PSI - Issue 41

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Author name / Structural Integrity Procedia 00 (2019) 000–000

N.A. Fountas et al. / Procedia Structural Integrity 41 (2022) 638–645 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the MedFract2Guest Editors. Keywords: Fused filament fabrication (FFF); PLA/wood material; Taguchi’s orthogonal design; response surface analysis; tensile strength.

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Nomenclature AM

Additive Manufacturing FDM Fused deposition modelling FFF Fused filament fabrication LT Layer thickness NN Neural Network NT Nozzle temperature OA Orthogonal array PLA Polylactic acid PS Printing speed RDA Raster deposition angle RSM Response surface methodology UTS Ultimate tensile strength

1. Introduction Additive manufacturing (AM) involves manufacturing processes that utilize all kinds of engineering materials in solid-state, i.e. powders, filaments, sheets and rods. It may as well use liquids or droplets of fluids which are deposited by implementing a range of deposition techniques (Wong and Hernandez 2012). Fused Deposition Modeling (FDM) or 3D printing (3DP), are the two most often-used alternative characterizations for Fused filament fabrication (FFF). This technique is the most extensively used of all AM methods owing to the simplicity of deposition mechanism as well as the range of materials available in the market. Currently, a number of innovative materials and colors are widely used in eco-friendly applications, like wood furniture, design and fashion (Pringle et al. 2018), etc. The strength of the FDM items is of paramount importance when FDM process-related parameters are set prior to the process execution (Chaidas and Kechagias 2021). When it comes to FDM parts, strength has been continuously investigated for over two decades (Cwikla et al. 2017). Part orientation inside the build space as well as material deposition influence the interlaminar bonding between the deposited material (Durgun and Ertan 2014) and thus attributes to strength and surface quality (Kain et al. 2019). Raster deposition angle (RDA) affects also the tensile strength of 3D-printed parts using polylactic acid (PLA) as the main material (Afrose et al. 2015). It is revealed that PLA parts exhibit higher tensile stress in X build orientation where orientation angle (DA) is zero than those in Y (90°) and 45° deposition angles. Solid structure for printing was applied for all experiments, which means that the printing parameters, nozzle temperature (NT); printing speed (PS) and layer thickness (LT) had fixed values. Layer thickness and part orientation on X-Y platform also influence tensile properties of ABS-FDM components (Vidakis et al. 2016; Farazin and Mohammadimehr, 2022). Many other research contributions have investigated the effects of layer thickness LT, part build orientation, raster angle, raster width, and air gap on strength characteristics of FFF test specimens (Srivastana and Rathee 2018; Gurrala and Regalla 2014; Mohan et al. 2017). With these studies as reference it appears that the strength of FFF items may vary with regard to the integrity of the interlayer bond formation. Thermal properties of polymeric materials and deposition rates must be optimized for achieving a robust bond interface and higher strength (Vanaei et al. 2021). All investigations conclude that given the material, different printing parameters are advantageous in order to optimize quality responses of FFF items, such as strength and shape accuracy.