Experimental and statistical study on the effects of fused filament fabrication parameters on the tensile strength of hybrid PLA/Wood fabricated parts

Fused filament fabrication (FFF) also referred to as fused deposition modeling (FDM) is the most extensively used among all the additive manufacturing (AM) technologies due to its low cost, ease of use and variety of materials commercially available. An FFF printer generates a 3-dimensional object by extruding a stream of heated and semi-melted thermoplastic material, which is deposited onto layer upon layer, working from the bottom up. The literature study reveals that primary attributes of FFF parts like surface texture, mechanical strength, surface roughness, and dimensional accuracy depend on crucial process-related parameters and, therefore, should be set appropriately. This study focuses on the effects of several FFF parameters on the ultimate tensile strength (UTS) of a 3D-printed organic, biocompatible PLA with wood flour. Taguchi’s design involving orthogonal array experiments runs was applied to fabricate the test specimens (according to ASTM D638-10 type I one) and obtain the results corresponding to stress-strain curves and the ultimate tensile strength (UTS). The independent FFF parameters examined are layer thickness (LT), nozzle temperature (NT), raster deposition angle (RDA) and printing speed (PS). The results obtained are further analyzed by implementing standard statistical analyses like contour plots emphasizing 2-way interactions and analysis of variance. Full quadratic models were obtained and proved of high accuracy in terms of predicting the results for the response of UTS. The statistical results are supported with micrographs of failure sections and validated by comparing them with previous studies performed on pure PLA material. Moreover, evaluation experiments were performed to validate the results.