Canadian Plastics

Plastics that impress, plastics that disappoint

The rate of change in our industry is, depending on how you look at it, either impressive or scary. Which way you look at it will probably depend on whether you're trying to make a living processing t...

February 1, 2007   By Jim Anderton, technical editor



The rate of change in our industry is, depending on how you look at it, either impressive or scary. Which way you look at it will probably depend on whether you’re trying to make a living processing the stuff, or are looking for a good two-dollar dishpan.

Right now, the real action appears to be in composites, at least in high drama applications. “High” is the right superlative here, because the recent flight into space by Scaled Composite LLC’s SpaceShipOne and Boeing’s new 787 “Dreamliner” both feature advanced composite construction. Carbon-carbon, carbon-graphite and aramid-based composite construction isn’t new, but the movement of these gold-plated technologies into areas where metals like aluminum and titanium rule is a good sign for the future

Unfortunately, down here on the ground, the automotive industry seems to be going sideways, if not backward. Twenty years ago you could buy a resin-bodied (SMC) Pontiac from GM, a firm that also made polymer-paneled minivans. No longer. Why?

The short answer is that the steel community counterattacked with HSLA (high strength low alloy), a product that could be made thinner, lighter and stiffer, ideal for stamping car bodies. There was a glimmer of hope in the chassis, too, with a Ford stabilizer link application, but not much else in metal replacement under the car.

Where we’re winning is in the fascia, but there it’s about bigger, smoother and more expensive moldings in the one place you don’t want exotic materials: in the bumpers.

A SENSIBLE SOLUTION

Plastic car bodies with metal bumpers capped with an extruded elastomeric strip would be a better way to go, in my opinion.

A U.S. insurance company testing lab compared low speed wall impacts with modern cars and a benchmark 1981 Ford Escort. The Escort emerged undamaged, while the modern vehicles varied from a few hundred to over a thousand dollars to repair. Why?

One reason is that auto manufacturers want to wrap the fascia around the car to the wheels, making it a very big molding. Also, because the part forms so much of the body surface area, it needs a “Class A” finish. The engineers asked, and our industry provided. That’s fine, but the high cost of repair is now common knowledge among mainstream consumers, especially the many that lease vehicles and face penalties if they surrender a vehicle with a cracked or gouged fascia.

More business for us, right? Maybe, but if or when the auto insurance industry starts connecting premiums to repair expenses, consumers will figure it out in a hurry. My solution? Stop this five mile per hour impact test nonsense and specify fascias for fast and easy replacement.

How about a thermoformed cap over EPS, reinforced with a simple drawn thin wall steel tube? Snap it on with the usual barbed frangible poly retainers and just throw it away after the accident. The way people drive here in Toronto, we could keep the industry going forever.

On the other hand, there are also doomsayers in the aviation industry that predict that Boeing’s plastic airliner will fail because it’s so difficult to repair composite structures compared to aluminum. Maybe, but if we have to keep baggage handlers from driving conveyors into the sides of aircraft to get a leap in aviation technology, so be it.

On the other hand, I don’t want to pay $700 to repair a two-inch gash in a bumper cover on a Honda Accord. Or more accurately, I didn’t and I won’t, ever again.


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