Though it was once relegated to cutting-edge aerospace programs and deep-pocketed factory race teams, the use of carbon fiber has become increasingly prevalent across a myriad of today’s industries. And while this has resulted in an increasing number of people being privy to carbon fiber, the majority of individual’s grasp on the finer points of carbon fiber is tenuous at best, not to mention its properties, its history, the various forms it takes, or the numerous manufacturing techniques used to produce it. So, in an effort to help explain the finer points behind this modern and technical weave, we’ve put together this complete guide to carbon fiber.
Offering five-times the strength of steel and double the stiffness while clocking in at just one-third its weight, carbon fiber is an ultra-lightweight, incredibly-stiff material with stellar heat tolerance and minimal thermal expansion. Also known as “graphite fiber,” carbon fiber’s remarkable properties have enabled it to permeate an ever-growing number of product spaces. And while it’s thought of as a fairly cutting-edge material, the story of carbon fiber — just like graphene — actually dates all the way back to the mid-1800s.
Unweaving The Past
The History & Origins Of Carbon Fiber
The first recorded use of carbon fiber took place in 1860 when Sir Joseph Wilson Swan used the material in an early incandescent light bulb. Not long after in 1879, Thomas Edison developed a cellulose-based carbon fiber filament in one of the first electrically-heated bulbs. By baking (or carbonizing) cotton threads and bamboo slivers through a process known as “pyrolysis” — a process in which organic matter is thermally decomposed via being heated to extreme temperatures — Edison was able to achieve a carbon fiber filament with incredible tolerance to high temperatures, making them perfect for conducting electricity.
While most aspects of the process have greatly evolved since the latter half of the 19th century, pyrolysis continues to be employed in production today. Edison’s system would remain a cutting-edge piece of technology until the turn of the early 1900s, at which point tungsten filaments became the new standard and carbon fiber was largely forgotten about, at least for another half-century or so.
20th Century Weaves
The Modern Era Of Carbon Fiber
When the 1950s rolled around, the aviation and rocket industries began requiring a material suitable for jet engine orifices, ultimately leading to new, higher-tensile strength carbon fibers being invented just outside Cleveland. These initial high-performance carbon fibers were composed of cotton fibers and a viscose rayon textile that acted as the precursor. And, while this marked a major stride in the overall development of carbon fiber, it had nothing on the numerous advancements that would follow.
By the dawn of the 1960s, Dr. Akio Shindo, of the Agency of Industrial Science and Technology in Japan experimented with utilizing polyacrylonitrile (or “PAN”) as a precursor. By using PAN — a synthetic, semi-crystalline organic polymer resin and the precursor used in roughly 90% of today’s commercial carbon fiber applications — Dr. Shindo was able to deliver on a carbon fiber with a 55% carbon content — a marked jump over the prior versions that boasted around 20% carbon — that was also substantially cheaper to produce. By 1967, the lab coats at Rolls Royce — who were developing carbon fiber for use in their jet engine fan assemblies — created an even more advanced version known as “CFRP,” or “Carbon Fiber Reinforced Polymer.”
The advancements made over the two decades from the ‘50s to the ‘70s left little to no doubt as to the blatant merits of this newly-emerging material and its superiority to aluminum and steel. Carbon fiber weighed considerably less than traditional production metals, while also offering much better overall tensile strength and heat resistance. It also boasted an unusually high resistance to warping or stretching, making it wildly-conducive to uses in rigid, aerodynamic bodies and structures like on the nose cone of an aircraft.
Japan’s Toray Industries — which currently stands as the world’s biggest carbon fiber manufacturer — had been developing its own types of carbon fiber for over a decade, and in the early ‘70s, the company started manufacturing and selling the production version of its PAN high-strength carbon fiber which was known as TORAYCA yarn T300. In addition to experiencing an influx in applications around this time — including adopting carbon fiber for the use in everything from fishing rods to golf clubs — the availability of T300 on the market meant that it was readily accessible, leading to it being utilized on noteworthy, high-profile projects like the radio telescope at the Tokyo Planetarium, components for a slew of Boeing and Airbus models, and even the cargo doors for the Space Shuttle Columbia.
In 1986, Toray rolled out its new and improved T1000 material, which now a vastly-improved tensile strength and was composed of close to 95% carbon. By this point, carbon fiber was increasingly looking like the trick woven material that we know today. Later advancements allowed the vaporizing process to cook off roughly 50% of the material, resulting in a modern material with a near-100% carbon content.
Carbon Fiber Basics
What It Is & How It’s Made
Most of us are used to seeing carbon fiber in its completed form, so many are unaware of exactly what goes into carbon fiber. Put simply: carbon fiber is an ultra-thin crystalline filament that by itself isn’t particularly strong, though when spooled together into a yarn can offer incredible strength. The yarn is made by heating strands of fibers to extreme temperatures while shielding them from any outside oxygen, thereby preventing the fiber from burning or combusting.
This heating process – known as carbonization – ultimately causes extreme vibrations on an atomic level that rids the fibers of its non-carbon content — with the majority of the remaining property being nitrogen. The resulting product is a strong, tightly-linked chain of carbon atoms that can then be turned into a yarn and then woven into a cloth-like material that can be shaped and molded over other products or objects.
Once the weave is created, there are two primary ways of producing regular molded carbon fiber parts, both of which involve coating/filling the material with a resin of some kind. The first is known as “pre-preg” (or “pre-impregnated”) which is a carbon fiber fabric that is reinforced with a resin and then set in a mold to be heated in an autoclave or over where it cures, forms, and sets. The other main method is called “Vacuum Infusion,” and it involves draping a carbon-weave fabric over an object or mold before being bestowed with epoxy resin.
Despite the significant strides made over the years, carbon fiber remains a fairly expensive material to manufacture and produce — granted it now costs only a fraction of what it once did in the early days. The precision involved in almost every step of the process makes it exceedingly difficult to work with the material on a mass scale. This not only explains why faux-carbon fiber (or “carbon-look”) parts have become so common but also why carbon fiber components are typically reserved for vehicles — and whatever other offerings — on the more elite end of the spectrum.
Working With Modern Carbon Fiber
Most rolls of carbon fiber fabrics can simply be cut with a utility knife, razor blade, or sharp scissors — assuming the sheet is less than 0.5mm thick. For pieces that aren’t that thin, you’ll need to use a powered cutting tool like a Dremel, small angle-grinder, or cutting wheel. Water-jetting and CNC-machining are also popular methods for cutting and/or working with thicker carbon fibers.
Chopped & Marbled
Exploring Forged Carbon Fiber
While it was at one time markedly less common, forged carbon fiber (also known as a “forged composite”) has become increasingly popular in recent years. Forged carbon fiber can be traced back to a collaborative effort between noted club company, Callaway and Lamborghini. Used by the golf outfit for its club and utilized by the elite auto marque for a variety of components including a forged carbon monocoque chassis (as seen on its Sesto Elemento concept), forged carbon fiber is made from a paste of finely cut up fibers — half-a-million turbostratic fibers for every square inch — that are combined with a resin that can be mixed and then formed into the desired shape.
Though forged carbon fiber doesn’t offer nearly as impressive tensile ratings or strength as normal carbon fiber, it can be utilized in a more structural capacity that allows it do perform applications that traditional pre-preg weaves can’t. It can also be manufactured at a much cheaper cost than traditional carbon fiber. Forged carbon also sports a unique “marbled carbon” appearance.
The Benefits & Characteristics Of Carbon Fiber
There are a number of traits that, when combined, have made carbon fiber such a popular choice in high-performance applications. Like steel, carbon fiber’s high carbon content gives it incredible strength, albeit carbon is a whopping five-times as strong, while also offering close to seven-times its resistance to stretching. Boasting superb stiffness and tensile strength despite its minimal weight, carbon is also renowned for its minimal thermal expansion, its chemical resistance, and its overall ability to withstand extreme heat. Lighter than both aluminum and glass, carbon fiber also never rusts and, unlike steel, isn’t prone to failure due to prolonged fatigue.
Harnessing Strength & Lightness
The Modern Applications And Uses Of Carbon Fiber
Because of carbon fiber’s aforementioned properties, the material is highly-conducive to a number of modern applications. Just like in the infancy of modern carbon fiber, the stuff continues to be a go-to choice in the aerospace and aviation industries. Modern commercial freight and passenger airliners feature main wings, tails, and bodies that are primarily composed of carbon fiber composites, allowing them to be lighter and more fuel-efficient. NASA recently filed a patent for a carbon fiber-reinforced phenolic composite for thermal protection systems — just one of several uses by the organization.
For the same reasons, carbon fiber is incredibly common in the high-performance motorsport sector, with the material being used liberally on sports cars and motorcycles — especially competition and track machines. The same goes for auto racing helmets which are often made of carbon fiber. On top of commonly being used for bodywork, heat-shields, and mufflers, carbon fiber is also used to make wheels, suspension components, and even entire frames such as on a number of the world’s fastest supercars and on ultra-elite two-wheelers like BMW’s HP4 Race and Ducati’s Superleggera models.
In recent months, the engineers over at Hennessey Performance Engineering managed to deliver a new all-carbon fiber chassis for its 300mph Venom F5 model (pictured directly below) that tips the scales at just 190lbs — which is roughly on par with the weight of the average American male. Recent years have also seen companies like Ford and Lamborghini experimenting with producing the lion’s share of engines from carbon fiber, including the cylinder block, head, con-rods, oil-pan, and front cover, though thus far the temperatures inside of an internal combustion engine are too great for this application to be fully realized.
Non-Motorsport & Aerospace Uses For Carbon Fiber
Its weight and strength have also made carbon fiber popular in numerous military applications, including for helmets and other protective products, the wings on drones and other UAV’s, to various weapons applications. The stuff also appears in the medical field. The material is commonly used by radiologists as it shows up as black on X-rays. Carbon has also become an increasingly popular choice for use in prosthetics. Knives are another popular segment in which carbon fiber — in both its woven and forged forms — is utilized for the handle material.
In the workwear sector, carbon fiber is now used in the shanks of (what were previously steel-toed) boots and is quickly becoming the most common material used for hardhats. Sporting goods are another area that has seen a massive influx in the use of carbon fiber. Everything from golf clubs and fishing poles to lacrosse and hockey sticks, to canoes to snowshoes, to tennis and ping-pong rackets. It’s also incredibly common to see carbon fiber used in the high-end bicycling segment.
The overall complexity and cutting-edge nature of carbon fiber — which is helped along by its unmistakably trick aesthetic — have also made it a popular material for appliquétions that don’t necessarily require the material’s remarkable strength-to-weight ratio or tolerance to excessive heat. Instead, carbon is used to spruce up products and make them more attractive and desirable. This includes carbon fiber watch components, wallets, pens, key-chains, etc. Carbon fiber is also used in vehicular applications to help achieve a more exotic and overall more desirable product, such as in carbon fiber interior trims and for protective elements on motorcycle riding gear.
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