Experimental and Analytical Investigation of Infill Pattern and Build Orientation Effects on the Flexural Strength of FFF-Printed PLA Components

Fused Filament Fabrication (FFF) is without a doubt the most widely adopted additive manufacturing method for polymer components. As in every additive manufacturing process, the mechanical performance of manufactured components is a result of process parameters and design considerations. These include the infill pattern and parameters, the build orientation, and the temperature and layer height, amongst others, and all play a significant role in the flexural, tensile and compression properties of components. The present study aims to uncover the underlying mechanisms behind the performance of FFF-manufactured components using a combination of analytical and experimental methods to understand the developed stresses on components and the failure mechanisms of said components.

The performance of additively manufactured components was evaluated using a standardised 3-point bending setup both in the numerical and experimental domains. Three-point bending tests were conducted in accordance with relevant standards to evaluate flexural strength and stiffness. Standardised test specimens from polylactic acid (PLA) were deposited with varying infill patterns and build orientations whilst keeping all other parameters stable. The results of the experimental campaign were combined with analytical modelling (based on classical beam theory) and finite element modelling to achieve an all-round view of the performance of components.