Thermoplastic polyurethane (TPU) is used in various fields because of its excellentelasticity, flexibility, mechanical strength, and shock absorption. In particular, in the fuseddeposition modeling (FDM), in which layers are extruded by heating and melting thermoplasticmaterials through a nozzle, the adhesion and mechanical properties of theoutput are affected according to the nozzle temperature. In this study, six types of TPUfilaments with various hardnesses (65A, 75A, 80A, and 85A) were manufactured throughcommercial chip and synthesis (comp) and extruded under five nozzle temperature conditions(190 °C, 200 °C, 210 °C, 220 °C, and 230 °C). Then, the most suitable nozzle temperaturefor the filament was confirmed, and the re-entrant pattern was printed. Extrudedfilaments and printed re-entrant patterns were analyzed through morphology analysis.
Finally, the tensile properties of the two samples of the optimal printed condition forFDM 3D printing were examined. Consequently, the optimal nozzle temperature of eachTPU filament was confirmed as 190 °C for Chip-65A, 210 °C for Chip-75A, 210 °C for Chip-80A, 200 °C for Chip-85A, 210 °C for Comp-75A, and 200 °C for Comp-85A. Through printingre-entrant patterns and morphologies, Chip-75A and Comp-75A were considered tobe the most suitable for 3D printing. The tensile properties showed that Chip-75A wasmore flexible than Comp-75A.