Fracture phases of the CT specimens printed in PLA according to the raster width

Abstract

Abstract This article investigates the impact of raster width on crack propagation resistance in structures manufactured using the FDM (Fused Deposition Modeling) additive manufacturing process. This process involves a large number of variables to be controlled, which influence the mechanical properties and quality of the parts produced. During layer-by-layer printing, the filaments making up each layer fuse together on adjacent and overlapping sides. This fusion occurs at the contact surfaces, which depend mainly on the raster's width and the deposited filaments' length. The quality of this fusion plays a crucial role in the resistance to crack propagation, both between filaments and between layers. Therefore, this article aims to examine how raster width affects resistance to crack propagation in FDM structures. In this study, we developed two approaches; one is experimental based on CT (Compact Tension) specimens to assess the fracture toughness of poly-lactic acid (PLA)-based polymers using the theoretical approach of the J integral. To do so, we determined the strength curves (J-∆a) and deduced the JIC parameter for different raster widths (l = 0.42 mm, l = 0.56 mm and l = 0.68 mm). To better understand the behavior of contact zones between filaments during fracture, we developed a simplified numerical approach. The numerical results obtained were analyzed and discussed on the basis of observations of the fracture facies of CT specimens.