Additive manufacturing of acrylonitrile butadiene styrene: Feedstock quality correlations, heat-induced shrinkage, and 4D printing applications

• Correlation between quality and properties of ABS filaments and printed parts was studied systematically. • Heat-induced shrinkage of printed ABS parts depends on polymer chain length and residue contents. • A novel direct 4D printing method based on strain mismatch of different ABS materials was successfully developed. • Self-bending behaviours of 4D printed ABS bilayer structures were optimized and validated with simulation results. Here we investigate the correlations between the quality and properties of Acrylonitrile Butadiene Styrene (ABS) feedstock filaments and their material extrusion 3D printed counterparts. Three ABS filaments with different dimensional accuracy, density, residue content, and defects were employed to fabricate ABS parts at the same printing conditions and evaluated for mechanical strength, dimensional precision, mesostructures, and heat-induced shrinkage. It was found that poor-quality ABS filaments could lower the mechanical performance and dimensional accuracy of the printed parts while feedstocks with higher density and lower residue content yielded higher heat-induced shrinkage rate (up to 21.4%). Exploiting this differential shrinkage, a novel direct four-dimensional (4D) printing method was developed to fabricate self-bending bilayer structures triggered by heat stimulus without programming process. The findings offer valuable insight into the critical role of the quality and properties of ABS feedstock filaments in defining the printed parts’ behaviors and suggest great potentials of the proposed 4D printing method for fabricating smart polymer structures made of a wide range of thermoplastic materials even without shape-memory properties.