Printability and geometric capability of L-PBF in manufacturing thin circular cross-sections

Laser Power Bed Fusion (L-PBF) is one of the sought-after Additive manufacturing methods for manufacturing metallic parts with complex geometries and functionally efficient porous materials. This has opened avenues of applications in aerospace, medical and automotive industry. The geometric parameters of these miniaturely architectured metamaterials can be varied to engineer the mechanical properties according to the applications. This paper has critically studied the geometric feasibility, surface features and resultant microstructure of struts, the basic building block of strut-and-node based lattice architectured metamaterials. The struts under focus are circular in cross-sections with diameters from 0.1 mm to 1 mm with various angles of inclination ranging from 10° to 90°. The studies have revealed that the inclination of these strut components not only affect the surface texture but also influences the microstructure of the material. Laser profilometric studies and SEM studies revealed that the best surface finish can be obtained roughly between 40° and 60° of inclination angles. The change in the angle of inclination influences the solidification kinetics along the same layer. Micro-structural studies using SEM and EBSD reveal that the architecture of the XY plane along which the load would be applied varies from an equiaxed structure for a 90° strut to a near to columnar structure for a 10° strut.