JEC COMPOSITES MAGAZINE - Issue #117 - November/December 2017 - 34

MANUFACTURING fibre placement
facilities including an autoclave used as
an oven and infusion equipment were
used together with an existing curing
mould.
Further development work was necessary to get a robust process to fill the
preform laid up with the new DFP
materials. So, a comprehensive trial
pyramid based on small coupon tests
to evaluate basic parameters, going on
to scale-up tests to evaluate effects on
larger parts and ending with a full-scale
demonstrator cover was implemented.
The main challenge of working with
DFP materials was their low permeability. This means the fibre layers are
packed so tight that the resin moves
very slowly through the preform. Here,
an infusion concept was needed where
the distance the resin has to flow is as
short as possible. The infusion of different skin and stringer materials had
to be considered as well for the infusion
concept. To maintain the vacuum
and for suction of the remaining air, a
semi-permeable membrane was used.
This foil worked like a breathable outdoor jacket and was permeable to gases
but impenetrable for the infusion resin.
There are two main questions the
developers want to answer before using
an infusion process: "How can I fill my
part in the required lead time? How
should I set up my process to achieve
good quality?" To estimate these points,
it is essential to get a precise prediction
of the resin flow, especially the position
of the flow fronts during the process.
Therefore, parallel to the practical trials, flow simulations were conducted in
close partnership with the Faserinstitut
Bremen e.V:. In the first step, resin flow
calculations were executed after the
physical tests to evaluate the material
parameters and to compare theory and
practice. For larger parts, this made it
possible to predict how the resin inlets,
distribution material and channels had
to be positioned. The objective was to
get a process faster than the curing time
of the reactive resin, without dry spots.
Finally, the 14-m demonstrator was

manufactured using the developed
concept. Non-destructive testing with
ultrasonic inspection confirmed a very
good inner quality without internal failures. Significant experience was gained
during the project and the potential
and further development needs could
be pointed out.
Summary and future work
As part of the project, an automated
process to layup about 400 kg of dry
fibres was validated successfully in a
vertical mould position. The successful
infusion of a thick demonstrator with
more than 200 kg of aerospace resin
completed the joint research activity.
The layup parameters chosen enabled
a safe deposition and robust infusion,
but resulted in a high bulking of the
preform, which was not optimised for
internal laminate quality. Therefore,
future activities are needed to optimise
the parameters taken into account for
mechanical performance.
The main approach was validated for
the vertical deposition of thick preforms. In addition to future technology
improvements, DLR validated a first
multi-robot process with two AFP
robots working simultaneously as part
of a LuFo V-1 funded project, EWiMa.
This approach will be improved in
the future to develop an intelligent
manufacturing execution system that
can schedule the layup tasks for several
robot units, both offline and online,
in an automated and productive way.
Furthermore, DLR will develop and
integrate systems for automated quality
inspection in order to increase process
automation and productivity compared
to state-of-the-art AFP and ATL processes with a visual inspection of each
ply by a worker.
The approach to minimize the resin
flow distance in the low permeability
skin preform turned out very well
and secured a successful infusion at
the first time. The parallel simulation
of the resin flow supports the setup
of the infusion inlets. The effort and

jec composites magazine / N°117 November - December 2017

additional auxiliary materials required
for the chosen infusion setup can offset
all potential material cost savings. So,
future projects have to focus on an
optimized infusion setup for industrial
applications.
More information:
www.DLR.de
Contact:
andreas.kolbe@dlr.de
Acknowledgement
Many thanks to BMWi and NBank
for funding the project.

References

[1] Airbus, www.airbus.com, 2015.
http://www.airbus.com/presscentre/
pressreleases/press-release-detail/detail/
airbus-to-boost-a320-production-to-60-amonth-in-mid-2019/, [Accessed 02 March
2017].
[2] MTorres, www.mtorres.es,2017.
http://www.mtorres.es/en/
communication/news/mtorres-delivers-hybrid-afpatl-gantry-machines-airbus-efficient-a350xwb-wings, [Accessed 24 April
2017].
[3] P.E. Irving and C. Soutis, Polymer
Composites in the Aerospace Industry, 2015,
Chapter 3.5 Page 62.
[4] G. Marsh, Reinforced Plastics Journal,
2011, Bombardier throws down the gauntlet
with CSeries airliner, pages 22-26, ISSN:
0034-3617.
[5] FACC, Composites World, 2014, FACC:
Aerospace infusion pioneer,
http://www.compositesworld.com/
articles/facc-aerospace-infusion-pioneer,
[Accessed 02 March 2017].
[6] Solvay, Press Releases 2014, Cytec
Providing Composite Products for the MS-21
Programme, http://www.solvay.com/en/
media/press_releases/20140311-cytec-providing-composite-products-ms-21-program.
html, [Accessed 02 June 2017].
[7] Composites World, News Post 5/30/2017,
Russian MC-21 makes first ight ith Solvay
materials, http://www.compositesworld.com/
ne s/russion-mc-21-makes-first- ight- ithcytec-solvay-materials, [Accessed 10 July
2017].
[8] Mtorres, www.mtorres.es, 2014. Dry
Carbon Fiber Automatic Placement (AFP)
on production in Aerocomposites, http://
www.mtorres.es/en/communication/news/
encintada-con- C3 A9xito-en-fibra-secael-ala-del-ms21-en-rusia, [Accessed 10 July
2017].
[9] C. Krombholz, J. Stüve and M. Wiedemann, Journal of Large-Scale Research
Facilities (JLSRF) 2016, GroFi: Large-scale
fiber placement research facility, Pages 1-4,
ISSN 2364-091X.

http://www.DLR.de http://www.airbus.com http://www.airbus.com/newsroom/press-releases/en/2015/10/airbus-to-boost-a320-production-to-60-a-month-in-mid-2019.html http://www.mtorres.es,2017 http://www.mtorres.es/en/communication/news/mtorres-delivers-hybrid-afpatl-gantry-machines-airbus-efficient-a350xwb-wings https://www.compositesworld.com/articles/facc-aerospace-infusion-pioneer https://www.solvay.com/en/media/press_releases/20140311-cytec-providing-composite-products-ms-21-program.html https://www.compositesworld.com/news/russion-mc-21-makes-first-flight-with-cytec-solvay-materials http://www.mtorres.es http://www.mtorres.es/en/communication/news/encintada-con-exito-en-fibra-seca-el-ala-del-ms21-en-rusia

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #117 - November/December 2017