JEC COMPOSITES MAGAZINE - Issue #81 - May/June 2013 - 55

to reduced fibre damage and thereby to more optimal use of
hybrid yarn strength in the fibre-reinforced composites.

Experimental

Fig. 1: Comparison between state-of-the-art and 3D-LightTrans manufacturing chain

The 3D-LightTrans advanced processes and equipment for
highly efficient weaving of multilayered and 3D-shaped textile
fabrics, based on results from the Collaborative Research
Centre (SFB 639) of the Technische Universität Dresden
(TU Dresden), will enable the development of innovative
applications and new functionalities for 3D-TRTC (e.g. multifunctional integration for cooling, wiring, sensing, acoustic,
etc.). Moreover, the 3D-LightTrans fully automated and highly
flexible manufacturing chain will not only enable cost-efficient
mass manufacturing, but it also employs a mass customisation
concept based on highly adjustable modules which are flexible
enough to be adapted to new technologies and uses. Other
cost- and time-efficient production technologies (e.g. braiding,
knitting) can be used and adapted to the tailoring needs of
high-tech customized products (multi-material components,
local reinforcement, functional integration) for different application sectors.
The research at SFB 639 is based on a continuous investigation of the whole process of developing lightweight structures
using hybrid yarn in a multi-material design for the future fibre
TRTC, i.e. from filament up to component part [7].
Based on the technical and technological experience gained by
SFB 639, multilayer woven fabrics with load-oriented noncrimp fibre arrangement are produced and improved for high
preform stiffness and reproducible manufacturing. This leads

Fig. 2: Process chain for TRTC developed by SFB 639

Hybrid yarn manufacturing
In air texturing, the hybrid yarn is produced by the pneumatic
opening of the filament yarn by cold or hot pressurized air, and
the subsequent reallocation of the initial filaments in a special
air nozzle. Commercially available yarn materials in a wide
range of setups can be processed, and the ratios of individual
components are widely variable.
The research priorities were to achieve a homogenous distribution of the individual components along the thread cross section, and gentle processing of reinforcement threads in relation
to selected process parameters.
An RMT-D air texturing machine (manufacturer: Stähle
GmbH) is available at TU Dresden for the production of
commingling hybrid yarns. Figure 3 shows a view of the
machine and the principle of hybrid yarn manufacturing. The
air texturing machine features a socket for various air nozzle
types and is fitted with a suitable system for the suction removal
of flying fibres. The reinforcement and matrix filament yarns are
guided in individual supply feeds, reaching the air jet (manufacturer: Temco GmbH, Germany) where the filaments are
opened and mingled by the air flow. Due to this principle, the
commingling hybrid yarns’ structure does not feature a fully
parallel alignment of reinforcement and matrix components
along the yarn axis. Other parameters influencing the hybrid
yarns’ features and their appearance are the nozzle construction
and adjustment, air pressure, overfeeds (the relation of filament
yarn feeding speed and the hybrid yarn’s haul-off speed), and
the general process speed. The components’ mass ratio can be
modulated by adjusting the number of threads fed [8,9]. To
minimize thread damage and homogenize the distribution of
the two filament types along the yarn cross section, the aim is
to achieve a gentle opening of the filament yarns and merging
of reinforcement and matrix filaments at preferably low air

Fig. 3: Modified RMT-D air texturing machine

No81 May - June 2013 /

jec composites magazine 55

JEC COMPOSITES MAGAZINE - Issue #81 - May/June 2013

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