Nationaal Lucht- en Ruimtevaartlaboratorium – National Aerospace Laboratory NLR

Advanced Materials International Forum – Bari - Italy September 18th – 19th, 2014

Recent developments in out-of-autoclave processing of fibre reinforced plastics Session 3 “Advanced Materials: a key driver for business competitiveness” Business Sector Focus: Aerospace

Ronald Klomp – de Boer - R&D Engineer Composites @ NLR

Out-Of-Autoclave: in general

Autoclave

(pressure-cooker)

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Oven

Aerospace standard and grade

Autoclave great, but unaffordable for rest of industry:

Automotive

Maritime

Tooling, Etc.

Infusion (RTM, VARTM, etc.)

Press (Compression Molding, SMC, BMC, etc.)

Out-Of-Autoclave; why?

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Oven Infusion Press

Investment oven of equivalent size & temp. Lower than autoclave

Resin & fibres separate “cheaper”

Attractive for large series

Enabling very large, integral composite structures

Preform has no outlife Complex geometries

Increased production flexibility

Large integral structures with VARTM

Integration of inserts

Reduced core crush/stabilsation problems

Complex, close tolerance parts with RTM

Close tolerance

Repairs of same quality as original

Repairs of same quality as original

Possible lower tool costs

Out-Of-Autoclave; examples Industry

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Out-Of-Autoclave; examples Aerospace

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Out-Of-Autoclave; why not?

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Laminate quality

Process control

Process duration

Performance

Out-life

Fibre volume content

Etc.

All of the above processes are just not as well established yet in aerospace as autoclave...but we’re getting there.

OOA: Oven Vacuum Bag only

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Examples of work at NLR:

IM7-BMI OOA prepreg for AFP

5320 slit tape AFP

Glass MTM45-1 fabric for engine nacelle

Challenges:

OOA: Oven Vacuum Bag only

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Work done and required

Contact with material supplier essential

Quality and material specifics (e.g. resin %)

Processing; from lay-up to bagging and curing really different from autoclave

OOA process simulation tools: air evacuation similar as already partly available for infusion

OOA: Infusion

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Examples of work at NLR:

BMI vacuum infusion

Landing gear component DFP preform & RTM

Vacuum infusion DFP preforms

Challenges: e.g. dry spots

OOA: Infusion

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OOA: Infusion

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Work required:

Adequate manufacturing simulation tools: infusion process from A to Z improvements

(constant) improvement of infusion resin mechanical properties compete with prepregs

Especially with RTM and complex, thick geometries; quality control - NDI

OOA: Compression moulding

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Examples of work at NLR:

TS caps

TP window frame

Ongoing research TS and TP materials

OOA: Compression Moulding

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Work required

Process control guarantee minimally required properties

Linked: reduce scatter in mechanical properties

Engineering: how to model random fibre properties acurately, corresponding with observed fibre distribution on moulded parts

Quality control: NDI of complex shaped parts CT scan offers promising results, however, how to relate observations to quality (mechanical properties)?

Conclusions

The field of composites is increasing rapidly: A wide range of materials are available and

continuously being developed And same for the processes and increasing level of

automation Especially now that composites outside Aerospace

are getting at a same level

Plenty of opportunity and possibility of using composites

This makes it a real challenge for companies to select the right Materials & Processes...but also very interesting!

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AMIF – Bari - Italy Sept. 18–19, 2014