Hexcel will be promoting its latest carbon fibre and composite technologies at Composites Europe 2014, in Stuttgart, Germany, from 7th to 9th October 2014. Hexcel will show how innovations in carbon fibre, prepregs and weaving technologies are transforming composite structures in aerospace, automotive, wind energy and marine markets.
Hexcel is promoting its proven fast cure system HexPly® M77 that meets the needs of large volume manufacturers in the automotive and sports goods industries, offering a 2-minute press-cure cycle at 150°C (80 bar pressure). With HexPly® M77 Hexcel has a product that is already addressing the challenges posed by very high volume production in the automotive industry. The low tack of HexPly® M77 enables the prepreg to be cut into precise shapes by laser cutter. For automated processing the individual plies can be oriented, assembled and consolidated into a flat preform by robot. Once in the mould HexPly® M77 has an optimized gel time that allows the resin to flow into the contours to produce the precise geometries required. The high Tg of 125°C enables the cured parts can be demoulded while hot for a faster production cycle. HexPly® M77 snap cure prepreg benefits from a 6-week outlife at room temperature and is available in various forms including unidirectional or woven reinforcements and heavy tow fibres.
HexPly® M77 epoxy resin is also supplied in the form of HexMC®, a high performance carbon fibre/epoxy compound developed specifically for compression moulding processes with a very high fibre volume content providing excellent mechanical performance. HexMC® is ideal for the series production of complex shaped parts with thickness variation, sharp angles or parts that require inserts to be integrated into the moulding process such as screw threads. HexPly® M77 is a suitable alternative to lightweight metals for structural applications, is capable of hybridization to metal and has superior mechanical properties to vinyl esters. Hexcel’s technical support team is adept at providing advice on the processing of HexMC, including mould design.
On Hexcel’s stand at Composites Europe there will be a number of automotive parts including spoilers for the BMW 2 series and BMW 3 series cars and the air intake for the BMW mini made by Benet Automotive s.r.o using HexPly® M49 carbon fibre prepreg. HexPly® M49 is a 120°C curing toughened epoxy matrix with good impact resistance that is self-adhesive to honeycomb and can be processed using a wide range of production techniques. HexPly® M49 also has high aesthetic appeal providing the desired look of real carbon fibre.
Wind Energy and Marine
Hexcel has expanded its prepreg range to meet the requirements for extra-large structures such as wind blades and yacht masts. Hexcel developed HexPly® M79 to provide a faster and lower temperature curing prepreg, with low exothermic reaction for very thick laminates. A number of cure cycle options are possible for HexPly® M79 including a very low temperature cure of 8-10 hours at 70°C or a more rapid cure cycle of just 4-6 hours at 80°C. With previous systems it could take 10 hours to cure a laminate at 80°C. HexPly® M79 also has a very long out life at room temperature of at least 6 weeks. When HexPly® M79 carbon fibre UD prepreg is used in conjunction with Hexcel’s patented grid technology a void content in the cured laminate of less than 1% is achievable, regardless of the part thickness.
On Hexcel’s stand at Composites Europe visitors can see a carbon prepreg laminate consisting of 695 plies of HexPly® M79 600 gsm carbon UD tape with Hexcel’s grid technology. This 400mm thick laminate cured in just 6 hours at 80°C. The very low exotherm of HexPly® M79 allowed the temperature to be increased more quickly in the mould, resulting in a shorter cure cycle. Hexcel will also display a yacht mast made with HexPly® M79 by Mates.
Hexcel’s HexPly® M92 prepreg for aerospace structures combines all the major benefits achieved individually with other 125⁰C curing epoxy resins in one new “multi-purpose” system. These benefits include a hot wet Tg of 115°C, allowing HexPly® M92 to operate at higher service temperatures from a lower temperature cure. The system is self-adhesive to honeycomb, making it suitable for sandwich structures as well as monolithic components. Other benefits include high toughness, fire resistance, low exotherm, a long out/tack life and the ability to cure by vacuum bag.
At Composites Europe Hexcel will display a Helicopter Rotor Hub Cap Fairing manufactured by Airbus Helicopters. This oven-cured part is a honeycomb sandwich structure in which the prepreg is bonded directly to the non-metallic core, without any additional adhesive. Airbus Helicopters estimates that weight savings of 8 to 15% will be achieved by manufacturing this part from HexPly® M92, depending on the helicopter type.
HiTape® advanced dry carbon fibre reinforcements combine the benefits of automated processing with the cost-effectiveness of Out of Autoclave infusion technologies for next generation aircraft primary structures. HiTape® allows preforms to be manufactured in a fully automated lay-up process, with high deposition rates. Parts produced with HiTape® and Hexcel’s HexFlow® infusion resins can be up to 30mm thick with a 58 to 60% Fibre Volume Content, resulting in mechanical properties that are as high as those achieved with primary structure prepregs.
Hexcel has added to its range of IM and AS fibres by launching a new High Modulus carbon fibre, called HexTow® HM63. This new fibre has the highest tensile strength of any HM fibre and provides outstanding translation of fibre properties in a composite, including superior interlaminar shear and compression strength. HexTow® HM63 is therefore ideal for any high stiffness and strength-critical applications including space, satellites, UAV, commercial aerospace and helicopters. It also meets the special requirements for premium sports and recreation applications including F1, marine craft, bikes and fishing rods.
Hexcel Corporation is a leading advanced composites company. It develops, manufactures and markets lightweight, high-performance structural materials, including carbon fibres, reinforcements, prepregs, honeycomb, matrix systems, adhesives and composite structures, used in commercial aerospace, space and defence and industrial applications.