Monday 19 February 2018
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British Research to Focus on Improving Prepregs

The British aerospace industry wants to find ways to make fabricating the largest airplane parts easier, faster, and more efficient when using composite materials. The British government wants to help them. As a result, public and private sector partners are on the verge of launching a $10 million research project accompanied by expanding a major manufacturing facility in Leicester, England.

Hexcel, a British composites technologies firm, is working with the UK Aerospace Technology Institute and the Department for Business Energy and Industrial Strategy to implement what is known as the MAXIM project. The four-year project aims to change the way the aerospace industry uses prepregs to create large aircraft parts like wings and bodies. If they succeed, they will open new doors to using prepregs in ways that have never been economically feasible before.

Current Manufacturing Practices

Manufacturing processes currently employed by the aerospace industry are effective enough, but they are not very cost-efficient or fast. For example, an aerospace company looking to manufacture aircraft wings using prepregs must use a high-pressure machine known as an autoclave to finish the process. An autoclave combines pressure and heat to remove excess resin and cure the composite material over time.

For the record, prepregs are composite materials that have been impregnated with resin by the manufacturer before being packaged and shipped. When an aerospace fabricator uses prepregs, they do not have to go through the long and arduous manual layup process. They simply lay prepregs into a form and send the form to an autoclave.

The challenge with this process is that it prevents manufacturing highly complicated parts quickly and efficiently. The MAXIM project aims to change things by finding new ways to use carbon fiber forms and different resins for manufacturing large, complex parts without the need for autoclaves.

Size Makes the Difference

At Rock West Composites outside of Salt Lake City, Utah, manufacturing prepregs is part of their daily operations. They currently produce 20 different lines of prepregs supporting a variety of industries from aerospace to manufacturing. There are no concerns at Rock West that research might make prepregs obsolete. Indeed, the British research is not looking to take prepregs out of the process. Rather, the intent is to find more efficient ways to use them.

Rock West explains that size really makes a difference. When manufacturers work with prepregs to fabricate something as small as a car door panel, use of an autoclave is not a big deal. The autoclave does what it is supposed to do in a relatively short amount of time, and the finished product is ready to be used almost immediately after heat curing is complete. By comparison, that same part fabricated via a manual layup process would require about 48 hours of wait time to allow complete curing.

Where the aerospace industry is running into problems is with much larger, more complex parts like aircraft wings. An aircraft wing made of composite materials will not fit in the same small autoclave used to cure a car door panel. Furthermore, the outside skin of the aircraft wing has to be fabricated around a whole host of internal components. This requires more care where the autoclave is concerned.

The consortium behind the British research is confident that the $10 million spent over the next four years will be well worth spending. They believe they can come up with better ways to use prepregs in aerospace fabrication and, in so doing, make things faster, more cost-effective, and greener. Now let’s see if they can actually pull off. It will be a game-changer if they do.