JEC COMPOSITES MAGAZINE - Issue #99 - September 2015 - 37

Fig. 6: Overall process of the continuous direct textile layup (DTL) process

to allow three-dimensional deformation
to fit properly into the mould contour.
This is insufficiently possible with the
standard NCF currently used in rotor
blade production. While newly developed
highly drapable NCF can be deposited in
a rotor blade mould, conventional fabrics
will form wrinkles in the critical areas [5].
The development of a draping unit for a
well-functioning DTL effector is inevitable
for a successful automated continuous
DTL process. Continuous DTL demonstrates the next step in the progressive
automation of rotor blade production and
offers a high savings potential for current
production processes. The BIK is part of
the BladeMaker joint project. As part of
the "Direct Textile Placement" (DTP) subproject, the BIK is developing the so-called
DTP effector, which is designed to deposit
a dry tailored pre-cut in the longitudinal or
transverse direction directly and properly
into a rotor blade moulding tool.

Conclusion and outlook
When comparing preforming and direct
textile placement, advantages and disadvantages can be seen on both sides, depending
on the blade section concerned. While
preforming seems to be useful for the root
ring area and the transition section, direct
textile placement offers many advantages
for the spar caps, the spars and the outer
shell. Both techniques depend on automatable NCF, which, just as the techniques
themselves, still requires a lot of research

References
[1] MÜLLER, D. H.; WEIGEL, L.:
Gemeinsamer Technischer Abschlussbericht
für das Verbundprojekt preblade: Bremer
Institut für Konstruktionstechnik, Abeking
& Rasmussen Rotec GmbH & Co. KG, 2008
[2] ROLBIECKI, M.; THOBEN, K.-D.; MÜLLER,
D. H.: Large Area Robot - Automated
Production of Rotor Blade Tension and
Compression Spars. In: Wind Energy &
Environment Forum (JEC Composites Show
Asia Singapore 2010), 2010
[3] ISCHTSCHUK, L.; OHLENDORF, J.-H.:
Mapretec: a new production process for
the wind energy sector. In: JEC Composite
Magazine vol. 90 (2014), pp. 30-32
[4] ROLBIECKI, M.; BRAUN, R.: BladeMaker:
Industrialisierung der Rotorblattproduktion.
In: Ingenieurspiegel vol. 4 (2014), pp. 10-11
[5] OHLENDORF, J.-H.; ROLBIECKI, M.;
SCHMOHL, T.; FRANKE, J.: Mapretec - ein
Verfahren zur preform-Herstellung durch
ebene Ablage für ein räumliches Bauteil als
Basis einer automatisiertenm Prozesskette
zur Rotorblattfertigung: Institut für integrierte Produktentwicklung, 2014 (ISBN:
978-3-95886-019-3)
[6] ROLBIECKI, M.; WORTHMANN, F.;
MAASS, R.; MÜLLER, D. H.; THOBEN,
K.-D.: Large Area Robot - Flexibel automatisierte Produktion großflächiger
Faserverbundstrukturen durch mobile
Fertigungseinrichtung (02PK2052): Institut
für integrierte Produktentwicklung, 2009
[7] ISCHTSCHUK, L.: Selbsthaftende Gelege
für höhere Produktionseffizienz und
Qualität. In: Lightweight Design (2011), pp.
57-61
[8] FRANKE, J.; THOBEN, K.-D.; ROLBIECKI,
M.; SCHMOHL, T.; OHLENDORF, J.-H.;
ISCHTSCHUK, L.: Binderapplikation
für biegeweiche Materialien. In: MM
MaschinenMarkt/Composite World (2014),
pp. 15-17

Fig. 7: Schematic depiction of a continuous DTP
process

No99 September 2015 /

More information:
www.bik.uni-bremen.de

Feature Wind Energy

transformation distance and the effector
inclination angles usually reach their maximum. During the transformation process,
the effector has to grip the textile edge
internally, then lead it to a defined position
while unwinding the fabric and, simultaneously, transform the NCF into the surface
contour. In such complex process steps, it is
necessary to have a comprehensive sensor
technology and extensive actuator devices
in the effector which are able to realize the
partly high transformation distances.
Fixing the dry NCF in the steeper mould
sections is essential to avoid slipping after
its deposition. Various binder technologies have been used in recent rotor blade
production [7]. The different automated
binder application systems have many
advantages, such as the reproducibility
of the application quantity, high speed
application velocity and a controllable
well-infusionable structural distribution.
Automated application can be implemented
by robot-supported tools, such as spray
application heads for hot melt adhesives or
special application effectors for rather solid
adhesives [8]. Since the surface of the rotor
blade mould is treated with a special release
agent to prevent sticking, a logical consequence is a lower adherence of the binder.
To automate a continuous DTL process,
it is important to have alternative fixation
solutions for the first fabric layer, such as
mechanical brackets in the mould edge area
or another formfit or forcefit solution.
The final draping step of the continuous
DTL process is probably the most challenging one. The deposited NCF is smoothed
with an effector-integrated draping unit
so that it is laid down onto the surface
of the rotor blade mould as accurately
as possible. Unwanted material defects
such as wrinkles, gaps or undulations may
cause problems for further production
steps and lead to a decreased quality of
the rotor blade. In the mould's complex
shaped sections, the applied NCF needs

work. Additionally, most rotor blade
manufacturers need to agree that automating rotor blade manufacturing is not only
needed but essential for future projects in
Europe and need to take part in this special
development. n

jec composites magazine 37
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Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #99 - September 2015
