What is the difference between an open mold and a closed mol

What is the difference between an open mold and a closed mold?

Solution

OPEN MOLD: An open mold is open to the atmosphere at the top; it is an open container in the desired
shape which must be flat at the top.

CLOSED MOLD: A closed mold has a cavity that is entirely enclosed by the mold, with a passageway (called the gating system) leading from the outside to the cavity. Moltenmetal is poured into this gating system to fill the mold.