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Qualified sources are helping to make it happen through close collaboration and the ability to integrate superior materials into workable designs.
By Mark Shortt
Editorial Director, Design-2-Part Magazine
Pressures on OEMs to consolidate their sources have forced suppliers to shoulder increased responsibility for value-added services and manufacturing of complete components and systems, as well as finished parts. The nature of the automotive industry today requires that suppliers have quick responsiveness, high operational efficiency, and excellent skills in supply chain management and collaborative operations.
Job shops and other suppliers to the automotive industry work with a variety of materials to manufacture parts and components ranging from copper wiring and ceramic spark plugs to lead battery parts, cast iron or aluminum engine blocks, composite bumpers and dashboards, rubber tires, and plastic tail light lenses, to name a few. Their ability to meet exacting industry specifications while satisfying the strict cost and delivery requirements of automotive manufacturers is paramount. But their success in meeting automakers' requirements may also hinge on their ability to incorporate the advantages of lower-cost engineered materials into manufacturing processes, while remaining focused on producing on-time parts with zero defects.
Tight Collaboration between Extruder, Automaker Puts GT Supercar on Road
A trend that has become more noticeable throughout the automotive industry in recent years is the increasing use of materials such as plastics, composites, aluminum, and magnesium to reduce vehicle weight and meet performance objectives. Many new automotive designs, for example, are calling for extruded aluminum and aluminum-alloy components to reduce weight in applications such as frames, suspensions, chassis, engine blocks, radiators, cylinder heads, bumpers, and side impact beams. Aluminum extruders are playing a vital role in this development by supplying critical parts to automakers for newly designed vehicles. Among the automobiles that make significant use of aluminum design elements are the 2005 Aston Martin DB9, the 2005 BMW 6 series, the 2005 Subaru Legacy, and the Jaguar XJ.
One of the more intriguing examples is the 2005 Ford GT, a re-designed and re-engineered model that has been brought back to production by popular demand. The high-performance sports car features an extruded aluminum space frame for strength, light weight, and cost effectiveness. Made possible by the close collaboration of Ford designers and engineers with extruders at Hydro Aluminum North America, the GT's all-aluminum space frame chassis incorporates extrusions to connect four corner castings to one behind the passenger compartment. The result is a welded frame that combines light weight with rigidity and strength.
"The frame needs to be light so that the GT can achieve its performance targets," said Jim Brown, sales manager for Hydro Aluminum Transportation Components, and a leading member of the Ford/Hydro team, in a statement from Hydro Aluminum North America. "Yet it must have the stiffness required by the high-tech suspension system. Aluminum meets these objectives, and the cost is highly competitive."
The GT makes use of two aluminum alloys - 6061, which provides strength and stands up to intense welding, and 6063, where weight, design, and ability to absorb impact are important. Hydro Aluminum supplied 35 individual extrusion profiles, 30 of which were developed specifically for Ford. They include, in addition to chassis and rocker panel extrusions, bolt-on extrusions that add structural support to the engine compartment and are also integrated into the bumper assembly. Hydro also supplied the extrusion for the rear sport bar.
By all accounts, the extrusions were essential to achieving the aggressive targets that were established for weight, performance, and cost. Ford's team of designers and engineers worked extensively with Hydro's extruders to analyze specs, fine-tune modifications, adapt dies to changes in profile shape or thickness, and meet welding heat requirements. "The relationship between designer and extruder is critical, particularly regarding the extruder's ability to meet design tolerance and material property targets," said Matt Zaluzec, Ford's manager of materials research and advanced engineering, in a case history published in the Aluminum Extrusion Showcase (www.aec.org), a publication of the Aluminum Extruders Council. Zaluzec went on to say that "the use of aluminum throughout the GT helped to reduce overall vehicle weight, thereby reducing fuel consumption and emissions generation."
Zaluzec also noted that the inexpensive tooling required to produce the aluminum extrusions was an important consideration. Once the tooling is complete, he said, long extrusion lengths can be easily made at a moderate cost. "Extrusion cross-sections are tightly tailored to the applications, minimizing material waste and weight," said Zaluzec. "All these characteristics are key to producing a low-volume vehicle that, although it competes in an expensive price class, must meet stringent cost and investment targets."
Ford, which brought the new GT from concept car to production in just 12 months, is producing 1500 of the cars per year. One of the assembly technologies being used in production is friction stir welding, a solid state process that joins the center tunnel of the GT to its floor pan without deformation.
Corvette Z06 Relies on Lightweight Aluminum Components
Another high-performance car that sports an aluminum space frame is General Motors' 2006 Chevrolet Corvette Z06, introduced in the fall of 2005. Its use of weight-saving materials, such as aluminum, is said to have helped the Corvette Z06 break the four-second barrier from 0 to 60, with a time of 3.7 seconds.
Alcoa announced last August that it was providing various lightweight aluminum components-as well as the power and signal distribution system-essential for the Z06. The company is the source for aluminum extrusions used in some of the main structural elements of the vehicle's aluminum space frame, including two, full-length aluminum frame rails and the roof-bow. The aluminum components are produced at Alcoa's automotive units in Cressona, Pennsylvania and Auburn, Indiana.
The full-length aluminum frame rails, engineered as a performance enhancer over the base C5 steel rails, are a key structural element of the Z06 body. Weighing approximately 50 pounds each, the frame rails measure 6 inches in diameter and 14 feet long, and "are some of the largest ever used for this type of application," according to Dave Dobson, president of Alcoa Global Engineered Products. After agreeing to supply extrusions that would fit into GM's existing hydroforming process, Alcoa worked closely with the OEM on specifications. As a result, GM didn't need to retrofit its tube bending or hydroforming equipment to accommodate aluminum. "Hydroforming of Alcoa's large-diameter seamless tube represents an exciting new application for both Alcoa and GM," said Dobson.
Alcoa's AFL Automotive unit designed and manufactured the power and signal distribution system used in the Z06. "AFL Automotive designed the distribution system for the 2005 Corvette; we enhanced that system to meet the high-performance requirements of the Z06," said Bob Alexander, vice president of Alcoa and AFL Automotive.
Aloca's Automotive Castings business received the Best Supplier Award last summer from the Energy & Chassis Division of Delphi (Saginaw, Mich.), a major producer of automotive systems and components. Alcoa Automotive Castings (AAC) uses Vacuum Riser-less and Pressure Riser-less (VRC/PRC) permanent mold casting, a technology that it developed to produce high-quality, structurally focused castings, to supply Delphi with aluminum front and rear knuckles that are used on automobile suspension systems. Alcoa, which produces the knuckles at the company's Michigan Casting Center, was commended for its customer responsiveness, proactive communications, and continuous improvement efforts.
"Our dedication and team efforts have earned us this recognition," said Allen Zwierzchowski, president of Alcoa Automotive Castings, in a press release. "This achievement reinforces our commitment to quality and highlights our mission of outstanding customer service every day."
Alcoa Automotive Castings produces a variety of components, including sub-frames, cradles, knuckles, brackets, and control arms, for the suspension and chassis markets. Headquartered at the Alcoa Automotive Center in Farmington Hills, Michigan, AAC has design offices in Frickenhausen, Germany, and at the Automotive Center. Its production facilities are located in Michigan, Kentucky, and Farsund, Norway.
In September, Alcoa signed a letter of intent with Seohan Industries Co., Ltd., a Korean manufacturer of automotive parts. Under the agreement, the two companies will form an alliance to produce cast aluminum chassis and suspension components and modules for the automotive industry in South Korea, Japan, China and Australia. The letter of intent reportedly provides the framework for both companies to identify, develop, and launch programs. While Alcoa intends to license its VRC/PRC technology and sell related production assets, Seohan will establish an aluminum castings plant in South Korea to supply OEMs with cast structural parts using Alcoa's proprietary technology. When operational, the Seohan plant will complement and expand Alcoa's current VRC/PRC aluminum casting capabilities in the United States and Europe.
"With ever-increasing demand on safety and fuel economy and with consumers desiring superior driving performance, we project a significant increase in the use of aluminum castings in the critical chassis and suspension areas of the vehicle," said Zwierzchowski. "We are excited to be working with a proven supplier like Seohan in order to establish the VRC/PRC technology in Asia."
Magnesium Engine Cradle Saves Weight as Single-Piece Casting
Another component of the Corvette Z06 made headlines recently when its innovative cast magnesium engine cradle earned honorable mention in the 2006 Automotive News PACE awards. Meridian Technologies, Inc. (Strathroy, Ontario), the manufacturer of the engine cradle, and Hydro Magnesium, the developer of the material used for the component, were recognized for their roles in producing the automotive industry's first structural chassis component from magnesium.
Cast as a single-piece component using Hydro's new high-temperature Magnesium Alloy AE44, the engine cradle replaces large multi-piece assemblies and provides a 35% weight saving versus the original aluminum design. At a weight of 10.85 kilograms (23.92 lb), the magnesium AE44 engine cradle is an integral part of the vehicle's crash management system. An executive at GM recently called it "a breakthrough as a structural bearing component."
"This is the first magnesium chassis component produced from the high-pressure die cast process," said Tom Alexander, market analyst for Meridian Technologies. "Previously, this process had not been used for structural chassis components as they were too large, the material properties were not sufficient to meet the application demands, and a capable process did not exist."
High strength, ductility, and stable performance over an extended period of time at high temperatures were properties that suited Magnesium AE44 alloy to this application, according to Alexander. As it turned out, the weight savings resulting from the use of Magnesium AE44 delivered improved fuel economy and better weight balance to the vehicle. For every 10 pounds of weight savings, an estimated 1% increase in fuel economy can be achieved. And a 50/50 front-to-rear weight distribution-what Alexander describes as "a Corvette hallmark" - allows designers to incorporate the 7.0L engine in place of the base vehicle 6.0L engine. For consumers, the improved weight balance and single-piece component integration make for a better ride and handling, while also qualifying the Z06 as "the first SAE-certified 500+HP vehicle to avoid paying the Gas Guzzler tax based on its fuel economy," Alexander says.
"This industry-first usage of magnesium in a front engine cradle marks a tremendously significant development in the important industry movement to implement material strategies that can both reduce weight and improve vehicle performance," said Kris Pfaehler, Meridian Technologies' vice president, business development and marketing, in a recent press release.
Meridian is a global magnesium die caster with six manufacturing facilities, ranging in size from 32,000 square feet to 230,000 square feet. The company's diversified products include instrument panel beams, 4-wheel drive transfer cases, front end carriers, radiator supports, seat frames, steering column brackets, engine cradles, and other body structure, chassis, and powertrain components.
"Typically, when we're developing structural components, we're competing against non-die-cast materials and processes," said Glen Simonds, director of product engineering and new application development. "The challenge is to design a magnesium structural component that will meet or exceed the performance requirements of those parts and still be commercially viable."
The company recently met Daimler Chrysler's objectives for its DCX Minivan seatback frames by replacing a traditional multi-piece, steel stamped assembly with a one-piece magnesium alloy (AM60B) die casting that reduced weight and met a compressed timing target of less than one year from design, tooling and validation to start of production. The previous steel design called for a 14-part, welded assembly for a 60% back frame, and an 11-part, welded assembly for a 40% back frame. By successfully integrating the multi-piece steel design into a single-piece magnesium die casting, Meridian eliminated welding from the manufacturing process. The firm also met or exceeded all DCX craftsmanship expectations and Federal Motor Vehicle Safety Standards (FMVSS) while delivering a 3.06-lb, 60% seat back frame and a 2.26-lb, 40% seat back frame.
Meridian has found success by integrating a well-rounded set of core competencies with its ability to manufacture a variety of magnesium die cast structural components and assemblies. Last July, the company announced that two of its divisions - its Magnesium Products Division of Strathroy, Ontario, and Magnesium Products of America Division, of Eaton Rapids, Michigan - were among 10 suppliers to DaimlerChrysler that were chosen to receive the 2004 Gold Award. The award recognizes world-class performance and is granted to an elite group of automotive suppliers who meet established ratings levels in the areas of quality, technology, cost, customer service, and delivery.
Simonds credits Meridian's design and development expertise, firm grasp of magnesium's properties, and effective use of finite element analysis (FEA) software as keys to its innovative manufacture of die cast magnesium components. He says that the company has "done a lot of work on understanding the performance capabilities of magnesium," which has helped greatly in optimizing designs for the manufacturing process.
"It's really important that you design to the material properties and to the manufacturing process," Simonds continued. "We've been able to reduce part mass by intelligent use of FEA tools and by understanding the materials and process."
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