The present investigation aims at the thermal conditions for the printability of nylon using fused deposition modeling (FDM). Dog-bone like specimens are manufactured under two printing temperatures to measure the tensile performance of 3D printed nylon with respect to the feedstock material properties. Both Scanning Electron Microscopy (SEM) and X-ray micro-tomography analysis are conducted to shed more light on the microstructural arrangement of nylon filaments. Finite element computation based on microstructural implementation is considered to study the main deformation mechanisms associated with the nylon filament arrangement and the process-induced porosity. The results show a narrow temperature range for printability of nylon, and a significant influence of the printing temperature on the thermal cycling, porosity content and mechanical performance. With the support of both numerical and experimental results, complex deformation mechanisms are revealed involving shearing related to the filament sequencing, compression at the junction points and tension within the raster and the frame. All these mechanisms are associated with the particular and regular arrangement of nylon filaments.