Temperature, diffusion, and stress modeling in filament extrusion additive manufacturing of polyetherimide: An examination of the influence of processing parameters and importance of modeling assumptions

Fused filament fabrication (FFF), a form of filament-based material extrusion additive manufacturing (AM), is an extremely useful technique for the rapid production highly customized products; however, empirical evidence heavily relied upon understanding process. Initial modeling attempts have traditionally focused on predicting heat transfer and either interlayer diffusion adhesion or stress development but not taken combined approach to analyze all three components simultaneously in multiphysics model. In this study, we implement finite difference models examine transfer, polymer represented as degree healing (Dh), residual FFF poly(ether imide) (PEI). Printing with PEI great interest because its desirable mechanical properties high use temperatures, it also creates more challenging problem higher thermal gradients greater potential processing window compared modeled AM materials, such acrylonitrile-butadiene-styrene (ABS) polylactic acid (PLA). The larger can potentially allow options significantly complicate optimization experimental analyses including trouser tear tests part warpage measurements provide correlation predicted Dh levels. suggest that temperature layer influenced by subsequent printing up at least layers geometry studied. results study further demonstrate sensitivity molecular mobility reptation time (τrep), small change τrep order 2–3x result magnitude before interfacial begin, culminating less occurring. Furthermore, predictions are reliant extrapolation method used extend temperatures below those which was measured resulting different predictive results, even if same data used.