Modelling and
simulation of the foam formation process
Institut für Kunststoffverarbeitung (IKV),
Pontstraße 49, D-52062 Aachen, Germany
In order to optimise existing process
techniques, it is necessary to achieve a more accurate estimate of the PU
material behaviour during the moulding process, before production actually
commences. At present, the lack of appropriate material models means that the
computer-aided prediction of the mould filling process for PU foam systems with
simulation programs is only possible to a limited extent. For this reason, a
model is presented of the density development during foam formation, which is
based on an experimental characterisation of the foaming process. This model
has been implemented in a program for simulating the filling process. In order
to assess the quality of the model formulation selected, the calculated mould
filling is compared with the results of an experimentally-conducted filling
study. The investigations have shown that the mould filling behaviour for
foaming processes that are constrained by mould walls can be readily described
with the aid of the simulation. For free foaming processes, however, the
elastic properties of the foam that develop have been seen to be a key material
parameter that will need to be taken into account in future.