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.
During its early development stages, 3D printing was primarily used for rapid prototyping, whereas it is currently employed to fabricate products in various fields, including aerospace, automobile production, dentistry, architecture, and food. The photopolymerization of the polymer used for 3D printing is precise and provides excellent surface roughness but has lower mechanical strength than traditional manufacturing methods. In this study, Multi-walled Carbon Nanotubes (MWCNTs) were blended with urethane acrylate-based resin as a filler. Mechanical strength enhancement was confirmed using a DLP 3D printer. The stabilities of MWCNT dispersions in resin were verified, and viscosity and curing depth measurements were conducted to establish 3D printing parameters. Tensile and flexural strengths were higher for an MWCNT length of 50 μm than one of 100 μm, and maximum values were obtained at an MWCNT content of 0.1 phr. Under optimal conditions, tensile and flexural strengths increased by 2.1 and 1.8-fold, respectively.
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