Empirical process model for shrinkage-induced warpage in 3D printing

Abstract

Purpose The purpose of this work is to explain the emergence of warpage due to a locally and temporally inhomogeneous shrinkage in 3D printing (Binder-Jetting) of polymers. Design/methodology/approach An analysis of shrinkage yields parameters for a one-dimensional layer model of the binding process. Based on this, residual stresses and deformation are calculated by means of a numerical simulation model. Findings The simulation supports the assumption that the curling of specimens is created by a force transmission between layers due to inhomogeneous shrinkage. Furthermore, the layered production process might contribute to nonlinear deformations of not horizontally orientated surfaces. Research limitations/implications The simulation allows imitating the warping during the manufacturing process qualitatively. Exact values of deformations cannot be predicted, yet. Practical implications The results expand the knowledge about warpage effects in 3D printing caused by the layer-wise building process. Originality/value The developed model imitates the mechanisms leading to deformations during the 3D printing process, focusing on the physical interaction of layers with each other.