JEC COMPOSITES MAGAZINE - Issue #114 - July 2017 - 24

MANUFACTURING

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Control

Fast development and
intelligent process control for RTM
Out-of-autoclave

New toughened out-of-autoclave prepreg
Recycling

Computed laminography - production-integrated
inspection of large-scale CFRP components

MANUFACTURING control

Fast development and
intelligent process control for RTM
Nikos PaNtelelis, Director,
Synthesites
kaPil Nayak, Research Specialist,
JoeP Breuer, Project manager,
MaarteN Bach, Project manager,
aNders BrodsJo, Technology
Manager, Airborne
Marius Muetzel, Product Manager,
Kistler

T

his work was performed in the framework of the Ecomise R&D project, an
EC-funded collaborative European
project led by DLR that involved Bombardier
Aerospace, Samtech, Fibre Institut Bremen,
Polyworx, Hutchinson, Synthesites, Loop
Technology, NLR, Airborne and Dassault
Systemes. This technology was used successfully in the project's industrial demonstrators, a CFRP wing skin, a CFRP tidal blade
and a GFRP suspension blade.
Advanced process monitoring
Within the Ecomise project, Synthesites
developed the OptiCure system, a comprehensive solution for speeding up composites
production and ensuring in-mould product
quality. OptiCure includes several sensors
connected to the OptiMold and OptiFlow
process monitoring systems focused on the

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In high-quality composites manufacturing, there is an urgent need for
online quality control tools to optimize and accelerate development and
production control. This paper presents an integrated and intelligent
quality monitoring system combining resin arrival, temperature and
cure sensors from Synthesites and advanced pressure sensors from
Kistler, which is used by Airborne to manufacture thick CFRP parts
using RTM.

industrial production of composite materials.
The DC-based monitoring systems measure
the material's resistivity and temperature
using durable and/or disposable sensors
and can monitor the full transformation of
a thermoset resin in-situ. Since the resin's
viscosity is directly related to its electrical
resistance besides resin arrival, the monitoring system can be used to verify the onset of
cure, measure the full cure, the quality of the
resin matrix or other processing parameters.
Comparisons between DC sensing and dielectric systems measuring resin impedance
showed the superiority of DC-based cure
monitoring, particularly after gelation, while
it is user friendly, cheaper and more robust,
with a wide range of sensors for industrial
applications. These sensors can be installed
in several locations in the mould: in the die
and at the inlets and/or vents to achieve
global process monitoring. Additionally, the
real-time transformation of these resistivity
and temperature measurements into useful

jec composites magazine / No114 July 2017

material properties such as the degree of cure
and/or Tg was developed in the Ecomise
project, making the system quite unique
and very useful in process development and
manufacturing in a range of closed mould
applications.
A new generation of pressure sensors
Kistler provided a new generation of pressure
sensors designed specifically for composite
manufacturing processes in the aerospace industry, such as the RTM process. With these
sensors, it is possible to analyse and monitor the pressure conditions inside the form
throughout the process. Due to the flow resistance inside the feeding tubes, the pressure
values displayed in the mixing unit can differ
significantly from the real pressures inside
the cavity. Inside the form, pressures can differ due to the flow resistance of the preform.
Important process information such as flow
resistance during impregnation of the preform, stable pressure during holding and
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #114 - July 2017
