Enhancing long-term performance of 3D-Printed carbon fiber-ABS composites: Experimental investigation on infill strategies

A balance of lightweight properties, strength, and manufacturability often qualifies carbon fiber (CF)-reinforced acrylonitrile butadiene styrene (ABS) polymer for applications such as drone parts, aerospace components, interior panels, consumer electronics, and sporting goods. Nevertheless, under continuous loading, CF-ABS composites exhibit time-dependent strain, resulting in warpage, dimensional inaccuracy, and accelerated creep, which ultimately shortens their service life. This study investigates the influence of slicing strategies and process parameters on the tensile and creep performance of CF-ABS and neat ABS fabricated via fused filament fabrication (FFF), (FFF). Variations in infill patterns (line, grid, hexagonal), infill densities, raster angles, and layer thicknesses were systematically examined. The results show that line infill yields the highest normalized tensile strength but exhibits the poorest creep resistance, while hexagonal infill provides superior creep stability due to improved stress distribution and interlayer adhesion. Increasing infill density enhances stiffness and creep life, though its effect is pattern-dependent. CF-ABS achieves optimal performance at a layer thickness of 0.125 mm, whereas neat ABS performs best at a layer thickness of 0.2 mm. Moreover, bidirectional ±45° rasters significantly improve creep resistance compared to 0° rasters by redistributing stresses and delaying interlayer delamination. Fractography, using scanning electron microscopy (SEM), revealed that void distribution and fiber alignment are the microstructural drivers of these behaviors. Overall, the findings establish parameter–performance linkages and provide practical guidelines for optimizing infill architecture, density, raster strategy, and layer thickness to achieve a balance between strength and long-term stability in FFF-based composite parts.