What does the gating system in a closed mold do?

The gating system in a closed mold is crucial for the casting process as it is designed to facilitate the flow of molten metal into the mold cavity. This system typically consists of various components, such as the gate, sprue, and downsprue, which guide the molten metal to ensure it fills the mold correctly. This filling process is essential for creating a complete and accurately formed casting.

By controlling the entrance point and path of the molten metal, the gating system helps to minimize issues like turbulence and allows for the even distribution of metal throughout the mold; this process ensures that all parts of the mold cavity are filled uniformly before the metal solidifies.

The other options do not accurately describe the primary function of the gating system. Holding the pattern in place is a function of the mold design itself, cooling during solidification is managed separately, and shaping the external dimensions is primarily the role of the mold cavity, not the gating system. Thus, the gating system’s main role is indeed to allow molten metal to flow into the cavity efficiently.