Quantifying the Impact of Multi-Stage Surface Mechanical Treatment Process on the Geometrical and Dimensional Characteristics of 316L Stainless Steel Components Fabricated via Multi-Step Material Extrusion Technology

Material Extrusion of metals (MEX/M) followed by debinding and sintering is a cost-effective multi-step route for producing complex metallic components. However, the inherent staircase effect and sintering-induced distortions often necessitate aggressive post-treatment processes to meet industrial requirements. The aim of this study is to investigate the effect of multi-stage surface mechanical treatment on a comprehensive benchmark sample containing diverse geometric primitives such as overhang prismatic features, cylinders, holes, pyramids, etc. A 3D structured light scanner was adopted to evaluate the evolution of dimensional accuracy and geometrical characteristics. The results indicate that sequential treatment effectively mitigates the layer-by-layer deposition. However, this effect carried an improvement in circular features such as cylinders or hollow rings, while for prismatic features such as prisms or pyramids it caused a measurable edge roll-off effect, highlighting a critical trade-off between smoothness and sharp-feature retention. Dimensional analysis reveals strong orientation-dependent shrinkage behavior during sintering, which is further modified by the material removal rates of the surface mechanical treatment stages. This work provides a qualitative and quantitative analysis of the final geometrical limits of the MEX/M technology cycle and offers insights into optimizing surface post-treatment parameters for high-performance applications.