In the present work, a micro‐extrusion‐based three‐dimensional (3D) printing process has been used to fabricate a metal‐polymer‐based green body. The fabricated parts consisted of carbonyl iron particles with a binder (polylactic acid) and a solvent mixture. From the pilot experiments, it was found that the process parameters, namely, Fe loading, layer thickness,and infill density, affect the green density, shrinkage, and surface roughness of the fabricated part. Moreover, to develop a statistical model with significant factors, experiments were performed based on the design of the experiment using a central composite design method. The experimental results revealed that green density and surface roughness of 3D printed parts increased with the increase in Fe loading and infill density. On the contrary, the shrinkage in the fabricated part decreased with an increase in Fe loading and increased with the rise in infill density. Further, with an increase in layer thickness, the green density decreased while shrinkage and roughness were observed to increase. To verify the accuracy of the developed model, confirmation experiments were also performed at the optimum set of process parameters obtained by the genetic algorithm optimization technique.

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The demand for the porous scaffold has been increasing globally in the biomedical field due to numerous advantages over dense structures like high damping capacity, high specific strength, and improved cell integration growth. In the present study, porous iron scaffolds were fabricated using micro-extrusion-based three-dimensional printing and pressureless microwave sintering. For the preparation of samples, metal-based polymeric ink was developed. Thereafter, cylindrical samples were printed and then sintered in a microwave sintering furnace. The experimental investigations were performed to estimate the effect of sintering parameters such as sintering temperature, heating rate and soaking time on the compressive and microstructural property of the fabricated samples. Microstructural characterization was done using the electron backscatter diffraction technique. The experimental observations deduced that the compressive yield strength and apparent density of the sintered sample increased with the increase in sintering temperature and decreased with a further rise in temperature. Moreover, the electron backscatter diffraction analysis unveiled that the high heating rate resulted in the reduction of compressive yield strength due to rapid grain growth. Additionally, the significant effect of soaking time on the compressive mechanical properties was also noticed due to the increase in the grain size diameter. From the X-ray diffraction plot, it was found that there was no contamination present in the fabricated scaffold. In order to evaluate the process capability, a case study was performed wherein the topologically ordered porous structure of iron was fabricated at optimum sintering parameters.

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