Twill weave or plain weave carbon fiber?

Today's Tech blog is about the type of weaving carbon fibers.

As I mentioned in the last article "What is CFRP? and species of carbon fiber prepregs", there are several types of prepregs or carbon fiber fabrics.

I will make reference to two types of weaving method, "twill" and "plain".

The above texture pattern is twill and plain weave pattern is in below.
Twill carbon's characteristics are as follow.
1. Nicer to look at
2. The fabric is more flexible and difficult to fit to mould.
3. Thanks to its flexibility, more chance to have wrinkles on its surface.
Basically twill carbon has greater looking but need more cost and time on the production.

Then plan carbon's characteristics are below.
1. Higher strength and stiffness.
2. The prepreg or fabric is cheaper than twill weave's
3. Easier to fit to the mould, less chance to have wrinkles.
Nowadays, It is rare to see plain weave in prepreg manufacturing method.
However, in the hand laminate FRP manufacturing, it is well use to reduce products cost.
*Hand laminate method is far more difficult to finish up product with great weave looking. Because weave of the fabric is easy to move and spoil its beauties.
On the other hand, prepreg are having resin matrix in it, weave wouldn't move.

 Let's talk about strength of the material.
Look at these pictures^, you will notice the number of points that the bundles are bended are less on "plain weave".
The bending point may cause break ore buckling when high stress is applied.
In addition, plain weave are tangled with more point than twill weave. And this makes the fabric stiffer.

In the surrounding CFRP car parts such as carbon rear wing or carbon bonnet, carefully looking at the surface, we will notice that almost every parts use twill carbon on its first layer. As we can see in above characteristics. This is simply because of the appearance problem.

^wikipedia 'https://ja.wikipedia.org/wiki/綾織 & https://ja.wikipedia.org/wiki/平織