Sand casting uses a mould made of green sand to cast components. Sand is tightly packed around the pattern to create the mould, with the mould itself typically consisting of a top and bottom half. These two halves are then firmly clamped together before the casting process begins.
Once the mould is ready, the molten material is poured into it as quickly as possible to avoid premature solidification. As the material cools inside the mould cavity, it begins to harden, adopting the shape of the cavity. Once the material has cooled sufficiently, the mould is broken apart and the cast component(s) retrieved.
The main advantage of sand casting is that it can be used for shorter production runs, since the sand needs to be removed from the mould in order to retrieve the cooled part(s). This means that the cost of the mould tool itself is often much less than with other casting methods. However, a pattern will still need to be produced in order to facilitate production of the sand mould.
Most metals can be used during the sand casting process; however, aluminium alloys are one of the most popular choices. As with most casting methods, finish machining may also be required to ensure a quality finish.
Used to produce
Typically short production runs of cast components.
Most metals can be used, although aluminium alloys are one of the most popular choices.
Allows for shorter production runs.
Can be used to cast large components.
A variety of materials can be used.
Reduced tooling costs compared to other casting methods.
Components may have a porous surface, meaning that they won't be as strong as machined parts.
The material may shrink as it cools, resulting in inaccuracies and other defects.
Finish machining may be required to improve the overall quality.