3 Fundamentals of press design

Shearing lines
Fig. 4.6.11 Rotor and stator blank of an electric motor
in widths of up to 1,300 mm. Rotor and stator sheet laminations can
accordingly be produced from a single piece only up to a maximum
outside diameter of 1,300 mm. All larger diameters are composed of
segments which can be used to produce stacks for electrical machines of
any optional size.
Depending on the geometrical shape and production lot size, the
economical production of laminations for electric motors calls for a
variety of die and machine technologies. Figure 4.6.12 indicates the
fields of application for single notch, complete blanking and progressive
dies. To manufacture rotor and stator laminations in larger lot
sizes, up to a circular blank diameter of 600 mm, compound dies are
used in high-speed blanking lines. For diameters up to 1,300 mm, complete
blanking dies are used in straight-sided presses (Fig. 4.6.13).
Where smaller lot sizes are involved, the laminations are produced
from circular blanks on notching machines using the single notch
blanking method.
Notching machines
Notching machines are generally open-front presses with mechanical
drive systems. The press is mounted in adjustable roller bearings on a
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