What is carbon fiber?

2025-09-29 09:44:05

Carbon fiber is a refined fiber material with a carbon content of over 90%. Many of the high-performance products we often see in everyday life aren't simply carbon fiber; they're more often carbon fiber composites. These are made by fusing carbon fiber precursors with resin to create high-performance composites. These composites are then processed and molded to achieve enhanced mechanical properties. They're used in automotive, medical, aerospace, and consumer applications.

Advantages of Carbon Fiber

The fundamental reason carbon fiber composites are used in so many fields is that they offer numerous advantages, primarily high strength, high modulus, low density, corrosion resistance, high temperature resistance, fatigue resistance, low thermal expansion coefficient, excellent X-ray transmittance, and electromagnetic shielding properties. It's also known as "black gold." Composites reinforced with carbon fiber inherit these properties, significantly outperforming traditional metal and plastic materials in performance and advantages, leading to their widespread application in various fields.

Why is carbon fiber so expensive?

The reason carbon fiber is so expensive actually refers to the high price of carbon fiber products, often several times the price of similar metal materials. A case in point is the carbon fiber hood on a car. Damage after a collision can cost tens of thousands of yuan. The high price of carbon fiber products stems from two factors: the high cost of the carbon fiber material itself, and the manufacturing process itself, which prevents full mechanization.

Carbon fiber composites are complex to manufacture. They require resin impregnation to ensure that each carbon fiber filament is connected, ensuring optimal product performance and providing superior shear and tensile strength in the finished product.

There are many different production processes for carbon fiber products. 

Here, we'll discuss some common ones used by carbon fiber manufacturers:

Vacuum forming: After the carbon fiber composite material is formed into prepreg tapes and laid into a mold, it is formed under a certain pressure. This enclosed vacuum pressure enhances the appearance and performance of the finished product, making the entire carbon fiber product more compact.

Winding: This process primarily involves winding carbon fiber composite filaments onto a core mold for complex tubular products, followed by curing and demolding.

Compression molding: This process utilizes two molds, one above the other, where pressure is applied to the molds to heat the product and then cure it.

Roll forming: Similar to winding, Zhishang roll forming utilizes carbon fiber prepreg tape, which is then rolled onto a core mold and demolded.

These processes appear simple, but each step requires manual labor, such as layup, cutting, covering the rolled product with PP film, and then demolding and machining. This results in a relatively high price for carbon fiber composite products.

Currently, thermoplastic carbon fiber composite products are relatively affordable, and the manufacturing process is relatively mature. Internationally, carbon fiber composite research and development is leading, primarily in thermoplastic carbon fibers, due to their poor impregnation with thermoplastic resins. Carbon fiber composites used in high-precision applications require thermoplastic carbon fibers.