Performance and rate of production comparison for HexMC® versus other technologies. (Source: HexMC User Guide.)
Performance and rate of production comparison for HexMC® versus other technologies. (Source: HexMC User Guide.)

As new aircraft designs move increasingly to composite primary structures, a number of smaller complex parts are required to connect them to the various system components, Hexcel explains. In the past these parts have been machined, cast or forged from aluminium or titanium and could not be made from composites in a cost-effective way.

HexMC is designed for compression moulding and applications include window frames, brackets, fittings, clips, and static guide vanes.

High volume components

The mould design and technology for HexMC are similar as for sheet moulding compound processing, reports Hexcel.

HexMC is delivered in rolls. It is cut, stacked or rolled to form a mould 'charge.' This is placed inside the compression mould. Under temperature and pressure, the material flows and fills the mould, and then cures. 

Depending on the specific part to be moulded, the moulding pressure is between 50-150 bars at a temperature between 110-125°C.

The exact curing conditions are dependant on tool and part design. Typical cure cycle is 15 minutes at 120°C.

HexMC can be combined with a prepreg and/or laminate to increase the strength and stiffness of the part.