The upper electrode 31 has a hole 35 extending from an upper surface 33 to a lower surface 34, a bolt 36 is inserted from the upper surface 33 of the upper electrode 31 into the hole 35, and secured in a lower electrode 32 by a screw. A disk unit is removably attached to the main body of the electronic apparatus and receives at least one removable hard disk as a removable electronic device removably attached thereto. Each point along the path has associated with it an idealized geometry comprising a melt pool, hot zone and bulk portion.