Experimental testing and process parametrization

In this chapter, a characterization to the resulting FDM-printed parts and hybrid manufactured, essentially in terms of mechanical properties, is exposed and discussed. Once evaluated the polymeric thermal and/or mechanical response of the neat filaments, we were able to move forward with the mechanical characterization of the different printed parts developed under different methodologies and distinct purposes. After all this, the performance of hybrid trials in order to evaluate system functionalities, as well as hybridization strategies associated with the presence of AM supports during milling and layer adhesion on the top of a completely cured and machined surface was pursued. Additionally, it was also studied advanced preprocessing methods such as adaptive or curved slicing assessed in the experimental hybrid system with a special attention to the constraints of using long or continuous carbon fibres. All the experimental methodologies carried out and obtained results are described in detail herein.The authors acknowledge the funding received by Project POCI-01-0145- FEDER-016414—FIBR3D, co-financed by COMPETE 2020 and LISBOA 2020, through Fundo Europeu de Desenvolvimento Regional (FEDER) and by National Funds through Fundação para a Ciência e Tecnologia (FCT)

Effect of infill pattern in Fused Filament Fabrication (FFF) 3D Printing on materials performance

Fused Filament Fabrication (FFF) is an Additive Manufacturing process popularized in the last decade due to its easiness of use and lower costs. However, despite its increasing popularity, the process itself has several gaps in knowledge, hindering further uses on more advanced objects. Also, the freedom of design allows significant variances in the printed parts, many influencing production and mechanical properties. This work studies the influences of the infill patterns in the mechanical response of printed parts. Using poly (lactic acid) (PLA), a widely used polymer in FFF process, the mechanical responses of parts printed with different infill patterns were analyzed. Rectilinear, Honeycomb, Triangle and Grid patterns were tested on impact resistance and tensile strength. Additionally, samples masses were measured and compared to the mechanical response. Results shown significant differences in the on tested properties. Tensile strength varied from 2.4 to 1.1 MPa, and impact resistance from 3.8 to 1.5 kJ/m² Also, measured mass was found to be significantly higher on the Honeycomb pattern. Considering mechanical response from both tensile and impact tests along with printed mass, Rectilinear pattern can be considered the most advantageous from the economic point of view