Pull and Foam - Injection moulding method: Foamed ribs for stiffening plane components

The pull and foam method is a foam injection moulding method which is currently being developed at the Institut für Werkstofftechnik (IfW) (Institute of Materials Engineering) at the University of Kassel. The processing principle represents an alternative to the existing foam injection moulding special procedures and introduces the possibility to partially foam a component. In so doing, thin-walled, hardly foamed components with foamed ribs can be made in one processing step, thus also components with graded properties. Conventional foaming methods do not enable the manufacture of complex component geometries, wall thickness variations, and components with areas with varying degrees of foaming while maintaining a satisfactory surface quality. The pull and foam method offers possible solutions and makes it possible to attain locally targeted, customised mechanical properties. Therefore, it is possible to produce components with foamed areas that possess a high stiffness and compact areas with a high surface quality. In doing so, the method introduces the advantages of foam injection moulding procedure (lower clamping forces = smaller machines, material efficiency, lower melt viscosity, etc.) to new application fields, which were previously barred due to insufficient surface qualities or for constructive reasons.