A Low-Cost Approach for Characterizing Melt Flow Properties of Filaments Used in Fused Filament Fabrication Additive Manufacturing

Users of Fused Filament Fabrication (FFF) can choose from a wide variety of new materials as filament producers continue to introduce new polymer and polymer composite filament into the marketplace. This paper describes a low-cost device capable of measuring the rheological properties of off-the-shelf polymer filament. In this approach, measurements are taken during filament extrusion which are combined with a pressure drop model based on simple shear flow within the FFF nozzle to perform inverse analysis that computes parameters for the power law generalized Newtonian fluid (GNF) model. The applicability of our FFF-filament rheometer is demonstrated with four commercially available polymer filaments by comparing the results to those obtained from a commercial rotational rheometer. A filament characterization approach similar to Melt Flow Index (MFI) is also proposed to assess the extrusion characteristics of materials specific to FFF.