There are two popular manufacturers (MAKERBOT and MARKFORGED) for carbon fiber 3D printers to provide a lightweight alternative to metal for structural applications. They use "Nylon carbon fiber" as a feedstock due to high strength, heat resistance, and stiffness properties. You can check the details of 3D printers on the link below.
- News
MAKERBOT(https://www.makerbot.com/): https://3dprintingindustry.com/news/makerbot-launches-carbon-fiber-desktop-3d-printers-172008/
MARKFORGED (https://markforged.com/): https://3dprintingindustry.com/news/mark-two-carbon-fiber-3d-printer-unveiled-by-mark-forged-65831/