Effect of fused layer modeling (FLM) processing parameters on impact strength of cellular polypropylene

Fused layer modeling (FLM) or fused deposition modeling (FDM) can be used to produce polymer components with a cellular structure. The existence of cells (voids) in FLM parts degrades mechanical properties. This study was done to understand the influence of two printing parameters, layer height (0.1 mm and 0.3 mm) and extrusion temperature (200 degrees C and 250 degrees C), on the Izod impact strength of polypropylene (PP). Morphological analysis showed that smaller layer height and higher extrusion temperature generally resulted in smaller cell size but larger cell density. Printed PP components were lighter than injection molded PP parts. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses confirmed that both a and 13 type crystals existed in printed PP. PP printed at 250 degrees C had lower impact strength while components printed at 200 degrees C had similar impact strength to injection molded PP. (C) 2017 Elsevier Ltd. All rights reserved.