Die filling process simulation using discrete element method (DEM)
| Autor: | Nasato, D.S., Goniva, C., König, B., Pirker, S., Kloss, C. |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| Popis: | Powder compaction and sintering are important techniques for the mass production of geometrically complex parts. Powder is poured from a reservoir into the feeding shoe, which then passes the cavity one or more times thereby delivering powder into it. The powder is then compressed to create a relatively brittle green body. Finally, the green body is ejected from the cavity and sintered in a furnace where thermal activation below the melting point produces a fully dense structure. Necks form and grow between adjacent grains thereby eliminating the porosity of the part. In general, a consistent and uniform die filling process is always desirable. Heterogeneity during die filling can propagate through the subsequent processes and finally lead to serious product defects, such as cracking, low strength, distortion and shrinkage [1]. Capillary cohesion is known to influence strongly the strength and flow properties of granular materials. At low levels of water content, the water forms a discontinuous phase composed of interparticle bridges that are unevenly distributed in the bulk (the pendular state) [2]. For powder filling process these capillary forces may have strong influence in the particle dynamics and subsequent packing. An approach using discrete element method (DEM) simulation is proposed to reproduce die filling process and investigate process characteristics that affect final sand cake shape and may lead to in-homogeneities in powder during the filling process. Also an experimental apparatus able to reproduce the die filling process was built to validate numerical model. A coarse grain model is also necessary to reduce the model size (reduce the number of particles). |
| Databáze: | OpenAIRE |
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