Extrusion-based additive manufacturing (EAM) is a relatively new process developed for the production of complex metallic and ceramic parts needed in smaller quantities. The debinding and sintering step of EAM is adopted from a well-known powder injection molding process. However, the 3D printing step needs special consideration to make EAM competent in the era of rapid manufacturing. This study is intended to investigate the effect of common printing parameters on the microstructure and mechanical properties of sintered stainless steel 316L (SS316L) parts manufactured through the EAM process. Part orientation (Ori), extrusion velocity (Ve), and layer height (h) were changed in experimental runs by following a full factorial design. Extrusion pressure as an indicator of melt stability and a grey relational grade as a combined response of sintered properties were analyzed against varying printing parameters. Physical characteristics measured during debinding and sintering shows near isotopic shrinkage and the process is stable.Metallographic characterization in terms of porosity and grain size indicated minor differences when Ve and h were altered. Sintered parts showed improved properties when printed with vertical part orientation and h = 0.5 mm. Whereas Ve which contributes significantly to the build-up rate was found to be responsible for melt stability. Ve at 12.5 mm/s exhibited melt stability and higher sintered properties.

The production of rapid tools for plastic molding, sheet metal forming, and blanking has always been a critical and important goal for applied research, and a very large number of alternative methods have been proposed over the decades for their production. Among these methods, the use of extrusion-based additive manufacturing (EAM), such as fused filament fabrication (FFF) or similar technologies, has not been frequently considered and needs to be explored extensively. EAM is generally considered a low-cost, low-quality, low-performance class of AM and not suited to produce real functional parts, but only for aesthetical prototypes. However, the capabilities of EAM technologies have greatly evolved and now it is possible to extrude a wide range of materials such as polymeric materials including both the low strength polymeric materials (such as nylon or PLA) and the high strength polymeric materials (such as PEI and PEEK), metals (such as tool steel), and even ceramics (such as zirconia). Starting from an extensive literature review, the purpose of the present paper is to further demonstrate the potential applicability and versatility of EAM as a rapid tool manufacturing technology for different applications in shearing, bending, deep drawing, and injection molding.

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The capability and applicability of additive manufacturing have mesmerized the entire manufacturing world. One major technique of additive manufacturing is extrusion-based additive manufacturing (EAM), which has been recently employed for the rapid production of ceramic components, among other applications. This study focused on establishing the process-property relations for extrusion-based additively manufactured ceramics, namely Alumina (Al2O3) and Zirconia (ZrO2), and then optimization of the relations to get the desired mechanical properties for applicability. Extrusion-based additive manufacturing was used to obtain the ceramic sample parts from ceramic-binder mixtures and by subsequent post-processing. The process parameters chosen for the study were extrusion velocity and part orientation whereas the mechanical properties selected were hardness and flexural strength. Extrusion velocity was varied at three levels i.e. 7.5 mm/s, 12.5 mm/s and 17.5 mm/s. Two levels selected for part orientation were horizontal and vertical. The design of experiments technique was used to establish the process-property relations by highlighting the most significant process parameters affecting the selected mechanical properties. Optimization was achieved by highlighting those levels of significant process parameters that provided the desired values of mechanical properties. Part orientation came out to be a significant factor affecting both the hardness and flexural strength of the two ceramics whereas extrusion velocity was found to be insignificant for both mechanical properties. Among the two levels of part orientation, vertical orientation samples showed higher values of hardness while horizontal samples showed higher flexural strength thus, aiding in the optimization of the process-property relations.