A Model for Residual Stress and Part Warpage Prediction in Material Extrusion with Application to Polypropylene

The layer-by-layer fabrication procedure causes residual stresses to accumulate due to the repetition of heating and cooling during the material extrusion process. In this study, residual stress and part warpage of a polypropylene copolymer are investigated. The effects of adjusting process variable settings, such as deposition temperature, deposition speed, and layer height, on part warpage are analyzed computationally and experimentally. Material extrusion process simulation models that are capable of predicting the temperature distributions, deposited filament shapes, and residual stresses of fabricated parts have been developed. These models are used to predict the warpages and deformations of the fabricated parts; these predictions are compared with experimental results to evaluate the models’ efficacy. Insights are gained on the effects of particulate inclusions on the residual stress and warpage behaviors of polypropylene copolymer.