Manufacturing breakthrough makes carbon fibre more flexible

Using carbon fibre to reduce car weight has been limited to high-end vehicles thanks to its prohibitive cost, and it has had few applications even within that field.

But a new manufacturing technique could open the way to more widespread use of the material. Traditional carbon fibre is made by weaving fibres into a perpendicular arrangement and then cutting the resulting fabric into the shape required. Instead, tailored fibre placement (TFP) arranges the fibres into bundles to provide strength exactly where it’s needed, and stitches them into position on a compatible base layer. This can cut fibre wastage to just 3% instead of the usual 30-70%. 

Faster manufacture

German supplier ZSK says it has improved on the technique further with innovations that reduce stitching time, and double the deposition rate. It can also be used to comingle other fibres with carbon fibre. “The demand for lightweight materials, to improve CO₂ emissions and product performance as vehicles become heavier and more complex, has never been greater but the cost of composite manufacture has remained unaffordable in all but niche applications,” says Melanie Hoerr, manager for technical embroidery at ZSK. 

“Our approach using TFP breaks through that barrier by eliminating most of the manual processing and waste of conventional composite manufacture, while increasing design freedom and improving quality control.”

The technology was put through its paces to create complex composite bodywork for Elemental’s RP1 car. TFP enabled creation of a complex 3D shape that would have been difficult to make out of carbon fibre using traditional methods. 

Complex curves

 “TFP changed our view of how carbon composites could help to achieve weight and cost targets,” says Elemental’s composites manager, Peter Kent. “It created pre-forms very quickly, is cost effective, and very durable. The rear bodywork on the RP1 is tough enough to withstand impacts such as extensive stone chips and has a complex 3D shape with compound curves. This is at odds with the traditional qualities of carbon-fibre parts.”