This technology requires an epoxy resin master manufactured using stereolithography. The surface quality and the dimensional precision of the master are decisive factors for the quality of vacuum cast parts. The master is submerged in silicone inside a vacuum machine to ensure the absence of bubbles and correct contact with all the master’s surfaces.
After curing, the silicone is cut down to the master and the mould is separated in as few pieces as possible, in order release it correctly. The silicone mould is then used again in the vacuum machine to cast the chosen polyurethane resin. Afterward, the polyurethane resin is left to cure to obtain the final product. In some cases a post-process may also be required to ensure the client’s specifications are met.
Two-component polyurethane is the material most commonly used to make vacuum cast copies. This technology makes it possible to produce high-quality parts in a short amount of time. Vacuum casting is a production technology used for short series (from 10 to 20 units per mould) or functional plastic prototypes.