These are the pins in the center of the mold used to pull the sprue away from the nozzle. They have an undercut just below the parting line that is used to ensure that the orifice of the sprue is pulled away. If the pin is too large it will cause the undercut to be larger than necessary and can increase the molding cycle because it must solidify before ejection.
Sprue Puller Pins
June 29, 2017 by