Automated fibre placement technology wins hands down for manufacturing complex composite components for the F-35 fighter aircraft
Albany Engineered Composites (AEC) has received a contract with Lockheed Martin to manufacture composite wing skins on a state-of-the-art automated fibre placement machine at its Salt Lake City operations. As a result of this and several other significant investments in technology and resources, AEC will be producing the wing skins for the F-35A (conventional take-off and landing variant) of the Lightning II fighter jet.
AEC currently fabricates 227 unique parts for the F-35 programme, delivering highly engineered products to 4 customers and 5 facilities including international locations. To date, AEC has delivered over 40,000 parts to support the F-35 programme and delivery of the latest wing skins began in January 2020.
According to Greg Harwell of AEC, a great deal of hard work and investment was put into the development of the fibre placement technology and this has now been rewarded with the new contract with Lockheed Martin.
“We are now able to supply additional part numbers and volume beyond our existing successful relationship with this strategic customer and we look forward to continuing to develop and deliver advanced composite technologies to the next generation of aircraft,” says Harwell.
Used extensively by allied forces, the Lockheed Martin F-35 Lightning II has three variants for conventional take-off and landing, short take-off and landing or for aircraft carrier operations.
Automatic Fibre Placement
The latest and most advanced method for fabricating composite structures, Automated Fibre Placement (AFP) makes use of continuous fibre reinforced tape, which is fed to a robot, which places the fibre material onto the structure to build it up by one ply or layer at a time.
By using the fibre method rather than sheets of material, highly customised and complex parts can be fabricated. This is because each layer can be placed at different angles to optimise load carrying capabilities. The use of robotics gives the operator active control over all of the process critical variables, making the process highly controllable and repeatable.
The narrow tape strips are referred to as “tows” and are typically up to 6.25mm wide with up to 32 tows being used in each ply of material. ITC (Individual Tow Control) is frequently used so that each line can be managed individually and can be started or stopped at different points along the band. This reduces scrapping levels and enables highly complex surfaces to be achieved if required.
Under robot control, the process is very repeatable and can be defined in very fine increments. As the robot lays the tows, a heat source and pressure device provide the bonding mechanism. The robot progresses tow by tow until one layer has been completed before moving onto the next layer. This way, the robot builds up the component layer by layer until it is complete.