| 摘要 |
PURPOSE:To prevent the wall surface of a hole from being chipped and cracked, by charging resin into a hole in a metallic base plate, and by drilling a through- hole in the thus resin-charged hole while the feed speed of a drill is specified. CONSTITUTION:A circuit conductor is disposed on the upper or lower surface of a holed metal plate through the intermediary of a resin layer to form a laminated body. Accordingly, resin is charged in a hole in the holed metal plate during the molding of the same. A hole is formed in the resin-charged hole in the metallic base plate by means of a drill having a drill feed speed of less than 1.8 m/sec. Therefore, no unreasonable force is exerted to the resin even in the vicinity of the base metal section in the wall surface of the hole, thereby it is possible to prevent the wall surface of the hole from being chipped and cracked.
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