Numerical simulation of the temperature history for plastic parts in fused filament fabrication (fff) process

Fused Filament Fabrication (FFF) is one of the major Additive Manufacturing (AM) processes for polymer materials. In FFF process, repetitive heating and cooling cycles occur when the filament is dispositioned onto a build platform to fabricate a three-dimensional part. The uneven temperature gradients and non-uniform cooling in the part may cause significant amount of warpage. The current practice of making an AM part to match the design intent is largely relied on time consuming trial-and-errors. Numerical simulation is an effective way to predict warpage. Accurate prediction of the thermal history during the FFF process is key for the success of warpage simulation. In this paper, an integrated approach is developed in LS-DYNA to model the FFF process and predict the temperature profile. Different from the traditional approaches, the tool path and FEM mesh are decoupled in this study to enable the flexibility of FEA mesh generation and improve computational efficiency. An innovated micro thermocouple is used to measure the temperature history inside the parts. The evolution of the thermal history is predicted and compared to the measurement data to demonstrate the accuracy and efficiency of the developed simulation model.