In sand casting, cores are generally made of sand
Gating System
Channel through which molten metal flows into cavity from outside of mold
Consists of a downsprue, through which metal enters a runner leading to the main cavity
At the top of downsprue, a pouring cup is often used to minimize splash and turbulence
as the metal flows into downsprue
Riser
Reservoir in the mold which is a source of liquid metal to compensate for shrinkage of
the part during solidification
The riser must be designed to freeze after the main casting in order to satisfy its function
Other Expendable Mold Processes
Shell Molding
Vacuum Molding
Expanded Polystyrene Process
Investment Casting
Plaster Mold and Ceramic Mold Casting
Shell Molding
Casting process in which the mold is a thin shell of sand held together by thermosetting resin
binder. Steps in shell-molding: (1) a match-plate or cope-and-drag metal pattern is heated and
placed over a box containing sand mixed with thermosetting resin.