Do you really know what Carbon fiber is?

February 01, 2017

Introduction.

Whether you are an super car fanatic or a luxury good connoisseur, the chance is that you have heard of the word "Carbon fiber" and you probably know some of the basic characteristics of Carbon fiber: lightweight, strong, durable and expensive. But, have you ever asked yourself "what exactly is this mysterious Carbon fiber?" 

What is Carbon fiber and why we care so much?

According to Wikipedia, "Carbon fibers or Carbon fibres are fibers about 5–10 micrometres in diameter and composed mostly of carbon atoms." To put in simpler terms, Carbon fiber is an arrangement of Carbon atoms that are 5 to 10 micrometers (1e-6 meters) in diameter. It is this particular alignment (tightly packed) of Carbon atoms that makes Carbon fiber this incredibly strong. Carbon fiber has high stiffness, tensile stress, high yield strength, low weight, high temperature tolerance, and low thermal expansion coefficient, thus making it a very popular material in aerospace, automotive racing, and lately other industries that require high performance gear such as sports, bicycles, etc.  

To see for yourself the incredible characteristics of Carbon fiber, please enjoy the video below. 

General misunderstanding and false claim.

Stronger than steel?
However, there is a general misunderstanding of Carbon fiber that it is stronger than steel and by extension aluminum. You may have encountered carbon fiber product websites where they claim it is stronger than steel. Simply by ultimate tensile strength, which is the point where a part breaks or snaps, steel is stronger than Carbon fiber Therefore, technically speaking, Carbon fiber is not stronger than steel. However, the very reason that such statement existed is that Carbon fiber has a higher strength to weight ratio (higher specific strength) than steel, which means that for the same amount of weight, Carbon fiber can handle more stress, thus stronger than steel. 
Just Carbon fiber?
There seems to be a common sense that when people say Carbon fiber, they actually meant the final Carbon fiber part that often has a glossy and shiny finish. However, this particular Carbon fiber part is actually made out of Carbon fiber and resin. Carbon fiber or Carbon fiber strand along is in reality soft, like cotton strand. It is the combination of both Carbon fiber strands and resin (often epoxy resin, you can use different resin or plastic to give you the specific properties you want.) that give us the wonderful properties that everyone loves. Hence, Carbon fiber is a composite material.
 

So why not Carbon fiber everything?

So far, we have established that Carbon fiber has a superior strength to weight ratio than steel. Why can we just replace steel or aluminum with Carbon fiber then? The answer is simple, carbon fiber is very, very expensive. A basic 2mm thick carbon fiber flat sheet that is 300 by 100 mm would cost you 30 plus dollars on Amazon, whereas you can buy a ton more steel. According to this source, "carbon fiber for automotive costs $10 to $12 a pound, compared to less than a buck for steel." Additionally, as the part becomes more complex and intricate, the price to make it out of Carbon fiber skyrockets, which is the very reason you only see Carbon fiber parts mostly in aerospace industry, automotive racing, exotic cars, military application, high performance equipment and luxury goods where the budget for production is simply insane.  

How is Carbon fiber made?

Remember what makes Carbon fiber so strong? Here is your refresher, it is the tightly bonded Carbon atoms. So, in order to create Carbon fiber, smart people have come up with ways to isolate Carbon atoms from Carbon-rich materials and arrange Carbon atoms in the desired structure. There are mainly two ways to do so. Most of the Carbon fibers (90%) around the world are made from this material called polyacrylonitrile (PAN) and now it is a good time to note that the raw material used to create Carbon fiber is called precursor. The rest 10% is made from rayon or the petroleum pitch process. In order to isolate the Carbon atoms, these process all need to heat up the precursors to extreme temperature,1,830-5,500° F (1,000-3,000° C) for several minutes in a furnace filled with a gas mixture that does not contain oxygen (to prevent Carbon fiber from burning). This is partially why Carbon fiber are so expensive compared to metal. Unfortunately, the exact compositions of the precursors and process materials are kept as trade secrets and vary from one manufacture to another.

If you are interested in more details about how Carbon fiber is made and its process, you can refer to this article for PAN process and this article for petroleum pitch.

A brief history lesson.

Carbon fiber was first developed in Cleveland Ohio in 1958 (is this the reason why we chose Ohio as our headquarter?) and the process (PAN) to make Carbon fiber was developed and improved by the Japanese a few years later and is still in use today.

In 1963 at Rolls Royce in England, high production quality and standard was achieved. Back then, due to its brittle properties and high production cost, Carbon fiber is only commercially available in few special industries.  

In 2005, Carbon fiber reached a $90 million market size and Carbon fiber global market size is projected to reach 3.51 billion by 2020 at a CAGR of 9.1%. 

Is Carbon fiber safe?

Final Carbon fiber product is relatively safe. That is if you don't take a piece of Carbon fiber and decide to eat it. However, Carbon fiber dust can irritate your skin and always wear respirator and protective suit if you are cutting Carbon fiber part since Carbon fiber dust is very fine and can be harmful to your respiratory system. A good ventilation system is recommended for a safe working environment. Cured Carbon fiber strands are very brittle. Therefore don't get chipped by Carbon fiber. It can be painful. When handling resin, wear respirator and gloves to protect yourself from Carbon fiber and resin to avoid skin and breathing irritation. Additionally, as a general rule of thumb with chemicals, don't drink or inhale it. Furthermore, Carbon Fibers have electric conductivity, fly or waste yarn can cause a short-circuit at electric lines.

Carbon fiber Challenges

  • One of the most important issues that Carbon fiber faces is to drive the cost down and make it possible for other industries to access this material. 
  • Carbon fiber parts, once broken, can be extremely difficult and expensive to repair. A cost-effective and viable Carbon fiber repair solution is needed.
  • 3D printed Carbon fiber part. As with most conventional manufacturing method, it is sometimes nearly impossible to manufacture some components. Therefore 3D printed Carbon fiber can make any product with amazing properties of Carbon fiber at a lower cost. 
  • As the market size of Carbon fiber grows, a viable and sound recycling solution for Carbon fiber is needed. 

Future of Carbon fiber and What we can expect. 

Due to its amazing strength to weight ratio and properties, Carbon fiber is believed by some to be one of the most important materials of our generation. As the cost of Carbon fiber falling and more industries gaining access to this material, Carbon fiber technology will soon trickle down from aerospace to many other industries. 

  • Renewable Energy, such as blades for windmill, turbines for hydroelectric dam. 
  • To further improve fuel efficiency, light weight Carbon fiber will be used not only on exotic and performance vehicle, but also everyday vehicle such as say your Honda Civic. 
  • Sporting goods and gear to improve performance. Just name a few examples: badminton, tennis, ping-pong rackets, surfing board and protective armor. 
  • Infrastructure and building. Earthquake protection. 
  • Oil exploration. Deep water drilling platforms, drill pipes.
  • 3D printed Carbon fiber parts. 
  • Robotics application. Robot (terminator) made out of Carbon fiber!

Some wild ideas

Remember shape changing BMW concept. What if we can make Carbon fiber that can change its shape?

Conclusion

This article gives a brief introduction on Carbon fiber material. It covers the topics: what is Carbon fiber, how Carbon fiber is made, some false claims, Carbon fiber safety, Carbon fiber history, Carbon fiber Challenges and the future of Carbon fiber. 

 

     



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