Besides additive techniques, Materialise offers another type of RP: manufacture of components and small series in silicone molds. Stereolithography masters are used to build these molds. Vacuum casting lead times are a bit longer than with 3D Printing technology but the result is astounding. Products made in silicone molds have a quality comparable to the final product, which makes them especially suitable for fit and function testing and marketing purposes.
The method uses cast silicone molds made as follows: a master model (that typically originates from stereolithography or selective laser sintering) is carefully prepared to ensure a high quality finish to the surface and the definition of the parting planes. Silicone is cast around the master, partially under vacuum in order to avoid air bubbles being trapped in between the master and silicone. After curing, the mold is cut according to the parting planes and the master is removed, leaving a cavity to make copies. The flexibility of the silicone allows limited undercuts, which might avoid slides or additional parting planes.
Two-component polyurethanes are typically used as copying material. This allows fast production of high quality parts. Vacuum casting is a copying technique typically used for the production of small series (10 to 20) of functional plastic prototypes.
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