Mold Base Terminology - R

Rails

Sometimes the rails are part of the ejector housing. They are used support the mold on each side of the ejector plates. The mold identification plate is usually mounted on the side of the rail. Rest Buttons- Buttons used to support the ejector plate and keep it flat. They are usually 5/16 in diameter and are strategically placed under the return pins and in between the support pillars.

Return Pins

These are used to return the ejector plates to the home position to prevent damage to the cavity in case the ejector plates are inadvertently left forward when the mold closes. The pins on the outside corners ejector plate used to return ejector system so the mold closing action does not have the ejector pins striking the inside of the cavity. With today's presses and the new standard press functions for low pressure close, this mold feature is practically obsolete.

Retainer Rings

These are used on round components such as stripper rings to keep the strippers in the plates from falling out. Care must be taken to make enough room in the counter bore to allow for the retaining ring to open up adequately during installation. The designer must also allow for access to for the retaining ring wrench to remove the ring when it is required to disassemble the mold.

Ring Gate

Used on cylindrical shapes, this gate encircles the core to permit the melt to first move around the core before filling the cavity.

Runner

The channels milled into a plate in an injection mold that allows material to flow from the machine nozzle to the cavity.

Runner Stripper Plate

This part is used to strip the runner off the sucker pins.

Printable Version