Invited Talk: Dr. Anil Chaudhary, Applied Optimization, presents, "Attain Higher Fatigue Performance for Parts Produced using the Laser Powder Bed Fusion Process"
Anil B. Chaudhary, Applied Optimization, Inc.; Logan Martin, Applied Optimization, Inc.
Abstract:
Laser Powder Bed Fusion (LPBF) can produce parts that are nearly fully dense, e.g., with relative density > 99.5% and voids < 0.5%. The voids (defects) in the interior of the part may be healed by post processing using Hot Isostatic Pressing (HIP), but surface-connected defects cannot be healed. Part-specific parameters, predicted using physics-based process simulations, can be used to reduce defects in the as-built parts by two-orders of magnitude or more, achieving relative density > 99.99%. The parameters are designed to account for thick/thin regions, up/down skin surfaces, surface features, etc., compensate for the residual heat buildup, attain consistent melt pool solidification conditions across the part, and reduce surface roughness. The parameters can also be designed feature-by-feature, vary within a layer and across the build height to eliminate surface defects, particularly for high-stress regions and complex features. Eliminating surface defects provides a solid seal around the interior of the part. If the part was subject to HIP, only very few interior defects need to healed to attain 100% dense material to produce a part with no surface defects for the high-stress regions. In addition, reduced surface roughness lowers stress concentrations, making it feasible to attain higher fatigue performance for parts produced with or without HIP.