Vacuum casting is particularly suitable for the fast and cost-effective production of small seires. The prototypes have a very good surface which comes very close to the quality of the series.
In vacuum casting, liquid plastic is introduced into a mold (negative) made of silicone under vacuum, whereby the vacuum prevents air inclusions in the component and thus avoids flow resistance. This plastic hardens and is later re-hardened in the oven. The silicone mold is produced by first producing the component using the stereolithography process, which then produces the negative in the silicone. The component is removed and the mold can now be filled and vented through channels. The silicone mold can be reused several times, whereby the frequency depends on the geometry and material of the component.
The properties of prototypes can be specifically designed with the selection of different PU casting resins in vacuum casting, and, for example, highly transparent or rubber-like castings can also be produced. Thanks to the flexibility of the silicone mold, vacuum casting can ignore smaller undercuts than injection molding, resulting in an uncomplicated workflow. The reusability of the mold depends on the material and the shape of the component, whereby the reusability is between 15-30 times.