What is Vacuum Casting?

Vacuum casting is used to create parts from silicone that have very fine details and walls that are extremely thin.  When an exact replica of an item is needed that will have the correct dimensions and no blemishes, the vacuum casting process is perfect for the job.  The textures and profiles of the intended items will be reproduced to exact measures.

The process of vacuum casting

There are two chambers in the vacuum casting machine.  The top section mixes the ingredients of the resin and the lower section is used to cast it into the mould.  This is a process that takes several steps to complete but it can produce amazing results.

The first step in the process is to have a pattern created. This pattern will be used to create the high quality finished product.  It has a casting gate fitted on it and it is set up right n the parting line. 
It is then suspended within the mould casting frame.  After the silicone rubber mixture is mixed completely it is then poured into the mould casting frame and it will flow around the pattern.

It is within this area that the mould is allowed to set up.  This gives it time to take the necessary form and to be ready to be removed from the frame.  When it is time to remove the mould another process is put in place.  This process involves cutting the mould along the parting line so that the pattern can be removed from the mould.

It is now time to measure the urethane resin.  It is also during this time that any colour is added by adding dye.  The casting funnels are placed and the mould is sealed entirely closed.  Equipment that is controlled by a computer mixes the resin and then pours it into a vacuum chamber.  The vacuum environment allows the resin to fill the mould completely.  There are no air pockets or any open voids in the mould because it is a vacuum environment.

Once the resin is cast it is time to move the mould into the hearting chamber.  The mould stays in this chamber for between two and four hours so that the urethane is given enough time to cure.  Once it has had time to harden, it will be taken out of the silicone mould.  The pattern is duplicated to an exact measure by cutting off the gate and risers.

At this point in the process, it is time to personalise the component.  The item is ready to have paint applied or to have it plated.  The creation of the component is complete.  The vacuum casting process is an alternative technique that can be used to create prototype castings.  It can look similar to the results that are produced with injected moulds. 

Benefits of vacuum casting