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Advanced Simulation Saves Time, Headaches

Jan. 31, 2007
Finite-element simulation is critical to cost-reducing efforts in metalcasting, and to shortening lead times for mold development while improving the yield and quality of the casting process. And, regular improvements in simulation software makes ...
Finite-element simulation is critical to cost-reducing efforts in metalcasting, and to shortening lead times for mold development while improving the yield and quality of the casting process. And, regular improvements in simulation software makes modeling less time-consuming, more accurate, and infinitely more user-friendly. ESI Group has released the latest version of its finite-element software for foundry simulation. ProCast 2006 introduces new features in meshing, improved processing capabilities, and more streamlined performance, according to the company. The software allows for automatic mesh generation; thermal analysis with radiation effects; flow analysis for mold filing; fully coupled thermal, flow and stress analysis; and advanced metallurgical options. It performs predictive evaluations of the entire casting process, including mold filling, solidification, microstructure, and thermomechanical simulations. Users can rapidly visualize the effects of mold design and apply correct decision-making at an early stage of the manufacturing process.

ProCast 2006 boasts significant new attributes: it predicts porosity by taking into account graphite expansion in nodular cast iron. In this material, the formation of graphite nodules during solidification leads to an expansion in volume that must be accounted for to assess the casting process accurately.

Also, the meshing time for models, which once took hours to complete, now takes only minutes. This improvement is due to the use of Geomesh, a tool for geometric analysis and repair that allows the use of major native CAD file formats.

Also, though parallel processing of mold filling and solidification was included in the previous ProCast release, the stress model in the new version is fully parallelized, allowing the complete casting process to be simulated in hours.

ProCast 2006 allows "full coupling between filling, solidification, stress, porosity, and microstructural features and allows even the most complex processes to be simulated overnight, providing foundries the ability to test more mold designs in less time," says Marco Gremaud, ESI Group's casting solutions product manager, summing up the new version.

The software covers a range of metalcasting processes, including high- and low-pressure diecasting; gravity diecasting; and sand, investment, shell, lost-foam, and centrifugal casting.

Success factors in sand casting, gravity diecasting, and tilt pouring focus on optimizing the runner system and eliminating possible shrinkage areas. The location of risers and the use of insulating or exothermic sleeves and their influence on shrinkage can be studied on the computer and visualized directly on the screen, in order to achieve optimal part quality.

The simulation of lost-foam processes requires detailed physical modeling of the counter-pressure generated by the foam combustion, as well as the effect of the permeability of the coating and sand. The software accurately portrays the complex physics behind lost-foam processes.

The specific needs of high-pressure diecasting, including squeeze casting and semi-solid material processes, are covered within ProCast 2006. Optimal piston velocity profiles, gating designs, and overflow positioning can be achieved with simulation, even for thin-walled structures. Thermo-mechanical die cycles can be performed to address not only die life but also in-service part performance, thus reducing manufacturing risks and costs.

To reproduce industrial production conditions in low-pressure diecasting, mold cycles can be performed numerically until the mold has reached steady-state temperature conditions. Based on thermal die profiles, mold filling, and solidification results, process parameters can be tuned to achieve optimal process quality while reducing time to market.

Also, the software has features to address the specific needs of investment casting foundries. For instance, ProCast 2006 can automatically generate a mesh representing the shell mold, allowing for multiple shell layers and the blending of non-uniform thicknesses. Also, the software takes into account radiation with view factors, including shadowing effects, which are critical when working with high-temperature alloys.

Read the full presentation, "Advanced Simulation Saves Time, Headaches."