JEC COMPOSITES MAGAZINE - Issue #109 - November/December 2016 - 23

Organo-sheet evolves from niche products to standard series production

facture of the seat pan and built up a
special production cell in its technical
centre (Figure 2). Besides a standard
horizontal injection moulding machine
with a clamping force of 4,200 kN, the
cell's main components include a combined thermoforming and injection
mould specially built by GK, a preheating unit and a handling system for the
incoming flat blanks of organo-sheet. In
this particular case, these sheets consist
of a glass fabric-reinforced polyamide
(PA) with a thickness of just 1 mm to
meet cost and weight requirements.
A 6-axis robot starts the production cycle by placing the preheated blanks into
the mould. The final processing temperature is obtained using IR radiant
heaters introduced into the still open
mould by means of a linear drive. Upon
completion of the heating-up phase, the
mould closes and forms the organosheet in the first of two quality-determining stages. In the second stage - injection moulding - an edging surround
with no subsequent finishing requirements and parts such as reinforcing ribs
and fastening elements made of a glass
fibre-reinforced polymer are moulded
onto the sheet. After the cooling phase,
the mould opens and the robot removes
the ready-to-install seat pan and places
it on a conveyor.

Fig. 3: Prototype of a car side impact protection
component. No creases should form during the
thermoforming of the organo-sheet (© Georg
Kaufmann Formenbau)

partners involved, in particular with
the OEM. GK gained the necessary
know-how in many gradual steps before the production of functional and
structural parts made of organo-sheet
was economically efficient and reliable
enough for standard production. These
parts must not only satisfy lightweight
design criteria but also meet economic
requirements, both of which are prerequisites for standard series production.

Thanks to the close cooperation between all the project participants and
the clear definition of responsibilities,
it took only one year from the beginning of the feasibility study to the start
of standard production. GK then took
over the start-up of series production
for roughly the same period of time at
their main site in Busslingen.

It was the combination of the thermoforming and injection moulding processes in conjunction with a newly developed mould technology [1] that first
made possible a decisive improvement
in quality as compared with a multistage manufacturing process. The production of the complete part within a
single heating process ensures that the
injection-moulded parts bond reliably
with the organo-sheet and prevents
the thermoplastic matrix material of
the semi-finished composite from being damaged through repeated heating
processes.

The key to success:
"marrying" thermoforming and
injection moulding processes
The reasons for the successful implementation of this and similar development projects include GK's more than
forty years' experience in mould design
and process integration, as well as the
trustful collaboration between all the

GK demonstrated the practical suitability of this concept at K 2010 in Düsseldorf by way of a stable production
process for the scrap-free production of
a passenger car side impact protection
component on a KraussMaffei injection
moulding machine. To produce this dynamically loaded component (Figure
3), a preheated, cut-to-size 3-mm-thick
No109 November - December 2016

organo-sheet comprising a polyamide
matrix and a glass fabric reinforcement
(PA6-GF) is initially thermoformed
while the mould closes, and back injected directly afterwards. The material
should remain free from wrinkles and
the fibre orientation has to be adapted
to the load directions in the component. The relatively thick organo-sheet
used in this particular application produces components with high buckling
and mechanical stress resistance, while
the material costs - in spite of a weight
saving of around 20% - are no less than
those for the production of an equivalent metal component.

Focus
LIPA stands for Lightweight Integrated
Process Application. In addition to Georg
Kaufmann Formenbau AG, the project
partners include the raw material manufacturers Borealis and DSM, the semifinished material supplier Quadrant, the
injection moulding machine manufacturer
KraussMaffei, the robot manufacturer
Kuka, the sensor technology specialist
Kistler, the Krelus firm as a manufacturer
of IR radiant heaters and the Technical
University of Dresden for calculations and
material tests. In this frame, the comprehensively equipped GK Tech-Center is
well prepared to deliver dedicated, rapid
and cost-efficient developments, covering
both basic research and application-specific solutions for upcoming challenges,
including local, load path-oriented reinforcements, sandwich structures with
continuous-fibre-reinforced top layers as
well as combinations of different lightweight technologies.

/ jec composites magazine

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Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #109 - November/December 2016
