Carbon fiber belongs to a polymer family and also referred to as amorphous graphite fiber. The unique quality of carbon fiber is that it is a strong material yet very light in weight. As compared to steel, carbon fiber is two times stiff and five times stronger. It is stronger and lighter than steel. Therefore, it is ideal for every chopped carbon fiber manufacturer. Apart from stiffness and weight, there are many qualities in carbon fiber, which makes it favourite for manufacturing and design engineers.
History of carbon fiber goes back to 1879. Back then, Thomas Edison baked threads of cotton and bamboo silvers at high temperatures; that carbonized them into fiber filament. History depicts that by 1958, carbon fibers with high performance were invented. Being inefficient yet effective, carbon fibers of that time were able to have properties of:
20 per cent carbon
A new manufacturing process back in 1963 was formed at a research centre in Britain. That is where the true potential of carbon fiber was realized.
Carbon Fiber Manufacturing Process
The raw material taken to make carbon fiber is called a precursor. Almost 90 per cent of the carbon fiber is created using polyacrylonitrile (PAN). The remaining proportion is produced from petroleum or rayon pitch. All the products, as mentioned above, are organic polymer. The precise composition of each precursor differs from company to company; typically taken as a trade secret.
The process for the production of carbon fiber is partly mechanical and partly chemical. During the manufacturing process, various liquids and gases are used. The precursor is dragged into long strands, and high-temperature heat is given without permitting it to contact with oxygen. Fiber cannot burn without oxygen.
The manufacturers use the high temperature that compels the atoms of chopped fiber to vibrate intensely until the majority of the non-carbon atoms are ousted. The process is called carbonization.
After carbonization is completed, long chains of tightly interlocked carbon atoms are left.
A regular sequence used to produce carbon fibers from polyacrylonitrile is stabilizing, carbonizing, surface treatment and sizing. Let’s briefly go through this sequence-wise:
Before fibers get carbonized, they are required to be altered chemically for the conversion of linear atomic bonding to thermal stable ladder bonding. This conversion is obtained by heating chopped carbon fibers in the air for 30 to 120 minutes at 390 to 590 degrees Fahrenheit. The heating causes the fibers to grab the oxygen molecules from the air and rearrange the atomic bonding pattern.
The chemical reactions during stabilizing involve many steps and are complicated too. They also produce their heat. The heat must be supervised to avert the fibers’ overheating.
Once the carbon fibers pass through stabilization, they are exposed to heat with the temperature range of 1000 to 3000 degree Celsius. The heating process continues for several minutes with a gas mixture in a furnace where oxygen is deliberately absent. The absence of oxygen prevents the fibers from burning. With the heat, fibers start to lose their non-carbon atoms. The leftover carbon atoms form tightly aligned carbon crystals.
After carbonizing, fibers need to be bonded well with epoxies and other composite materials. To better the bonding properties of fibers, their surface is finely oxidized. When the oxygen atoms are added to the surface, they give the best chemical bonding characteristics. As a result, the surface gets roughen for better properties of mechanical bonding.
The supplier or chopped carbon fiber manufacturer carefully treats and controls the surface for the avoidance of forming tiny surface defects.
After treating the surface, manufacturers do coating on fibers to shield them from damage. The process of protection is called sizing. The materials used for coating include urethane, nylon, polyester, epoxy etc.
Uses of Chopped Carbon Fiber
Manufacturers use carbon fiber for anything they need. Carbon fiber print glass can be produced via carbon fiber. Following are some more stuff that can be made with carbon fiber:
- Car components
- Propeller blades
- Automotive shafts
- Aircraft wings
- Motorcycle frames
According to a study, composites of carbon fiber can lessen a passenger car’s weight by 50 per cent. As a result, fuel efficiency would enhance by about 35 per cent. Rest assured that the performance or safety of the passengers will not be jeopardized.
The chemical and mechanical industry is growing leaps and bounds. The growth has brought us 3D printing technology. The carbon fiber helps in two different ways. One is chopped carbon fiber printing, and other is continuous carbon fiber printing.
Now, every chopped carbon fiber manufacturer is putting efforts to replace the usage of aluminum and steel completely. But to turn the efforts into reality, production cost needs to cut down. All in all, carbon fiber is one of the best things that happen to the industrial revolution.