Composite materials are being increasingly specified in aircraft structures and components, with Boeing's 787 Dreamliner currently featuring composites structures for over 50% of its structure, including the fuselage. This allows dramatic savings in weight allowing corresponding improvements in fuel economy.
The Hyde Group was founded in 1968 and is a leading global company with many years of experience of project management, design, production and support aspects of aircraft tooling. The scope of its tooling capabilities ranges from automated assembly systems, including robotic integration, bespoke machine tool design and manufacture, major assembly jigs, sub-assembly and all facets of detail tool manufacture from simple rubber and fluid press tooling to sophisticated lay-up tools and super plastic form tools.
It carries out extensive research and development projects and programmes for aircraft manufacturers and one such project involves the forming of multi-ply, pre-preg composites. Multi-ply composite assemblies are rigid by nature and, consequently, they must be softened if they are to be formed into specified profiles on moulding tools before curing in autoclaves. Hyde's project engineers investigated various heating techniques to achieve the required softening of the multi-ply assemblies. The softening process was first investigated using hot air guns but warm air ovens were rejected as a solution because of their space requirement and oil-heated mould tools were considered to be potentially contaminating in a process which demands extreme cleanliness.
Eventually, after successful tests at Heraeus's Neston Applications Centre, it was decided to use a fast-response, medium wave infrared heating system. This is installed in a robotic cell and the multi-ply assembly is located in front of the 6 kW infrared emitter by two robots, heated to around 70ºC until it is suitably pliable and then laid on the moulding tool, where specially designed rollers ensure that it follows the tool profile.
"We had used infrared previously to assist in glueing processes," explains project engineer, Matt Garner. "We have been very pleased with their precise controllability and compactness in this new important project."
Process Improvement by Exact Matching Infrared heating technology offers various possibilities to optimize industrial processes:
- High heat transfer capacity
- Contact-free heat transfer
- High efficiency
- Efficient energy transfer by selecting optimum wavelengths
- Spatially focused application of energy by matching the heating to the product shape
- Fast response times to reduce energy consumption
Consequently, infrared heat is always used when heat processes are to be implemented which require particular targets in terms of space, time or quality.
Source: Heraeus Holding GmbH