When automakers talk about redesigning vehicles, they don’t always mean just the styling or the engine.
They are also increasingly looking at new materials for cars, whether it’s to bring down the weight, or to incorporate renewable content.
I recently toured Ford’s Research and Advanced Engineering complex in Dearborn, Michigan, where experts from some 55 countries are working on just about anything and everything to do with automobiles, from developing digital people to use in auto design programs, to steering wheels with just the right number of buttons. But perhaps the most fascinating was the work being done in lightweight construction and in “bio” materials.
Disclosure: Transportation to Michigan, accommodation, and food and drink were provided to the author by the automaker.
Lightweight materials but heavier cars?
Making cars lighter is an incredibly complex balancing act. Lighter weight can improve fuel economy, and whenever it’s possible to use less material, costs will go down. Even so, most of today’s cars are heavier than models from a decade ago.
That’s primarily because they contain more safety equipment, as well as more features as consumers demand increasing levels of comfort and entertainment. The body is a relatively small portion of the vehicle’s weight. The powertrain and interior usually make up most of it, and they’re candidates for substitution of lighter-weight materials as well.
Although the lightweight labs weren’t open for viewing, Ford had several examples of experimental and production components on display. To replace steel, the company is primarily looking at aluminum and magnesium.
“The researchers take materials and start to cut and form them, and see what can be done to the material,” says George Luckey, a technical specialist in manufacturing research. “If something is promising, they start to make parts out of it. The first things we look at in lightweight are ‘hang-on’ parts, such as fenders and doors.”
Cost can be a major factor with alternative materials: magnesium, for example, is more than double the price of steel per pound. However, if the material is stronger, it may be possible to use less of it.
By looking at the vehicle as a whole, rather than as a collection of parts and materials, engineers are able to make decisions on what to use. If enough body weight is shaved off, for example, it may be possible to use a smaller engine. The savings in the powertrain could be enough to offset or even undercut the cost of the materials.
Put it together
Another factor is construction. Auto plants have traditionally been set up to work with steel, and incorporating new materials may require new equipment or assembly methods, not all of which are adaptable to mass production.
Ford is working with different methods of stamping for various types of parts and materials. These include stamping hot metal with a room-temperature die, or “warm forming,” where the die is heated as well.
Warm forming produces the best results in magnesium and aluminum, but it can take 10 to 20 minutes to form each piece. This made it acceptable when used to form the fuel filler panel on the low-volume Ford GT, but wouldn’t work for the higher-paced production of a regular assembly line.
In some cases, production issues can be overcome: the Lincoln MKZ has an inner liftgate panel made of magnesium. Hot aluminum and magnesium can be extruded, “just like squeezing toothpaste out of a tube,” Luckey says. This process can produce straight pieces with channels molded into them, which are difficult to make otherwise.
Meanwhile, engineers have to determine if panels made from different materials can be fastened together, and if they will corrode. And price must also be considered not just at the manufacturer level, but for the consumer as well.
“We have to take repairs into account,” Luckey says. “We work with teams, including body shops and repair facilities, to determine the cost of repairs when using these materials. If you crunch a fender, it can’t be enough to write off the car.”
Looking at "not-metals"
Lightweight materials go beyond metal, of course. Composites are playing an increasingly important role in automobiles. But composite parts have to be as strong as any metal parts they replace, and that involves not just the material used, but how the part is shaped.
Ford is even looking at replacements for glass, which means not just finding something that’s transparent, but which also has sufficient scratch resistance and will meet safety standards for structural rigidity and breakage.
There’s a bit of overlap with Ford’s Bio Materials Lab, since lightweight materials are often unconventional as well. The Bio Lab’s main focus is renewable materials, both in the components that go into composites, and in products that can be reused or recycled when the vehicle is finally scrapped.
History repeats itself
Ford is no stranger to this game. Henry Ford always remembered his rural roots, and was keen to work with products that could benefit farmers. He experimented with plant-based fuels such as ethanol, and with soy-based plastics and resins.
There’s even a famous photo of him smacking a car’s plastic trunk lid with an axe to prove how strong it was. But these substitutes were expensive, and cheap petroleum, along with the constraints of WW2 production, brought an end to the research.
When oil prices soared, Ford went back to the lab about 12 years ago. The first soy foams produced weren’t very good, but the researchers kept at it, and were finally able to create a viable product made of 40 per cent soybean oil.
The 2007 Mustang was the company’s first car to use soybean-based seat foam, and today, it is used in every vehicle made in North America.
From the farm
Experiments in Ontario also led to wheat straw in plastic. The straw, which is often burned by farmers if it won’t compost quickly enough after the grain is harvested, is used in place of glass fibres for reinforcement. The plastic is currently used for storage bins that are 20 per cent straw by weight, in the Ford Flex.
“This diverts 20,000 pounds of petroleum,” says plastics research expert Ellen Lee. “We’re now looking at a number of agricultural waste streams, including coconut shells and rice hulls.”
Of course, just as when working with lightweight materials, there are a lot of hurdles to overcome. First there is the product itself: it must perform to the same standards as conventional material, and has to cure in a reasonable amount of time for mass production.
Next, it must be scalable to commercial production. According to Lee, the lab has produced some composites that work well when they’re blended in small quantities in beakers, but which clog a full-size mixer. In some cases, new processes and machinery are required to make things work.
When wheat straw plastic was still in the planning stages, researchers had to chop the straw by hand, since agricultural cutting machines used to make animal fodder couldn’t cut pieces small enough.
Every new material has to be tested for failure modes. “It could be something like putting sunscreen on the plastic, like when you get into the car after being at the beach,” Lee says. “We have to see if someone with allergies to the organic material is affected by the finished material. And we have to be able to ensure a steady supply. If it’s an agricultural product, a drought or hurricane could affect it.”
A general estimate is that about 10 per cent of the lab’s research work actually ends up making it to market.
Not everything the lab tries is plant-based, and there’s a lot of work done on recycled materials to keep them out of the waste stream.
The company currently makes carpet fibres from shredded soft drink bottles, and insulation from textile waste, specifically that left over from making jeans.
Nothing from money
Most of these experimental substances are expensive to develop, but the price comes down once they go into mass production. There’s one that will always command a lot of money, though: plastic made of cash.
When paper currency gets too worn, the U.S. Mint shreds it, presses it into bricks, and sends it to landfill sites. Ford is using this high-quality paper, primarily made from cotton and linen, to produce polypropylene that is 20 per cent shredded currency.
And appropriately enough, the first prototype made from it is a coin tray. It may never actually make it to market, but it’s all part of the research that goes into automobiles today.