In injection molds with conventional cooling, the cooling system is manufactured with as little as possible drill holes.
A change in direction is realized by intersecting drill holes.
These auxiliary holes need to be closed by a plug to avoid the coolant flowing out of the mold.
Additionally plugs need to be inserted to define a clear direction of the coolant stream.
This way the coolant can flow through a drill hole in multiple areas.
The plugs prevent the coolant to flow into uncertain directions and support with the enforced flow direction a good cooling system of the mold.