Optimizing the Mechanical Performance of Glass Fiber Reinforced Polypropylene (GF-PP) Fabricated by Fused Deposition Modelling

Abstract

The aim of this research project is to investigate the mechanical behavior of short glass-fiber reinforced polypropylene (GF-PP) fabricated by Fused Deposition Modelling (FDM) and to optimize its mechanical properties.

The short glass fiber reinforced polypropylene feedstock filament for FDM varied by its melt flow index (MFI) values and carbon black (CB) additive content. As for FDM printing parameters, the extrusion temperature was also varied to find the best printing performance along the best filament feedstock. Other factors in the study, such as printing speed, layer thickness, printing orientation, raster orientation, infill density and number of contours were held constant according to pre-trials and screening studies of printing the GF-PP filaments. To decide the best outcome, the mechanical properties of the printed parts were characterized by stress-strain behavior in tension (i.e. tensile modulus, tensile strength and the tensile strain at break) and fracture surface analyses. The extent of warpage was also quantified. The fracture surfaces of the printed parts were examined by microscopic techniques to identify the modes of fracture and type of defects.

The outcome of the study shows that the short glass fiber polypropylene FDM fabrication is optimized in terms of tensile behavior by the highest melt flow index, 13.9g/10min, and excluding the carbon black additive. The analysis indicates that the tensile performance increases as the MFI increases with 0% CB content and the addition of the CB lowers the tensile performance. The extrusion temperature is only significant to the strain at break of 7.53 g/10 min material with 5% CB where the strain at break increases when increasing extrusion temperature. The tensile fracture surface defect analysis shows the decrease in stress concentration when fabricating specimens including carbon black. Moreover, the variable factors show no marginal effect on the warpage behavior, yet the highest MFI material promises fabricating specimens with less than 50% warpage.

Date of Award	Aug 2023
Original language	American English
Supervisor	Rashid Abu Al Rub (Supervisor)