| 摘要 |
A high precision die particularly adapted to form, from a relatively heavy foil sheet, a circuit board where the individual circuit elements and the spacing thereof are of relatively small dimensions. The die is made as follows. A working surface of a die block is covered with a first protective overlay having an enlarged pattern corresponding to the pattern of the die elements to be formed, but enlarged by a substantially uniform width dimension. The surface is then exposed to an etching solution to remove material from the exposed area. These two steps are repeated a second time with a pattern enlarged to a lesser degree, and again a third time to bring the die elements being formed from the die block within quite close tolerances to the original pattern. The die faces of the die elements are then etched to form knife edges on the die elements, in a plurality of etching steps using reduced protective overlay patterns. |
