|About this Abstract
||Materials Science & Technology 2020
||Additive Manufacturing: Qualification and Certification
||Reducing Heat Buildup and Regularizing Melt Pool Dimensions in Laser Powder Bed Fusion through a “Powder Moat” Scan Strategy
||Evan P. Diewald, Christian Gobert, Nicholas Jones, Jack Beuth
|On-Site Speaker (Planned)
The stochastic nature of the laser powder bed fusion (LPBF) process results in undesired defects such as porosity, residual stress, and inconsistent microstructure. Many flaws are related to erratic thermal conditions caused, in part, by suboptimal infill scanning strategies. This article presents an approach for reducing heat buildup in metals additive manufacturing (AM) that can be implemented within the bounds of most commercial machines. The “Powder Moat” strategy, where a thin wall is built outside the boundaries of the intended part, eliminates in-plane hotspots by inducing a predictable delay after each raster. A semi-analytical model is used to generate process maps of delay times and moat thicknesses as a function of laser power and velocity, and the approach is validated through high speed imaging. By standardizing melt pool dimensions and thermal distributions, the strategy serves the broad goal of process qualification and is a practical step toward increasing AM’s reliability.