Improving mechanical performance of fused deposition modeling lattice structures by a snap-fitting method

A snap-fitting method is introduced into fused deposition modeling (FDM) technique to fabricate BCC lattice structures of polylactic acid (PLA plus) with relative densities ranging from 2.1% to 8.3%. This method makes it possible to deposit all the filaments along the length direction of the strut. The measured peak strengths, compressive moduli and energy absorptions per unit volume of the snap-fitted FDM structures are improved by 37.6%-65.3%, 11.4%-39.6% and 67%-270%, respectively, compared with the conventional integrated FDM structures of the same relative density. Apart from improved mechanical properties, good surface quality and higher printing efficiency are also achieved in this method. Analytical models considering node volume are developed and able to predict the peak strengths and the compressive moduli of the integrated FDM structures and the snap-fitted FDM structures, for all relative densities tested. The paper also demonstrated that this method can be extended to other additive manufacturing technologies such as PolyJet. (C) 2019 The Authors. Published by Elsevier Ltd.