Characteristics of typical geometrical features shaped by selective laser melting

3D models that consisted of thin walls, sharp corners, cylinders, tetrahedrons, round and square holes were designed and constructed for this study, so that the capability of selective laser melting (SLM) to fabricate typical geometrical features could be ascertained and useful guidance for the direct manufacture of metallic parts presented. These geometrical features were produced via SLM using three devices (EOSING M270, SLM 250HL, and DiMetal-100) using 316 L stainless steel metal powders with optimized processing parameters. The similarities and differences between the geometrical features fabricated by three devices were compared and analyzed. Based on the experiments above, the additional geometrical features were further investigated to analyze the limits of both size and accuracy of each SLM-fabricated geometrical feature. Subsequently, the ability of SLM to produce inclined planes was studied, specifically the effects of inclination angle, scanning speed, and laser power on the quality of SLM-fabrication. Finally, by setting the value of the clearance parameter to 0.2 mm, a foldable abacus was constructed. Experimental results demonstrated that the constraints of the technique (e.g., optical spot diameter, laser penetration, powder adhesion, and stair effect) are the main factors that influence the ability of SLM to fabricate various geometrical features. By studying these constraints, some design guidelines were proposed for metal 3D printing, providing designers with rules for the design of innovative products.