Ulrich
Dajek, hybrid design expert at Lanxess, explains: “Our easy-flowing polyamide 6
can be processed at lower injection pressures. For this reason, smaller
injection molding machines with lower clamping forces can be used in the
production of the hybrid bolster. This has a positive effect on the machine
running costs and allows greater flexibility in terms of machine selection and
production planning.”
Four integrated
active grille shutters
The
bolster houses an actively controllable unit consisting of four active grille
shutters that ensure a demand-oriented supply of air to the engine cooling
system. The bolster contains reinforcing metal inserts at the sides and in the
upper chord. The latter accommodates the highly loaded hood latch. The main
task of the hybrid design is to support the cooling systems and hold them in
position. Numerous additional functions are also integrated in the bolster –
such as guides, mounts for the adjustment drive and fasteners.
“Our
development engineers have succeeded in integrating all these elements,
functions and interfaces so that the functional and load requirements are met.
At the same time, they have ensured that the entire front-end module can be
produced in different region-specific versions in an automated high-volume
process in a cost-efficient manner,” comments Horst-Dieter Haltrich, Product
Development Team Leader at Montaplast.
Direct threaded
connections with greater stability thanks to polyamide 6
As
a plastic component for the hybrid bolster, polyamide 6 has two main advantages
over the possible alternative material, polypropylene (PP). The first advantage
is that the component contains several direct threaded connections; these are
more cost-efficient than using additional metal inserts. The threaded
connections designed using polyamide 6 are significantly more stable, have a
longer service life and are more reliable than with PP. The second advantage of
polyamide is that it withstands the thermal loads that arise when the grille
shutters are closed, in contrast to PP.
Easier to achieve
filigree, thin-walled component areas
Due
to the high flowability of polyamide 6, component areas with filigree
geometries can be designed with thinner walls. “It was possible to reduce the
wall thickness by around 20% in the areas subject to lower loads. Compared to a
standard polyamide 6 with the same fiberglass content, this results in an
appreciable weight saving,” according to Dajek. Due to the lower filling pressure,
another benefit of the easy-flowing material is that components with lower
stresses can be produced, minimizing the distortion.
Extensive HiAnt
services
Ford,
Montaplast and Lanxess worked closely together over the entire development
process for the hybrid bolster right up to the start of series production.
Lanxess also brought in its HiAnt engineering service. In one of several
engineering studies, a component topology analysis was carried out to provide
suggestions for the design and position of the reinforcing polyamide ribs that
took account of the relevant load cases. Various calculations and simulations,
such as analysing the rigidity of the radiator mount and the dynamic stability
and noise vibration harshness (NVH) of the bolster, were also highly
challenging.
The
load-bearing capacity of the metal-reinforced latch area (hood latch) as well
as several insurance-relevant load cases – such as lower leg impact tests for
pedestrian protection or the behavior of the overall assembly in the case of
minor collisions, e.g. knocks while parking – were also simulated. In addition,
Lanxess carried out tests on the prototype and series-production part to the
specifications of Ford. Dajek: “For example, we allowed the complete assembly
to ice up in a climatic chamber and tested the reliable opening and closing of
the grille shutters.”
Source:
Lanxess