A process-structure-performance modeling for thermoplastic polymers via material extrusion additive manufacturing

Abstract

Qualities of polymeric parts fabricated by material extrusion (ME) additive manufacturing is sensitive to the processing conditions. However, the linkages among ME polymers’ mesostructure, effective properties, and printing conditions are still not clear enough. In this context, the present work aims to establish a model capable of estimating the structure and elastic properties of unidirectionally extruded thermoplastic polymers just by setting printing conditions and intrinsic material properties as primary variables. To this end, according to the principle of mass conservation and a thermal-sintering model, the geometry of ME polymers, characterized by strands’ shape, size, and the bonding condition, are predicted firstly. Next, based on the representative volume element (RVE), numerical homogenization is conducted via the finite element method to gain the products’ orthotropic properties. Tests on ME Acrylonitrile Butadiene Styrene (ABS) products are also made. Our experimental results, together with the existing experimental data, verified the present model. Furthermore, parametric analyses are carried out. Effects of layer thickness, printing speed, flaw rate and extrusion temperature et al. on ME polymers’ porosity and mechanical behaviors are revealed, which may have important implications in the future ME additive manufacturing of thermoplastic polymers.