This study investigates the fused deposition modeling (FDM) process for polyamide 6 (PA6), also known as nylon, reinforced by carbon fibers (PA6 + CF composite), using both experimental and statistical analyses. The influence of key FDM process parameters, including layer height or layer thickness (LT), material fill ratio or infill percentage (IP), and deposition orientation or raster angle (RA), on print time, build mass, elongation at fracture, and maximum fracture force or load was examined. The response surface methodology (RSM) approach was applied to optimize these parameters. The findings indicate that LT has the most significant impact on all response variables, followed by a moderate influence of IP and a minimal effect of RA. Increasing LT from 0.1 mm to 0.5 mm led to a linear reduction in both build mass and elongation at fracture. In contrast, the maximum force initially increased, peaking at approximately 2000 N at 0.3 mm LT, before declining. When IP was raised from 10 to 50%, both mass and print time increased slightly, whereas elongation at fracture decreased and maximum force improved. Changes in RA from 0 to 90 resulted in a minor reduction in elongation at fracture and maximum fracture force, with a slight increase in mass and negligible impact on print time.
