Study on the Tightness of Parts Manufactured by FDM

Fused Deposition Modeling (FDM) is widely used in additive manufacturing due to its low cost and accessibility. However, printed parts often exhibit inter – layer porosity affecting their watertightness. This study examines the influence of extrusion flow rate and wall thickness (via line width) on the fluid retention of PLA cylindrical parts fabricated using a Creality Ender 3 V3 SE printer. A Taguchi L16 plan was implemented, varying Flow (85 - 102%) and wall line width (0.40 - 0.80 mm) across four levels. Parts were printed under identical settings and tested for leakage using static water retention and immersion methods. Results indicate that higher flow rates and thicker walls significantly enhance watertightness. Optimal sealing occurred at 96 - 102% Flow and wall widths higher or equal with 0.64 mm. In contrast, low Flow and thin walls consistently resulted in leakage. The findings highlight the importance of process optimization for producing watertight FDM parts without postprocessing, offering practical guidance for sealed polymer component fabrication.