Reaction Injection Molding (RIM) produces parts with intricate details that are dimensionally stable, chemically resistant, physically tough and wear resistant. This process is an excellent choice for larger plastic parts (car bumpers, electronic enclosures and panels) produced in short run or low volume production quantities.
Reaction injection molding can produce strong, flexible, lightweight parts which can easily be painted. It also has the advantage of quick cycle times compared to typical vacuum cast materials. The bi-component mixture injected into the mold has a much lower viscosity than molten thermoplastic polymers, therefore large, light-weight, and thin-walled items can be successfully RIM processed. This thinner mixture also requires less clamping forces, which leads to smaller equipment and ultimately lower capital expenditures. Another advantage of RIM processed foam is that a high-density skin is formed with a low-density core.
The disadvantages are slow cycle times, compared to injection molding, and expensive raw materials.