Yes, you can. In fact, carbon fiber cuts very easily on the STEPCRAFT. The main issue with cutting carbon is the dust that is created is very hazardous to your health if you breathe it in. To combat this, STEPCRAFT has a Milling Bath in three separate sizes for the 420, 600 and 840 machines. You can find information on the Milling Baths here: https://stepcraft.us/product-category/accessories/system-accessories-accessories/cnc-accessories/ Additionally here are a couple videos that you can watch containing more information on using a STEPCRAFT CNC for carbon fiber.
Working With Carbon Fiber
Can I cut carbon fiber on the STEPCRAFT CNC?