This paper investigates repeatability of additive manufacturing on the energy absorption capacity of polymer Body-Centered Cubic (BCC) lattice structures. As a class of cellular materials, lattice structures enable the tailoring of macroscopic properties through controlled microgeometry, where relative density, unit cell topology, print quality and manufacturing defects play a significant role. BCC lattice structures with a relative density of approximately 0.2 were designed in Rhinoceros using Grasshopper plugin and fabricated using fused filament fabrication (FFF) technology with PLA material. Experimental compression tests were conducted to evaluate the force – displacement response and determine the energy absorption characteristics of the structures. The results showed that lattice structures with uniform spatial distribution of BCC unit cells achieved an average peak force of 2529.89 N at an average compression displacement of 4.04 mm. Although manufacturing defects did not significantly affect the maximum load-bearing capacity, it strongly influenced the deformation behavior of the lattice structures. After reaching the peak load, diagonal collapse of the structures was observed, indicating limited post-elastic energy absorption capability. The average specific energy absorption of the tested structures was 0.41 J/g, with a coefficient variation of 11.32%. The results demonstrate that manufacturing defects contribute to the variability in energy absorption of FFF-fabricated BCC lattice structures. Their mechanical influence is governed not only by defect number but also by defect type relative to load-bearing struts and nodes. These findings highlight the importance of defects caused by FFF production in usable products for achieving favorable energy absorption characteristics.
