Fused deposition modeling (FDM) is a popular technique for polymer additive manufacturing. However, the hygroscopic nature of thermoplastic filaments can lead to moisture-related defects during extrusion. When moisture is absorbed and vaporizes inside the nozzle, bubbles form, resulting in voids within the extrudate and deposited roads. This can compromise inter-road bonding and diminish mechanical performance. This study examines how the initial moisture content of ABS filaments affects the tensile behavior of parts fabricated by FDM. ABS filaments were conditioned to seven different moisture levels through water immersion for periods ranging from 0 to 12 hours, with moisture content quantified using the loss-in-weight method (ASTM D6980). ASTM D638 Type I specimens were printed under consistent processing conditions and tested in tension (n = 5 per condition). The results showed that ultimate tensile strength (UTS) decreased as filament moisture content increased, with a maximum reduction of 9.3% observed at 0.69% moisture compared to the dried condition (0.05%). Ductility was assessed by measuring strain at break, and its relationship with moisture content is illustrated in Fig. 4, along with statistical analysis (one-way ANOVA and post-hoc comparisons). These findings offer valuable insights for moisture management and quality control in ABS FDM processes.
