Vacuum Casting 

Vacuum casting is a casting process that requires a vacuum to draw liquid eslatomer into a mould.

In many instances vacuum casting is an ideal solution for low volume prototype production as it is fast and cost effective.

Due to the relatively low tooling costs (in comparison to injection moulding and hard tooling) changes to a master can be made quickly and new moulds created, thus lending itself particularly well to the iterative development process.

 The Process 

 1.  The process begins with the fabrication of a master. The master can be 3D printed, machined or made using traditional model making techniques.

The master must also include the required surface finish, as this will be transferred to the mould and all subsequent parts.

 2.  The master is suspended within a fabricated container, and a flexible, high strength silicone rubber is poured into the mould container. The silicone used is dependent on the complexity of the master. A low viscosity silicone would is best suited for intricate detail. Curing can be accelerated by placing the mould into an oven.

 3.  Once the silicon has cured, the master must then be released along a predefined seam or release mark. At this stage the two part mould can be cleaned and prepared.

 4.  A release agent is applied to the inside of the mould to ensure that cast parts are easily removed and not damaged during demoulding. The two piece mould is placed into a vacuum chamber where the raw material is mixed (tints can be added if required), degassed and added to the mould.

 5.  The final stages include curing the part and releasing it from the mould. Oven curing time is dependent on the quantity and type of resin used.

There are many options available with regards to resin properties, colour and finish. Please feel to contact us to discuss your project and vacuum casting requirements.