JEC COMPOSITES MAGAZINE - Issue #103 - March 2016 - 60

performing

Holistic development of high-quality composite parts based on automated preforming

By
Dr.-Ing. Farbod Nezami,
Dipl.-Ing. Jan-Philipp Fuhr,
Dipl.-Ing. Diego Schierle,
CIKONI Composites Innovation
Prof. Dr.-Ing. Chokri Cherif,
Institute of Textile Machinery and High Performance Material Technology, TU Dresden
Prof. Dr.-Ing. Peter Middendorf,
Institute of Aircraft Design,
University of Stuttgart

n series production of composite parts,
some of the most important challenges
are quality, reproducibility and reliability.
Fabric forming technologies show a high
potential for automation and are suitable
for medium- to high-volume production
when they are combined with liquid composite moulding (LCM) processes.

Quality issues as reasons for
increasing cost and weight
The preforming process step plays an
important role in overall quality issues.
The defects that occur at this stage can
lead to the rejection of whole preforms,
influence the subsequent process steps
or result in tool damage due to folds and
wrinkles. Beyond that, geometries that
are not suitable for composite forming
can cause time-consuming modification
loops of the manufacturing tools.
Furthermore, the fibre angles and other
quality aspects that dominate the final
mechanical properties are revealed only
after forming on the geometry. Since the
actual preform quality and its structural

The reduction of production costs and the realization of lightweight
targets for composite forming parts can only be successfully achieved
by thinking and planning quality aspects in an integral way. Using the
example of automated preforming, this article introduces a holistic
development approach that covers process selection and process
design as well as error detection and mechanical analysis of manufacturing effects on part performance.

impact are typically unknown, composite parts tend to be overdimensioned to
compensate the uncertainties related to
part quality. Fibre sliding, fibre waviness
or the loss of structural integrity of the
fabrics have a direct influence on part
performance, but are rarely taken into
account at the initial component dimensioning stage [1].
Therefore, a holistic quality approach
contributes not only to the reduction of
production costs, but can also improve
the weight saving potential and structural

performance if already embedded at an
early stage of part and process design.

Optimizing and ensuring
quality by holistic approaches
For high-performance composite parts,
there is a strong interaction between the
manufacturing process and the lightweight design objectives. The sooner
these dependencies are considered in the
overall development process, the faster
the development cycles for new parts and
products can be.

Fig. 1: The four pillars of quality improvement using the example of automated preforming

60 jec composites magazine / No103 March 2016

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #103 - March 2016