Common Molding Processes for Carbon Fiber 

Carbon fiber processing mainly consists of molding and post-processing. Molding determines the basic shape and properties of the part, while post-processing involves finishing and assembling the molded part. This article primarily introduces the carbon fiber molding process. This is the most crucial step in manufacturing carbon fiber composites, directly determining the material's mechanical properties, appearance quality, and cost.

Manual Lay-up

The most basic and flexible method. Operators manually lay pre-impregnated resin-coated carbon fiber cloth (prepreg) or dry carbon cloth onto a mold according to the designed direction and number of layers, then cure it using methods such as vacuum bag pressing.

Advantages: Low mold cost, ideal for small-batch production, prototyping, and large, structurally complex parts (such as vehicle bodies).

Disadvantages: Quality stability highly dependent on operator skill; low production efficiency; resin content and uniformity are difficult to control.

Resin Transfer Molding (RTM)

Dry carbon fiber fabric is pre-molded and placed in a closed mold. Resin is then injected into the mold under pressure or vacuum, impregnating the fibers and curing them.

Advantages: Smooth, high-quality products with stable fiber content, excellent mechanical properties, and environmentally friendly (low volatile organic compound emissions).

Disadvantages: High mold costs and complex technical requirements.

Applications: High-performance automotive parts, drone fuselages, bicycle frames.

Autoclave Molding

Manually laid prepreg blanks are sealed in vacuum bags and placed in an autoclave. Curing occurs under high temperature, high pressure (provided by compressed air or inert gas), and vacuum conditions.

Advantages: Currently the gold standard for manufacturing high-performance composite parts. Uniform pressure and temperature significantly reduce porosity, maximizing fiber content and optimizing part performance.

Disadvantages: Extremely expensive equipment (autoclave) and operating costs; long production cycles; used only in high-value fields such as aerospace.

Compression Molding

Prepreg or sheet molding compound (SMC) is placed in a metal mold and cured under heat and pressure.

Advantages: High production efficiency, suitable for mass production, high dimensional accuracy, and good surface quality.

Disadvantages: High mold cost; unsuitable for large or complex structural components.

Applications: Automotive exterior parts, electronic product housings.

Filament Winding

Resin-impregnated carbon fiber tows are continuously wound onto a rotating mandrel according to a predetermined pattern, then cured.

Advantages: Achieves extremely high fiber strength and material utilization, ideal for axisymmetric structures subjected to internal pressure.

Disadvantages: Primarily suitable for cylindrical, spherical, and other rotating bodies.

Applications: High-pressure gas cylinders, missile launch tubes, fishing rods.

Pultrusion

Resin-impregnated carbon fiber tows are continuously extruded through a heated mold under traction and cured to form a profile with a constant cross-section.

Advantages: Continuous production, extremely high efficiency, relatively low cost, excellent mechanical properties (especially longitudinal).

Disadvantages: Can only produce straight components with a constant cross-section.

Applications: Building structural profiles, cable trays, tent poles.

Summary and Selection

When selecting a processing technology, it is necessary to comprehensively consider the production volume, part performance requirements, structural complexity, and cost budget to find the most suitable technical solution. We are a Chinese carbon fiber raw material manufacturer. For more information, please contact us via email at annayu@169chem.net or WhatsApp +8618909016373.