Every day I enjoy the wonders of a carbon engineered vehicle: my race bike is light, strong and stiff, and hence fast and stable during cornering and accelerations. For similar strength, carbon fibers are about 30% lighter than aluminum and 50% lighter than steel.
I recall studying the material science of reinforced thermoset polymers in engineering school in the 1980s. Since then these high-tech materials have found their way in high-end sports toys (rackets, clubs, bikes, F1 race cars, special low-volume editions of BMW’s M3). Now Boeing is building the Dreamliner with substantial carbon fiber. So I always wondered how long it would take before we see this into a mass product category where weight and strength is important: mass produced cars?
Answer: it is happening at BMW!
BMW is building its carbon operating system to manufacture the i3 battery-powered city car, due in 2013 and also marketed as the MCV Megacity Vehicle, and the higher end i8 hybrid sports car, which will be featured in the next Mission Impossible movie (according to my nephew who works at BMW Munich). According to the Seattle Times: “The vehicle’s lower weight will allow it to travel farther between charges,” said Friedrich Eichiner, BMW Group’s chief financial officer.
The operating system involves an entire global network:
- The raw material for the carbon fiber, a coarser chemical fiber, will be produced in Japan by a joint venture of SGL, which makes carbon products, and Mitsubishi Rayon.
- From there it will be shipped to Seattle and trucked to Moses Lake, where it will be spun into carbon fibers one-tenth as wide as a human hair.
- The fibers will be woven into fabric at another new factory in Wackersdorf, Germany.
- BMW will turn the fabric into structural, body and interior parts for the Megacity at another German plant.
Exciting! But why haven’t we seen this earlier in the mass-car industry? Carbon has several challenges (which explain why we won’t see it soon in true mass products):
- Carbon is expensive: Carbon fiber costs about $20 a kilogram, according to Frost & Sullivan. That compares to less than $1 for steel.
- Why? Apparently the fiber production process is very energy intensive— Cheap, abundant hydroelectric power (and state incentives) is the chief reason for the choice of Moses Lake, Washington, according to BMW executives.
- Carbon is “difficult to work with,” according to Business Week. (Note that, based on my limited knowledge, I don’t think that this is very high tech: it basically involves weaving fibers into a fabric mesh (sure, pattern, direction, and density of fibers matters but the manufacturing is similar to textiles), pour some resin over, put it into an oven to harden. In other words: as opposed to steel forming, any hobbyist can try this at home. The key, obviously, is found in scale–more on this below.)
- Carbon can be fragile: my carbon handlebars suddenly broke when riding through a pothole on Sheridan road last Fall! No more carbon bars for me!
- Carbon is very hard to repair. (Contrast this with the steel based body shops correcting any dents you have in your current car. Apparently repairing carbon may release microscopic dust particles which may be harmful. My nephew tells me that there’s a lot of practicing and trials happening on the floor in Munich to learn and control this process.)
- Carbon is very hard to recycle. Together with point 1, it is not a “green” technology.
Back to the operations strategy, I was thinking about two questions: Why is the car industry behind airplanes and why is BMW “upward integrating” into this process?
The answer to both is, I conjecture, found in the nitty gritty of the production process: Recall that I don’t think this is a high tech process (like semiconductor foundries). So, what makes it hard? According to Business Week:
Carmakers have also in the past avoided carbon fiber because the parts require drying times that aren’t currently compatible with the pace of assembly lines. Planemakers including Boeing Co. started using the material much earlier because they produce at a slower rate and have simpler structures to form out of the reinforced plastics.
So baking is the issue and a baking takt time at 10 or 20 minutes is not compatible with that of mass produced cars (which is about 1min). Bringing the carbon takt time down requires new innovations and it appears that BMW and partners are working on some type of injection molding process. According to the Economist:
The company has been working with SGL on a type of injection-moulding process that can produce parts in minutes, and be handled mainly by robots. Parts can be bonded together or larger parts made as a single component.
Any cycling fan knows that Taiwan is the design and manufacturing centrum of the world for carbon frames. But clearly takt times are not a big worry for high-end road bikes. Now, according to a comment on the Economist article, it also appears that
“Toray carbon fibre factory in Matsuyama, Japan, has done this a couple of years ago already. Even the Taiwanese can’t produce Carbon Fibre body at a rate of 1 per 90 seconds (the current throughput at Toray). … Toray was set a goal of 1 minute by Japanese car manufacturers as a condition of more widespread use of its carbon fibre car body parts.
I am curious to see how this will all unfold and how/when/where this technology will trickle down from the high-end to the common products. For now, I’m already enjoying carbon on every ride and I hope you’ll enjoying watching the TdF this July too…!