Carbon fibers manufacturing

Ahmed Samy
2 Nov, 2023

The production of carbon fiber is a intricate and multi-step procedure aimed at crafting robust, lightweight, and long-lasting composite materials. These materials find applications in a wide range of industries such as aerospace, automotive, sports equipment, and beyond.


Carbon Fiber Manufacturing Process

Carbon fibers go through several stages to obtain the final form suitable for use in various applications, including:

  1. Precursor Material Selection.
  2. Stabilization.
  3. Carbonization.
  4. Graphitization (Optional).
  5. Surface Treatment.
  6. Sizing Application.
  7. Fiber Forming.
  8. Composite Fabrication.
  9. Curing.
  10. Finishing.


1. Precursor Material Selection

The process begins with selecting a suitable precursor material, which is typically a polymer material with high carbon content. Polyacrylonitrile (PAN), pitch, and rayon are common precursor materials used in carbon fiber production.

2. Stabilization

The precursor material is first subjected to a stabilization process. In the case of PAN-based precursors, this involves heating the material in the presence of air at relatively low temperatures (200-300°C) to crosslink the polymer chains and remove volatile components. This step helps to prevent the precursor from melting during subsequent high-temperature processes.

3. Carbonization

After stabilization, the material is carbonized in a high-temperature furnace in an inert atmosphere (such as nitrogen or argon) at temperatures exceeding 1000°C. During this process, the remaining non-carbon elements are gradually removed through pyrolysis, leaving behind a mostly carbon structure.

5. Graphitization (Optional)

Some high-performance applications require additional graphitization to align the carbon atoms in a more ordered manner, resulting in improved mechanical and thermal properties. This step involves further heating the material at even higher temperatures (2500-3000°C) under controlled conditions.

6. Surface Treatment

The carbon fibers are often treated with various chemicals or gases to modify their surface properties. This treatment enhances bonding between the fibers and the resin matrix in the final composite product.

7. Sizing Application

Sizing is a protective coating applied to the carbon fibers. It consists of materials like epoxy or other polymers that improve adhesion between the fibers and the matrix while also protecting the fibers during handling and processing.

8. Fiber Forming

The carbon fibers are bundled together to form a fiber tow. These tows can contain thousands of individual carbon filaments. Fiber tows can undergo additional processing to create various formats, including fabrics, mats, and unidirectional tapes.

9. Composite Fabrication

Carbon fiber composites are commonly manufactured using techniques such as lay-up, filament winding, or resin transfer molding. In the lay-up process, carbon fiber sheets are layered with a polymer resin matrix and then cured under heat and pressure to create a solid composite part.

10. Curing

Once the composite structure is formed, it is placed in an autoclave or an oven for curing. Curing involves applying heat and pressure to the composite to harden the resin matrix and create a strong bond between the fibers and the matrix.

11. Finishing

After curing, the composite part may undergo additional processes such as trimming, machining, and surface finishing to achieve the desired shape, dimensions, and surface quality.

The precise details of carbon fiber manufacturing can vary depending on the specific applications, desired properties, and the manufacturer's technology. The process is complex and requires careful control of temperature, pressure, and other parameters to ensure the final product meets the required standards for strength, durability, and quality.

Learn more about carbon fibers from Here.

Manufacturing Carbon Fiber Parts

Manufacturing carbon fiber parts involves several steps, from design and material selection to actual fabrication and finishing.

There are several steps to get the final carbon fiber part, including :

  1. Design and Material Selection.
  2. Pattern and Mold Creation.
  3. Cutting and Layering.
  4. Application of Resin.
  5. Debulking and Vacuum Bagging.
  6. Curing.
  7. Demolding and Trimming.
  8. Surface Finish.
  9. Quality Control.
  10. Assembly (If Applicable).
  11. Testing and Certification.

Design and Material Selection

  • Identify the specific requirements for the carbon fiber part, including mechanical properties, dimensions, weight, and intended use.
  • Choose the appropriate carbon fiber precursor material (e.g., PAN-based, pitch-based) based on the desired characteristics.
  • Design the part considering factors like fiber orientation, lay-up pattern, and overall geometry.

Pattern and Mold Creation

  • Develop a pattern or mold for the carbon fiber part. This could involve CNC machining, 3D printing, or manual fabrication.
  • If necessary, create a split mold to enable easy removal of the finished part.

Cutting and Layering

  • Cut carbon fiber fabric or prepreg sheets (pre-impregnated with resin) into the required shapes based on the pattern.
  • Layer the cut sheets according to the desired fiber orientation and lay-up pattern. This arrangement determines the mechanical properties of the final part.

Application of Resin

  • Apply resin to the carbon fiber layers. This can be done using various methods such as hand lay-up, vacuum infusion, or resin transfer molding (RTM).
  • Make sure the resin wets out the fibers evenly to ensure good adhesion and minimize voids.

Debulking and Vacuum Bagging

  • Use vacuum bagging techniques to remove excess air and achieve uniform pressure on the part during curing.
  • Debulking involves using rollers or other tools to eliminate air pockets and ensure proper resin impregnation.

Curing

  • Place the lay-up in an autoclave, oven, or heated press to cure the resin. The curing cycle involves controlled temperature and pressure to achieve optimal mechanical properties.
  • Follow the manufacturer's specifications for the curing time and temperature profile based on the chosen resin system.

Demolding and Trimming

  • After curing, remove the part from the mold or tooling carefully.
  • Trim excess material using machining or cutting methods to achieve the final part geometry.

Surface Finish

  • Sand or machine the edges and surfaces to achieve the desired finish and dimensions.
  • Apply paint, clear coat, or other finishing treatments if necessary.

Quality Control

  • Inspect the finished carbon fiber part for defects such as voids, delamination, and dimensional inaccuracies.
  • Perform non-destructive testing if required to ensure the part meets quality standards.

Assembly (If Applicable)

  • If the carbon fiber part is part of a larger assembly, integrate it with other components as needed.

Testing and Certification

  • Conduct mechanical and performance tests on the finished part to validate its properties.
  • Ensure the part complies with industry standards and safety regulations


Manufacturing carbon fiber parts requires expertise in composite materials, fabrication techniques, and quality control. The process can vary based on the complexity of the part and the available manufacturing capabilities. Collaboration between design engineers, materials specialists, and manufacturing experts is essential to achieve the desired results.
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