Supplementary Data: Design Guidelines for Material Extrusion of Metals (MEX/M)

Context: This data is supplementary material to the publication with the title ‘Design guidelines for Material Extrusion of Metals (MEX/M)’
The corresponding paper investigates systematic framework for developing design guidelines for filament-based Material Extrusion of Metals (MEX/M), an additive manufacturing (AM) process classified under ISO/ASTM 52900. MEX/M presents a cost-efficient and sustainable alternative to conventional manufacturing techniques, particularly in the context of rapid prototyping. While AM inherently provides extensive design freedom, the MEX/M process introduces unique geometrical and process-related constraints that must be addressed for optimized component fabrication.
This research formulates and validates design principles for the MEX/M process utilizing an austenitic steel 316L (1.4404) alloy filament. The feedstock comprises a homogeneous mixture of 316L stainless steel powder and a polymeric binder within a thermoplastic matrix, which is extruded and deposited in successive layers. To systematically evaluate the geometric feasibility of MEX/M, benchmark specimens were fabricated, analysing critical parameters such as minimum printable wall thickness, feature inclination, borehole formation, overhang stability, and the resolution of horizontal and vertical gaps. The green-state components, post-fabrication, undergo a two-stage thermal treatment comprising de-binding and sintering at elevated temperatures to achieve near-full densification. The process parameters for fabrication and sintering were adapted from prior empirical studies.
A quantitative assessment of geometric deviations was conducted through 3D scanning, correlating the fabricated components with their corresponding CAD models to determine deformation (mm) and shrinkage rates (%). To further validate the practical applicability of the developed guidelines, an impeller was manufactured, incorporating key geometrical constraints intrinsic to MEX/M. As an outcome, this study proposes ten design guidelines that not only reinforce existing best practices but also extend their applicability, contributing to the enhancement of process reliability and structural integrity in MEX/M-based additive manufacturing