Hayes Lemmerz Montague delivers a permanent solution: established as a casting facility in 2000, this suspension component supplier has taken its vacuum/pressure permanent mold process and surrounded it with automation to enhance production.

Imagine the following.

The economy is in the middle of a recession.

Your casting facility, which used to be strictly a machining operation just a couple years ago, is building its production from scratch with a new vacuum/pressure casting process.

Your customer base--the automotive industry--is possibly the most demanding in terms of quality, delivery and cost. And, oh yeah, your parent firm recently emerged successfully from Chapter 11 bankruptcy.

You thought your metalcasting facility was in a pickle the last few years ... try being Hayes Lemmerz International, Inc.'s Montague, Mich. operation. Change was the word of the year for this facility from 2000-03 as it grew from a dedicated machining facility to a full-service cast component supplier offering heat treat, 100% x-ray and fluorescent penetrant inspection, machining and assembly.

With this growth, Montague has become one of the global firm's manufacturing jewels in the suspension components division. The facility earned an honorable mention in the 2003 AFS/ Engineered Casting Solutions casting contest for its cast crossmember for Ford (Fig. 1) and was recently awarded a new steering knuckle contract that will grow this portion of its business by 300%.

[FIGURE 1 OMITTED]

With this success, Montague feels it is on the cusp of even greater things. Armed with its new vacuum/pressure permanent mold casting technology, new doors are opening in the automotive industry for its aluminum components due to the mechanical properties and cost levels it can achieve. This process, combined with the firm's automated production throughout the plant, is placing Montague at the forefront of cast aluminum suspension component suppliers.

VRC/PRC

Developed by Alcoa, Inc., and CMI International, Inc., in the late '90s in their former ACMI joint venture technical center, Ferndale, Mich., vacuum riserless casting/pressure riserless casting (VRC/PRC) became property of Hayes Lemmerz when it purchased CMI International in 1999. Similar to low-pressure permanent mold casting but with the incorporation of vacuum to further control mold fill, the process is able to achieve mechanical properties similar to squeeze casting but at costs close or equal to traditional permanent mold. These capabilities are what drove Hayes Lemmerz to build its Montague casting facility with only this casting process.

"This process gives us an advantage over the competition," said Michael Weber, account manager, suspension components, Hayes Lemmerz. "The combination of cost and mechanical properties is unique for permanent mold, opening the eyes of our automotive customers."

In VRC/PRC production, once the mold has been prepared for fill and cores are set, the mold is closed and a vacuum is drawn through the cope. Pressure is then increased on the furnace located below the mold and the combination of pressure/vacuum draws the molten metal at a controlled rate into the mold. The pressure and vacuum are held until the mold has filled and directional solidification takes place. The casting then is automatically ejected after solidification.

In the process, multiple ingates are used to feed the casting to ensure casting quality in thru-walled sections. Yields of greater than 95% are achieved on certain jobs like the Ford crossmember because most of the excess metal from the ingate flows back into the furnace after it feeds the solidifying casting. To enhance directional solidification, the process utilizes water cooling throughout the mold.

According to Weber, the strengths of the process are:

* the ability to use multiple cavity molds lot four-on or six on production, allowing for reduced cycle times per part as compared to traditional permanent mold processes;

* ability to core components;

* water-cooled directional solidification;

* high casting yield;

* mechanical properties near and/or equal to semi solid casting;

* reduced oxides and other non metallic inclusions due to tranquil mold fill, direct coupling of mold to melt, and the elimination of graphite.

Another unique facet of the VRC/ PRC casting systems is that the cast components, once solidified, are designed to stay in the upper half of the mold (due to the vacuum) once the mold is opened. As a result, a robot can then present a platform underneath the castings so when the vacuum is re leased, the castings fall to this platform and are easily transferred to the first stages of cleaning and finishing.

In terms of cost, Montague estimates that castings produced using VRC/PRC are 15-20% less per component than those produced via squeeze casting and 4-5% higher than permanent mold. Montague believes, however, that within a few years, it will be able to produce at the same cost levels as traditional permanent mold. The key is familiarly" with the process that can only be achieved through years of continual production and refinement.

"Our production strength with VRC/PRC has grown every day," said Bruce Graff, plant manager. "These efficiencies will drive our quality higher, and allow us to push the casting design envelope further."

The results that can be achieved are illustrated by Montague's defect rate, which has reduced from 50 ppm 3-4 years ago to less than 8 ppm today. In addition, the firm typically is able to achieve 5 into nominal wall thickness [+ or -] 1.5 mm on a component with wall thicknesses as low as 3.5 mm possible.

The facility is built with five HL3 and 11 HL2 VRC/PRC casting systems, each manufactured by its corporate partner Hayes Lemmerz Equipment & Engineering, Au Gres, Mich. The difference between the two models is size. The HL3 utilizes a 3 ft x 4 ft mold to produce the Ford crossmembers (weighing 51 lb, measuring 48 x 14 x 17 in.) two on with 5 min. cycle times. The HL2 utilizes a 3 ft x 40 in. mold to produce steering knuckles and control arms from four- to six-on with 3 min. cycle times. According to Montague, Hayes Lemmerz is the highest-volume independent steering knuckle producer in North America.

Advanced Casting Automation

For crossmember production, the HL3 VRC/PRC permanent mold casting cells are the most advanced at Montague. The process begins with a robot delivering two shell cores to the permanent mold casting machine. Once the cores are placed and the mold closed, the casting process (as described previously) begins.

One unique feature Hayes Lemmerz has built into its HL3 casting systems is the immersion heated fabricated refractory-lined furnace (also built by Hayes Lemmerz Equipment & Engineering) from which the melt is drawn. This furnace heats from within the melt instead of from above it, increasing energy efficiency and reducing oxides. (Standard crucible furnaces are used in HL2 systems for control arm and steering knuckle production.)

"These efficiencies in production such as the energy efficient melting aren't often noticed by customers but they are key to keeping our costs down," said Graft. "Without them, we couldn't achieve what we do."

Once the castings are" solidified, the mold opens and the castings are ejected from the top portion of the mold onto a platform carried by the robot. The solidified castings are then transferred to the same area the cores were pulled from, placed in a fixture and transferred via a palletized conveyor to a robotic cell for cleaning and finishing. Within each casting cell, only one operator is required to spray mold coating, place cores, visually inspect the crossmembers and maintain the production system.

To ensure optimized production levels from the HL3 casting cells, Montague has placed robots on both sides of the casting machine for core placement and casting removal. Due to the manual visual inspection of cores and castings and automated moving of pallets that occurs to transfer cores and castings, one robot would create downtime for the casting machine. To ensure the production (if 1200 crossmembers/day, downtime is not all option.

After casting, Montague uses a robotic finishing cell that incorporates two robots (Fig. 2). The palletized conveyor brings the castings to the cell and the first robot picks up the casting to perform a drilling operation and vibration to remove the core sand from the interior and then transfers the casting to a trim press to remove flash. The second robot then enables the crossmembers to saw off the sprue and passes them through an automated x-ray system lot inspection.

[FIGURE 2 OMITTED]

Knuckles & Control Arms

While the level of automation throughout casting production for the knuckles and control arms isn't currently to the same degree as it is for the crossmembers, elements of robotic casting and finishing are prevalent in the HL2 VRC/PRC cells. The most advanced cell for steering knuckle production incorporates three VRC/PRC casting systems with one robotic finishing cell.

Once the cast knuckles are solidified and ejected onto the platform, they are water-quenched. Then, four castings at once are manually placed in fixtures for the robotic cell that performs trim operations, sprue removal and x ray inspection on two castings at a time (Fig. 3). Overall, the firm produces 600,000 control arms and 600,000 steering knuckles/yr, with a new program about to begin that will add an additional 1.2 million knuckles/yr.

[FIGURE 3 OMITTED]

Currently, Montague has achieved more than 90% yields on its steering knuckles (85% on control arms), but in the same way that familiarity with the vacuum/pressure casting process reduces defects, it also allows the firm to improve its production and gating system designs to improve yield.

"We are still in the learning process with VRC/PRC," said Todd Greve, senior process engineer. "From the gating and coring perspective, some of our work is trial and error to achieve the highest quality component with the best yield and production cost."

The other three casting cells for steering knuckles and control arms incorporate greater levels of manual labor to complete the various processes from casting removal, quench, cleaning and finishing, and x ray inspection. However, Montague is in the process of upgrading these cells in anticipation of further production levels and the increased need for automation.

"We have set the bar with the crossmember and knuckle production's high level of automation," said Chris Kraynak, former engineering manager who now is plant manager for Hayes' Cadillac, Mich. operation. "But our growing knowledge of the casting process with robotic finishing operations will allow us fine opportunity to automate these other casting cells more quickly and more efficiently."

Advanced Manufacturing Automation

The focus of Montague from a casting perspective is its VRC/ PRC technology. However, the firm has advanced automation and efficient production throughout the 170,000-sq-ft plant for both pre and post-casting, incorporating automated conveyors whenever possible to move castings from process to process. According to Kraynak, this is what can be achieved when designing production flow" from scratch.

"The opportunity for expansion was best at this facility because we had an empty facility to engineer," said Graft. "The casting plant was built with it in mind so we were able to lay out production flow how we wanted it."

The facility melts using two 14,000 lb/hr reverberatory furnaces. They feed a covered launder system (Fig. 4) that tans the length of the 16 permanent mold casting machines, feeding each individual casting system's 1500-1b reverberatory holding furnace (at which rotary degassing is performed) as needed. These holding furnaces work in tandem with the casting machines' furnaces using an auto ladle system to regulate the flow of molten aluminum after each shot.

[FIGURE 4 OMITTED]

For coremaking (cores only are used on the crossmember casting), the plant buys all its shell cores on the outside. While the crossmember doesn't necessarily require a core for casting, Montague decided to use cores because the firm found that the ribbing required with a noncored design was too thick, increasing component weight and cost. The cores also allow for improved metal flow during casting.

In terms of other post-casting services performed by Montague, all the crossmembers undergo a straightening procedure before joining the control arms and steering knuckles for fluorescent penetrant inspection. From there, the castings are sent to their in-house machine shop customer for further processing.

Another reason the machine house was a logical location for a casting expansion is that the proximity furthers Hayes Lemmerz' corporate goal of being a one-stop shop for customers.

"With machining next door, we strive to provide as much value-added to each job as we can," said Weber. "Assembly has become a big service our customers are requesting because for them it can be a difficult endeavor to assemble components before hitting the manufacturing line. They want to be able to drop in sub-systems into the automobile."

Crossmember Development

The casting and tooling design of Montague's award-winning Ford crossmember (as well as 95% of all cast components in the suspension group) began in the Hayes Lemmerz Technical Center in Ferndale, Mich.

"This facility is designed to provide full-service engineering and development activities for production programs as well as to enhance the firm's competitive advantage through the development of new products, materials and processes," said Weber.

The facility has CAE, CAD and CAM capabilities, casting process modeling and rapid prototyping as well as research labs for metallurgical issues and various casting process (VRC/PRC, semisolid casting, and low-pressure and tilt-pour permanent mold) and technology evaluations. In addition, the center has product testing facilities for its castings, including fatigue testing, brake dynamometer, hot and cold chassis dynamometers and an air flow test lab.

For the crossmember, the tech center worked to redesign the component from a complex fabrication of steel stampings to a single, 51-lb A356 aluminum casting. Working with designers from Ford, Hayes Lemmerz was able to reduce weight and improve functionality of the part by converting it to a casting. The cast crossmember provides increased mounting features for the shock assembly, lower and upper control arms, steering gear, the frame rail and the engine.

Beyond the design, without the tech center and its work in developing the vacuum/pressure permanent mold process, the achievements of the crossmember component wouldn't have been possible.

"While we want to expound to our customers about the benefits of the VRC/PRC process, it is not in our best interest to grow too fast," said Weber. "We need controlled growth by beginning with low numbers of jobs and perfecting them. Then, the orders will continue to come. If we were to fail, we might as well pick up and leave because our customer base won't wait."

After four years of production, automotive customers are beginning to wait at the door to get their crack at Montague's vacuum/pressure casting process. It may just be the permanent solution the suspension business needed.

Hayes Lemmerz Montague Operations
Montague, Michigan

    Metals Cast:    A356 aluminum.
        Process:    Vacuum and pressure
                    assisted permanent mold
                    casting.
           Size:    170,000 sq ft (casting) and
                    170,000 sq ft (machining).
  Market Served:    Automotive suspension
                    components
                    (crossmembers, control
                    arms and steering
                    knuckles).
    Value-added:    Machining, heat treat, x-ray
                    and fluorescent
                    penetrant inspection, and
                    assembly.
      Employees:    612.
2003 Production:    42,000 tons (50%
capacity).

Emerging from Bankruptcy

In December 2001, Hayes Lemmerz International, Inc., filed for Chapter 11 Bankruptcy. According to the firm, it had a highly leverage capital structure with too much debt to secure. As a result, the bankruptcy step was the only one it could take to remove itself from under a weight that was placing a stranglehold on operations.

In the months leading up to this move, as well as in the six months after, the firm began to develop a new management team designed to help improve its cost structure. Led by the appointment of a new president, CEO and chairman of the board, Curt Clawson, in August 2001, reorganization was begun to centralize and standardize the firm's functions, such as purchasing, accounting and information technology, in addition, the firm reorganized its products into five areas--North American Wheels, International Wheels, Suspension Components and, Brakes and Powertrain, and Commercial Highway and Aftermarket.

"The key" was that even under Chapter 11, we didn't lose any customers," said Weber. In fact, according to Weber, Hayes Lemmerz secured the Ford crossmember job while under bankruptcy.

All the moves have appeared to pay off for Hayes Lemmerz as it successfully emerged from bankruptcy in June 2003.