Making Your Own Prepregs
Composite materials that are used as reinforcements can be impregnated with resin ahead of time, are called prepregs. You use a prepreg in manufacturing different composite parts by cutting it out and laying it onto your mold, shaping as required. Since it has already been impregnated with resin, there are not any concerns with spreading the resin and curing agents on the dry materials while they are in the mold.
Pre-impregnated materials can be purchased from a composites supplier, or they can be made yourself. Woodward Aerospace shows us how.
Carbon Fiber Pipe Wrap
Carbon Fiber can be used to wrap the outside or the inside of pipelines as a way to reinforce and strengthen them. Carbon Fiber is lightweight yet extremely strong. It can be field-installed on pipelines that are clean and non-pressurized.
Repairs to pipelines can be extremely expensive if they need to be dug out of the ground, cut out, and replaced with new sections. This is time-consuming work requiring long shutdowns. Composites repairs can be accomplished by professionals that can access the work area and have a line that is non-pressurized and clean.
These carbon fiber reinforcements help to restore structural integrity that has been lost through age, damage, or other new design requirements. There are many advantages to repairing existing pipelines and other structures rather than replacement.
Interior repair from ABC 10 News in California demonstrates an interior pipeline repair:
An external pipeline repair is shown here in an instructional video. I do have a few concerns about the use of all of the unreinforced resin that is used to cover the carbon fiber wrap. I am not sure what the purpose there is, other than maybe to protect the carbon fiber from future damage.
Compression Molding Large Vehicle Parts
Compression molding with composite resins can yield very durable, strong, and well-engineered parts.
Placing reinforcements (usually fibered glass) and resin in a heated metal mold before compressing it under high temperatures will result in a finished piece with very unique properties. The parts made in these matched metal molds have very repeatable properties, high strength to weight ratios, and are corrosion and chemically resistant. The parts can be painted, and have many positive design attributes.
Ashley Industrial Molding is a company that manufactures such parts. These large parts are made with compression and RIM molding for customer such as John Deere and Case tractors. They have a good video demonstrating their equipment, processes, and finished parts.
Auto Racing Composites
Roush Racing takes us viewers on a tour through their composites shop in a short clip from Roush TV.
Using mostly carbon fiber and kevlar reinforcements, Roush Racing fabricates many different components for the racing industry using epoxy resin systems. Ranging from the front noses for the NASCAR Car of Tomorrow car to drag racecar bodies and small ductwork, Roush Racing’s composites shop does all sorts of fabrication.
The race shop includes two different fabrication processes. Wet layup vacuum bagging is used for some parts, while others are made using prepreg material that goes into an autoclave.
The video tour is well done, and includes everything from the Eastman material cutter to the fabrication process, bagging process, and trim. We also get to see some of the finished parts after they are demolded and trimmed.
These parts are very expensive to manufacture, due to the high cost of materials and labor. Tooling and equipment costs for this type of process are somewhat reasonable, with the exception of the autoclave and the automated cutting table. Composites fabrication of this caliber is labor intensive, but can produce very unique parts that are lightweight and strong.
Cirrus Composite Airframes
I found a very interesting Youtube peek inside of the Cirrus airplane assembly factory in Minnesota. While it would be cool to learn more about the actual composites fabrication of the individual parts, there is some great information about part bonding, inspection, and final assembly of the Cirrus aircraft. They use fiberglass and carbon fiber reinforcements to create a very strong and durable fuselage, and it is great to see in action.
Personal jets made of composite materials offer many advantages and unique properties. Design of complex shapes and anti corrosion of aluminum are two advantages. Disadvantages include repeatability and upgrading/modification.
Composites that are properly designed and fabricated can be used in many applications where safety is a big concern. Proper design and inspection during production can create an airplane that can be easily maintained and have a very long life.
Great factory tour courtesy of Aero-TV:
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