Learn About the Different Carbon Fiber Manufacturing Techniques

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Carbon fiber products have revolutionized various industries with their remarkable properties. These attributes make them ideal for a wide range of applications, from aerospace and automotive to sports equipment and construction. The manufacturing of carbon fiber products involves several techniques that are tailored to specific applications and production requirements. Understanding the different manufacturing techniques used to produce carbon fiber products like sheets, tubes, carbon fiber pultruded profiles, and rods is essential for appreciating their benefits and selecting the right materials for specific applications. Read through as we explore the different carbon fiber manufacturing techniques.

Prepreg Lay-Up

Prepreg lay-up is a widely used technique for manufacturing carbon fiber products. It Involves using carbon fiber pre-impregnated with resin, which is then cured under heat and pressure. Carbon fiber products made from prepreg are strong, lightweight, and well-suited for high-end applications, offering higher stiffness and strength. The advantage of this manufacturing technique includes high precision; it allows for precise control over fiber orientation and resin content, resulting in high-quality, consistent parts. It is ideal for producing complex, high-strength parts. This technique is extensively used in the aerospace and motorsport industries for parts that require high strength and low weight, such as aircraft wings and car body panels.

Wet Lay-ups

In wet lay-up, the fiber is cut and laid into the mould then resin is applied via a brush, roller, or spray gun. curing is done under room temperature or with heat and pressure. This method requires the most skills to create high-quality parts, but it is also the least expensive workflow with the lowest requirements to get started with making “do it yourself” carbon fiber products. It is suitable for creating parts of various sizes and shapes, making it ideal for prototyping or small-scale production. If you are new to carbon fiber parts manufacturing and not equipped yet, we would recommend starting with wet lay-up hand lamination.

Roll Wrapping

Roll wrapping is a process commonly used to produce carbon fiber tubes. Roll wrapping is typically done with a prepreg product to ensure consistency. This technique involves wrapping prepreg carbon fiber sheets around a mandrel. The mandrel and prepreg are then wrapped in a plastic film to contain the epoxy resin and compress the layers during curing. The wrapped mandrel is then cured in an oven or autoclave. Once curing is complete, the mandrel is removed from the center of the finished tubed. Roll wrapping allows for complex shapes and precise control over the tube's wall thickness and fiber orientation. The roll wrapping process is used to produce high-strength carbon fibre tubes, either with a basic unfinished appearance or with a cosmetic finished appearance.

Filament Winding

In this method, carbon fibers are wound around a mandrel in a predetermined pattern and then coated with resin. The mandrel is heated to cure the resin and harden the tube. Filament winding allows for precise control over the fiber orientation, resulting in carbon fiber tubes with high strength and stiffness. Filament winding is a technique primarily used to manufacture hollow, circular, or prismatic parts such as pipes and tanks. This technique can also be used to produce carbon fiber rods, particularly when specific fiber orientations are required for enhanced performance. Filament wound parts are commonly used in the aerospace, energy, and consumer product industries.

Pultrusion

Pultrusion is the primary method for producing carbon fiber pultruded profiles and carbon fiber rods with consistent quality and properties. Pultrusion involves pulling carbon fibers through a thermoset resin bath and then through a heated die. The fibers are aligned in the direction of the pull, resulting in a carbon fiber tube with excellent longitudinal strength. This process is efficient, producing strong and lightweight products, making it suitable for the production of long, straight parts like beams, strips, or tubing. The advantage of this process is that it produces a continuous, unidirectional length of tubing that can be cut to size after curing. Since pultrusion is highly automated, it’s a much more cost-effective production process than both roll wrapping and filament winding. Pultrusion makes it easy to produce tubing in various lengths and thicknesses simply by changing up both mandrel and die.

Pullbraiding

Pullbraiding is an extension of pultrusion. It is also used for producing carbon fiber pultruded profiles. This process is essentially the same as pultrusion with one added feature: the fibers are braided together as they are being pulled through the heated die and onto the mandrel. Layers of different angles can be made by varying the braid, and even unidirectional layers can be inserted. Pullbraiding creates finished products with high stiffness and strength-to-weight ratios. The main advantage of the pullbraiding process is that it creates a more balanced carbon fiber tube that performs under a wide range of loads. It also adds an element of aesthetic beauty since the braid is more in line with the traditional “carbon fiber” look. And since this process is highly automated like pultrusion, pullbraided carbon fiber tubes are often less expensive than roll-wrapped or filament-wound carbon fiber products.

Compression Moulding

Compression moulding involves placing carbon fiber preforms prepreg into a heated mould, which is then closed with pressure to shape and cure the part. It is a cost-effective and efficient way to produce large quantities of carbon fiber products and provides excellent control over part dimensions and surface finish. It is commonly used for producing sports equipment, consumer electronics casings, and for creating high-performance automotive parts such as Car body panels, Sports helmets, Tennis rackets etc.

Resin Transfer Moulding (RTM)

This process utilizes a closed mould where dry reinforcement is placed, and low-viscosity resin is injected under pressure. This method is efficient and suitable for producing complex parts with high strength and durability. A variant of this manufacturing process is the Vacuum-Assisted Resin Transfer Moulding (VARTM). It involves placing the carbon fiber material on a tool under a vacuum bag, pulling a vacuum on the bag, transferring the resin by vacuum into the fiber, and curing the composite under heat and pressure. This process results in strong and lightweight parts that are well-suited for use in a variety of applications. VARTM is best used for the production of parts with complex geometry, such as sailboat hulls or motorcycle farings because the process allows time to carefully lay the carbon fiber in the tool before mixing and applying the resin.

Conclusion

The diverse manufacturing techniques for carbon fiber products highlight the versatility and adaptability of this advanced material. Each technique offers unique advantages, making it possible to tailor carbon fiber products to meet specific performance requirements across a wide range of industries. As technology continues to advance, the applications and capabilities of carbon fiber will undoubtedly expand, solidifying its role as a cornerstone of modern engineering and design.