Investigation of Sintering Parameters for Low-Cost 3D-Printed Cast Iron Using Material Extrusion

Metal Material Extrusion (MEX/M) provides a rapid, low-cost additive manufacturing option for individual and batch productions; however, cast materials are not typically available in the material pool. White cast iron is subject to long casting lead times and high foundry costsThis research details a comparative sintering process study for MEX/M printed white cast iron, a novel addition to the metal additive manufacturing field. A mechanical properties and microscopic evaluation on MEX/M white cast iron samples was completed to compare the influence of three sintering parameters: peak sintering temperature, dwell time, and cooling process. It was observed that increasing the peak sintering temperature increased the sintered density by 23.2% and the volumetric shrinkage by 14.25%. A longer dwell time increased the sintered density by 30.1% and the volumetric shrinkage by 9.42% but decreased the microhardness of the sample. A change in the cooling process of the sample had no effect on the mechanical properties or the microstructure of the sample. The samples achieved a 79.9% increased average density after sintering to 5.75 g/cc, with 57.82% volumetric shrinkage and a 23.3% mass loss. Overall, the samples were 85.8% less dense than casted white cast iron but showed features of a white cast iron microstructure.