How are carbon fiber parts made?

How are Carbon Fiber Parts Made?

Carbon fiber parts are being used increasingly in various industries, including aerospace, automotive, sports equipment, and biomedical devices, due to their exceptional properties such as high strength-to-weight ratio, corrosion resistance, and lightweight. The manufacturing process of carbon fiber parts is a complex and multi-stage procedure that requires careful handling, precision, and automation.

Production of Raw Carbon Fiber

The process starts with the production of raw carbon fiber, also known as tow. There are two main methods to produce raw carbon fiber:

• Gas Phase Process: In this method, a catalyst and a carbon-containing material such as methane or naphthalene are used to produce carbon fibers in the gas phase. Helium is commonly used as the carrier gas. The process involves polymerizing the carbon-containing material at high temperatures, usually between 800°C and 1000°C.
• Liquid Phase Process: In this method, a polymer solution is deposited on a metal wire mandrel, and then undergoes a process called wetting, where the liquid carbon fibers bond to the metal wire. The wet fibers are then drawn, a process that involves pulling and stretching the fibers to orient the molecules and produce fibers with the desired mechanical properties.

Spinning of Carbon Fiber Tows

The raw carbon fiber from the production process is called tow, a bundled collection of fibers typically composed of 3,000 to 50,000 individual fibers. Tows are then spun into thin ropes called yarn. The spinning process involves:

• Converting: The tow is heated and converted into a fluid state to facilitate its spinability.
• Twisting: The hot carbon fiber tow is then twisted to align the fibers in the desired direction.

Carbon Fiber Fabrics

The yarn is then used to create carbon fiber fabrics, which are also known as preimpregnated carbon fiber cloth (prepreg) or carbon fiber weave (CFW). Fabrications can be achieved using different weaving techniques, including:

• Weft-warp weaving: Also known as plain weave or rectangular weave, this technique interlaces the yarn at 90-degree angles.
• Twill weave: The yarn is interwoven at a 45-degree angle, creating a stronger and more flexible fabric.

Manufacturing Methods for Carbon Fiber Parts

The carbon fiber fabric is then cut and shaped according to the desired part design, followed by various manufacturing techniques such as:

• Layering: Multiple carbon fiber layers are stacked upon each other, bonded by adhesive or thermoplastic bonding.
• Fabric molding: The carbon fiber fabric is molded using resins, heat, or other processes to create three-dimensional shapes.
• Bonding: Carbon fibers are bonded together using chemical agents, heat, or light.

Tables and Flowcharts:

Below is a simplified production process flowchart for a typical carbon fiber part.

Additionally, the following chart displays the different types of composite materials used in aerospace manufacturing:

Automation in Carbon Fiber Part Production

To increase efficiency, manufacturers are increasingly using automated technologies, such as robots and computer-aided systems, to perform repetitive and precise tasks, ensuring precision and reducing human errors. Automated processes, such as robotic lacing, tape laying, or automated fiber placement, improve the rate of production, ensuring accuracy and quality.

In summary, the production process for carbon fiber parts begins with the production of raw carbon fiber, followed by the spinning of carbon fiber yarn, fabric weaving, cutting, shaping, bonding, and final assembly to form the desired part.

References:
(1) Carbon fiber reinforced polymers (CFRP) in aerospace,
Published by NASA,
Year, 2020)
https://www.nasa.gov/hrp/CFRP

(2) carbon-fiber-manufacturing-processing-and-characterization.,
Published by Hindawi.com,
Year, 2019)
https://www.hindawi.com/journals/ampn/pdfs/201933111.pdf

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