Perforated panel excess punching tool - GIF

[Toolmaker51]

Unsure why this is needed. Most injection molds "shut off" to prevent flash. Might be inadequate clamp pressure; large hydraulic cylinder opens and closes the mold halves. Tonnage required is calculated mainly by total surface area and injection pressure x time needed to fill while the material is still hot enough to flow. This drain thing might need 1200+ tons.
Largest molds I ever built and hung ran in a 3000 ton press. Just 1 mold half, 29,000 pounds. The busboy box that's about 18"x 20" x 24" started as a pair of 11 ton blocks. With all the machine work carving out the cavity and cooling holes, took out about 3 thousand pounds, which the core made up. Wall thickness of the box is .125.
In dieset terminology the punch enters the die opening, just like a paper punch. In molds, the 'punch' is the core, die is the 'cavity'. . ., and cores in casting are the interior of a body, such as a manifold or valve.