The University of Sheffield's Advanced Manufacturing Research Centre (AMRC, Sheffield, UK) reports that it has invested £150,000 in an FT Dornier rapier loom, specially designed to weave fibers without the risk of the highly electrically conductive carbon fibers causing it to short circuit.
In the past, says AMRC, team members have been limited to using commercially available woven reinforcements. The new capability means AMRC will be able more aggressively research processes like resin transfer molding (RTM). “Resin transfer molding is a bit of a ‘dark art,’” says the AMRC Composite Centre’s Dr. Jody Turner. “RTM is supposed to be a very rapid and highly production-orientated process, but getting it right can involve trial and error. Sometimes the resin doesn’t penetrate all of the material and parts of the component are left completely dry, which makes it useless. We plan to carry out research that will help us to understand more about what happens during RTM injection and why results can be so erratic.”
Composite Centre researchers have already been studying how resin flows through fabrics made from carbon fiber and found the resin flow through the fabric isn’t symmetrical, despite the weave pattern being perfectly symmetrical. They believe this may be a result of slightly differing yarn tensions within the fabric.
Now researchers hope to increase their knowledge by experimenting with different tensions for the warp – the long continuous threads – and the weft – the thread that is fed across the loom between the warp threads to create the woven material.
“If we can control warp and weft tension we might be able to influence resin flow,” says Turner. “We also want to push the machine to the limit of its capabilities. For example, it isn’t designed to produce three dimensional structures, but we are hoping to create structures like pockets and flaps.”
AMRC says that if researchers are successful, they could be able to weave materials that could be opened up to form a series of boxes or a honeycomb structure that would give the completed composite component additional strength.