Build Plate Roughness Study on Part Bonding for the Laser Powder Bed Fusion Process

Additive manufacturing (AM) processes have emerged as valuable partners in conventional manufacturing, facilitating the production of low-batch components with complex geometries across diverse industries. However, despite ongoing advancements in various AM technologies, consistently achieving reliable and defect-free components remains a challenge. In powder metal AM, the use of substrates or build plates to support the entire build plays a crucial role in ensuring build stability. Build plate preparation typically involves surface grinding followed by finishing sanding, leading to variations in surface roughness between different manufacturing runs. This study aimed to elucidate the bonding characteristics at the build plate-part interface by investigating the porosity and build plate-part strength at different substrate surface roughness. To this end, a multi-roughness build plate was designed and fabricated for tensile testing via laser powder bed fusion (LPBF) processing of upright specimens. The specimens were subjected to computed tomography (CT) scans for porosity assessment, followed by tensile tests to evaluate the mechanical performance at the build plate-part interface (bp-p). CT inspection revealed no porosity at the interface for any roughness level. Furthermore, analysis of the tensile behavior in relation to substrate roughness (Ra values of 0.8 mu m, 1.4 mu m, 3.5 mu m, and 4.4 mu m) did not reveal statistically significant differences.