When carbon atoms bond together and form a chain, it is called carbon fiber. The fibers can be stiff, lightweight, and extremely strong. As a result, the common use of carbon fiber panels is to create durable building materials.
Carbon fiber materials are available in the form of building blocks such as braids, yarns, etc, which are also used to derive composite parts. Carbon fiber has properties similar to steel, while its weight is close to plastic. Hence, the ratio of strength to weight is higher than both steel and plastic. As carbon fiber is extremely strong, it is typically used in engineering for maximum benefits.
The process of machining carbon fiber sheets is complicated. Each composite has unique properties, which include:
- Lightweight (at least 40% lighter than sheets made of aluminum)
- Five times stronger than steel
- Low thermal expansion
- Neat appearance
- Dampens vibration
These attributes are the reasons for the rising popularity of carbon fiber in civil engineering, aerospace, motorsports, military, and other sports. However, compared to simple fibers like plastic or glass, they are relatively more expensive.
Properties of Carbon Fiber
High Strength to Weight Ratio (Specific Strength)
The force per unit area at failure divided by density determines the strength of any material.
Any strong and light material has a favorable Specific Weight. Materials like aluminum, magnesium, titanium, glass fiber and some steel alloys have excellent strength/weight ratio.
Carbon Fiber is Rigid
The Young Modulus of material is used to measure its stiffness or rigidity. It also measures how much the material deflects under stress. It is observed that carbon fiber reinforced plastic is four times stiffer and stronger than glass-reinforced plastic; twenty times more than pine and 2.5 times more than aluminum.
Chemically Stable and Corrosion-Resistant
Carbon fiber does not deteriorate. However, Epoxy is a type of carbon fiber that is sensitive to sunlight.
While it is an excellent properly, it could cause issues too. For instance, when building a boat using carbon fiber conductivity could facilitate galvanic corrosion in the fittings. If the installation is done carefully, this problem can be reduced.
Carbon fiber composites are fatigue-resistant. However, when carbon fiber fails, it is a disaster. Tensile fatigue damage is observed, which reduced stiffness with multiple stress cycles. Tests showed that failure is not a problem when fiber orientation coincides with cyclic stress. Carbon fiber is much superior to E glass in static strength, stiffness, and fatigue.
Exceptional Tensile Strength
Tensile strength is the maximum strength material can bear under stress – when pulled or stretched, before necking or falling.
Depending on the process of manufacturing and the precursor material used, carbon fiber could be soft and made into or integrated into protective gear for firefighting. For example, nickel-coated fiber.
As carbon fiber is chemically inert, it is also used when the fire is combined with corrosive agents.
Outstanding Thermal Conductivity
Thermal conductivity is defined as the amount of heat transmitted through a certain unit thickness, in the normal direction to a surface of a certain unit area, because of the unit temperature gradient, under stable conditions. Precisely, it is the measurement of how easily heat can flow through a certain material.
Lower Co-efficiency of Thermal Expansion
This measures the expansion and contraction of a material when the temperature increases or decreases. Because carbon fiber is a low coefficient, it is suitable for all types of applications where there could be small movements. For example, telescope and, similar optical machinery.
Non-Poisonous & Biologically Inert
These traits of carbon fiber make it useful for medical applications. Implants, prosthesis use, tendon repair, x-ray accessories, surgical equipment can be developed with carbon fiber sheets.
Carbon Fiber is Brittle
Strong covalent of autoclave composites form the layers of carbon fiber, which makes it brittle. When carbon fibers bend, they fail at a low strain.
Common Applications of Carbon Fiber
Based on characteristics, carbon fibers have several applications.
Physical strength, lightweight, and toughness of carbon fibers make it appropriate for aerospace, sporting goods and marine transport.
Due to its high dimension stability, low abrasion, and low coefficient of thermal expansion, it is used in missiles, aerospace antenna, aircraft brakes, support structure, large telescopes, waveguides for high-frequency precision measurement frames and stability, optical benches.
Its good vibration damping, toughness, and strength make it an appropriate choice for audio equipment, pickup arm, loudspeakers, and robot arms.
Owing to the biological inertness and permeability to x-ray, it is widely used in medical applications like x-ray equipment, tendon/ligament repair, prostheses, and implants.
The fatigue resistance, high damping, and self-lubricating properties of carbon fibers make it suitable for textile machinery and general engineering.
Carbon fiber also has electromagnetic properties. It can be used in radiological equipment and large generator retaining rings.
Carbon fiber’s chemical inertness and high corrosion resistance qualities make it suitable for the chemical industry and nuclear field. It is used to manufacture seals, valves, pump components etc.
Machining Carbon Fiber Sheets – The Process
There are common methods to process and shape carbon fiber panels. It can be drilled, milled, sanded, and sawed. Cutting tools and blades wear out fast as carbon fiber is highly abrasive. In addition, it creates dust particles, which should be collected and further disposed of to ensure the workers, as well as machinery, is protected.
CNC milling machine is the right choice for complex design processing. This allows precise and fine cutting and shaping; it is possible to make small indents and holes too.
Water jet cutting is another method, which is faster than CNC milling. However, it yields a low-quality result.
The last method is laser cutting, which is, again, not the best -fitting cutting technique, as it is difficult to find a good quality surface.
How are Carbon Finer Composites Joined?
Joining composites is a detailed and intricate process, more complicated than joining two metal parts. As composites can neither be threaded nor welded, gluing is the only option. The structural adhesive is an excellent method of bonding.
The glue creates a permanent strong bond between components. Adhesives also have a greater advantage; it serves a bigger surface area and maintains even load. Gluing does not cause bending or inner tension, compared to threading and welding.
Laminating is another option; the process takes time, but gives strong and even load. It is a great choice for larger composite sizes like reservoirs and containers.
Lastly, screws, bolts, and rivets can be used to join carbon fiber sheets. This is the easiest and simplest method of joining.
Carbon fiber panels have multiple uses. However, its functions depend on the traits.