Nowadays, 3D printing Fused Filament Fabrication (FFF) currently presents obstacles to achieve high printing speeds, mainly due to the inability of the hotend to process the filament fast enough. This article presents the results of the thermodynamic flow analysis carried out on commercial designs of hotends, in the aim intending to identify the design parameters with a higher incidence in the mass flow of material output, so therefore, in the speed and quality of printing. Finite elements thermal analysis was carried out performed in order to characterize the effect of the materials and geometric design elements of the hotends. In this analysis the behavior of the commercial, the commercial melters' behavior and the effects caused by the changes in geometry and materials were obtained. The control variables were the chamber volume and the glass transition volume of each model. These results will be used as the design criteria of a new hotend.