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

2021-9-01
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.

Suggestions

Characterization of novel materials for fused filament fabrication
AL-DUAIS, ABDULLAH ABDULRAHMAN NAJI; Özerinç, Sezer; Kazanç Özerinç, Feyza; Department of Mechanical Engineering (2021-6-24)
Fused filament fabrication (FFF) is a polymer additive manufacturing technology that is suitable for a wide range of applications due to its low cost and ease of use. This thesis investigated two types of novel materials for FFF use. First, a foaming PLA filament is considered and the mechanical properties of 3D printed specimens using this filament is characterized. The results show that the strength, modulus and density of the foaming PLA can be tuned over a wide range of values by varying FFF process par...
Effect of fused deposition modeling process parameters on the mechanical properties of recycled polyethylene terephthalate parts
Bakir, Ali Alperen; Atik, Resul; Özerinç, Sezer (Wiley, 2020-08-01)
Fused deposition modeling (FDM) filaments made of recycled materials are desirable for environmentally friendly and sustainable manufacturing of prototypes and load-bearing components in many applications. We investigate the effect of FDM process parameters on the mechanical properties of 3D-printed parts made of recycled polyethylene terephthalate (rPET) filaments. Increasing the nozzle temperature from 230 degrees C to 260 degrees C improves the strength of the specimens by 100%. Using a raster orientatio...
EFFECT OF OUT-OF-AUTOCLAVE CURING ON THE BENDING STRENGTH OF TPNCF AND UNIDIRECTIONAL LAMINATES
Bozkurt, Mirac Onur; Bilge, Kaan; Papila, Melih; Çöker, Demirkan (null; 2017-09-20)
Out-of-autoclave(ooA)treatments in composite manufacturing draw the attention ofmanufacturers anddesigners in aerospace industry by offering numerous advantages over the traditional autoclave processing. Besides, thin ply non crimp fabric (TPNCF) architecture is proven for improved delamination resistance and fracture toughness. The objective of the study is comparingthe bending strength of flat and curved beams of TPNCF [0/45] and Unidirectional (UD)[0/45] aut...
Mechanical behavior of additively manufactured polymer composite structures and interfaces
Kepenekci, Mehmet; Özerinç, Sezer; Department of Mechanical Engineering (2021-9-6)
Additive manufacturing (AM) is a technology based on the layer-by-layer production of parts. Fused filament fabrication (FFF) is one of the most cost-effective and popular AM techniques for the production of polymeric structures. While the initial use of FFF was limited to thermoplastics such as PLA and ABS, recent advances enabled the printing of composite materials and structures for superior mechanical performance. Multi-material printing through dual-nozzle systems offers a unique opportunity towards t...
Investigation of variable bead widths in FFF process
Gharehpapagh, Bahar; Dölen, Melik; Yaman, Ulaş (2019-01-01)
Fused filament fabrication technology provides the opportunity to produce complex objects with sophisticated interior features. Here, extruding variable bead widths for desktop 3D printers is presented in order to improve resolution and to decrease the build time. In the proposed method, the cross-section is continuously varied according to the geometric features associated with the layers. That is, thinner beads can be utilized to print features with higher accuracy such as the outer surfaces, edges/corner...
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.