How is carbon fiber powder produced? This article thoroughly explains the process.

Pre-treatment of raw materials, making necessary preparations

The sources of carbon fiber powder mainly fall into two categories: one is the leftover materials and waste fibers produced during the carbon fiber manufacturing process, and the other is the recycled materials from the formed carbon fiber products. The raw materials must first be sorted and impurities of other materials mixed in should be removed to avoid foreign substances contaminating the powder quality.

If the surface of the raw materials is covered with resins, coatings, or wetting agents, they need to be removed. Commonly, thermal treatment is used to remove the organic components on the surface, or solvent cleaning processes can be adopted to clean the impurities on the surface of the fibers, ensuring the purity of the subsequent powder. After treatment, drying is carried out to control the moisture content of the materials and prevent agglomeration during the grinding process.

The particle sizes of the ground materials vary, so they need to enter the classification equipment. Using air flow sieving, different particle sizes of powder can be separated, and the finished powder meeting the requirements can be selected. The coarse materials that do not meet the particle size requirements will be sent back to the grinding unit for further processing to achieve a circular process. The classification stage can also further separate the residual trace impurities to improve the uniformity of the powder.

Post-treatment and packaging control

After the carbon fiber powder is classified, according to the downstream usage requirements, surface modification treatment can be selected. The compatibility between carbon fibers and resins, plastics, etc. is relatively weak. Through surface modification, the wettability of the powder can be improved, enhancing its dispersion effect in composite materials and reducing agglomeration phenomena. The modification method can be selected according to the application scenario, adjusting the surface activity of the powder.

After modification, the powder is re-sieved to remove impurities and the dispersion, purity, etc. of the powder are tested to confirm its qualification. Then, it is sealed and packaged. carbon fiber powder is prone to absorbing moisture, so the packaging generally uses moisture-proof and sealed materials. The storage environment should be kept dry to prevent the powder from absorbing moisture and forming lumps, affecting subsequent mixing and processing.

Process selection and application key points

The carbon fiber powder produced by different process routes has significant differences in powder morphology and aspect ratio. The process that focuses on retaining the fiber structure results in powder with short fiber characteristics, providing better reinforcement effects; the ultra-fine grinding process yields powder with finer particle sizes, suitable for scenarios requiring filling and heat conduction.

During the production process, dust prevention and protection should also be done well. Carbon fiber powder is lightweight and prone to scattering. When selecting the downstream, in addition to particle size, attention should also be paid to the cleanliness and surface condition of the powder, matching injection molding, extrusion, coating, etc. systems. Only by stably controlling the entire process of pre-treatment, grinding, classification, and modification can stable batches of carbon fiber powder with good dispersion be obtained, meeting the filling and reinforcement requirements of composite materials.