3 Fundamentals of press design

Fine blanking
subsequently quenched and tempered. Gear teeth and various chain
wheels can also be highly economically fine blanked.
4.7.3 Fine blanking tools
Tool types
Internally and externally contoured parts are produced in a single
stroke of the slide using complete blanking dies. The blanking burr is
located on the same side for both the inside and outside contour. Parts
manufactured in this way exhibit a high degree of flatness. The dimensional
tolerances of the parts depend largely on the manufacturing
quality of the die. Tolerances in the coil feed do not influence the
dimensional tolerances of the blank.
Due to the complex part geometries involved, in the case of progressive
blanking dies, blanking of part contours takes place in a number of
stages (cf. Sect. 4.1.1). For internal transfer from one station to the next
within the die, the part remains in the strip or scrap web. These are
referred to as pre-piercing dies whereby the pre-piercing process can
take place in one or more stages and is performed prior to blanking of
the outside contour. Here, the differences in feed exert an influence on
Fig. 4.7.20 Fine blanked parts used in the automobile industry
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