JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - 62

JEC WORLD 2017
Low cost roof frame by
thermoplastic T-RTM
The aim of this project is to develop the
near net shape T-RTM (thermoplastic resin
transfer moulding) process for high volume
production. This innovative process combines
the advantages of thermoplastic resin and
the design freedom offered by HP-RTM
technology for complex parts.
To demonstrate the process potential, a
roof frame for the Roding Roadster was redesigned, having in mind that the roof frame
is a structural element for the car. The roof
structure is made of a complex multi-preform
part with hybrid textiles and integrated
metal inserts, impregnated by a low viscosity
polyamide 6 (PA6) by HP-RTM. This low
viscosity allows better impregnation of the
fibres, a higher fibre-volume-fraction, and
thus improved mechanical properties and an
overall reduced wall thickness, which reduces
material cost.
To further reduce cost, the expensive carbon
fibre was partly replaced by glass fibre, thanks
to in-ply hybridisation within a non-crimp

AUTOMOTIVE, STRUCTURAL
fabric (NCF). As such, a low amount of
carbon fibres is enough to add stiffness to
the glass fibre layers. All these optimisations
lead to a 30% material cost savings for the
roof frame compared to a pure CFRP lay-up
without near net-shape technology.

Company: Forward Engineering GmbH
(Germany)
Partners: KraussMaffei (Germany),
Alpex Technologies GmbH (Austria),
Dieffenbacher (Germany), Saertex
(Germany), Henkel (Germany), Handtmann
(Germany), TUM/LCC (Germany)

To ensure a cost as low as possible, Forward
Engineering also focused on the integration
of metal inserts in order to ensure optimised
load transfer and to minimise roof assembly
cost in mass production. Two types of inserts
are used in the demonstrator: Al-casted inserts
treated for ideal matrix adhesion applied
directly on the dry preforms, and steelthreaded inserts applied by river nuts. During
the RTM process, an additional form locking
due to overmoulding with pure resin occurs,
and the resin also prevents galvanic corrosion.
The production cell provided by KraussMaffei
melts the material for a few shots only.
This makes it possible to prevent a material
aging of the two caprolactam components

(caprolactam base material and activator or
catalyst) by minimizing the thermal load on
the melt.

AUTOMOTIVE, EXTERIOR

Lightweight one-piece roof rack
With increasing pressure on automobile
manufacturers to reduce the carbon
footprint of their vehicles, weight
reduction is becoming a prerequisite. The
goal of this project is to reduce the weight
and cost of a part that is traditionally
made of aluminium and largely unnoticed
in the composite industry.
This innovation aim to reduce the weight
and cost of a roof rack through the
use of continuous-fibre thermoplastic
(CFT) composite. To achieve this goal,
LG Hausys developed a manufacturing
process where the CFT, made of
polypropylene and glass fibres, is first
pre-formed to the desired shape and then
overmoulded to form the ribs that will
add rigidity to the rack. In the final step,
the formed roof rack is painted using a

62

new surface treatment technology.
The advantage of this project is that the
technology was developed for high design
freedom, enabling better adaptation of the
rack on the roof, which will help reduce
the part cost for mass production across
a broad range of vehicles. This innovation
reduced the part's weight 3,8 kg to 2,76 kg,
which represents a 28% reduction, while
maintaining the required performance.

jec composites magazine / No111 March 2017

Company: LG Hausys (South Korea)
Co-Winner: Hyundai Motor Company
(South Korea)
This CFT roof rack is also beneficial from
an assembly point of view as the number
of parts is reduced to 1 from 5 in existing
aluminium roof racks.
Overall, compared to an aluminium roof
rack, the cost is reduced by 5.2€/part.
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World
