Provided are a flexible printed circuit that reduces the chance of the occurrence of short-circuit failures caused by swarf generated from punching out flexible printed circuit, and an electric circuit structure having this flexible printed circuit and an electric circuit substrate to which the flexible printed circuit is connected. A file object is identified in the computer that is required by the process. A sheet of material suitable for bending using the process also is disclosed, as are the use of coatings, shin guards and displacing the area of the sheet between bending inducing slits. A charge starting point is calculated by the computer, at which the ignition output stage begins to control a current flow through the primary side.