RTV molds are created using a master pattern. The master pattern can either be created using CNC machining or a 3D printer, such as an SLA machine. Silicone rubber is poured around the master pattern, creating a cavity and a core. The master is removed once the silicone rubber sets and leaves a void into which several materials may be cast.
RTV molding is an inexpensive way to bridge the gap between prototype and production. It is most effective when you need a short run of parts to simulate production parts. More common materials used for RTV molding are polyurethanes, wax and silicone. Polyurethane can simulate a wide range of materials from soft rubber to hard plastic.
Cast Urethane parts can produce incredible detail and excellent surface finish. Often times little finishing is required on cast Urethane parts because the details and textures are applied to the master pattern. Because of the flexibility of Silicone, reverse draft, inserts and undercuts are all easy to deal with.
Urethane casting can be used for several applications including visual models, product testing, color and texture studies and even low volume production. Urethane parts can be of nearly any size and shape and can also be color matched.