Carbon Fiber: what you need to know
Carbon fiber is a thin material of microscopic diameter composed of carbon atoms linked together in cross-sectional alignment. This kind of alignment makes the fiber highly tensile by resisting any kind of pressure to unweave it. This material has been solely utilized for Aerospace, but due to various modifications that carbon fiber can be manipulated into, it now serves many functions. Millions of carbon fibers are wound together to actually form a carbon fabric, which is then impregnated in resin before being molded into various designs.
There are many advantages of carbon fiber which makes it much more preferable for industrial purposes than steel. The most obvious advantage is that carbon fiber is versatile, it’s like a malleable form of steel which you can manipulate into anything while at the same time proving to be at least twice as tough as steel depending on the weaving pattern. Other advantages of carbon fiber are, high stiffness and tensile strength, lightweight, very low thermal expansion, high resistance to chemical and temperature tolerance.
Types of carbon fiber weave
Fiber weaves are made differently to serve different purposes and carry various levels of stiffness depending on their patterns and molding.
1. Unidirectional Weave
In unidirectional carbon weave, the fiber strands are arranged in a uniform direction with select fibers weaving across the restto hold them together. This kind of pattern is better utilized in single direction force like cables.
2. Plain Weave
This type of weave is also called one-by-one and the fiber strands intertwine above and below each other to form a trellis impression. It is probably the most common pattern with high strength capability.
3. Twill Weave
The twill pattern is doubly intertwined to follow a diagonal direction. It is much tougher than the plain weave due to its intricate pattern made to absorb greater pressure. It can be manipulated easily into various contours since the strands are not closer together.
4. Harness Satin weave
The harness Satin fiber has a zigzag pattern and it can be way stiffer than the Twill when properly utilized due to the structure of its pattern.
Resins used for carbon fibers
The Epoxy resin is the most expensive of resin type due to its high strength and ability to hold fast to carbon fiber. These kinds of resins have the highest performance and weather resistance compared to other types of resins in the market. Unlike Polyester resins, Epoxy reveals an incredible resistance to water degradation.
The Vinyl ester structure or properties does not differ widely form Polyester but it is much better at withstanding shock than Polyester. Also, the fewer esters in Vinyl ester make it stronger than Polyester in terms of water susceptibility considering esters are prone to degradation by water.
Polyester resins are commonly used since they are not as expensive compared to the other two and offer mid-level performance and strength like resistance to corrosion and temperatures. They also cure really fast and are much easier to handle. Most people prefer molding carbon fiber with Polyester resin.
Carbon fiber is a structurally tough component, but its reliability and strength will mostly depend on the form of extrusion, weave pattern and the type of resin used. While Vinyl ester and Polyester are commonly used on carbon fiber, they show poor adherence, and are much better used on fiberglass. This leaves Epoxy as the ideal resin for carbon fiber.