3 Fundamentals of press design

Shearing lines
Fig. 4.6.21 Automatic die change using a die changeover cart
Larger rotor and stator laminations, in contrast, are still arranged in
accordance with their notching pattern in the die, stacked on mandrels
or in magazines up to a preselected stack height and conveyed out of
the press by means of transport systems. A sequence of stacks of varying
heights, for example for ventilated motors, can also be programmed.
Another method for the ordered unloading of electric laminations is
by punch-bundling (Fig. 4.6.22). For this purpose, additional punches
are located in the die set and they punch for example lugs, cams or neps
into the laminations. During the cut-out process, these raised areas
press the laminations into the corresponding recess in the previously
punched part (Fig. 4.6.23). Once the required stack height has been
reached, the following lamination is pierced where the raised area is
prior to bundling by means of a piercing hole punch. This ensures that
the pierced lamination is not able to link up with the previous lamination
and becomes the first lamination of the new stack.
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
309