1. 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

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 vacuum bagging and autoclave cure Resin Infusion under Flexible Tooling (RIFT) Resin Transfer Moulding (RTM) filament winding pultrusion

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

5. Change from hand lay-up ? Increased consolidation pressure –1 atmosphere = full vacuum = 10 5 N/m 2 (10 tonnes/m 2 ) Occupational Exposure Levels –Germany/Sweden20 ppm –France/Spain50 ppm –United Kingdom100 ppm –EU harmonisation (long overdue) in 201x ? Pollution Prevention and Control Act 1999 –styrene has an odour threshold of 0.034 ppm i.e 630 µg/m 3

6. 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 the raw materials –long cycle times –capital cost of equipment

7. 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

8. “Acronym” anarchy ! CIRTM: co-injection RTM Crystic VI:vacuum infusion (Scott Bader) DRDF:double RIFT diaphragm forming (University of Warwick) LRI: liquid resin infusion MVImodified vacuum infusion (Airbus) Quickstepuse 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 SCRIMPSeeman Composites Resin Infusion Molding Process (TPI) VAIM: vacuum-assisted injection moulding VAPvacuum 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

9. 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

10. 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 –slow process due to limited pressure gradient –may need flow enhancement tows within the reinforcement Resin feed Vacuum KEY Reinforcement

11. 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

12. 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.

13. 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

14. 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.

15. 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

16. 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

17. Comparison of HL and RI resins SP resin systemshand laminationinfusion Ampreg 20 Prime 20 PropertyUnits ViscositymPa.s447 188 Tg (50  C post-cure) °C 85 86 Tensile strength MPa 83 74

18. 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.

19. RIFT vacuum forming RIDFT image from JR Thagard, PhD thesis, Florida State University, 2003.

20. RIFT with flow medium RIFT 2 of 4 A high permeability fabric allows resin to flood one surface followed by through-thickness flow commonly referred to as either: –V(A)RTM Vacuum (assisted) resin transfer moulding –SCRIMP TM Seeman Composites Resin Infusion Manufacturing Process patented in the USA but prior-art exists in Europe Resin feed Vacuum KEY Flow medium Reinforcement

21. Princess Yachts Infusion of 42-foot and 75-foot boat hulls http://www.tech.plym.ac.uk/sme/mats324/Video/PYinfusion.wmv

22. EADS VAP ® process Membrane = Gore Composite Manufacturing Membrane (GCM) Image reproduced with permission from EADS

23. 2m diameter CFRP sonar dome non-crimp carbon fibre fabric monolithic composite from 9 mm to 50 mm thick, Vf = 60%, Vv = negligible

24. 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 @ 50 º C

25. Manufactured by the SCRIMP TM process J-boats Poma-Otis mass transit Images from www.tpicomp.comwww.tpicomp.com Reitnouer flat bed trailer NABI 30-foot bus

26. Benefits of SCRIMP TM 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 SCRIMP TM. increased laminate strength due to the higher fibre fraction and reduced void content. reduced styrene emissions and waste resin.

27. The NEG-Micon 40 m radius AL40 carbon-wood epoxy wind turbine blade Resin infusion manufacturing process developed with ACMC

28. 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

29. Civil engineering structures DML Composites rehabilitate fractured structures for London Underground

30. 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)!

31. 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 unlike prepreg, there are air channels within the bagged laminate Vacuum KEY Resin film Reinforcement

32. 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

33. “Semi-preg” infusion RIFT 4 of 4 fabric partially pre-impregnated with resin Commercial systems include –Advanced Composites Group ZPREG resin stripes on one side of fabric –Cytec Carboform resin impregnated random mat between the two fabric layers –SP Systems SPRINT ® : SP Resin Infusion New Technology resin between two fabric layers Vacuum KEY Resin stripes Reinforcement

34. Comparisons (debateable) In-planeFlow mediumRFISemi-preg Material costs Consumables Process time Quality £€$

35. 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.

36. 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.

37. Publication The text of this presentation has been refereed and is published in Proceedings of the Institution of Mechanical Engineers Part L - Journal of Materials: Design and Applications, February 2005, volume L219(1), 45-58.

38. Based on earlier PowerPoint by John Summerscales and TJ Searle “Low pressure (vacuum infusion) techniques for moulding large composite structures” by John Summerscales “A taxonomy for resin infusion” 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

39. .. to contact me Dr John Summerscales  jsummerscales@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