Effect of the infill patterns on the mechanical properties of the carbon fiber 3D printed parts

The future in the aeronautical industry is in our conception to obtain 3D printed parts from composite materials of the polymer type reinforced with various materials (fibreglass, carbon, Kevlar, etc.), with very good mechanical properties. In this paper authors analyse the mechanical properties of 3D printed parts obtained by material extrusion of Polyamide based filament reinforced with 15% chopped carbon fibres by three types of infill pattern: grid, triangular and lines and with an infill density of 50%. After testing the specimens, the grid infill pattern showed the lowest average value in the two types of mechanical tests, but the values are higher than those reported in the literature by other researchers. Another fact, it can be concluded that the core configuration does not have a significant influence on the mechanical property's performance. After microstructures analysis with an optical microscope was observed the defects specific to 3D printing (pores, gaps and agglomerations) were and we determined that the share of defects decreases from grid pattern to lines pattern and for the triangular pattern they are minor even insignificant.