Sand Casting for Non Ferrous Castings
Sand casting offers the simplest medium for production of non ferrous castings, by pouring molten zinc, aluminium or copper into a sand mould.
This process is chosen for the production of small numbers of castings, for complex shape castings requiring intricate cores, or for large castings. Advantages include low tooling costs, largest casting sizes achievable, very low gas porosity is possible, and general versatility of the process is good.
Limitations include low casting rate, 3-5mm minimum wall thickness, poor linear tolerance (e.g. 4mm/m), rough surface finish (6.5-12.5mm), and a coarser grain size than gravity die castings.
The huge advantage of sand casting is the production of complex shapes however the surface finish and tolerances of the finished casting are poor relative to die castings. Production times can also be a lot longer than other casting processes such as gravity die casting and high pressure die casting.