To improve rust-preventing properties by forming a plating layer on an inner circumferential surface of a through-hole made in a board, at the same time as with burr treatment.
A first plating layer 9 is provided on one surface of a steel plate 8, a second plating layer 10 is provided on the other surface, and the steel plates 8 are combined to provide a box body of an electric apparatus. The through-hole 4 having burr 12 formed on one surface by machining is provided at a predetermined position of the steel plate, and a third plating layer 20 formed, by biting by a first plating layer 9 and a fourth plating layer 21, formed by folding the burr 12 of the second plating layer 10, are provided in the inner circumferential surface of the through-hole 4.
MATSUNO YOSUKE
KIKUCHI HIDEJI
| JP2009287082A | 2009-12-10 | |||
| JP2008155219A | 2008-07-10 | |||
| JP2002066653A | 2002-03-05 |