Both Reaction Injection Molding and Urethane Casting offer a good deal of design freedom,Â including the ability to mold-in features and encapsulate materials. Â They differ in the fact that only RIM allows for part design withÂ significant wall thickness variationsâ€”typically from .125″ to 1.125″Â in the same part.
RIM as well as urethane casting can be used to encapsulate a variety of materials, from metals toÂ electronics. Each also produce a high quality finish, and take paint, silk screening and texturing well forÂ improved branding.
Urethane casting in silicone rubber molds is often the more cost-effective choice for small productionÂ volumes, but rubber molds have a limited cycle life and long-term production can become costÂ prohibitive compared to RIM. Both processes are appropriate for producing molds for quick turnaround.
The initial tooling costs of urethane casting are lower than that of RIM. Tooling modification is also veryÂ cost-effective, but when aiming for production parts, RIM becomes the better choice cost-wise.
OTHER DESIGN CONSIDERATIONS: Many companies utilize rubber molds for years prior to convertingÂ to more permanent tooling, which can end up being extremely expensive. Because RIM can bridge theÂ gap between prototype and production with parts that are precision molded instead of fabricated orÂ cast, it can actually be most cost effective to utilize RIM in lieu of rubber molding.