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      06-21-2012, 05:13 PM   #59
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Drives: E92 M3
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Originally Posted by mapezzul View Post
Considering the whole side of an i3 life module can be supported by an index finger (I would bet it weighs in at max 30 lbs.) so what is that $150 per side? That's dirt cheap. A pound of CF is a lot of material compared to a pound of cold pressed steal (looking at you fat F10). If you look at your study they in 2006 were using this "Carbon Fiber: $11.05/kg" (which is $5/lb) and I can tell you BMW is way way under that for the CF.
Full CF chassis can be quite light. One person can lift the entire MP4-12C chassis. Components even more so, no debate there. The study discussed $11/kg but actually used $22/kg which is about $10/lb. That is also the figure I used. I suspect BMW is around $5/lb now but definitely not way below that. If they were cars would very rapidly be all going to a very high composite content. It will be rolled out slowly as the volume/cost curve can be worked. Either way they are not going to be adding significantly to cost, either at the component level or BIW level. That just is not sound business.

Originally Posted by mapezzul View Post
What I was told by BMW was that the biggest difference aside from producing cheaper material bc of energy costs in savings was the less time and energy required to produce the parts with their molding/resin process, making them much much cheaper. Requires less equipment, less heat, less electric less of everything and makes the operating costs less of an issue. They are also using the cut fabric scraps (non chopped) for other parts- basically they cut everything like a giant jigsaw so true scraps are minimum and they get the most out the CF fabric as possible.
No disagreement there. The study shows this as well.

Originally Posted by mkoesel View Post
This is an interesting study.

The first thing that comes to mind here is what exactly constitutes raw material. When speaking about the costs up until now, I was imagining the material costs of CF to be only that of the actual carbon itself (or carbon compound as it may be - I don't know the specifics of that) - not the costs associated with refining it into a useable fiber or weave of fibers. I.e. I was considering the latter to be associated with manufacturing or production, not material itself.

In other words, there is something of an apples to oranges comparison here. Do you see what I am referring to? A bit like comparing the cost of wood to the cost of paper. Or perhaps, like comparing the cost of cotton fabric to the cost of corn.
Carbon fiber must indeed come from raw sources of carbon. Heck if you could get the carbon from CO2 you could then call the CF free by your point of view! The fibers themselves are produced and then typically woven into mats. Adhesives are also considered part of the composite material cost. I'm pretty sure that most figures of cost/lb are in fact for woven products, excluding binders/adhesives and the vast majority of that cost is the fiber manufacturing itself. I certainly agree that you can not say that the cost of paper is the same as the cost of wood but I don't see how that impacted this disagreement. Either way the conclusion firmly stands that for the automotive industry (and many others) the cost of introducing CF is driven by raw material cost.
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