Reaction injection molding

Reaction injection molding ( RIM ), or reinforced reaction injection molding ( RRIM ) is a molding method for the production of plastics moldings. Two components ( and possibly other additives) are intensively mixed in a mixer and then immediately injected as reaction mass in a shaping tool. The curing takes place in the mold. Characteristic of this method is, inter alia, a small clamping force of the molds. The mold life, that is the time required to make the mold for a new mold part is available, this procedure are between one and five minutes. RIM is preferably used for the production of molded polyurethane parts such as the automotive industry use.

Moldings of the RIM process are in competition with those of the injection molding process. The reaction masses from the RIM process have, compared to the thermoplastic melt, due to their low viscosity, a more favorable flow characteristics. Thus, larger flow paths can be achieved with the same wall thickness. This is offset by the increased workload in the gasket and dosage and longer process times during production.