Surface Roughness Variation in Laser Powder Bed Fusion Additive Manufacturing

The surface roughness of an additively manufactured part produced through laser powder bed fusion has a significantly higher roughness than surfaces produced through traditional manufacturing processes. This roughness can have a significant impact on mechanical properties such as the fatigue life. Additionally, there is still a lack of understanding of the variation of the surface roughness and the appropriate metrics to represent the surface. This work presents line of sight measurements across several large surfaces with changing processing parameters and layer geometry. The measured areas are divided into regions where surface measurement metrics are calculated, and the surface variation within and across the surface is discussed. The calculated metrics and variation are related to the expected impact that the surface will have on the mechanical performance. Results from this research will provide guidance towards surface roughness metric specifications to ensure quality parts with consistent mechanical performance.