Resin Infusion under Flexible Tooling (RIFT)

1
Resin Infusionunder Flexible Tooling (RIFT)

• John Summerscales
• Advanced Composites Manufacturing Centre
• School of Marine Science and Engineering -
  University of Plymouth
• Plymouth, PL4 8AA, United Kingdom

2
Outline of presentation

• other manufacturing processes
• four variants on resin infusion
• advantages and disadvantages
• applications using the process
• notional cost comparisons
• brief summary

3
Manufacturing processes

• spray
• hand lamination
• hot press
• Resin Transfer Moulding (RTM)
• Resin Infusion under Flexible Tooling (RIFT)
• vacuum bagging and autoclave cure
• filament winding
• pultrusion

4
Manufacturing processes

• Resin transfer moulding (RTM)
• long-range flow of resin into a dry fibre pack
  preloaded into a defined mould cavity.
• Resin infusion (RIFT)
• A range of intermediate techniques
• Vacuum bagging and autoclave cure
• wet resin or prepreg lamination followed by
  bagging and cure under pressure

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Change from hand lay-up ?

• Increased consolidation pressure
• 1 atmosphere full vacuum 105 N/m2 (10
  tonnes/m2)
• Occupational Exposure Levels
• Germany/Sweden 20 ppm
• France/Spain 50 ppm
• United Kingdom 100 ppm
• EU harmonisation via SPA recommendation for end
  2013
• Pollution Prevention and Control Act 1999
• styrene has an odour threshold of 0.034 ppm i.e
  630 µg/m3

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Why resin infusion ?

• Resin transfer moulding (RTM)
• as mouldings increase in size,mould clamping
  forces become excessive
• Vacuum bagging and autoclave cure
• premium price forpre-impregnation of
  reinforcements
• long cycle times
• capital cost of equipment

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Resin infusion

• Muskat patent application, 1945
• the fibrous base to be impregnated preferably
  in a substantially dry state
• drive the resin into the base to impregnate it
• one tube being connected to a source of resin and
  the other to a vacuum pump
• complementary moulds appear to be free to move
  together under vacuum
• process introduced to UK by Scott Bader in 1946

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Acronym anarchy !

• CIRTM co-injection RTM
• Crystic VI vacuum infusion (Scott Bader)
• DRDF double RIFT diaphragm forming (University
  of Warwick)
• LRI liquid resin infusion
• MVI modified vacuum infusion (Airbus)
• Quickstep use of liquids for enhanced heat
  transfer in infusion
• RFI resin film infusion
• RIFT resin infusion under flexible tooling
  (ACMC Plymouth)
• RIRM resin injection recirculation moulding
• SCRIMP Seeman Composites Resin Infusion Molding
  Process (TPI)
• VAIM vacuum-assisted injection moulding
• VAP vacuum assisted processing (patented by
  EADS)
• VARI vacuum assisted resin injection system
  (Lotus Cars)
• VARIM vacuum assisted resin injection moulding
• V(A)RTM vacuum (-assisted) resin transfer
  moulding
• VIM vacuum infusion moulding.
• VIMP vacuum infusion moulding process
• VM/RTM Light a hybrid RIFT/RTM (Plastech)
• VIP vacuum infusion process

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Resin infusion

• RTM with one tool face replaced by a flexible
  film or a light splash tool
• flow of resin results only from vacuum and
  gravity effects
• mould cavity varies with local pressure
• thickness of the part depends onpressure history

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Resin Infusion underFlexible Tooling (RIFT 1 of
4)

• Basic RIFT process
• resin flows in the plane of the fabricbetween
  the mould and the bag
• slow process due to limited pressure gradient
• Only good for
• low fibre volume fraction/high loft fabrics
• reinforcement with flow enhancement tows

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RIFT 1slow flow in the process

• Special fabrics
• Commercial process needs flow-enhancing tows,
  e.g.
• Brochier Injectex
• Carbon fabrics from Carr Reinforcements
• Glass fabrics experimental programme with
  Interglas-Technologies

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Potential advantages ?

• Process
• use most resin systems.
• use most forms of reinforcement fabrics.
• large structural components can be fabricated.
• relatively low tooling costs for high-performance
  components.
• better than wet-laid components with little
  modification of tooling.
• heavy fabrics more easily wetted than by hand
  lamination.
• lower material costs than for prepreg and vacuum
  bagging.

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Potential advantages ?

• Performance
• higher fibre volume fraction gives improved
  mechanical performance.
• minimal void content relative to hand lamination.
• more uniform microstructure than hand lay-up.
• cored structures can be produced in a single flow
  process.
• hand-lamination resin infusion

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Disadvantages ?

• Process
• complex process requires different skills to
  hand-lamination.
• emphasis on preparation, not on the actual
  moulding process.
• sensitive to leaks (air paths) in the mould tool
  and the bag.
• quality control of the resin mixing is
  "in-house".
• slow resin flow through densely packed fibre
• uneven flow could result in unimpregnated
  areas/scrap parts.
• not easily implemented for honeycomb core
  laminates.

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Disadvantages ?

• Performance
• only one moulded surface
• low resin viscosity means lower thermal and
  mechanical properties.
• thinner components have lower structural moduli
• laminate thickness dependent on flow history
  (next slide)
• licensing costs where aspects of the process
  patented in the USA

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Fabric compressibility in RIFT

• A B
  C
• 2.2 mm
• 2.0 mm
• 1.8 mm
• 0 2000 4000 Time (s)
  7500 11500
• nine layers of plain weave E-glass/UPE resin
• compression by vacuum
• lubrication by resin front at A
• relaxation as pressure gradient falls
• resin inlet closed at C

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Comparison of HL and RI resins

• SP resin systems hand lamination infusion
• Ampreg 20 Prime 20
• Property Units
• Viscosity mPa.s 447 188
• Tg (50?C post-cure) C 85 86
• Tensile strength MPa 83 74

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RIFT vacuum forming

• Known as
• DRDF Double RIFT Diaphragm Forming, or
• RIDFT Resin Infusion betweenDouble Flexible
  Tooling
• dry fabric is placed between two elastomeric
  membranes
• resin is infused into the fabric
• the sandwich is vacuum-formed over the mould
  shape.

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RIFT vacuum forming
RIDFT image from JR Thagard, PhD thesis, Florida
State University, 2003.
20
RIFT with flow mediumRIFT 2 of 4

• A high permeability fabricallows resin to flood
  one surfacefollowed by through-thickness flow
• commonly referred to as either
• V(A)RTM
• Vacuum (assisted) resin transfer moulding
• SCRIMPTM
• Seeman Composites Resin Infusion Manufacturing
  Process
• patented in the USA but prior-art exists in Europe

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EADS VAP process

• Membrane Gore Composite Manufacturing Membrane
  (GCM)
• Image reproduced with permission from EADS

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2m diameter CFRP sonar dome

• non-crimp carbon fibre fabric monolithic
  composite
• from 9 mm to 50 mm thick, Vf 60, Vv
  negligible

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CFRP catamaran forward beam60v/o NCF (6000 x 300
x 50 mm)
Manufactured by Julian Spooner Channel section
to form box with a second joggled moulding -
integral top hat supports   Web 600gsm triax /
9mm balsa / 600gsm carbon triax Flanges 600gsm
triax / 4mm UD / 600gsm triax Sicomin SR8100
resin system   Layup 7 man hours, Infusion 25
minutes,  20ºC / 20mB Postcure 10h _at_ 50ºC
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Manufactured by theSCRIMPTM process
J-boats Poma-Otis mass
transit Images from www.tpicomp.com
Reitnouer flat bed trailer NABI
30-foot bus
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Benefits of SCRIMPTM

• Vosper Thornycroft state
• resin infusion into tows is independent of fabric
  weight.
• reduced costs and greater efficiency in
  productionfewer layers of heavier
  fabriccompared to 35 separate plies of 800 gsm
  woven roving glass used in hand lamination.
• reduced component weight (up to 72 fibre by
  weight).
• void content down from 5 by HL to lt1 by
  SCRIMPTM.
• increased laminate strengthdue to the higher
  fibre fraction and reduced void content.
• reduced styrene emissions and waste resin.

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The NEG-Micon40 m radius AL40 carbon-wood epoxy
wind turbine blade Resin infusion manufacturing
process developed with ACMC
27
Advanced Composite Armoured Vehicle Platform
(ACAVP)

• demonstrator manufactured by VARTM
• reinforcement is quasi-isotropicnon-crimp
  E-glass fabric
• bare hull weight is around 6000 kg

Image from http//www.janes.com/defence/land_force
s/news/jdw/jdw010312_3_n.shtml
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Civil engineering structures

• DML Composites rehabilitate fractured structures
  for London Underground

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CFRP infusionvs welded steel repair

• London underground
• 40K/day lost revenuefor closing the line
  between two stations
• Offshore exploration and exploitation
• 500K/day of crude oil through small platform
• need to drain down before hot work (welding)!

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Resin Film Infusion (RFI)RIFT 3 of 4

• B-stage prepreg resin film without fibres
• interleaved with reinforcementor grouped film
  layers in dry laminate
• unlike prepreg, there are air channels within the
  bagged laminate

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RFI (RIFT 3) for aerospace

• T-beams, aileron skin, swaged wing rib, three-bay
  box
• Kruckenberg et al , SAMPE J, 2001
• fuselage skin panel for the Boeing 767 aircraft
  was moulded as a demonstrator with integral
  stiffeners
• Cytec 5250-4RTM bismaleimide resin (100 mPa.s at
  100C)
• 880 x 780 mm woven 5-axis 3-D fabric preform
• Uchida et al , SAMPE J, 2001
• fuselage panels in TANGO Technology Application
  to the Near-term business Goals and Objectives of
  the aerospace industry
• skins will be non-crimp fabric preforms
• integrated stringers to be triaxial braids with
  unidirectional fibres
• Fiedler et al, SAMPE J, 2003

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Semi-preg infusionRIFT 4 of 4

• fabric partially pre-impregnated with resin
• Commercial systems include
• Cytec Carboform
• resin impregnated random mat between the two
  fabric layers
• Hexcel Composites HexFITTM
• film of prepreg resin combined with dry
  reinforcements
• SP Systems SPRINT SP Resin Infusion New
  Technology
• resin between two fabric layers
• Umeco (ACG) ZPREG
• resin stripes on one side of fabric

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Comparisons ( debateable! )



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Summary

• reviewed the four major variants of the Resin
  Infusion under Flexible Tooling process.
• considered the application of these techniques to
  the manufacture of large composite structures.
• recommend this route for the manufacture of large
  composite structures.

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ACKNOWLEDGEMENTS

• Higher Education Funding Council of England
  (HEFCE) Development of Research for funding early
  research into resin infusion
• Christopher Williams and Jim Craen for their
  respective contributions to the project.
• David Cripps at SP Systems Limited for most
  helpful discussions of an earlier version of this
  paper.
• Paul Hill at DML Composites for permission to use
  his Figure.
• Use of trade names/trade marks in the text of
  this chapter does not imply endorsement by the
  authors of any specific product. Such
  descriptions are provided simply in the interest
  of traceability.

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Publication

• The content this presentation has been refereed
  and is published as
• John Summerscales and TJ SearleLow pressure
  (vacuum infusion) techniques for moulding large
  composite structures
• in Proceedings of the Institution of Mechanical
  Engineers Part L - Journal of Materials Design
  and Applications, February 2005, L219(1), 45-58 .

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Based on earlier PowerPoint

• previously presented at
• Universiti Putra Malaysia, Bangi, Sept 2004
• Imperial College London, Dec 2004
• SAMPE out-of-autoclave symposium, Feb 2005
• Forum for Plastkompositter Norway, Nov 2005
• Composite Innovations Barcelona, Oct 2007
• ICMAC Belfast, March 2009
• RINA London, February 2010
• SWCG Plymouth, September 2012.

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? .. to contact me

• Dr John Summerscales
• jsummerscales_at_plymouth.ac.uk
• http//www.plymouth.ac.uk/staff/jsummerscales
• School of Engineering Reynolds Building RYB
  008 University of Plymouth Devon PL4 8AA
  England
• 01752.5.86150
• 01752.5.86101