Benjamin Davis, a 16-year-old sophomore at Bishop Feehan High School in Attleboro, Massachusetts, spent much of the past two school years building a machine in his family’s home in Wrentham that turns plastic waste into fresh filament for 3D printers. In May 2025, the project carried him to the 75th Regeneron International Science and Engineering Fair in Columbus, Ohio, where he became the first Bishop Feehan student to win a national ISEF award.
Davis entered a project titled “Pultrusion and Extrusion to Recycle Filament,” which placed first in the Engineering Technology: Statics and Dynamics category before judges selected it for one of the fair’s two Regeneron Young Scientist Awards, each worth $75,000. That prize is the fair’s second-highest individual honor, after the $100,000 George D. Yancopoulos Innovator Award, and according to the fair’s own grand awards announcement, it went to only two students among the nearly 1,700 who competed in 2025.
How pultrusion and extrusion combine to remake old filament
The device is a desktop-scale recycling system that Davis describes as combining electrical, mechanical and chemical engineering into one process. Extrusion, the more familiar half of the design, melts shredded or ground plastic and pushes it through a heated die to form a continuous strand of filament. Davis paired that step with pultrusion, a technique more commonly associated with pulling continuous fiber through resin to make rigid composite parts, in an attempt to produce filament that holds its shape and strength better than output from simpler home recyclers.
In a Society for Science interview published after the fair, Davis said his system runs roughly 45 percent more efficiently than comparable home recycling machines while producing higher-quality filament, and that it costs about 90 percent less to build than commercial recycling units aimed at makerspaces and small manufacturers. He also designed the interface to be usable by people with no engineering background, a detail he and his school have both pointed to as central to the project’s practical appeal.
Targeting the waste that home 3D printing leaves behind
The problem Davis set out to address is specific to additive manufacturing rather than plastic waste in general. Regeneron ISEF’s announcement cites a figure Davis used in his research: up to 67 percent of the filament used in a typical 3D printing project can end up as waste, in the form of failed prints, support structures, and the purge material printers extrude before a job to clear old filament from the nozzle. His machine is built to take in that purge waste alongside discarded PET plastic, such as bottle material, and convert both into filament that can go back into a printer rather than into the trash…