A movable iron core unit includes a movable iron core, which is attracted toward a fixed iron core under excitation of a coil, and a guide member made from a resin material and mounted on an outer circumferential side of the movable iron core. Disclosed herein too is a method of aligning a work piece 12 comprising disposing the work piece 12 upon a first plate 30 of a programmable shim 28; activating an actuator 34 with an external stimulus; wherein the actuator 34 is in operative communication with the first plate 30; and displacing the work piece 12. An encoding unit groups a new part acquired by the new-part acquiring unit and a retransmission part acquired by the retransmission-part acquiring unit, and generates a packet. The raw data is processed to generate test result data. In the early stage of a heating cycle the top glass surface is subjected to convection heating more powerful than that applied to the bottom surface and in the final stage of a heating cycle the bottom glass surface is subjected to convection heating more powerful than that applied to the top surface.