reaction injection molding


Reaction injection molding (RIM) involves the high-speed mixing of two or more reactive chemicals,space such as prepolymers, as an integral part of injecting them into a mold.
RIM Manufacturing produces polyurethane plastic parts using a process called Reaction Injection Molding (RIM). Because the words “Injection Molding” are in the name of the RIM  technology, a lot of folks think RIM Molding is the same process as injection molding. This is not the case! Reaction Injection Molding gets its name from the chemical reaction that occurs when liquid polymers are injected into a heated mold. This is why RIM is known as a Thermoset and not a Thermoplastic.

As low temperature polymers enter a heated mold, the polymers quickly experience an exothermic reaction – approximately 325 °F – and then the material quickly cools and becomes a molded part. The cure time can occur in less than a minute or in several minutes depending on the part’s size, geometry, function and wall thickness. The finished polyurethane part can be solid, elastomeric, rigid foam, or flexible foam.
Furthermore, because the RIM process involves injecting low viscous polyurethane into a heated mold at low pressure and at low temperatures, Reaction Injection Molding offers significant advantages over other processes including: injection molding, vacuum or pressure forming, and cast molding.