Toward Faster and Lower-Cost Prosthetic Socket Fabrication: Mechanical Coupon-Level Testing of FDM-Printed PLA/PETG Versus Lamination

Additive manufacturing is increasingly being adopted in prosthetic manufacturing because digital workflows can reduce production time and improve repeatability compared to traditional lamination. This study measured two FDM polymers—polylactic acid (PLA) and polyethylene terephthalate glycol (PETG)—against a baseline of Perlon epoxy laminate (not including carbon reinforcement) using standardized coupon tests (n = 3 per test). PLA and PETG samples were printed at 100% fill with a 0.6 mm nozzle, while laminate coupons were prepared by wet layup and cut to the required geometry. Tensile testing followed ASTM D638 and three-point bending followed ASTM D790, modulus, 0.2% offset yield strength, and ultimate strength were derived from stress-strain curves. In tension, PETG showed higher UTS (38.71 ± 1.97 MPa), while PLA showed a slightly higher modulus (0.363 ± 0.104 GPa); The laminate showed lower tensile strength (28.33 ± 2.29 MPa). In bending, PETG achieved the highest bending strength (70.62 ± 3.15 MPa), while PLA showed higher bending stiffness (Ef = 2.07 ± 0.12 GPa) than PETG (1.72 ± 0.02 GPa). To strengthen the technical relevance, a simplified linear elastic finite element model of a three-point bending configuration was demonstrated, confirming the expected midpoint stress concentration and material-dependent deflection. Overall, the findings support evidence-based material screening for prosthetic socket construction, while socket-level validation under standardized structural loading is still needed.