<p>Currently, 3D printing technology has attracted much attention as new molding methods for carbon fiber reinforced thermoplastics (CFRTP). The purpose of this study is to investigate in situ resin impregnation during 3D printing of CFRTP. The specimen was manufactured by fused deposition molding (FDM) using carbon fiber yarn and polylactic acid (PLA) filament. Tensile tests were conducted on the molded specimens in order to investigate the effect of process parameters during 3D printing on mechanical properties. As a result, we recommend the modeling temperature T=220°C, print speed v=100 mm/min and filament extrusion speed f=18 mm/min for the PLA composites.</p>