Vacuum casting is a technology used to avoid expensive injection moulds. Its worthwhile particularly in the development process of injection moulded parts or for small to medium series. Components with very high surface quality - in injection moulding quality - can be produced. The technology is used for prototypes too, whose properties must be very close to those of injection moulded components. As the name suggests, vacuum casting is a technology where material is poured and distributed in the mould by means of a vacuum.
The manufacturing works like this: First, the component - the "positive" - is made using 3D printing. The additive manufacturing technology SLA is usually used for this. This positive form of the desired component is ground exactly smooth that the surface no longer has any visible layers and any small form errors can be eliminated. This positive mould of the component is then used to create a casting mould together with the sprue, risers, etc. The original mould is made of silicone. The original mould is produced from silicone and cured in the oven. This creates a complex mould with a high surface quality. Vacuum casting is then used to produce the components: the material is poured into the mould and vacuum is used to distribute it cleanly into all cavities.
The advantage of this technology is that complex shapes and undercuts can be produced. In addition, components can be produced in injection moulding quality without expensive injection moulding tools.