This research aims to analyze the tensile strength and microstructure of Polyethylene Terephthalate (PET) filaments with variations in infill and speed at a nozzle diameter of 0.4 mm and a layer thickness of 0.2 mm. The research method involves making test specimens using a 3D printing machine, followed by tensile strength testing using a Zwick Roell Z020 tensile tester and microstructure analy…