Monday, April 28, 2008

Economical Carbon Fiber?

Are we heading into the age of cost effective carbon fiber composites? I sure hope so. The only way its going to come down is to continually invest in new technologies, particularly on the manufacturing side (automation, saving energy and time for production and less scrap/wastage for efficiency).

Check out this cool video from Fiberforge Composites that details a new patented manufacturing process that promises to bring down costs of advanced composites in high volume for wide variety of applications. Its educative and makes you think why someone else didn't come up with this ages ago. A section of the video shows some examples of products they have tried the process on, including a glass fiber shoe insole for a cycling shoe.

I think they're definitely onto something here. Should bicycle companies start consulting them? I think they should keep an open mind and make an effort. The cost of performance bicycles continues to grow to ridiculous proportions, making many people rethink even getting into the sport in the first place.


carpetfiber101 said...

Not to pop anyone's balloon here, but the fundamental concepts of FiberForge are not new. Google "automated tape laying" and you'll see it's been around. FiberForge's unique qualities come from the resins being thermoPLASTIC (milk jugs, polypropylene, PEEK, HDPE ect...), not thermoSETS (epoxies). The composite bicycle industry is nearly 100% epoxy thermoset based. The only non-thermoset resin I've heard of on a bike was by GT, they had a nylon/carbon fiber frame in the 1990's/2000.

The other pit fall in fiber forge technology infiltrating bicycles is the geometry of the parts that can be made. NOTICE:all of the parts made in the video are FLAT. Hollow or complex parts (like tubes) are not easily made/not possible with FiberForge, but it is a step in the correct direction.
Any questions?

Chris said...

I stopped at the FiberForge booth at the JEC in Paris a few weeks ago. The have made some bicycle frame lugs that they had on display. The inserts were diamond shaped rather than round.

carpetfiber101 said...

Chris: that's cool they're making bike lugs, I would really like to see them!

Ron: The Hyper car looks like a good concept. From FiberForge video posted it said they use thermoplastic (which can greatly reduce cycle time by not having to wait for epoxies to cure). I'm sorry if my post was confusing, but there is absolutely nothing wrong with thermosets. Thermosets have great structural, chemical, and most importantly adhesion properties.

carpetfiber101 said...

Ron: Firstly, I have to admit that I am not an expert on thermoplastics.

Strength t-plastic (thermoplastic) and t-set (thermoset) are very similar.

Elongation: typically t-plastics exhibit more elongation than t-sets. Epoxies are in the range of 3-7% strain to failure and t-plastics are more. Keep in mind that the elongation is only 1-2%, so the effect may not have a great effect.

Adhesion: Adhesion (aka "bonding" or "gluing") is MUCH better in thermosets, namely epoxies. Nearly every composite bicycle has bonded parts. The tube/lugs, cable guides, front derailieur "braze" on, drop outs, metallic head tube/headset inserts, metal seat tube inserts ect... all rely on adhesion to the frame to perform reliably.
The bond strength of thermoplastics is much less than that of thermosets.

Availability: prepreg (carbon fabric impregnated with epoxy) is used for most bicycles and components. Prepregs can be t-set or t-plastic. T-set prepregs have been around for 25+ years while t-plastic prepregs are relatively new to the industry. I'm trying to say that t-plastic prepregs are extremely uncommon, hence, not popular.

The processing temperatures for t-plastics is much higher than t-sets. T-plastics need to be heated to 400F or more while t-sets typically cure at 250F. This requires molds/tooling to withstand much higher temperatures (making them more expensive and not last at long) and more thermal expansion occurs (introducing additional streses into the part).
I'm sure you can make a wheelchair out of PVC. I would think racing wheelchairs have similar loading to that of bicycles.
I think this is enough for one reply! Keep the questions coming! As you can tell, I really like composites. :]