When produced manually, individual components could be produced only in steps, and all components were confined to a certain length. Components produced with the combination system can be made continuously, so they can be made much longer. The development partners for this method are Audi and Voith, a mechanical engineering firm.
We've reported before on other efforts to make fiber-reinforced composites easier to use in automotive manufacturing. They include a German team that developed the innovative SpriForm hybrid process that combines injection molding and thermoforming. That process combines thermoformed parts made of continuous, fiber-reinforced thermoplastic sheets with thermoplastic injection-molded parts.
In the US, the White House recently renewed funding for Department of Energy research on replacing cast iron and steel components with lighter materials, including lighter metals and high-strength carbon-fiber composites. The research focuses on predictive modeling of carbon-fiber composites and advanced steels, as well as developing advanced alloys for automotive and heavy-duty engines.
Last year, the Oak Ridge National Laboratories joined with 14 companies to form a carbon-fiber composites consortium. The Oak Ridge Carbon Fiber Composites Consortium is aimed at accelerating the development and commercial application of new, low-cost carbon-fiber and composite materials in several application areas, including automotive.
Ann, this is a good use of government research funds in both countries. One thing people should understand, though, is that race cars and passenger cars have very different structures. Personally I think we should produce passenger cars more like race cars, but I don't design them.
Race cars generally have some sort of frame (often a space frame) that supports all the mechanical equipment and the driver. The body then sits on this frame giving it the aerodynamic properties desired. The frames are generally designed so that in a crash the driver is well protected in a strong cage and the car dissentigrates around him (or her). It works fairly well. You will sometimes notice at races a car with the body off. The only car I know of in the US that has a separate body is the Corvette. The fiberglass body has been a design feature of this marque for decades. The cars are very lightweight and of a very high performance. If you compare other high performance vehicles (such as the Jaguar) you will notice that they weigh at least two tons compared for about 2,600 lbs for the Vette. So, without a sophiscated engine the Vette can easily match the performance of these more expensive vehicles.
It would be interesting to understand why the separate frame concept has not been more widely embraced. With metal bodied cars and integral body and frame can be lighter that standard production. Of course, such cars are harder to repair. With composites, even in non-structural applications, the cars can be much lighter and fuel effecient.
naperlou, I've also wondered why the separate body or whole-body concept has been used in race cars but not in commercial automobiles. Offhand, you'd think that it would not be a problem in the highly automated high-volume production lines of passenger cars. I do know it's being considered.
Building my first Freedom EV prototpye body/chassis only took 10 manhrs as a 1 off from the production molds. If in real mass production using 3-4 person teams it could be cut to 2 manhrs/car so labor is a rather small part.
I just don't see the canard that composites are too expensive, labor intensive especially when it costs $1B to set up a steel production line.
My Miata size 2 seat sportwagon only uses 235lbs of composites with present OEM prices on non CF composites running $2-$4/lb the math clearly says composites are very cost effective against steel. I've been doing car size composite vehicle constrution for 45 yrs now, mostly highly stressed boats. And don't forget the bigger motor, brakes, suspension, etc needed to move the 5-600lbs of steel version adds to steel's cost.
If you need higher production just have more lines.
While steel is a little cheaper/lb it costs far more to stamp, weld, fair, paint than composites. Which combined with the fact that they don't rust and only needing a 100 unit run vs 100k/yr for steel to make a good profit and you can see why big auto is dragging their feet on all composite cars.
And it's expensive CF they use to claim composites are too costly when medium tech FG and Kevlar type fibers are stronger in the right ways at 10% of CF costs.
They are doing the same with EV's making them overweight, very expensive when they could have been made for under $10k for an 80 mph, 80 mile range 800-1000lb commuter, towncar in composites like I'm building.
And it's only taking a 50lb gasoline 5kw generator to give it unlimited range.
Both construction methods work fine. Remember monocoque construction in racing? Probably where the unibody came from.
It seems that the method is determined by what material is used. Carbon fiber makes better structural beam type products than a structural sheet type products (unless you honeycomb). And then there is the welding or fastening methods. Beams take conventional fasters well. We are stuck with adhesives or bonding for structural sheet construction.
The story talks about replacing cast iron parts with lighter material as well. Interesting!
Chuck, thanks for that input. Looks like the automotive industry, as well as the aerospace industry, may need the robots and lasers repair approach I reported on last week: http://www.designnews.com/author.asp?section_id=1392&doc_id=243715
I think it's great when consortiums come together to focus on a specific issue like this. It means that something will actually get done. Often it also means that eventually there will be cheaper carbon fiber "shapes" like angle, tube, I-beams available to the consumer market as well. Maybe those $5000 CF bicycle frames will become affordable to the common man (or woman) after all.
I was also impressed at the number of companies getting together in this consortium. I think the motivation levels in this industry for transitioning to automotive manufacturing are very high right now.
A lightweight electric urban concept car designed by several European companies weighs only 992 lb without its battery. It would have weighed 26.7 lb more if its windows were made of glass instead of the specially coated LEXAN polycarbonate resin from SABIC Innovative Plastics.
Skylar Tibbits' team in MIT's Self-Assembly Lab is now 4D printing self-assembling shapes made of programmable carbon composites and custom wood grain. The composites are being used in a sport car airfoil, and the wood grain is beautiful.
The NanoSteel Company has produced high-hardness ferrous metal matrix composite (MMC) parts using a new nanosteel powder in a one-step 3D-printing process. Parts are 99.9% dense, crack-free, and with wear resistance comparable to M2 tool steels.
The company that brought you 3D-printed eyeglasses has launched both an improved clear polymer material for 3D printing optical components and a high-speed, precision, 3D-printing process for making small- and medium-sized batches in a few days.
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