Geometric feature reproducibility for laser powder bed fusion (L-PBF) additive manufacturing with Inconel 718
Paul Gradl, Darren C. Tinker, John C. Ivester, Shawn W. Skinner, Thomas W. Teasley, John L. Bili
Abstract
This study evaluates a series of additively manufactured geometric feature build plates to baseline variations and process capability between multiple Laser Powder Bed Fusion (L-PBF) machine configurations. The geometric feature build plate has dimensions of 140 mm in X-orientation, 140 mm in Y-orientation, and 31.8 mm in Z-height. Geometric features incorporated include but are not limited to X- and Y-distances; varying angle walls; horizontal holes; and vertical features including round holes, concentric hollow cylinders, protruding cylinders, square channels, thin wall thicknesses, freeform surface, and slots. Select features are based on standardized ISO/ASTM test artifact geometry. Additional features were included that are of interest for various aerospace or industrial applications and to understand practical limitations of various machine configurations. All the features are designed and located to be visually and geometrically accessible for inspection without removal from the base plate and to have high probability for successful printing among L-PBF platforms. Features from each of the 16 build plates were measured using optical and mechanical measurement methods and data compiled for a detailed evaluation of each feature. The systematic error for build accuracy across all features was 23.8 ± 5.5 µm with a 99.9% confidence interval.