What we are doing...
Engineers use investment casting as a method to fabricate a variety of high quality components in mechanical systems. Cast components, unfortunately, have a large lead time associated with their fabrication. In addition, a casting engineer must have years of experience in order to consistently pour high-quality castings. For example, a casting can be defective due to its geometry and how it is gated (how the molten metal is poured into the mold). The engineer recognizes problem geometries and gates them according to past successes and failures.
In 1989, Sandia National Laboratories created the FASTCAST consortium to improve investment casting technology. This includes software that aids engineers in predicting casting defects. This software, called WinMod, is currently under development at Sandia. WinMod was originally created by Robert G. Erdmann from the University of Arizona. Alpha versions of WinMod are now being used by FASTCAST member companies. WinMod allows you to import a .STL file that defines the part geometry (produced by ProEngineer or AutoCAD for example). You can add gates, mesh the part including gates, and calculate a point modulus. WinMod then becomes a sophisticated visualization tool, allowing you to see possible defects. The part's mesh can be sliced open or modulus values stripped away to aid in analysis. The casting can also be viewed from different angles and zoom magnifications. The WinMod interface is very simple to use, and runs on Windows 95 or Windows NT operating systems. It does not require a super-computer to run unlike other casting analysis programs that use finite element analysis. An average, Pentium-equipped PC will do.
Fig. 1 shows an STL file of an air intake manifold that has been imported into WinMod. Fig. 2 shows the meshed part after the point modulus has been calculated. The sectioning control bar is used to cut away part of the mesh. Red areas inside the part are possible hot spots and can lead to casting defects.
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