Dynamic simulation of powder packing structure for powder bed additive manufacturing
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Powder packing structure is a critical parameter of powder bed-based additive manufacturing (AM). Experimental characterization of powder is typically limited to measuring bulk properties, whereas many numerical models of AM powder packing are based on geometrical consideration without accounting for particle-to-particle interactions. In the present paper, the powder packing dynamics is simulated using a discrete element method (DEM)-based model that solves the mechanical contact forces and moments between individual particles. As DEM uses explicit time integration, a main challenge in modeling dynamics of metallic powder packing is the need for extremely fine time increment size (e.g., in the order of 1 ns for a 10-μm-diameter particle). The effect of mass scaling, employed for speeding up the calculation, on the simulation results is examined in a test case of powder particles packed inside a box container. The calculated packing density for two different particle size distributions is validated against independent literature data for laser powder bed AM with AISI 316L stainless steel powder. The sensitivity of key input parameters (e.g., friction coefficient) is further evaluated in this test case. The powder packing model is then applied to a practical situation of binder jet AM involving rolling of multiple layers of IN718 powder particles onto a powder bed, for which the calculated packing density is also validated with independent literature data.
KeywordsAdditive manufacturing Packing density Discrete element method Powder bed Binder jet
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WZ would like to acknowledge the support from U.S. NASA ESI Program, Award No. NNX17AD13G. Finally, the authors thank Dr. Ryan Dehoff of Oak Ridge National Laboratory (in Oak Ridge, TN, USA) for intellectual contribution to this work.
- 1.Sames W, List F, Pannala S, Dehoff R, Babu S (2016) The metallurgy and processing science of metal additive manufacturing. Int Mater Rev:1–46Google Scholar
- 6.Liu B, Wildman R, Tuck C, Ashcroft I, Hague R (2011) Investigation the effect of particle size distribution on processing parameters optimisation in selective laser melting process, In Proc of Solid Freeform Fabr Symp, Austin: 227–238Google Scholar
- 10.Lee YS, Zhang W (2015) Mesoscopic simulation of heat transfer and fluid flow in laser powder bed additive manufacturing, In Proc of Solid Freeform Fabr Symp, Austin: 1154–1165Google Scholar
- 15.Bai Y, Wagner G, Williams CB (2015) Effect of bimodal powder mixture on powder packing density and sintered density in binder jetting of metals, In Proc of Solid Freeform Fabr Symp, Austin: 758–771Google Scholar
- 31.A.M. Elliott, P. Nandwana, D. Siddel, Compton BG (2016) A method for measuring powder bed density in binder jet additive manufacturing process and the powder feedstock characteristics influencing the powder bed density, In Proc of Solid Freeform Fabr Symp, Austin: 1031–1037Google Scholar
- 34.Spierings A, Levy G (2009) Comparison of density of stainless steel 316L parts produced with selective laser melting using different powder grades, In Proc of Solid Freeform Fabr Symp, Austin: 342–353Google Scholar
- 35.Šmilauer V, Catalano E, Chareyre B, Dorofeenko S, Duriez J, Gladky A, Kozicki J, Modenese C, Scholtès L, Sibille L, Stránský J, and Thoeni K (2010) Yade documentation (Šmilauer V, ed.), The Yade project, 1st ed., http://yade-dem.org/doc/
- 36.Karapatis NP, Egger G, Gygax PE, Glardon R (1999) Optimization of powder layer density in selective laser sintering, In Proc of Solid Freeform Fabr Symp, Austin: 255–263Google Scholar
- 41.Uskoković D, Exner HE (1990) The kinetics of contact formation during sintering by diffusion mechanisms. In: Sōmiya S, Moriyoshi Y (eds) Sintering key papers. Springer, Dordrecht, Netherlands, pp 111–146. https://doi.org/10.1007/978-94-009-0741-6_8
- 45.O’Sullivan C, Cui L, Bray JD (2004) Three-dimensional discrete element simulations of direct shear tests, In Proc of the 2nd Int PFC Symp, Kyoto: 373–382Google Scholar