Carbon 3K / 12K / UD

[mikesbytes]

Looking at a web site selling carbon components, they have the option of 3K or 12K or UD. There is no price differential.

Whats the difference between 3K / 12K / UD ?

[ldrcycles]

Coolness .

Wouldn't have a clue TBH.

[DavidTomic]

Looking at a web site selling carbon components, they have the option of 3K or 12K or UD. There is no price differential.

Whats the difference between 3K / 12K / UD ?

http://www.yoe" onclick="window.open(this.href);return false;<remove>leo.com/weave (Spam filter doesn't like that site for some reason?)
http://www.light-bicycle.com/the-3k-12k ... frame.html" onclick="window.open(this.href);return false;

Lots more sites / information if you just Google "3K 12K UD carbon fiber"

[Mark Kelly]

UD = unidirectional, all the fibres are parallel so no weave pattern visible.

3k and 12k are types of weave, the number refers to the number of fibres in each tow of the weave (3000 and 12000).

12k weave has 1/16th the number of visible pattern elements per unit area.

[AndrewBurns]

If they give you the option it's only for the surface 'cosmetic' layer and won't have any effect on the performance of the part. Basically UD = a more solid black finish, 3K = small chequerboard style finish, 12K = larger chequerboard style finish.

[trailgumby]

UD = unidirectional, all the fibres are parallel so no weave pattern visible.

Ummm... not quite. That would be monodirectional if they were all parallel.

Unidirectional means fibres go every which way in no organised pattern, as in uni = universal = everywhere.

[mikesbytes]

So I shouldn't take any attention to this detail apart from what I think looks good. There's also the choice of gloss or matt

I'm thinking of getting a track front wheel as there is no braking and no drive stress plus the ride surface is much better. Hence there is little risk of wheel failure due to the quality of the manufacturing.

[clackers]

Yeah, they talk about those patterns and they're associated with different strengths, but they're only the finishing layer, not structural.

Better not be. I've just ordered a Hongfu 26" frame to convert into my first dually!

[AndrewBurns]

UD = unidirectional, all the fibres are parallel so no weave pattern visible.

Ummm... not quite. That would be monodirectional if they were all parallel.

Unidirectional means fibres go every which way in no organised pattern, as in uni = universal = everywhere.

No he's right.

u·ni·di·rec·tion·al
/ˌyo͞onidiˈrekSHənl/

Adjective
Moving or operating in a single direction.

Synonyms
one-way

Unidrectional composite cloth has all the fibres aligned parallel in one direction, no such thing as monodirectional. You're thinking about omnidirectional.

[Mark Kelly]

UD = unidirectional, all the fibres are parallel so no weave p,attern visible.

Ummm... not quite. That would be monodirectional if they were all parallel.

Unidirectional means fibres go every which way in no organised pattern, as in uni = universal = everywhere.

Sorry, that's completely wrong. Uno = one, unidirectional = all in one direction.

I have three types of UD CF on hand at the moment and in all of them the fibres are all parallel. The UD boron fibre prepreg I use also has all the boron fibres in one direction along the tape.



image from http://specmaterials.com/boronprepregtape.htm

The fabric with randomly oriented fibres is known as "tissue", it is available in CF



image fromhttp://www.acpsales.com/Carbon-Fiber-Tissue.html

but it's fairly rare. I've never worked with it whereas I have two weights of tissue in glass on hand. There's also a fabric known as quasi-isotropic which is approximately what you said, but it's actually made from a number of layers of UD oriented at angles to each other.

[Crawf]

For the generic Chinese manuf's, they all build their frames/rims in 3k, then offer the top layer finish in 3k/UD/12k (it's purely cosmetic) with a gloss or matte finish. 18k also seems to be becoming popular.