What distinguishes an open mold from a closed mold?

The distinction between an open mold and a closed mold lies primarily in their configurations and methods of operation. An open mold is essentially a flat or two-dimensional container that does not have a top cover, allowing for easy access to the open cavity for filling with material. This design is advantageous for certain types of casting processes where the material can be poured directly into the mold without any restrictions.

On the other hand, a closed mold typically refers to a three-dimensional mold that has a gating system designed to control how material enters the mold cavity. This gating system is crucial for directing the flow of material, minimizing defects during the filling process, and ensuring uniformity in the final product. The closed mold can also facilitate processes such as pressure injection, which is not feasible with an open mold due to lack of containment.

This understanding highlights why the choice indicates that an open mold is a flat container while a closed mold includes a gating system; the two types of molds serve different purposes and are used in varying contexts in manufacturing and production processes.