RTV Molding or Polyurethane’s refers to a low volume production method that produces parts from a Polyurethane plastic material for prototyping purposes. These parts are similar to and sometimes can mimics plastic injected parts.
The method behind producing Polyurethane parts is relatively old as compared to Rapid Prototyping however; the advent of Rapid Prototyped models introduced a new method of producing patterns for RTV Molding.
The first step in creating Polyurethane parts is to produce a master pattern. Anything can be used as a pattern however, for products that do not exist yet from production tooling, SLA, SLS, FDM or CNC models are typically used. The master pattern is finished to a high level via sanding and priming. The finish level of the master represents the finish level of the final Polyurethane part.
Next, the master pattern is encased in RTV (Room Temperature Vulcanization) Silicone. When the RTV cures, it is split and the master pattern is removed, revealing a cavity into which Polyurethane can be cast.
Polyurethane is used for this process because it requires low pressure and is a cold cast mixture. Typically, it is multiple component mixture that once mixed, is poured into the cavity where it cures to the shape of the cavity.
Polyurethane’s come in many varieties and colors allowing simulation of virtually any production material. It is possible to simulate anything that is possible in production.
There are many uses for Polyurethane components and is often a valued step in the engineering process. With their advanced material properties and endless array of colors and finishes, they offer a level of testing and simulation above traditional Rapid Prototyped models.