Sprue removal in an injection molding machine

A method of controlling the movement of a picker assembly when removing a solidified sprue plastic from an injection molding machine, the method comprising:

• providing the picker assembly with an end-effector having a gripper;
• providing the injection molding machine with a stationary platen having a first mold, and with a moveable platen having a second mold;
• monitoring the movement of the moveable platen when the second mold is moving;
• moving the gripper based on the monitored movement of the moveable platen to remove the solidified sprue plastic from the injection molding machine;
• moving the gripper in a direction that is generally perpendicular to the movement of the second mold when the first mold and the second mold are opening;
• and
• grabbing the solidified sprue plastic before the first mold and the second mold move to a fully open position.

An assembly comprising:

• an injection molding machine having a stationary platen with a first mold, and having a moveable platen with a second mold, the injection molding machine including a position sensor to monitor the position of the second mold;
• a picker assembly including an end-effector with a gripper, and including a first servo motor to drive the gripper in a direction that is generally parallel to the movement of the second mold when the first mold and the second mold are opening, and including a second servo motor to drive the gripper in a direction that is generally perpendicular to the movement of the second mold when the first mold and the second mold are opening;
• and
• a controller communicating with the position sensor and commanding the movement of the gripper based on the monitored position of the second mold causing the gripper to grap the solidified sprue plastic before the first mold and the second mold move to a fully open position.