Process Sensitivity and Significant Parameters Investigation in Metal Fused Filament Fabrication of Ti-6Al-4V

Metal fused filament fabrication (MF3) combines fused filament fabrication and sintering processes to fabricate complex metal components. To design for MF3, an understanding of part geometry, printing parameters and material properties' effects on processability, part quality and ensuing properties is required. However, such investigation is a complex problem having several linked geometry, process and material variables to be considered that influence the process outcome. Moreover, such investigations through the experimental trial-and-error approach are costly and time-consuming, and sometimes not even feasible due to so many input variables involved. This study investigated the sensitivity of key output parameters toward each of the input parameters in MF3. FEA-based thermomechanical process simulations were used to estimate the process outcome in response to variable inputs, and a systematic procedure for sensitivity analysis has been successfully developed for the printing phase of the MF3 process. Dimensionless sensitivity values for all output parameters were calculated in the response of each input parameter, which allows parameters with different units to be compared quantitatively with a single yardstick. Moreover, three different part geometries were studied to identify how the process sensitivity varies with part geometry. For each output parameter, the most influential input parameters were identified from the whole set of input parameters and their influence trends were evaluated for different part geometries. The present sensitivity analysis procedure is expected to be an invaluable tool not only for process parameters optimization but also for the development of material and part geometry for MF3, hence enabling design for MF3 (DfMF3).