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

背景：本数据为标题为《金属材料挤出成型（Material Extrusion of Metals, MEX/M）设计指南》的学术出版物的补充材料。对应论文研究了开发基于丝材的金属材料挤出成型（MEX/M）设计指南的系统性框架，该工艺属于ISO/ASTM 52900标准定义的增材制造（Additive Manufacturing, AM）范畴。MEX/M是传统制造技术的高性价比且可持续的替代方案，尤其适用于快速原型制造场景。尽管增材制造本身具备极高的设计自由度，但MEX/M工艺存在独特的几何与工艺相关约束，若要实现优化的构件制备，必须解决这些约束问题。本研究采用奥氏体不锈钢316L（1.4404）合金丝材，针对MEX/M工艺制定并验证了设计原则。该成型原料为316L不锈钢粉末与热塑性基体中聚合物粘合剂的均匀混合物料，通过逐层挤出沉积完成成型。为系统评估MEX/M的几何可制造性，研究人员制备了基准试样，针对多项关键参数展开分析，包括最小可打印壁厚、特征倾角、孔成型性能、悬垂结构稳定性以及水平与垂直间隙的分辨率。成型后的生坯组件需经过两步热处理：脱脂与高温烧结，以实现近全致密化。制备与烧结的工艺参数均参考了既往的实证研究成果。研究通过3D扫描对几何偏差进行定量评估，将制备完成的构件与其对应的CAD模型进行比对，以测算变形量（单位：毫米）与收缩率（单位：%）。为进一步验证所提出指南的实际应用价值，研究人员还制造了一款叶轮，该叶轮整合了MEX/M工艺固有的关键几何约束条件。本研究最终提出了十条设计指南，这些指南不仅强化了现有的最佳实践，还拓展了其适用范围，有助于提升基于MEX/M的增材制造的工艺可靠性与构件结构完整性。