Perhaps now more than ever, university research is critical. Inquisitive researchers on campuses across the U.S. are working on projects related to materials, technologies, processes and applications in the composites industry that have the potential to not only shape the industry itself, but also bolster an economy weakened by the COVID-19 pandemic and offer solutions to help strengthen systems that are vital to the country, such as infrastructure and transportation.
In this year’s annual report on university research and development, Composites Manufacturing magazine highlights five potentially ground-breaking innovations, from new manufacturing processes to novel materials.
While the lightweighting advantages of multi-material components are attractive to many industries, such as automotive, there are significant challenges to their use. Mixing materials typically necessitates additional manufacturing processes and joining techniques, which hike up the costs for components. Researchers in the Clemson Composites Center think they have a solution with their single-shot manufacturing process for dissimilar materials.
“Most current technologies use multi-stage manufacturing processes,” says Saeed Farahani, a postdoctoral fellow in Clemson’s Department of Automotive Engineering. “You need to first form the metal in a stamping process, then insert it in an overmolding process. Or, you can laminate a sheet metal with a layer of polymer, then use a cold or hot forming process to form the laminated structure. But these have limitations and challenges.”
Farahani and Srikanth Pilla, Jenkins Endowed Professor in the Department of Automotive Engineering, developed a process they call hybrid single-shot manufacturing, which integrates manufacturing of metals and composites in one piece of equipment using a single tooling system. The researchers opted to use injection molding equipment for the technique because it’s readily available in industrial manufacturing settings.
“The general idea behind the integration is to use the pressure of the melt during the injection to form the sheet metal,” says Farahani. “Then, the polymer is injected onto the sheet metal, and the two materials are bonded during the solidification.” Another option is to pre-form the sheet metal while the mold is closing, then inject the polymer after it is closed to make the final formation.
The first materials that Farahani and Pilla tested a few years ago were aluminum and a simple polypropylene. Next, they moved to advanced steel. They have also tested several composite materials, including carbon fiber prepreg sheets with epoxy resin. “In that case, we manufactured a hybrid thermoset/thermoplastic structure in a single shot,” says Farahani. “From the composite standpoint, as long as you can put the material inside the injection molding equipment, we can make it work.”