“3D weaving of composite fabrics can produce complex, single-piece structures that are strong and lightweight. Compared to traditional 2D fabrics, 3D weaving reduces weight, eliminates the delamination often experienced with 2D fabrics, reduces crack risks, and lowers production time. 3D fabrics also offer direct and indirect manufacturing and operational cost reductions,” said Mark Harries, Marketing Executive, Bally Ribbon Mills.

In 1991, Bally Ribbon Mills (BRM) received a research contract from the United States Air Force Research Laboratory that started the company on the path to developing the requisite technology for 3D weaving. The experience gained from researching and building the first fully automated 3D bias loom, gave BRM the knowledge and experience to develop other 3D woven composites for the aerospace, automotive, construction, military, and safety industries.

Benefits

“3D woven composites are drastically lighter than metal structures. This is particularly relevant to the aerospace industry. Every pound of weight saved from an aircraft is estimated to save the aircraft’s operator roughly US$ 1 million in operating expenses, primarily fuel, over that aircraft’s lifetime. Smart utilisation of 3D woven composite structures in aircraft design can reduce the weight of an aircraft by up to 30 percent, resulting in considerable operational cost savings,” continued Harries.

Delamination occurs when two or more layers of a 2D woven composite come apart, or delaminate, from each other. “3D weaving can produce near-net-shape composite structures that are fully interconnected by their yarn, as opposed to 2D composites which include a number of different layers of materials artificially bonded together. This means there is no risk of delamination in 3D woven composites,” added Harries.

“Utilising 3D woven composite structures in place of traditional metal or 2D laminated composites can provide cost savings through both the manufacturing process and the product’s operational lifetime. Automated 3D weaving technology and near net shape capabilities reduce direct labour and secondary machining costs,” commented Harries. “Indirect cost savings result from operational cost savings, for example reduced fuel.”

Lower production times

2D composite production is a long and precise process. By contrast, 3D weaving of composite structures is simpler, faster, and more cost efficient. Similar to 2D looms, 3D weaving looms weave weft and warp yarns along the X and Y axis. The difference in a 3D loom is that instead of the fabric continuing along the Y axis, it builds upon itself vertically – weft and warp yarns are not only woven together on one plane, but one plane is woven together with the next.

Aside from designing a 3D weave, which requires highly skilled design engineers, the 3D weaving process is fully automated and results in net shape or near net shape parts. This dramatically reduces manufacturing time despite the increased complexity of the 3D weaving process.

By weaving entire structures in 3D, the slow and costly plying process – the longest and most costly portion of manufacturing a 2D laminated composite structure – is completely eliminated, significantly speeding production and lowering cost.

Applications

Using polymer composites within aircraft engines has long been a challenge, thanks to the high temperatures and complex geometries involved in aircraft engine manufacture. 3D weaving has been particularly successful in advancing aviation heat shield technology. Thermal protection systems (TPS) are mission-critical components in space exploration vehicles. The ability to vary yarn types, density, thickness, and width, as well as resin type, allows for the creation of a fully customizable TPS to fit specific mission needs.

Quartz compression pads, for example, have been woven by BRM for the Orion capsule in order to ensure structural strength during launch and heat resistance during re-entry. Additionally, NASA’s Heatshield for Extreme Entry Environment Technology (HEEET) programme is developing a carbon TPS for extreme entries, intended to be capable of surviving the challenging environments of Saturn or Venus. Both these technologies are being developed through extensive additional research, but both rely on the basic principles and strengths of 3D weaving.

www.ballyribbon.com