摘要 |
The invention is directed to a method of working a small recess portion. In the method, prior to press-forming small recess portions arrayed in a row by pressing a predetermined number of pieces of aligned male dies to a metal base plate, the metal base plate is previously formed with a highly rigid portion at a predetermined portion at a vicinity of an imaginary line extending in a row direction along end portions of predicted press portions to which the respective male dies are pressed.
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