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Insight into Reverie

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Title: Insight into Reverie


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Insight into Reverie autoclaved
compositesBySimon FarrenPresented at US
Distributor Sector 111 11th April 2009
3
History of Reverie
  • Founded in May of 2000 by Simon Farren,
    previously on the management team for engineering
    the Lotus 340R into a production reality.
  • Created to offer affordable autoclaved
    composites to clients. We design and manufacture
    a range of quality parts for track days and
    professional race team consumers for distribution
    via worldwide dealers emphasizing Lotus enhancing
    products.

4
What is Carbon Fiber?
  • Carbon fiber is a synthetic thread
    (poly-acrylo-nitrile, rayon or pitch) heated in
    an argon atmosphere where carbonization occurs.
  • Carbonization temperatures can be altered to
    produce different strengths and modulus of the
    carbon fiber.
  • The very fine carbon threads are left as long
    fibers along the roll length (UD fiber) with
    strength in that axis only or woven together to
    form a fabric cloth resulting multi-directional
    strength.
  • Carbon fiber can be left dry or pre-impregnated
    with a thermoset resin to make it pre-preg.
  • The cured resin gives the finished part its
    molded shape, stiffness, rigidity and protection
    of the stressed fibers.

5
History Of Carbon Fiber
  • First developed in 1958 by Dr. Roger Bacon in
    Cleveland, Ohio,fibers were manufactured by
    heating strands of Rayon until they carbonized.
    This process was inefficient. The resulting
    fibers contained approximately 20 carbon, which
    resulted in less strength and stiffness
    properties.
  • Early in the 1960s, a process was developed
    using poly-acrylo-nitrile, as a raw material.
    This produced a carbon fiber, containing55
    carbon, compared to 93-95 today.
  • Early in 1969, Carr Reinforcements in
  • England first wove a carbon fiber fabric.

6
Why Composites?
  • Carbon fiber is typically 3 X stronger than steel
    yet 4 X lighter.
  • Its 7 X stronger than 6061 alloy and 2 X
    stronger than tensile modulus, with similar
    weight.
  • Tensile modulus (stiffness) ranges from 230 GPa
    to 441 GPa and tensile strengths range from 3.5
    GPa to 5.9 GPa.
  • The ultimate strength and the breaking strength
    are the same for carbon fiber. Steel yields
    prior to reaching its ultimate strength.
  • There is no yield to carbon fiber, so parts can
    be repaired with lamination to the same shape
    easily.
  • Kevlar has a yield strength 7 X higher than steel
    and about 4 X lighter than steel. Bullet proof
    vests are manufactured with it.

7
Uses Of Composites
  • Carbon fibers weight, stiffness and strength
    benefits make it widely used in boat building,
    aerospace, motorsport and sporting goods.
  • Other fibers like Kevlar, Dyneema and fiberglass
  • can be used independently or incorporated
  • into laminates.
  • Resin systems are selected to give the required
    toughness, temperature range protect the
    stressed fibers from damage.
  • Modulus strengths of fibers, thickness and
    direction of fibers can be varied to give the
    properties required for the part.

8
Autoclave Processing Pre-Pregs
  • We process thermoset epoxy pre-pregs using one
    of two pressurized temperature computer
    controlled autoclaves, which are used by Formula
    One teams.
  • The use of elevated pressure in the autoclave
    facilitates a high fiber volume fraction and low
    void content for maximum strength.

9
Autoclave Processing Pre-Pregs
  • The UD pre-preg fiber or woven cloth is hand cut
    or done by machine into the shapes and
    orientation required for each ply of the
    component, which form the kit of parts.

10
Autoclave Processing Pre-Pregs
  • A mold tool, either male or female, is required
    to obtain a good surface finish on one side.
    Both a male and female compression tool is needed
    for a dual molded surface.
  • First the tool has a release agent applied to
    its surface to avoid sticking.

11
Autoclave Processing Pre-Pregs
  • Each section of a ply is hand placed into the
    female mold or over the male mold in the
    orientations required by the drawing.

12
Autoclave Processing Pre-Pregs
  • Some components require the molds to be
    multi-pieced and overlapping joints in the
    pre-preg are often required.

13
Autoclave Processing Pre-Pregs
  • Once lay-up is complete, a layer of thin release
    film (approx 15 microns) is applied over the
    surface of the pre-preg, where the vacuum bag may
    make contact. This allows the breather layer or
    bag to release from the cured composite surfaces.

14
Autoclave Processing Pre-Pregs
  • A polyester breather fabric layer is then
    applied to the outside of the mold and where
    possible across the component surface. The
    purpose of this fabric is to allow a full vacuum
    path over the complete mold and component area.

15
Autoclave Processing Pre-Pregs
  • Vacuum bags are applied. They can be a single
    sheet sealed with tacky tape against the molds
    outer perimeter on a male or female tool or a
    tubular envelope bag sealed at both ends to
    vacuum the complete perimeter of the mold tool.
    Any internal tubular bags or molded latex
    bladders can be left out of one or both ends of
    the tubular bag. A vacuum breach fitting goes
    through the bag surface to allow air to be
    removed.

16
Autoclave Processing Pre-Pregs
  • The air is slowly sucked out by a very powerful
    vacuum pump down to 5 Torr. The pre-preg resin
    matrix layers are forced together onto the mold
    surface at nearly one atmosphere (14.7 psi
    approx). As the air is removed the vacuum bag is
    carefully manipulated to ensure it does not
    stretch too tightly over features.

17
Autoclave Processing Pre-Pregs
  • The component is under full vacuum, any internal
    tubes or bladders open to atmosphere will be
    exerting 14.7 psi pressure internally. The mold
    is now ready for its thermo set process either in
    an oven to cure at 14.7 psi or in an autoclave to
    cure at up to 100 psi. The greater the pressure
    the lower the void content and the higher the
    strength and greater surface finish.

18
Autoclave Processing Pre-Pregs
  • Once in the autoclave, the vacuum bag is
    connected to a vacuum line a steel wire
    reinforced line which will not collapse under
    pressure. Once the autoclave reaches 14.7 psi,
    the vacuum circuit can be externally vented to
    atmosphere or left connected to remove volatiles.
    Most of our component pre-pregs cycle at
    temperature for 90 minutes at 120c or 248f.
  • The pressure used depends on the quality of the
    mold, if the component is monolithic or features
    a core material such as foam or honeycomb.

19
Autoclave Processing Pre-Pregs
  • Once the cure has finished, the mold and
    component are left to cool. The bagging film is
    removed and the mold unbolted, if
    multi-sectioned. The component is carefully
    released with plastic wedges. The component is
    now ready to be trimmed to size, secondary bonded
    and polished or sanded for paint.

20
Product Design _at_ Reverie
  • Identifying a market niche for a new product,
    either from customers, dealer feedback, demand
    or via our own research.
  • Each product design is optimized for
    strength/weight and shaped within constraints of
    packaging and aerodynamic performance. Materials
    selected by experience, or where required by
    mathematical analysis using either hand
    calculations or computerized FEA.
  • Passionate about improvements

21
Product Design _at_ Reverie
  • Products are designed on CAD where packaging
    requirements and draft angles can be checked and
    amended before machining.
  • Products are prototyped and tested at low cost
    to prove design performance these results are
    factored into future design enhancements.

22
Design to Production _at_ Reverie
  • Male patterns from foam or clay are either
    handmade or CNC machined from CAD data out of
    aluminium block or solid epoxy tooling slabs,
    which are bonded together to form the cubic
    block.

23
Design to Production _at_ Reverie
  • Once a male pattern is available, any split
    lines required for undercuts can be defined by
    removable weir walls at 90 to the surface
    featuring dowel location holes to ensure
    alignment. A mold tool can then be hand laid
    from the pattern with weirs in carbon fiber and
    autoclave cured . For low volume projects,
    sometimes a high temperature GRP hand laminated
    tool is produced.
  • Tools can also be machined direct from alloy.
  • A layup drawing is then produced for the
    laminating shop.

24
Reverie In High End Motorsport
WRC WSB FIA GT AMLS
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Why Choose a Reverie Part?
  • Established reputation for high quality.
  • Exceptional design and product testing.
  • Autoclaved manufacturing ensuring
  • high fiber to resin ratio and very low
    voids.
  • Manufacturing controlled on-site.
  • Use the highest quality Cytec pre-preg materials.
  • Excellent customer service, technical data and
    help.
  • Chosen by some of the best engine builders and
    race teams.
  • Passionate about continuous and constant
    improvements and enhancements.
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