Robot-arm-assisted 3D printing: Virginia Tech develops load-adapted fiber structures

A research team at Virginia Tech is working on a 3D printing process that is oriented more toward models from nature than toward classical layer-by-layer structures. With a three-year NSF-funded project worth 3.5 million US dollars, a robot-based 3D printing process for fiber-reinforced composites is to be developed, in which material paths are deposited along curved trajectories and from multiple directions. This creates structures whose fiber orientation carries loads in a way similar to wood fibers in a tree trunk and, according to initial results, achieves up to ten times the strength of conventionally printed components.

While the early additive manufacturing approach relied on planar, stacked layers, the new approach uses multi-axis robot arms as carriers for the print head. This can guide the nozzle along arbitrarily chosen spatial curves and thus generate material paths that follow the load paths. In combination with new printable composite materials, components can be produced that combine electrical, mechanical, or functional requirements in a single geometry, such as lighter aircraft components, flexible electronic modules, or multifunctional machine elements.

“We have been exploring how robotic arms could benefit 3D printing for almost 10 years now,” said Christopher Williams, director of Virginia Tech Made: The Center for Advanced Manufacturing. “We found that to truly leverage the flexibility of these robotic arms for improving printed part strength, we needed to combine our collective knowledge of design optimization, advanced materials, robotic controls, and additive manufacturing. Our early results of putting these pieces together are really exciting.”

The project brings together experts from mechanics, materials science, robotics, and engineering education. For example, the group led by Pinar Acar is developing simulation and machine learning models for the optimal arrangement of the fibers, while the team of Michael Bartlett contributes new, customizable composite materials. In parallel, Lisa McNair is developing concepts to anchor the insights gained in engineering education through teaching formats, outreach programs, and a “manufacturing spine.”

“This project needs all of us, because any individual researcher can’t make the progress needed to enable the materials, the process, the design, and the robotics,” Michael Bartlett said. “You can’t put this work in a single lab because you will not have the expertise needed to push it forward.”