JEC COMPOSITES MAGAZINE - Issue #96 - April 2015 - 70

machining center

Fig. 2: Sketch of the STAXX system during predevelopment

materials for automotive applications,
towpreg seems to be the most promising material. Towpreg is a directly impregnated carbon fibre roving. Today's
towpregs consist of 24 k or 50 k fibre
rovings. The material development
process is close to market readiness and
is seeking new machine concepts for
production, as it has already been widely used with the winding technology.

Value for production
The value of the STAXX Compact
fiber placement machining center for
the production of composite parts
is highlighted by the following three
aspects: First of all, the new machine
technology enables the operator to
produce parts with minimal scrap by
using the full anisotropic properties of
carbon fibre. Secondly, the machine
is specially designed to use towpreg
material, which is a low-cost prepreg
unidirectional material. In addition to
process advantages, the machine offers
the added value of being a standalone
solution, which can conduct fibre
placement in any industrial environment.
The technology of a fibre placement
machining center also addresses production systems. These production systems are defined by the combination of
several fibre placement units. Their intelligent combination into a production
system enables the operator to produce
part families simultaneously, so that
production can be actively aligned
to actual requirements. When creating such an agile production system,

several individual fibre placement cells
are connected to each other. Therefore,
the production volume can be scaled
up with an established and verified
technology, one that uses automation
methods similar to those already applied in high-volume production.
The development of the machine was
driven by the need for large-volume
production methods for high-performance composite parts, which are
currently produced predominantly by
textile technologies. The main aim
of the development was to create a
machine that significantly reduces the
wastage of carbon fibre material during
the production process. As fibre placement proves to be the most promising technology for this purpose, fibre
placement machines have to be further
developed to offer a robust process,
which fulfils the requirements of highvolume production, especially in the
automotive industry. With regard to the
automotive industry, the Siemens 840
D-SL Transline machine control system was chosen as it has the inherent
potential to be linked up to complex
production systems.

Two proven technologies
Launching the innovation involved the
combination of two existing technologies. First of all, the fibre placement process had to be made more
robust. The second task was to find

Fig. 3: The STAXX Compact 1700

70 jec composites magazine / No96 April 2015

an automation method that suited this
more robust fibre placement process.
To handle the complexity of fibre
placement coupled with the need for
automation to obtain higher production rates, the design of the machine
resulted in a robust fibre placement
mechanism, as well as a second mechanism for dealing with the complexity of production parts. This second
mechanism was designed to be fully
independent from the fibre placement
technology. Hence, the fibre placement
cell was designed to a use a robust layup technology combined with a flexible
positioning system.
Combining these two technologies provided a defined starting point for automation. In fibre placement processes,
automation should provide a high part
throughput and a defined handling of
the parts produced. One aspect was to
design the machine so that it was able
to load a palette while simultaneously
carrying out fibre placement on another palette. This parallel palette loading significantly reduces the machine's
downtime, especially if parts with a
short cycle time have to be produced.
The palette technology enables the
machine to provide the produced parts
under defined conditions, which is essential for further automation along the
process chain.

JEC COMPOSITES MAGAZINE - Issue #96 - April 2015

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