Why are aircraft and spacecraft manufacturers replacing aluminum with carbon fiber? In flight, especially space flight, every ounce matters. Carbon fiber composites are highly flexible and durable materials that weigh about 40% less than aluminum for a similar component.
Composite materials, especially carbon fiber, have revolutionized the way aircraft are designed and built. Their incredible strength-to-weight ratios and advanced structural properties make them crucial in the industry. To manufacture wings and other components from carbon fiber, engineers need efficient curing methods that require heat.
Curing aircraft composites involves heat, pressure, and chemical processes to achieve the desired structural rigidity and material properties. This article will reveal what carbon fiber is and how this product is making the aerospace industry more competitive.
Understanding Composite Materials and Their Role in Aerospace
Composite materials used in aerospace incorporate two or more base materials, such as sheets of woven carbon fiber and epoxy resin. These composite materials offer exceptional advantages over traditional materials, like aluminum, because they exhibit enhanced strength, reduced weight, and improved corrosion resistance.
Here is a comparison table between conventional and composite materials.
| Traditional Materials | Composite Materials |
| Heavier | Lighter |
| Less durable | More durable |
| Lower strength | Higher strength |
| Less resistant to corrosion | More resistant to corrosion |
| Slower manufacturing process | Faster manufacturing process |
| Less environmentally friendly | More environmentally friendly |
| Lower performance | Higher performance |
Aerospace and aircraft design have experienced significant benefits from carbon fiber composites. Carbon fiber is two times stiffer and five times stronger, yet lighter than steel. These properties allow for the creation of lightweight, high-strength components and structures.
Carbon fiber composites allow aircraft manufacturers to mold and optimize the design of various parts. Flexibility in the design of new wings, fuselage, and control surfaces results in improved performance, increased payload capacity, and enhanced durability. For example, modern jets use an upturned wing tip made with carbon fiber. This innovation alone increases fuel efficiency by up to 5%. Overall, composites can reduce the weight of an aircraft by up to 20%.
Innovations in Curing Technology for Aerospace Applications
Curing transforms the flexible carbon fibers into high-strength, hardened structures we call composites. Efficient curing methods ensure even heat distribution and prevent the formation of air bubbles. Here are some of the latest curing technology and tools.
- Ambient Temperature Curing: Some resins can cure at room temperature. However, vacuum bags can help remove air bubbles for better compaction and denser material.
- Electric Curing Blankets: Electric custom curing blankets have revolutionized the composite curing process. These blankets provide even heating across large surface areas, ensuring that the epoxy resins cure uniformly at the optimal temperature.
- Press Curing: Compression molds use heat and pressure to mold complex shaped parts.
- Autoclave Curing: Bulky vessels use high pressure and heat to cure the parts inside. Temperatures can be controlled to 1 degree. Autoclaves create perfect surface quality, resulting in the highest quality parts for aerospace projects.
- Oven Curing: Higher temperatures result in faster curing for oversized parts or batch-producing many smaller parts. Learn more about epoxy and carbon fiber curing ovens.
- Customized Solutions: Working with large parts like curing wind turbine composites or aircraft parts requires a unique approach. Companies like Powerblanket offer epoxy curing blankets with customizable sizes, wattage, and voltage to cater to the unique needs of aerospace manufacturers. Download the epoxy blanket spec sheet for more details. These tailored solutions can optimize operations, reduce costs, and streamline production processes.
Proper curing solutions lead to improved mechanical and heat resistance properties, resulting in stronger and more reliable components.
Modern Curing Methods for Carbon Fiber Composites
Traditional curing methods, such as autoclaves, ovens, and vacuum bags, have been the standard for many years. However, advancements in curing technology have led to the development of new curing methods, such as curing blankets.
Autoclave cure involves placing the composite in a pressurized oven, where it is subjected to high temperatures and pressure. This method ensures even heat distribution and rapid curing, resulting in the smoothest surfaces and high-quality composite materials. However, it can be expensive, time-consuming, and has a limited size.
Vacuum bagging involves placing the composite in a bag while applying heat and creating a vacuum to remove voids. This method is cost-effective and used for smaller parts. Other methods include radiation curing, thermal curing, induction heating, ultrasonic heating, resistance heating, and thermal additives. Most of these methods are still in development for large-scale manufacturing.
The latest method for curing wind turbine composites and other oversized parts is curing blankets. Epoxy-curing blankets lay on top of the surface or wrap around to distribute heat evenly. They are lightweight, portable, and customizable, making them an attractive option for aerospace manufacturers.
Practical Applications of Curing Technologies in Aircraft Manufacturing
Whether repairing a section of composite or building a new part, uniform heat is essential to the success of the process. Typical repair patches and larger sheets of carbon fiber laminates come pre-impregnated (carbon fiber prepreg) with resin requiring heat between 250°F to 350°F (121°C to 176°C) for proper curing.
The aerospace industry has adopted electric curing technologies, like curing blankets and hot bonders. They support “out-of-autoclave or oven” processing and are instrumental in remote repairs. Epoxy-curing blankets enable manufacturers to achieve the optimal curing conditions for composite materials without the added cost or footprint of autoclaves or ovens.
Optimizing the Curing Process:
The goal of curing carbon fiber components is to create a product without defects.
Here are best practices for selecting suitable curing methods and equipment, monitoring process parameters, and post-curing treatments.
Curing Process Tips:
- Ensure that the production system exceeds limitations such as the maximum allowable heating rate and the maximum allowable cooling rate.
- Monitor process parameters, such as maximum temperature of the part, pressure, and curing time, to ensure that the composite reaches the desired level of strength and durability.
- Post-curing treatments can enhance the composite’s properties by up to 20%. It is the process of adding heat to the part within 12 hours of the initial cure.
Following these tips helps engineers optimize the curing process and achieve the best possible results for aerospace applications.
FAQs on Curing Carbon Fiber Composites
If you have questions about the curing of carbon fiber composites, we have some answers for you.
1. How Do You Cure Carbon Fiber?
The two primary methods for curing carbon fiber composites are “In-Autoclave” or oven, or “Out-Of-Autoclave.” An autoclave is a large vessel that generates high heat and pressure inside to cure the components. An oven uses high heat at standard pressure.
Out-of-autoclave methods include air drying, heating blankets, and vacuum bagging. Vacuum bagging is a technique that encloses the part in a bag and then removes the air to create a vacuum to increase pressure and remove voids between layers.
2. How Long Does Carbon Fiber Take to Cure?
Resin curing times for carbon fiber composites will vary depending on the part’s size and thickness, the type of resin used, and the temperature. Typically, the curing process takes several hours to complete, with some parts requiring overnight curing.
3. Does Carbon Fiber Require Heat to Cure?
Yes, heat is an essential component of the curing process for carbon fiber composites. The application of heat, combined with pressure, accelerates the chemical reaction between the resin and the carbon fiber. The reaction results in a strong and durable composite material.
4. Do You Need an Oven to Cure Carbon Fiber?
Oven curing is one of the most common methods for curing carbon fiber composites, but it is not the only option. Alternative methods include curing blankets or autoclave curing. The choice of curing method depends on factors such as the size and complexity of the part, the desired properties of the final product, and the available equipment and resources.
As the aerospace industry evolves, advancements in composite materials and curing technologies will shape the future of aircraft manufacturing.
The Future of Aerospace Composites and Curing Technologies
The aerospace industry is continuing to seek ever lighter and stronger composites to build the latest generation of aircraft and spacecraft. One of these super lightweight materials is Carbon Nanotube (CNT) reinforced composites. This material is suitable for nuclear thermal propulsion (NTP) and structural elements of the Lunar/Mars space vehicle. Carbon nanotubes are chemically bound carbon atoms shaped like cylinders. Although they are less than 1/80,000 the diameter of human hair, they are about 100 times stronger than steel and approximately eight times lighter.
New curing methods in development or already in use include direct electric, microwave, induction, and radio frequency heating. The end result will be faster manufacturing times at a lower cost.
Embracing Innovation for Aerospace Excellence
By adopting these innovations, aerospace businesses can ensure the highest quality in aerospace composites and maintain a competitive edge. Advanced curing tools and techniques are essential in aerospace manufacturing, enhancing material quality and reducing costs.
Embracing innovation is vital to achieving aerospace excellence. Upgrade your epoxy resin curing process with Powerblanket and experience faster, easier curing. Discover Custom Curing today.
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