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

Structure-properties correlation in PP/thermoplastic starch blends containing sustainable compatibilizer agent

It was studied the effect of different sustainable compatibilizer agents(myristic and stearic acid), at varied content (0% to 10%), on the properties of polypropylene (PP)/thermoplastic starch (TPS) blends. The performance was evaluated by impact resistance, scanning electron microscopy (SEM), melt flow index (MFI), colorimetric analysis and biodegradability. In addition, the influence of two PP grades—Low-Flow and High-Flow Index—was evaluated. Impact strength of uncompatibilized blends did not show PP melt flow index influence. Compatibilized blends were positively influenced by acid addition. The optimum acid content for 30% of thermoplastic starch was 6.5%. For each polypropylene there was a preferential acid. At higher contents(10%), the acids appear to act as plasticizers as well. Scanning electron microscopy images showed improvements in the components interphase. PP with high melt flow had its rheology more affected by acid insertion, while PP with low flow index had its biodegradability more affect