Increasingly, plastic articles are being developed and manufactured from several components. This is mainly due to the endeavour to obtain “ready-to-install” serial parts from an injection mould. The two-component process is very efficient and the material properties of the materials used can be exploited to even better effect. In contrast to the usual injection moulding process, in this process different materials or colours are injected into the mould one after the other. The components are connected to each other in different ways. The success depends on factors such as the joining properties of the plastics, the moulded-part geometry and the processing parameters in injection moulding. If these are taken into account, however, the application possibilities are almost inexhaustible.