Top contenders in a recent design competition sponsored by the North American Die Casting Assoc., Wheeling Ill., included steering knuckles for luxury carmaker Jaguar made using a high-vacuum squeeze casting process. The die-cast knuckles from SPX Contech, Portage, Mich., were one of 10 entries chosen from a pool of nearly 40 that show the benefits possible with aluminum, zinc, and magnesium die-cast parts. The steering knuckles, along with an automotive subframe for Honda and a magnesium engine cradle used in Corvette's Z06, are all first-time die castings and replace aluminum castings, steel stampings, and plastics.
The steering knuckle took the Aluminum, Squeeze/Semi-Solid prize. A proprietary P2000 HVSC (high-vacuum squeeze casting) process let SPX Contech meet tight production schedules and weight constraints set by Jaguar designers. Steering knuckles are typically forged or cast from steel or iron. Jaguar's previous supplier failed to produce acceptable aluminum castings and opened the door for P2000 HVSC processing. The technique produces aluminum parts with minimum ultimate tensile strength of 276 MPa and minimum 0.2% proof stress of 207 MPa, while also providing elongation to a minimum of 6%.
To produce the Aluminum over 10 lb award-winning subframe for Honda, Ahresty Corp., Tokyo, developed a high-vacuum diecasting process that let them reduce weight by 38% compared to the previous steel stamping. The high-vacuum process let Ahresty capitalize on traditional advantages of die casting: high productivity, freedom of shape, and dimensional accuracy. It also let them bolster part strength via the use of special aluminum alloys and a holding furnace that reduced debris and gases in the molten metal. The die castings are MIG weldable.
Meridian Technologies Inc.,
Strathroy, Ontario, used a new high-temperature AE44 magnesium alloy to create the 24-lb engine cradle that captured the Magnesium over 0.5 lb prize. The alloy features the same properties as aluminum, but drops cradle weight 33% and, thus, reportedly improves vehicle handling. The Corvette engine cradle is the first commercial use of AE44 alloy and demonstrates that magnesium chassis components can be made using high-pressure die casting.
In the Under 1 lb, Aluminum category, PHB Die Cast Inc., Fairview, Pa., was tops with its cast-aluminum auto reflector. The diecast part replaces a previous design consisting of a plastic housing and aluminum casting. The die casting for North American Lighting Inc., Paris, Ill., is used on minivans and not only serves as the reflector but also supports and lets drivers adjust the light. The die casting provides nearly a 15% cost savings, is leakproof, and sports thin walls for further weight reduction.
Toral Cast Light Metal Technologies, Concord, Ontario, took the Aluminum 1 to 10 lb honor for a die-cast aluminum cam cover that replaces plastic cam covers on GM inline fourcylinder engines. The aluminum cam cover was cast using a threeplate die with a central gating system. This technique let designers optimize flow channels and solidification patterns to boost performance. The design maintains structural integrity at temperatures to 300°F (150°C), requires fewer fasteners, and seals better against oil leaks. The cam cover is also 100% recyclable.
Product Technologies, Maple Lake, Minn., nailed the top award in the Magnesium under 0.5 lb category for the "backbone" of a cordless nail gun for DeWalt. They produced right and left backbones that serve as the skeletal support for all internal and external components. Cast with AM60 magnesium, each of the parts weighs less than a quarter-pound and needs little machining.
The Zinc under 6 oz/ nonelectroplated prize went to Production Castings Inc., Fenton, Mo., for a low-voltage, waterproof wire connector. The die casting eliminated the need for wire strippers or pliers to complete the long-term waterproof connection. It also reduced tooling, parts, and assembly costs for Blazing Products Inc., Chesterfield, Mo., while improving quality and ease of use. The connector demonstrated a new use for zinc die casting by creating a thin-wall part in a fourcavity mold on a high speed 2 X 2-in. die-casting machine.
ZF Lemforder Corp., Brewer, Maine, along with diecasting machinesupplier FisherCast Global, Peterborough, Ontario, took the Zinc over 6 oz/ nonelectroplated honor for creating a new process to die cast rings directly onto the end of stabilizer link rods. The highly automated process replaces a previous assembly operation that welded precisionstamped rings onto the ends of the rods. Die casting reduced material costs by 20% and let ZF use preplated rods that reduce inventory and shipping costs.
The Zinc any size with decorative finish honor went to Quebec's Dero Enterprises Inc. The ornamental, electroplated handle cover for caskets significantly improved aesthetics and quality over a previous utilitarian steel stamping. Patterned after a piece of religious artwork, the handle cover is temporarily used during funeral services. The die casting is more durable for extended use, reproduces the fine artwork details, and can be recycled once the cover is no longer serviceable.
F5 Networks Inc., Liberty Lake, Wash., walked away with the Honorable Mention (Best Use of Die Castings in a Final Assembly) for bezels and faceplates used on controllers and other network hardware. The die castings feature core inserts to permit easy installation of different connectors and product variations including doors for power-supply access. They come in two sizes for equipment in standard computer racks. The aluminum and zinc die castings replace previous plastic versions and provide greater structural rigidity, the ability to mold all features needed in a single piece, and EMI shielding with no need for secondary-coating operations.
North American Die Casting Assoc., 847.808.3153, www.diecasting.org