Chrysler's concept car steers nickel shell tooling to new roads

Weber Manufacturing Ltd. (Midland, ON) has pushed the technological envelope like it's never been pushed before in creating a complete nickel shell mold for Chrysler Corp.'s prototype Composite Concept Vehicle (CCV). The mold is capable of producing a gas-assist injection molded body panel in glass-fiber-reinforced PET that represents the length of half of the entire CCV body in a single shot. Its work in the CCV project has attracted a number of new customers to Weber Manufacturing's Nickel Tooling Technology (NTT) division from both automotive and nonautomotive markets, like housewares. And it has fundamentally changed the way NTT does business.

Weber Manufacturing designed and built a $2 million mold for the CCV's left inner body panel that measures approximately 14 by 8 by 6 ft and that weighs just 163,000 lb. A comparable three-piece steel CCV body panel mold built with more conventional materials of construction and traditional moldmaking methods by the other moldmaking member of the CCV Body Core Team, Paragon Die & Engineering Co. (Grand Rapids, MI), weighs in at 330,000 lb - twice as much.

Chrysler's advanced engineering organization, the Liberty & Technical Affairs group, originally commissioned four body panel molds for the CCV - inners and outers for the right and left sides of the car. The three conventional steel molds were too massive to make in one piece. Each was built in three sections and put together. NTT built the fourth. A lighter weight mold means that smaller cranes can be used. And lighter molds also may allow the use of molding machines with less clamp tonnage if and when the CCV goes into full-scale production. Its large size for unibody panel production means less floor space required to make the cars. This all adds up to lower capital investment for production molding machines. (Husky has reportedly been identified by Chrysler as its preferred supplier.)

Cascade Engineering (Grand Rapids, MI) is currently performing CCV body panel molding trials on its 9000-ton Battenfeld. All four of the molds are fully instrumented, gathering data for analysis at Chrysler's technical center. There's a lot of data to gather. After all, the CCV project involves much more than a new type of mold. The custom-formulated Ticona PET body panel composite is new. The Ashland adhesive for bonding body panels together and bonding the assemblies to the CCV's steel chassis frame is new. The project involves Chrysler's new Extended Enterprise approach to empowering suppliers early on. And the unibody panels are new types of parts molded today on the largest molding machine in the U.S.

The Hybrid Mold

Alan B. Sundeen, president and CEO of Weber Manufacturing, is confident that his company's nickel shell mold will be found to have "vastly" outperformed the heavier steel tooling after all the tests are completed. He feels this way despite the fact that this is the first complete nickel shell injection mold his company has ever built. Production of nickel shells using the nickel vapor deposition (NVD) process was developed in conjunction with Weber's strategic ally, Inco. Growth has been exponential each year and today, nickel shells account for about 25 percent of Weber's business. But, before the CCV project, NTT manufactured mostly shells and very few complete nickel shell molds.

Sundeen explains: "Up until this year we thought only of making the nickel shells that customers would then put into a frame or a mold. With our NVD process, we were competing against electroformed nickel shells. We had not made complete nickel shell injection molds with mold bases, hot runners, ejection, core pulls, slides, or all the rest until the CCV project. So I call the CCV mold a 'hybrid,' since it is neither a traditional nickel shell, nor a traditional mold, but both. It's a first for us. Yet, through our Tool & Mold Div., Weber has been building conventional complete injection molds and has been dealing with automotive customers for 35 years. Only Weber could have built this hybrid."

Still, as you can imagine, the CCV mold was quite a challenge. "We had never done anything that big before," Sundeen says. Prior to the CCV project, the largest nickel shell NTT had built was for molding doors, about 8 by 4 ft. The CCV necessitated CNC machining of the NVD mandrel into sections that could fit in Inco's vapor deposition chambers.

Properly supporting the nickel shell in the tooling was another major challenge. Shells can range from 1 mm to, in this case, 30 mm. Surface hardness typically is 40 to 42 Rockwell C. After much experimentation, Sundeen says a support structure was developed that resembles an egg crate. Epoxy and particulate material fill the voids. A neighbor in Midland, the Industrial Research and Development Institute, plus the University of Toronto's Engineering Dept. helped Weber with the structural analysis.

Faster Cycles

These epoxy and particulate void fillers also help support one of nickel's best performance properties - its excellent thermal conductivity. Heat transfer is fast, from the nickel shell core and cavity, through the fillers, all the way to the water cooling channels, which were designed and built to follow the contour of the body panel, and were laid right into the mold. Better thermal performance in the mold translates into faster molding cycles.

Gas assist and the mold's Husky hot runner system also speed cycle times. Weber's CCV mold cycles in less than 3 minutes - that's down from 10 minutes if the body panels were molded in structural reaction injection molding, according to Chrysler.

Jerry Smith, Weber's sales and marketing manager, recalls how it all began. "I gave a presentation on NVD at a technical conference in 1995. Don Jay of Chrysler's Liberty group was in the audience. We chatted, and he visited us about three months later." The total project time, from the first discussions through the build time, was about 15 months. "It won't take that long the second time," Sundeen jokes. The NVD process typically produces 1.25-inch-thick nickel shells in just 100 hours, so delivery times can be reduced, and lead times are shorter for duplicates. NVD also reproduces all surface features, and can produce a Class A diamond finish or a textured finish.

Its experiences in the CCV project have convinced Weber's NTT to change the way it does business. "Everyone who sees one of our CCV mold photos begins to think of something applicable to his or her business. We have new customers who've signed on this year. They want complete molds. It's a very significant change for us."

The Pop-Bottle Car

Before now, you could have a lightweight car made of expensive, exotic Materials, or you could have an affordable car. But you could not have both," says Bernard Robertson, vice president, engineering technologies and general manager of Jeep/Truck operations at Chrysler Corp. Chrysler's Composite Concept Vehicle "If the CCV does indeed work, it could ultimately change the way Chrysler makes cars and trucks in the future," Robertson says.

In its current iteration, the CCV is a 50-mpg, nearly 100 percent recyclable, five-passenger sedan with ample ground clearance for underdeveloped roads. It is expected to sell for about $6000. It's powered by a .8-liter, 2-cylinder, overhead-valve, air-cooled engine, and it goes from 0 to 60 mph in 25 seconds. The CCV is designed from the ground up for manufacturing and assembly. The number of pieces required to make the car is cut by 75 percent, from more than 4000 in a conventional car down to about 1100.

The body consists of only four large molded body panels that are bonded together. The only use of stell is in the frame chassis, which bears the weight of the vehicle and all its structural loads, such as steering, independent suspension, and braking systems. The four-piece molded body fits together with the frame with adhesive bonds and only four bolts.

The CCV requires 6.5 hours to build vs. the 19 hours required to build a Chrysler Neon. Plant investment is less than $300 million, about one-third the typical investment for assembly, stamping, and engine plants combined. It eliminates the need for a satellite stamping plant and engine plant, and the $350 million in the cost of a paint shop, including regulatory costs, since the color can be molded in with the PET composite. "The fact that these resins are commonly used in disposable bottles means we can use the same resin suppliers, or recycle plastic bottle material in combination with virgin plastic when producing CCV bodies," Robertson adds. For an initial report on the CCV, see February 1997 IMM.