Additive manufacturing of polymer gears: A review on FDM materials, parameters, and performance

This review comprehensively explores the mechanical and microstructural properties of polymer gears fabricated using Fused Deposition Modeling (FDM), a widely used additive manufacturing technique. The paper discusses various thermoplastic polymers including PLA, ABS, PETG, Nylon, POM, and PEEK as well as their reinforced and composite counterparts. Emphasis is placed on how printing parameters (e.g., raster angle, infill density, temperature, and layer height etc.) influence gear performance, wear resistance, and dimensional accuracy. Recent advances in fiber and particle-reinforced composites, including biochar, carbon fiber, glass fiber, and metal-filled polymers, are critically examined to assess their potential for enhancing the strength, fatigue life, and thermal behavior of FDM-printed gears. Manufacturing methods such as injection molding and machining are also compared with FDM to evaluate gear accuracy and load-bearing capacity. The review identifies key challenges including moisture absorption, warpage, and print anisotropy, service temperature and highlights the importance of post-processing treatments and hybrid material strategies. By consolidating findings across recent experimental studies, this article provides insights for material selection, parameter optimization, and future research directions for developing durable, high-performance polymer gears for power transmission applications.