Process Optimization for the 3D Printing of PLA and HNT Composites with Arburg Plastic Freeforming

Abstract

The industrial use of additive manufacturing continues to rapidly increase as new technology developments become available. The Arburg plastic freeforming (APF) process is designed to utilize standard polymeric granules in order to print parts with properties similar to those of molded parts. Despite the emerging industrial importance of APF, the current body of knowledge regarding this technology is still very limited, especially in the field of biodegradable polymer composites. To this end, poly(lactic acid) (PLA) was reinforced with halloysite nanotubes (HNTs) by hot melt extrusion. The PLA/HNT (0–10 wt%.) composites were analyzed in terms of their rheology, morphology, and thermal and mechanical properties. A study of the processing properties of these composites in the context of APF was performed to ensure the consistency of 3D-printed, high-quality components. The optimized machine settings were used to evaluate the tensile properties of specimens printed with different axis orientations (XY and XZ) and deposition angles (0 and 45°). Specimens printed with an XY orientation and deposition angle starting at 0° resulted in the highest mechanical properties. In this study, the use of PLA/HNT composites in an APF process was reported for the first time, and the current methodology achieved satisfactory results in terms of the 3D printing and evaluation of successful PLA/HNT composites to be used as feedstock in an APF process.