The versatility of the injection moulding process can be increased by
combining multiple polymers in one product. The multi-component inject
ion moulding process (MCIM) offers the possibility to inject two or th
ree materials sequentially or simultaneously into a mould to make prod
ucts that consist of e.g. a layered structure. For a successful applic
ation of this technique for geometrically complex products or multiple
materials, the material distribution in the product has to be predict
ed In this paper numerical tools are described for calculating the pos
itions of material particles during the flow in the mould cavity. Thes
e tools make it possible to solve the inverse problem of predicting th
e injection sequence in MCIM given a required material distribution in
the product. The simulations are validated using experimental results
of a co-injected strip with stiffener ribs. Furthermore the effect of
a bifurcation of the midsurface on the material distribution is inves
tigated numerically using a simplified model based on the local mass b
alance.