RIM Process Explained
Reaction Injection Molding (RIM) is a process where two liquid components are injected into a mold and a chemical reaction between the liquids results in a solid plastic part being formed.
Materials that can be Reaction Injection Molded are typically polyurethanes where the two liquids are isocyanate and polyol, or dicyclopentadienes where the two liquids are monomers. Some of the materials used in RIM molding including: rigid urethanes, urethane elastomers, urethane foam, DCPDs, SRIM and LFT.
Injection and cycle times vary, depending on the part size and the RIM system used. A typical RIM process can fill the mold in a few seconds but some systems are designed with a delayed reactivity so that extremely large parts can be molded.
Many RIM systems are designed to accept filler material. This filler material can be for the purpose of enhancing the mechanical properties of the molded part or to reduce the cost of the plastics system. Reinforced RIM (RRIM) and Structural RIM (SRIM) are two variants of the RIM process wherein filler materials are utilized.
Courtesy of Bayer MaterialScience