Machinery's Handbook, 31st Edition
1454
Classification of Dies Classification of Dies
Dies may be classified according to a variety of elements and in keeping with the diver sity of die design. According to the number of stations involved, dies for sheet metal work ing may be classified as: a) single-station dies (either compound dies or combination dies) or b) multiple-station dies (progressive dies and transfer dies). Single-Station Dies.— Single-station dies may be compound dies or combination dies. Compound Die: This is a die in which two or more cutting operations are performed to produce a part in a single press stroke. A die that produces washers is a good example of a compound die (Fig. 61).
Piercing punch
Blanking die
Sheet metal strip
Blanking punch and piercing die
Workpiece
Fig. 61. Compound Die Combination Die: This is a die in which both cutting and noncutting operations are per formed to produce a part at one stroke of the press. A combination die is economical, and a more accurate part is obtained because it eliminates the problem of relocating the work piece. However, a combination die is not always desirable; for example, when the punch ing hole is too close to the edge of the blank, the cutting edge would be so weak that failure would result. A die that produces cups with flanges is a good example of the suitable use of combination dies (Fig. 62).
Knockout pin
Knockout plate
Shoe
Stripper plate Sheet metal
Spring
Blanking punch and drawing die
Workpiece
Blankholder
Shoe
Drawing punch
Blanking die
Fig. 62. Combination Die Multiple-Station Dies.— Multiple-station dies are arranged so that a series of sequential operations is performed with each press stroke. Two die types are used:
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