What is woven carbon fiber prepreg?

Carbon fiber materials can be categorized as either woven or unidirectional, depending on how they are formed.Woven carbon fiber materials can be further classified based on their weave, or the pattern used to join fibers into a fabric. These differences are not purely aesthetic—different weaves look very different from one another, but they also have distinct performance characteristics. Accordingly, some weaves are more appropriate for certain applications than others.

First, the fibers are bundled into groups called tows, 3K and 12K are standard industry fiber bundles which are 3,000 and 12,000 fibers densely packed together. The way these tows are combined determines the fabric's strength, stability, and formability.

Plain Weave:The simplest carbon fiber weave is known as a plain weave. The plain weave is formed by crossing tows in a one-over, one-under pattern, creating the checkerboard seen on many woven fabrics. These materials are strong and highly stable, but they are not very pliable. Plain woven carbon fiber is best for components that are flat or only slightly contoured.

Twill Weave:Like the plain weave, the twill weave comes from passing tows in an even over/under pattern. However, rather than passing over a single tow, each strand passes over multiple tows, then under the same number of tows. This is typically done in a two-over, two-under pattern, but 4 x 4 twills are also common. In either case, the resulting pattern appears to form rows of rectangles proceeding diagonally up the fabric. Twill weaves are more formable than plain weaves, so they can be used with more complex shapes. However, this means that they are not as stiff and stable as plain weaves.

Woven carbon fiber prepreg is used both for aesthetics and durability. Whereas uni-directional prepreg offers a higher stiffness-to-weight ratio, woven prepregs are typically more damage tolerant. Often, the best option is a combination of uni-directional composite material in the core of a laminate and woven prepreg face plies (or skins). This gives the finished part the carbon fiber look many people want while also reducing the changes a splitting or fiber tow pull-out during machining or while the part undergoes localized stresses (for example, during an impact). For higher impact resistance, or when there are many holes or other small features, an all-woven prepreg layup schedule may be the best option.

Woven carbon fiber prepreg is available in a variety of weights, aesthetic weaves, and resin content. Fabrics weights range from lightweight 3k weaves up to heavy 12K twill that lays up at 0.025" per ply. We carry many standard options in woven prepregs, we also works with customers to develop custom solutions. 

However, many applications subject composite materials to multidirectional tensile forces. Woven carbon fibers are more appropriate for these applications. Because of this, woven fabrics are frequently used in the automotive industry. Woven fabrics also tend to be more workable and machinable than unidirectional fiber.