In this work an experimental design was developed using DOE to determine the effects of printing parameters in FDM processes on mechanical properties of an improved PLA, the Ultrafuse ® PLA PRO1. Test specimens were manufactured on a Wietech-Durbot large semi-industrial printer considering as variables the extruder temperature, platform temperature, printing speed and infill percentage in the ranges 200–220 °C, 40–60 °C, 50 mm/s-60 mm/s and 30%-70%, respectively. Afterwards, mechanical tensile tests and fracture surface analysis were carried out. The mechanical properties obtained from samples printed with lower infill percentage was lower than mechanical properties obtained from samples with higher infill percentage, which in turn, was lower than the reference mechanical properties of Ultrafuse ® PLA PRO1. The fracture surfaces showed predominance of brittle behaviour regions on samples with 30% infill and more extensive ductile regions on samples with 70% infill. The analysis of response surfaces showed that the infill percentage has a statistically significant influence on all properties, which allowed us to establish the more appropriate printing parameters combination to maximize the mechanical response of manufactured parts. The results show that Ultrafuse ® PLA PRO1 is a material with great potential to manufacture more robust and durable parts, such as functional components, mechanisms and structural elements.
Mélo et al. (Fri,) studied this question.