1. business and industrial
2. chemicals industry
3. plastics and polymers

Resin Infusion
under Flexible Tooling (RIFT)
John Summerscales
Advanced Composites Manufacturing Centre
School of Marine Science and Engineering University of Plymouth
Plymouth, PL4 8AA, United Kingdom
Outline of presentation
• other manufacturing processes
• four variants on resin infusion
– advantages and disadvantages
– applications using the process
• notional cost comparisons
• brief summary
Manufacturing processes
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spray
hand lamination
hot press
Resin Transfer Moulding (RTM)
Resin Infusion under Flexible Tooling (RIFT)
vacuum bagging and autoclave cure
filament winding
pultrusion
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
Change from hand lay-up ?
• Increased consolidation pressure
– 1 atmosphere = full vacuum = 105 N/m2 (10 tonnes/m2)
• Occupational Exposure Levels
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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
Why resin infusion ?
• Resin transfer moulding (RTM)
– as mouldings increase in size,
mould clamping forces become excessive
• Vacuum bagging and autoclave cure
– premium price for
pre-impregnation of reinforcements
– long cycle times
– capital cost of equipment
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
“Acronym” anarchy !
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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
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 on
pressure history
Resin Infusion under
Flexible Tooling (RIFT 1 of 4)
• Basic RIFT process:
– resin flows in the plane of the fabric
between the mould and the bag
KEY
Resin feed
Vacuum
Reinforcement
– slow process due to limited pressure gradient
– Only good for
• low fibre volume fraction/high loft fabrics
• reinforcement with flow enhancement tows
RIFT 1:
slow 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
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.
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
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.
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
Fabric compressibility in RIFT
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A
B
C
2.2 mm
2.0 mm
1.8 mm
0
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2000
4000 Time (s) 7500
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
11500
Comparison of HL and RI resins
SP resin systems
Property
hand lamination
infusion
Ampreg 20
Prime 20
Units
Viscosity
mPa.s
Tg (50C post-cure) °C
Tensile strength
MPa
447
85
83
188
86
74
RIFT vacuum forming
• Known as
– DRDF: Double RIFT Diaphragm Forming, or
– RIDFT: Resin Infusion between
Double 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.
RIFT vacuum forming
RIDFT image from JR Thagard, PhD thesis,
Florida State University, 2003.
RIFT with flow medium
RIFT 2 of 4
• A high permeability fabric
allows resin to flood one surface
followed by through-thickness flow
KEY
Resin feed
Vacuum
Reinforcement
Flow medium
• 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
EADS
®
VAP
process
Membrane = Gore Composite Manufacturing Membrane (GCM)
Image reproduced with permission from EADS
2m diameter CFRP sonar dome
• non-crimp carbon fibre fabric monolithic composite
• from 9 mm to 50 mm thick, Vf = 60%, Vv = negligible
CFRP catamaran forward beam
60v/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 @ 50ºC
Manufactured by the
SCRIMPTM process
J-boats
Poma-Otis mass transit
Images from www.tpicomp.com
Reitnouer flat bed trailer
NABI 30-foot bus
Benefits of
TM
SCRIMP
• Vosper Thornycroft state:
• resin infusion into tows is independent of fabric weight.
• reduced costs and greater efficiency in production:
fewer layers of heavier fabric
compared 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 <1% by SCRIMPTM.
• increased laminate strength
due to the higher fibre fraction and reduced void content.
• reduced styrene emissions and waste resin.
The NEG-Micon
40 m radius AL40
carbon-wood epoxy
wind turbine blade
Resin infusion
manufacturing process
developed with ACMC
Advanced Composite
Armoured Vehicle Platform (ACAVP)
• demonstrator manufactured by “VARTM”
• reinforcement is quasi-isotropic
non-crimp E-glass fabric
• bare hull weight is around 6000 kg
Image from http://www.janes.com/defence/land_forces/news/jdw/jdw010312_3_n.shtml
Civil engineering structures
• DML Composites rehabilitate fractured
structures for London Underground
CFRP infusion
vs welded steel repair
• London underground
– ~£40K/day lost revenue
for 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)!
Resin Film Infusion (RFI)
RIFT 3 of 4
• B-stage “prepreg” resin film without fibres
• interleaved with reinforcement
or grouped film layers in dry laminate
KEY
Reinforcement
Vacuum
Resin film
• unlike prepreg, there are air channels
within the bagged laminate
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 100°C)
– 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
“Semi-preg” infusion
RIFT 4 of 4
• fabric partially pre-impregnated with resin
KEY
Reinforcement
Vacuum
Resin stripes
• 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
Comparisons ( debateable! )
In-plane
Material costs
£€$
Consumables
£€$
Flow medium
£€$
£€$ £€$ £€$
RFI
£€$ £€$
£€$ £€$
Semi-preg
£€$ £€$ £€$
£€$ £€$
Process time
Quality
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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.
ACKNOWLEDGEMENTS
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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.
Publication
The content this presentation has been
refereed and is published as
John Summerscales and TJ Searle
Low 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 .
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.
 .. to contact me
Dr John Summerscales
 [email protected]
 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