Experimental investigation and discrete element modeling for particle-scale powder spreading dynamics in powder-bed-fusion-based additive manufacturing

Experiments and discrete element method simulation are combined to systematically reveal the particle-scale powder spreading dynamics based on the actual situation in additive manufacturing. To the best of our knowledge, this is the first report that introduces experimental calibration of powder layer height and line-contact triangular blade in the simulation. The results show that contributions of powder bed to the packing density fluctuations originate from the combined effect of gap height, particle jamming, and scraping effect. Due to the presence of force arches, long-duration jamming events with duration more than 5 times the normalized survival time, are necessary for the formation of empty patch. Instantaneous scraping effects lead to particle collisions and elastic deformation, which enhances the sensitivity of particle bursts after the blade. Overall, this study establishes a practical solution to optimize the particle packing state and provides support for subsequent modeling of laser-material interaction and melt pool dynamics. (c) 2022 Elsevier B.V. All rights reserved.