The development of so-called “Desktop Manufacturing” processes for rapid prototyping has enabled today's engineer to quickly create hard, tangible models directly from CAD data. To date, these models have accurately depicted the shape and volume of the design, but lack the material characteristics desired in a typical prototype. These characteristics include brittleness, surface roughness and certain internal material flaws, all inherent to the processes used to create them.
This report describes the use of castable silicone or RTV (Room Temperature Vulcanization) rubber to create molds directly from stereolithographic masters and it compares the results to the prototyping methods used historically. This comparison describes improved dimensional accuracy, cost reduction and cycle time reduction.
Finally, the use of this technique and the development of methods using castable, sprayable, and thermoformable harder tools, with a potential use in creating production intent tools, are described.
August 9,1991
S.S.Odette