Carbon fiber manufacturing is the process of creating carbon-fiber reinforced plastics (CFRP). Products made from carbon fiber offer one of the highest strength-to-weight ratios of any material, and also offer superior thermal and conductive properties. This high strength and low weight makes carbon fiber manufacturing a popular choice in the aerospace, marine, and sporting goods industries. Certain blends of carbon fiber materials may also be referred to as graphite.
The carbon fiber manufacturing process begins as producers process raw materials into fine carbon strands. They start with a base of coal tar, or pitch, which is used to make low-end carbon fiber products. For high-quality products, manufacturers start with a base material of polyacrylonitrile, which consists of propylene and ammonia. After this base material as been heated multiple times, it changes structures dramatically. Eventually, the material transforms into a chain of carbon molecules, and all other molecules drop away.
These carbon molecules are blended with chemicals and subject to a process known as wet spinning. During wet spinning, the liquid carbon blend passes through a die known as a spinneret, which features many tiny holes. The spinneret forms the material into long, thin filaments of carbon. By blending these filaments with epoxy or other resins, manufacturers can produce CFRP.
Carbon fiber production is fairly precise, and even a small change during production can impact the quality of the product. Each carbon fiber manufacturing facility utilizes its own unique blend of base materials, chemicals, and temperature ranges throughout this manufacturing process. This leads to subtle differences among carbon fiber materials from one manufacturer to the next.
Manufacturers shape carbon fiber into a variety of products using several types of manufacturing processes. They may create molds out of fiberglass or metal to cast individual parts. Melted carbon fiber reinforced plastics are often layered with sheets of mesh for added strength and stability during the molding process. Companies may also extrude melted carbon fiber plastics through a steel die to form different shapes.
Since its invention in the mid 20th century, carbon fiber manufacturing has been used to produce aircraft, boats, and automobiles. Since that time, it has also been widely used to produce sporting goods like bicycles, tennis rackets, and gold clubs. By the start of the 21st century, the wind energy industry had become the world's largest consumer of carbon fiber, which is used to make large-scale wind turbines.