So, the team turned to domain experts at Boeing to examine each image and label the tow boundaries. It was a painstaking process that resulted in a training set of approximately 3,500 images. While the data set was smaller than the team would have liked, it was enough to demonstrate that the automated inspection method reduced post-processing manual inspection by 90%.

Boeing is considering using a scaled-up version for its production lines, and a joint Boeing-UW patent has been filed. Banerjee says, “This research has the potential to save hours of manual inspection work for every large-scale aerospace component part.”

Making New Composites from Obsolete Ones

Project: Pyrolysis-Based Recycling Technology

School: The University of Tennessee, Knoxville

Location: Knoxville, Tenn.

Principal Investigator: Ryan Ginder

A major issue on the minds of not only composites manufacturers, but all global producers is sustainability. One drawback to widespread adoption of composites is the lack of an efficient way to break down the materials once they have reached end of life. Ryan S. Ginder, research assistant professor at the University of Tennessee, Knoxville has created a remedy to that. Ginder, along with colleagues at Carbon Rivers LLC, have developed a pyrolysis-based recycling technology to turn end-of-life composites into new composite applications.

The venture began when Ginder discussed the technology with the founders of Carbon Rivers in 2018, and they were eager to bring him into the fold. A year later, they used Ginder’s research and plans to pursue funding from the U.S. Department of Energy for wind blade recycling. Flash forward to 2021, and they have successfully recovered fiberglass from polymer composites used in the window industry and turned it into nonwoven fabrics and injection molding pellets, which can be used to manufacture next-generation composite products.

As a demonstration project, Ginder fabricated a small boat mold and radio-controlled boat made from nonwoven fabric with recycled fiberglass and epoxy resin using hand lay-up.

“The input vinyl window production scrap was first size reduced to a wood chip consistency for both feeding into the pyrolysis system and to set the fiber length that would be eventually recovered,” says Ginder. “The scrap material was then put through a multistage pyrolysis process where heat energy is primarily used to break down all of the composite’s organic components followed by residual carbon removal and final glass rinsing.” He declined to explain precisely how the university’s proprietary pyrolysis technology works but noted that the recycled fibers can be used in place of traditional virgin fibers with no difference in tensile stiffness or comparable properties.