A system for removing from a molding tool a runner assembly having a plurality of molded parts that are connected to a runner via gates and subsequently degating the plurality of molded parts from the runner is provided. A metal detection unit is activated to scan for the presence of a metal object placed into a cooking area of the microwave cooking unit. The invention also may leverage a chronological timeline of user action information to infer additional relationships with the focal object. The third NMOS transistor is connected between sources of the first and second NMOS transistors, the main ground line is connected to its one node, and the sub-ground voltage is generated at its other node.