Casting, in itself, is a relatively simple process. You have a basic mould in which you pour liquid polymer or something like plaster of Paris or molten metal and allow it to set. The mould may then be broken or removed. There are several ways one can cast material such as sand box casting and investment casting. Each has its pros and cons. Better techniques such as investment casting and vacuum mould casting result in products with nil or fewer defects such as pin holes and blow holes. While investment casting is used on a production scale, vacuum casting can be used for prototyping, for producing smaller number of parts or for commercial manufacturing.
Vacuum casting can be used to cast metal. The vacuum mould casting process can also be used for casting polymer resin parts. Metal casting is relatively simple. A pattern is made of wood and then used to create a sand mould in a mould box. The mould box with sand is placed inside a sealed chamber with facilities to draw out air through a vacuum pump and molten metal is poured in the mould. This results in casting with virtually no blow holes. Polymer vacuum casting follows a similar process. A master model is made using 3D printing or CNC machining. This is then coated with silicone rubber resin and cured at high temperature. The mould coating of cured silicone is cut into two sections. This is used as the mould for vacuum mould casting of polymers, usually polyurethane being the material of choice for industrial purposes.
This silicone mould in two parts is joined together and it is suspended inside the vacuum chamber where a vacuum is created and polyurethane resin is injected into the mould and cured at high temperature. Silicone material may deteriorate after a few such pieces have been taken out and the mould may need to be made all over again from the master model.
One of the chief advantages of vacuum moulding is that air is completely evacuated from within the chamber so the cast pieces do not have any pinholes or blowholes inside that mar the look and affect the structural strength.
Another advantage of Binashree vacuum mould casting is that one can easily and quickly manufacture components that are required in small quantity. It saves time and money too.
Prototypes can be developed cheaply and quickly and be evaluated and the component design further refined before going in for more traditional bulk manufacturing methods.
It is easy to create parts with thinner wall thicknesses and quite complicated shapes that may not be possible with other processes or if done, may be quite expensive and time consuming.
Some products are sold in low quantities such as medical prosthetics or decorative objects and for such items, this is the best solution.
Binashree is one of the few companies with expertise in delivering high quality vacuum moulded products for a variety of end uses.
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