The Heraeus infra-red system at GKN.
The Heraeus infra-red system at GKN.

The infra-red system was custom-designed in cooperation with GKN Aerospace engineers following initial tests at Heraeus’ Application Centre in Neston, Wirral.

GKN Aerospace has invested £170 million in its new composite wing structures manufacturing and assembly facility. An important work package already underway at the Western Approach site is the manufacture of the composite rear wing spars for the Airbus A350 XWB.

Each of the three rear wing spars is manufactured by laying up carbon fibre prepreg tape on a mandrel and then curing the assembly in an autoclave. However, this operation can sometimes produce wrinkling of the final surface because of voids and excess resin between plies or laminates. One answer to this problem is de-bulking, which involves enclosing the composite structure in a vacuum bag at various stages in its manufacture and then compacting or squeezing out of air and volatiles between plies or prepreg laminates under moderate heat and vacuum.

GKN Aerospace decided that de-bulking could provide significant benefits and asked Heraeus to carry out initial trials using infra-red emitters to provide the required heat. These were followed by on-site trials using a portable infra-red system at Western Approach. A prototype system was then supplied.

This prototype system was finally replaced by a scaled-up 465 kW production system, where each of the three heating sections now has seven controllable zones to provide precise surface heating.