Investigating the influence of FFF process parameters on flexural strength: comparison with three materials using response surface methodology and open-source 3D printer

This study seeks to assess the influence of the key infill design variables on the flexural strength of fused filament fabrication samples. In this regard, the study focuses on evaluation of maximum flexural stress of recycled polyethylene terephthalate (RPET), polyethylene terephthalate glycol (PETG) and polycarbonate (PC) with varying layer thickness, infill percentage and raster angle. The fractional factorial DOE approach was used to design the test samples. Validation tests were performed to ensure the viability of the generated results as well as applicability of the materials in the industrial setup. Across each material selected, higher infill percentage resulted in higher flexural strength, whereas raster angle was observed as the least significant parameter. If the process of creating 3D printing filament from recycled plastics is refined, RPET filament will become cheaper and more desirable for hospital and healthcare applications.