Effect of annealing on the mechanical properties of pla parts produced by fused filament fabrication

Aydın, Sencer
Additive manufacturing has become a disruptive technology for the production of load bearing components in a wide range of applications. Fused filament fabrication (FFF) is among the most effective and economical techniques for the printing of polymeric parts. There are numerous thermoplastic materials suitable for FFF. Among these, Polylactic acid (PLA) is a renewable, sustainable and cost-effective alternative. For better utilization of PLA parts produced by FFF, there is a need to understand the structure-property relationships in this system. This thesis investigated the effect of annealing on the mechanical properties of FFF produced parts made of polylactic acid (PLA). The as-printed specimens exhibit an amorphous structure, whereas annealing at elevated temperatures, ranging from 80°C to 140°C for 24 hours resulted in the formation of different crystalline phases. 100°C annealing for 24 hours provided the best results in terms of ductility and strength improvement; the tensile strength increased by 6.5 % and elongation at break increased by 33%. A further increase in the annealing temperature resulted in a decrease in the strength and ductility. In the second part of the thesis, the effect of annealing for different infill ratios were investigated. The 60% infill ratio case with 100 °C annealing showed the best normalized mechanical properties. The findings of the thesis show the importance of the microstructure on the mechanical properties and demonstrate the feasibility of annealing for the process and property optimization of FFF-produced parts.


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Citation Formats
S. Aydın, “Effect of annealing on the mechanical properties of pla parts produced by fused filament fabrication,” M.S. - Master of Science, Middle East Technical University, 2021.