dr. Yourdkhani’s research interests include advanced and sustainable manufacturing of polymer composites, digital manufacturing of structural composites, processing science of composites, multifunctional materials, self-healing materials, and bio-inspired material design. He has received several awards and recognition for his research, including the 2023 CAREER award from the National Science Foundation (NSF) and 2024 ACS PMSE Early Investigator award.

Authors:

Carter Dojan Colorado State University
Alireza Masoumipour Colorado State University
Mostafa Yourdkhani Colorado State University