In Reaction Injection Moulding (RIM), duroplastic PU material is filled into a hard mold made of ureol or aluminum at an injection pressure of 4 to 6 bar and cures in the mold as a result of the cross-linking reaction.
The RIM process is thus in competition with injection molding and is better suited for large, thin-walled, complex components, since the lower viscosity allows greater flow paths to be achieved here than with injection molding. When the components are removed, any undercuts are removed from the mold using loose parts.
Since the mold halves are usually milled, no separate master model is required for forming the cavities.
The high strength of the mold surfaces make the technology particularly interesting for the production of larger quantities.