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Aluminating tooling

By: Rhoda Miel

April 27, 2009

A new generation of injection mold tooling made from aluminum is gaining business and traction in the North American auto industry, with savings promised for mold makers, molders and automakers alike.

Aluminum has been used extensively in prototype tools and some niche production in the past, but stronger aluminum alloys are now being used in production molds in place of steel for high-volume vehicles including Honda Motor Co. Ltd.'s Accord sedan.

“One of the biggest topics and buzzwords out there right now is aluminum tooling,” said Darcy King, president of Unique Tool & Gauge Inc., during an interview at Unique's headquarters in Windsor.

Aluminum is more than just hype.

Honda already has been using the material for more than two years and has slated its use in future vehicles. Some other top automakers, including General Motors Corp. and Ford Motor Co., are taking a serious look at aluminum as well.

“It's amazing to see the interest in this out there,” said Rich Oles, president of tooling component supplier PSG Plastic Service Group Inc., headquartered in Stevensville, Mich.

PSG has coordinated conferences on aluminum injection mold toolmaking, along with the Society of Plastics Engineers.

Aluminum tooling — when it's produced properly — offers savings beyond just the mold itself. Because the material can heat up and cool down more quickly, molding cycle time is cut by 30-80 percent, depending on the size of the mold. Because it is lighter, there is less wear and tear on equipment and molders can use smaller presses.

Unique has been at the leading edge of the auto industry's new interest in aluminum and has created proprietary manufacturing systems, working with Honda on the development.

The company is one of a handful of tool and die makers selected by Honda's Honda of America Manufacturing Inc. unit for a long-term partnership, called “co-management.” The business arrangement ensures a set level of business with Honda in exchange for providing the carmaker with a steady partner that also can bring new technology to the forefront.

Unique already had seen good production from tools it made from softer M1 aluminum grades, and proposed to Honda that they see what was possible from stronger “7,000 grade” alloys introduced recently by aluminum suppliers.

Because aluminum is softer than the standard P20 steel used in most injection mold tooling, it is easier to machine and faster to produce, reducing overall costs although the aluminum itself costs more than steel. However, that softness also leads to faster wear problems with the final mold, so it typically is not used in high-volume parts.

While a few toolmakers have had success with aluminum in high-volume production in the past, conservative buyers in the auto industry were hesitant to take a chance on investing in the material. But through its relationship with Honda, Unique was able to develop ways to use the new grades, along with standards for production, and Honda — once convinced the material could perform — was then able to bring in its key molders to begin full production.

“Without co-management [from Honda], this never would have happened,” King said.

Honda used Unique's aluminum tools for instrument panel side covers on its CR-V small sport utility vehicle, and for the rear window tray on its Accord. The CR-V tool has produced more than 300,000 parts, the Accord more than 400,000. More production is under way at Unique, and other toolmakers are making the investments in aluminum capabilities now as well.

“Two things are happening out there that are driving this,” PSG's Oles said. “One is that people are trying to find ways that they can be unique and be noticed in today's market. The second is Honda and its support.”

But the sudden interest worries King, who fears that if toolmakers try to jump in too fast, they won't understand the differences between aluminum and steel, and will damage aluminum tooling's reputation just as it begins to take off.

Aluminum has its limits. Unique had to develop new ways of designing tools specifically for aluminum and allow for thermal expansion with parting lines and operating guidelines different from steel. The company also works closely with molders to test and set operating guidelines for presses that normally use steel, noted Al Standaert, technical sales manager for Unique.

The company has targeted only polypropylene and thermoplastic polyolefin uses for aluminum tooling so far, steering clear of glass-filled parts, which could cause minute damages to the mold surface.

With growing support from carmakers, the industry could see a real breakthrough if it develops the technology carefully, said Oles, who works with suppliers and experienced mold makers in the educational seminars.

“We want to generate real discussion on this for the industry so that people really understand what they're doing,” he said.