The role of an engineer in designing risers is to make sure that risers provide the feed metal in the right amount, at the right place, and at the right time. This article addresses feed metal volume, riser location, and duration of liquid feed metal. It discusses the three types of feeding systems used in riser design: riser sleeves, topping compounds, and breaker cores.

A gating system is the conduit network through which liquid metal enters a mold and flows to fill the mold cavity, where the metal can then solidify to form the desired casting shape. This...