www.flow3d.com

Casting aluminum alloys into metal molds using processes such as gravity, low pressure and high pressure die casting is a cost-effective means of producing complex shapes that require minimal machining. Governmental fuel efficiency standards for automobiles have provided impetus for greater use of light-weight materials, as well as for more thin-walled parts. However, what is saved by minimizing machining requirements can be lost if parts must be discarded due to excessive defects. And, as limits are stretched for thinning the walls of parts, the impacts of defects such as porosity and inclusions become greater.

Castings with exposed surface pores, blisters and blemishes are typically spotted at the foundry and discarded before they are used. However, those castings with defects under the surface can only be detected after machining and, sometimes, after assembly. Losses from having to discard parts after machining or assembly can be dramatically decreased if the flaw produced by the original casting operations can be reduced. Reduce the frequency of casting defects will in turn save energy in melting and remelting. Solving these waste and cost issues can result in increased use of lightweight aluminum components, producing the secondary benefit of improved fuel efficiency and environment.

Advanced metal flow analysis early in the product design stage can contribute greatly to the understanding and reduction of sources of defects. Sometimes, very minor changes to gating or runner design can radically alter flow patterns and result in significant reduction in defects. Multiple alternate designs can be evaluated prior to die or mold construction, avoiding the time and expense of multiple physical modifications. The cost savings can be tremendous and the improvement in time-to-market for cast components can be considerable.

FLOW-3D®’s accuracy shows in this comparison of short shot to simulation results for an aluminum oil pan.

Sophisticated predictive analysis is the contribution that simulation software can make to successful product development. FLOW-3D^® from Flow Science (Santa Fe, NM) has numerous powerful modeling features that enable accurate prediction of the filling and solidification dynamics of the metal casting process. The fundamental distinguishing characteristics of FLOW-3D^® that enable the engineer to better understand his processes are:

• Better than any other simulation package, FLOW-3D^® can accurately predict fluid flow complexities. FLOW-3D^®’s TruVOF^® algorithms track sharp liquid interfaces through arbitrary deformations and applies the correct normal and tangential stress boundary conditions -- an accuracy feature that distinguishes it from other CFD programs. This is particularly important in high pressure die casting, where metal enters the die cavity at great speeds. The jetting and splashing of metal throughout the die cavity can lead to porosity defects, folds and inclusions. With FLOW-3D^®, an engineer can isolate areas where these defects are most likely to occur and make corrective changes before testing the design on the floor.
• FLOW-3D^®’s special technique, FAVOR™, accurately characterizes the most complex geometry on a simple structured mesh. FAVOR™ uses fractional pieces of the rectangular elements to accurately represent the die geometry, eliminating the “stairstep” effect that can plague other software packages using structured meshes. With this approach, it is possible to more accurately track the location of metal fronts and to apply the proper dynamic conditions at those surfaces.
• FLOW-3D^® has powerful defect prediction capabilities that allow the user to readily and quickly locate defects. By accurately simulating the formation, movement and final location of such defects, FLOW-3D^® permits the engineer to make informed adjustments to designs.

Importantly, FLOW-3D^® is easy to learn and use, with a straight-forward user interface that gives the engineer control of model setup, simulation monitoring and post-processing/visualization. An all-inclusive package that does not require the acquisition of multiple modules to satisfy different needs, FLOW-3D^® is an economic choice.
 

Contact information:

email: cfd@flow3d.com
web: www.flow3d.com
phone: 505-982-0088

 

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