ejector pins apply a force to eject a part from the mold, since in some cases they can leave marks, it is important to give proper forethought to their placement when designing a mould. Generally, ejector pins are in the b-side mold half, the side in which the part will stay when the mold opens. Once the mold is opened, the pins extend into the mold cavity, push the part out, and then retract, allowing the mold to close and be refilled.

ejector pins apply a force to eject a part from the mold, since in some cases they can leave marks, it is important to give proper forethought to their placement when designing a mould. Generally, ejector pins are in the b-side mold half, the side in which the part will stay when the mold opens. Once the mold is opened, the pins extend into the mold cavity, push the part out, and then retract, allowing the mold to close and be refilled.