| 摘要 |
PROBLEM TO BE SOLVED: To discharge the punching dusts of a flexible printed board from a lower die taper part one after another without flying out the dust on the surface of the lower die, even when using a die having a stroke so short that a punching-through punch inserted in the die does not reach a position, where it projects to the lower die taper part from its punch holeat the shape work such as removal of blind through-holes or unused portions of a flexible printed board. SOLUTION: A flexible printed board 14 has circular lands formed on both sides of an insulation layer 17 with copper foils 16a, 16b. When punching a portion surrounded by the dashed line A, the copper foil of a part 18 inside the dashed line A is previously etched to expose the insulation layer 17. A dashed line A part is punched by a punching-through punch to make the inside portion 18 of the punching dust easy to bend, as this portion is of only the insulation layer 17. This relaxes the repulsion force of the punching dust and the lower die to prevent the dust from flying out of the lower die. COPYRIGHT: (C)2006,JPO&NCIPI
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