Carbon fiber is a strong, stiff, and lightweight material that can be used in a variety of structural and cosmetic applications. The carbon fiber manufacturing process may seem complex, but there are only a few key steps you really need to understand. In this blog post, we will outline the basic carbon fiber manufacturing process from start to finish.
Step 1: The Precursor
Carbon fiber manufacturing begins with a precursor in the form of fibers, typically PAN (polyacrylonitrile). These fibers will be heated and carbonized to create carbon fiber. After the carbonization process, the carbon fibers are wound onto spools, then further processed for use in industrial applications such as:
- aerospace materials
- sports equipment
- medical devices
- carbon fiber parts for electric vehicles
- robotic components
Step 2: Carbonization
The carbonization process involves heating the carbon fibers, assembled into strands called “tows,” in an inert atmosphere at a temperature of 1000-3000 degrees Celsius to convert them to graphite. In the carbonization process, non-carbon elements such as hydrogen and oxygen are driven from the fibers through heating, and a portion of the remaining carbon content is converted into graphite. This stage takes several hours to complete and is extremely expensive.
Step 3: Weaving, Braiding
At the end of the carbonization process, the carbon fiber tow is wound on bobbins. These bobbins are next processed into multiple formats. These include.
- Cloth is woven in multiple weaves and densities
- Braided tubes and sheets
- Unidirectional ribbons
- Prepreg – All of the above pre-wetted with epoxy, partially cured, then frozen
Step 4: Molding
The final step in the carbon fiber manufacturing process involves molding the carbon fiber into different structures such as:
- Complex carbon fiber parts
This is typically accomplished by placing carbon fiber wetted with epoxy, or a pre-wet prepreg, in a tool and curing the epoxy with heat.
There are many specific processes including:
- Wet layup
- Vacuum bagging
- Resin transfer
- Sandwich structures
- Insert molding
- Matched tooling
- Winding on mandrels
After the cure cycle, the molded part is removed from the tool and trimmed to its final shape
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