Investigation of contour-related parameters’ effects on anisotropic mechanical properties and surface roughness of FDM-printed parts

Contours, forming the outer shells of FDM-printed components, are important for surface quality and may dominate the mechanical performance of small-size or low-infill components. Despite their significance, contour-dominated effects have been relatively underexplored in prior studies. This study investigates the impact of contours on both anisotropic mechanical properties and surface quality of FDM-fabricated components. Utilizing fractional factorial design and analysis of variance (ANOVA), five contour-related printing parameters were examined: contour width, contour number, contour printing speed, layer thickness, and extrusion temperature. Our findings highlight that increasing the contour number from 1 to 3 can significantly enhance ultimate tensile strength by up to 18.9% in edge building orientations, while the elastic modulus shows minimal sensitivity to contour variations. Removing the contours significantly degraded both mechanical properties and surface quality. The building orientations and contour parameters can affect the quality and quantity of the filament bonding, which mainly contributes to variations in mechanical properties. This study provides practical insights for optimizing FDM manufacturing process of contour-dominated polymer-based components.