Investigation of effects of processing parameters on the impact strength and microstructure of thick tri-material based layered composite fabricated via extrusion based additive manufacturing

Abstract

Additive manufacturing composites have been employed in applications including, aerospace, automotive industries etc. and there are a number of properties required for such applications including better impact strength (I-S) which is the resistance to withstand impact loading. The present study investigates for the first time the effects of processing parameters on the I-S of thick tri-material based layered (Tmbl) composite of Polylactic acid (PLA), Polyethylene Terephthalate Glycol (PETG), and Acrylonitrile Butadiene Styrene (ABS) fabricated via Fused Filament Fabrication (FFF). 3 process parameters are varied in three levels each, whereas the I-S is chosen as output. Analysis of variance (ANOVA) is conducted. The surface plots of the significant parameter interactions are plotted showing the effects-trends of each variable on the I-S of the composite and various inter-layer, macro and micro observation of the composite was also performed using optical microscopy. It was observed that various shortcomings such as pores, delamination, peeling-like structure formation occurred at high layer thickness (t), high printing speed (v) and low infill density (ρ) whereas, there was absence of substantial defects at high ρ. Therefore, it was concluded that the selected parameters are significantly affecting the I-S of the composite. At the end, optimization of processing conditions was performed which resulted in enhanced I-S to weight ratio as compared to the highest I-S of single solid three dimensional (3d) printed base material.