A Methodology for Manufacturing 3D Disordered Metamaterials Using Laser Powder Bed Fusion from Granular Packings and Hyperuniform Point Clouds

Abstract

Three-dimensional open geometries originating from nontraditional manufacturing designs such as point clouds, sphere packings, and mathematical file generation can be challenging to manufacture when the structures have disorder and overhanging geometric features. This study algorithmically created rigid 3D geometries representing granular packings and hyperuniform point clouds suitable for fabricating metallic disordered metamaterial (MDM) geometries using additive manufacturing. This approach produced nonrepeating connecting beam angles ranging from 0° to 90° relative to the build plate. Prototyping using laser powder bed fusion (LPBF) was challenging for the low-angle connecting beams, due to heat transfer differences when printing on powder compared with a solid substrate. An initial set of unsupported MDM geometries revealed failed connecting beams and geometric inaccuracy. We performed a systematic study to emulate the complex beam angles by printing cylinders ranging from 1.0 mm to 3.0 mm in diameter and angles ranging from 10°, to 90°, relative to the build plate. Unsupported connecting beams tended to lose geometric integrity at angles below 30°, and failed at 10°, resulting in geometric deviation on the downfacing surfaces. However, varying LPBF input energies and support strategies mitigated the geometric deviati