Innovating Processes, Technology at Hayes Lemmerz Wabash.

This aluminum foundry has added an innovative permanent mold cell to its unique green sand line to serve a diverse range of needs for its engine customers.

In today's global foundry industry, everyone is looking for an edge. Whether this edge is found in technology, process or value-added services, foundries are finding the need to differentiate themselves from the competition and establish themselves as innovators in the eyes of their customers.

Foundries have relied largely on industry suppliers to provide the technological innovations that laid a foundation for their competitive success. However, as competition continues to increase and suppliers have fewer resources to focus on research and development, the onus for innovation may begin to become the responsibility of both foundries and suppliers to ensure future success.

At Hayes Lemmerz International, Inc.'s Wabash, Indiana operation, they believe that innovation should be integral to a foundry's mode of operation. From its unique green sand molding line to its self-developed stopper-rod pouring permanent mold casting cell to its intake manifold testing system, this foundry is relying on innovative technology to serve its customers. This belief follows in-line with the Hayes Lemmerz corporate focus of becoming a supplier that is customer--not product--driven.

"Our engineering staff is aggressive when solving product and process challenges," said Gary Barlow, plant manager. "We can not count on past successes as long term solutions because technology does not allow us to."

Following is a look at Hayes Lemmerz's Wabash foundry and its innovative permanent mold and green sand casting. In addition, this article takes a look at the shift in philosophy Wabash has undergone and how it is becoming integral in the design and testing of its components.

A Shift in Philosophy

In the late 90s, Wabash underwent a shift in production. This was due to a shift in philosophy from the foundry's new corporate parent-Hayes Lemmerz International, Inc. When Hayes Lemmerz purchased CMI International in February 1999, minimal operational or personnel changes were made on the foundry level. However, Hayes Lemmerz believes in aligning each of its plants with the customers it serves. Under its previous ownership, each foundry in the family focused on components with similar design and casting needs--such as producing only aluminum intake manifolds at Wabash, for example--and served a variety of customers. Under Hayes Lemmerz, each foundry focuses on specific customers--such as Wabash becoming a powertrain foundry, serving the needs of engine plants for Ford, DaimlerChrysler and GM--and producing a variety of components for each customer.

"The result is a more customer-driven process for casting design and production," said Jim Bohlen, quality manager. "We work with the same design engineers and purchasers, and we work with the same assembly and manufacturing operations for our customers. Solid relationships are built and communication is smooth."

Becoming a more customer-driven operation meant that Wabash had to better diversify itself to serve those customers. Whether this meant learning new casting designs and production for new components in green sand or adding new production processes, the foundry was expected to respond.

The result has been the addition of new components to its product line, which included a shift from the 4 jobs and 30,000 castings/week previously performed on its green sand line to 12 jobs at the same level of production. This new production included a diversification beyond intake manifolds to wheel hubs, intake ducts and cylinder heads. In addition, it was determined that the foundry needed to add permanent mold casting to its operation to produce more complex components requiring higher metallurgical quality (tighter dendrite arm spacing), thinner walls (to 3 mm) and greater surface finishes.

Innovative Molding

The initial decision to add permanent mold casting at Wabash came in 1999, within a year after Hayes Lemmerz took control. At that time, Hayes Lemmerz' Bristol, Indiana permanent mold casting facility was refocusing itself as a supplier of cast components for the structural side of automobiles and light trucks. As a result, its powertrain components were being shifted to other Hayes Lemmerz facilities. Although Wabash was strictly a green sand plant for the previous 20 years, it was determined that the permanent mold casting 319 intake manifold for Jaguar's 3.0L engine would be a good fit for its facility from the customer's perspective, because it correlated with Wabash's other engine customers. Wabash couldn't convert this component to green sand because its flask size wouldn't economically handle a casting of this size. In 1999, Wabash began the design and education process for developing a permanent mold cell within its green sand foundry.

"We had a steep learning curve, especially when it came to permanent mold coatings," said Mike Bean, technical services manager. "But our experience with aluminum and intake manifolds in general laid a good foundation from which to grow."

In March of this year, Wabash began production on the 24-lb manifold for Jaguar in its new permanent mold casting cell (Fig. 1).

"Any new process involves acquiring additional skills and implementing those skills into a robust process," said Barlow. "The biggest challenge is embracing the technology that is associated with each new process by empowering our employees."

This cell is comprised of two tilt-pour permanent mold systems. By utilizing robotics for core handling, pouring and casting extraction, the cell requires only two workers whose sole purpose is to place the manifold's coldbox core packages into fixtures on either side of the cell. Once the core package is set, the fixture shuttles the core to where a robot picks up the core package and places it in the permanent mold.

The true innovation in this permanent mold cell begins with the pouring robot, which utilizes two PLC-controlled stopper-rod automatic pouring ladles. This robot dips the ladles into a 4200-lb reverberatory holding furnace and submerges them 4-in, under the molten metal surface. Then, the stopper-rod raises and the molten metal slowly fills into the ladles from the bottom. The result is that the ladles receive clean metal without any oxides created from breaking the surface of the melt.

"Our greatest design challenge was working with the robotics and furnace systems to develop the timing required for stopper-rod pouring of aluminum," said Bean. "This type of pouring only had been performed in low-pressure permanent mold, so our tilt-pour concept was new ground to tackle."

After the ladles are filled, the robot transfers them to the dual pour cups attached to the manifold's permanent mold tool. Due to the pour size (48 lb) of the manifold and its complex core package, dual pour cups are required. By utilizing the stopper-rod pouring to transfer the molten aluminum from the ladle to the pour cup, Wabash minimizes melt turbulence. The permanent mold casting system then tilts to fill the molds and the casting solidifies. The core-handling robot extracts the casting and places it on a conveyor to proceed to shakeout and to cleaning and finishing. The total cycle time for the tilt-pour casting machines is 4 min./casting and the two casting cells work intermittently so a single core/extraction robot and a single pouring robot can serve each.

The melting for permanent mold casting is done in an 8500lb reverberatory furnace dedicated to the cell. This melt is transferred by launder to the holding furnace. Wabash is dedicated to reducing the avenues for oxide entrapment in the melt as well as maintaining a [+ or -]3F temperature range on the melt. "This dedication has paid off as we have not detected an oxide-related defect on the Jaguar manifold in four months of production," said Bean.

The expected production for the cell is 600 manifolds/week and the foundry plans to duplicate this cell for future expansion when job orders deem it necessary.

Until the addition of permanent mold casting, the Wabash operation was centered around its automatic flaskless green sand mold line. (Only one other European foundry uses a similar model molding line). Producing 240 molds/hr at a size of 30 x 34 x 13/13 in., this line is one of the world's largest flaskless systems. This size mold can be poured flaskless in aluminum because the molding line is able to use 1700 psi of squeeze pressure to achieve more than a 95 mold hardness at the mold face.

Wabash molds its components in 2-to 6-on arrangements. "This is what allows us to produce 15 million lb of components each year with only one mold line" said Bean. In addition, said Bean, the sand system delivers 5000-lb batches to the mold line every 60 sec to ensure continuous mold flow. The foundry uses 57 GFN sand to provide a high surface finish. "We also hold tight ranges for sand control, and we have never been without sand for molding," he said.

Two other advantages the mold line provides Wabash are inspection and pattern changeover. This mold line presents both the cope and drag to molding personnel for a plain and easy visual inspection and manual core placement. Wabash is able to complete pattern changes in 7 mm.

During production, cores are fed to the green sand line by one of ten coldbox core machines producing core packages comprised of up to 12 cores. Jhese same core cells also feed the permanent mold casting cell.) Melting for green sand molding is done in two 140,000-lb reverberatory furnaces (14,000 lb/hr melt rate). For 319 aluminum alloy, the foundry receives the metal molten from its supplier and then remelts scrap and the gating systems. For A356 aluminum, the foundry melts sows and the returns. To deliver the metal to the molding line, one of two launder systems is used to bring the metal to one of two 15,000-lb reverberatory holding furnaces.

For pouring, two PLC-controlled ladles automatically dip into the holding furnace and pour two green sand molds simultaneously (Fig. 2). This automatic pouring is computer-controlled. Wabash inputs the jobs each day and the computerized system directs the ladles as to the pour weight for each mold. "The greatest advantage to the automatic pouring is the repeatability of the ladles," said Bean. "With a new mold poured every 13 sec this would be difficult to achieve manually."

The molds cool for 25 mm. until shakeout. Both green sand and permanent mold casting feed the same cleaning and finishing line for further processing (see "Best Cleaning & Finishing Operation-2001," modern casting, January 2001, p.32). The foundry machines 80% of its components in-house in its 45,000-sq-ft machine shop. This machining operation also serves external customers as Wabash also performs assembly operations for customers.

Customer--Not Product--Focus at Wabash

The restructuring of the Hayes Lemmerz philosophy meant more than a swapping of casting jobs and the addition of new processes for Wabash. It also meant an opportunity to promote its design and value-added services to customers.

Aluminum intake manifolds are in a battle with polymer intake manifolds for market share. According to Stratecasts, Inc., Fort Myers, Florida, aluminum held 65% market share in automobile intake manifolds last year, but projections show a decrease to 34% by 2006. As engines are designed to run hotter [400F (204C) at the intake manifold] and expected to last longer, engineers are focused on components' fatigue strength and durability to ensure there are no warranty issues down the road. This focus is a plus for Wabash, but it is in a constant fight with the same engineers over weight and wall thickness issues. As a result, Wabash has taken a keen interest in component design by working with the Hayes Lemmerz Technical Center in Ferndale, Michigan, during initial product design and also by becoming involved with the customer directly before and after casting manufacture.

"We have to be involved with the production part approval process (PPAP) and during failure mode effect analysis (FMEA) to work with the engineer customers on design," said Bohlen. "We are the experts on cast intake manifolds and we have the production know-how." Bohlen believes that the new realignment of Wabash into a powertrain division is only going to help because he now interacts with the same customers daily and is a valuable resource during troubleshooting on the assembly line.

"Understanding customer needs is critical, and this philosophy goes beyond meeting blue print specifications," said Barlow. "To ensure we meet customer needs, we must have strong quality planning, clear communication at the point of use, and an ongoing dialogue that generates continuous improvement."

Another step Wabash has taken is to build prototype coreboxes and molds to cast components for customers to test for form, fit and function. Wabash dedicates two of its core machines for this purpose. Beyond machining and assembly, Wabash has developed an automatic, in-line intake manifold leak test system (Fig. 3). The system sends 20 psi of air pressure through each machined intake manifold to test for defects. This guarantees for the customer that the component is ready to assemble once they receive it.

Wabash's future is tied to its ability to keep innovating. Whether it is on the casting side or in the way it services its customers, its focus must be on building brand recognition for its aluminum engine components.

Hayes Lemmerz International, Inc.

Wabash Operation

Wabash, Indiana

Metals Cast: 319 (85% of production) and A356 (15%) aluminum alloy.

Mold Capabilities: Green sand and tilt-pour permanent mold.

Core Capabilities: Coldbox.

Melt Capabilities: Reverberatory furnaces.

Size: 120,000 sq ft.

Key Markets: Automotive and light truck.

2000 Shipments: 15 million lb (components range from 3-25 Ib).

Employees: 250.

Year Founded: 1978.

Plant Officials: Gaty Barlow, plant manager; Jerry VanAelst, manager-product engineering; Brian Nyland, controller, Gary Devore, purchasing manager Marty Foder, human resources manager Randy Baer, engineering manager Will Davis, operations manager; Pat Meredith, tooling engineering manager; and Jim Bohlen, quality manager.