Lightweighting Through Redesign Furthers Fuel Economy Goals
An automotive OEM diligently working to meet government-mandated fuel economy goals sought Waupaca
Foundry to achieve its lightweighting objectives.The targeted component is a differential carrier in the driveline on the company’s light duty trucks
already in production.
By developing design modifications, Waupaca Foundry was able to reduce the weight of the high-volume
part on one of America’s most popular trucks. Tooling engineers worked collaboratively with the OEM’s
casting design engineers to achieve a differential carrier that was
both lightweight and durable, creating a part that is now 12 percent lighter.
Casting design engineers first modified the machining line on the locator surface of the part to eliminate
weight, but during 3D modeling, Waupaca Foundry found an issue. The challenge was uncovered when computer
models using MAGMA® solidification simulation indicated the part would be prone to shrinkage porosity,
thereby placing the product outside the specification. The team set out to solve the problem by adding and
reducing material in the porosity-stricken areas.
The overall design evolution included tweaks to wall thickness and the transition of radii to create
better feed paths. The changes were exacting—adding or decreasing amounts roughly the width of five sheets
of paper to get the desired results. Also, increasing the fillet moved the porosity away from the oil
return and grease pocket, preventing it from opening up. This combined with a proprietary alloy helped to
control shrinkage porosity.
Following 3-D modeling and dimensional analysis, the part was prototyped, and Waupaca Foundry did
extensive physical inspections including microstructural analysis of the casting and X-rays to validate
that the design changes were structurally sound.
By changing the design of the casting with elongation, porosity was reduced in problematic areas, creating
a thinner wall while still ensuring integrity and meeting safety requirements.
With this new design, the team was able to reduce mass decrease weight and cost.
The result is ductile iron casting that is 12 percent lighter with porosity removed and casting quality
while maintaining critical performance requirements. This solution proved that lightweighting is not
dependent on material solutions alone, but can also be achieved through casting design modifications.
Removed 12 percent of the casting weight, just shy of 10 pounds (4.5 kg).
Aided consistent machinability.
Helped meet US Environmental Protection Agency’s CAFÉ program requirements.
Looking for casting quality improvement, engineering support, or cost reduction? Waupaca Foundry is eager
to join your team in the problem-solving process. Connect with us at