3 Fundamentals of press design

6 Solid forming (Forging)
6.8 Presses used for solid forming
6.8.1 Choice of press
The most suitable press for solid forming is selected by taking into
account the following factors:
– part geometry and material,
– batch sizes and
– the user’s existing equipment (e.g. annealing and phosphating lines).
On the basis of this information, process engineers can select the most
economical production method and recommend a suitable press.
As a general rule, mechanical presses are recommended for large production
lots and batch sizes. The maximum possible part length
depends on the slide stroke and the available ejector stroke. Another
determining factor is the time-motion curve of the press and the automatic
feed system. In the case of shaft-type parts, the maximum transport
length applies instead of the maximum part length. For the preliminary
stages, this dimension is often greater than that of the finished
part. For parts with an internal contour, the penetration depth of the
punch must be taken into consideration. As a rough guideline, the maximum
possible part or transport length suitable for continuous automatic
operation of mechanical presses can be calculated using the following
formula:
for parts with internal contour: 0.35 to 0.45 times slide stroke
for shaft-type parts: 0.45 to 0.60 times slide stroke
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998