3 Fundamentals of press design

226 Sheet metal forming and blanking
blank
destacker
blank
feeder
swing arm
feeder
intermediate station with turnover station intermediate station with longitudinal transport
Fig. 4.4.21 Interlinkage of presses with swing arm feeders
ion. However, in this case the energy requirement is greater compared
to a double-action press because the slide is additionally required to
press against the draw cushion (cf. Fig. 4.2.3).
In press lines, the design of the clutch and brake system is important
because automated press lines are frequently operated in the controlled
single-stroke or intermittent mode. As a result of demands for greater
performance, the cycle times of the large-panel presses are continuously
being increased and today can reach as many as 15 strokes per
minute. Consequently, hydraulically actuated clutches and brakes are
frequently used. In combination with a heat exchanger, this design
alternative can sustain a higher energy rate than pneumatically actuated
units, resulting in a higher stroking rate when operated intermittently,
in the controlled single stroke mode. The engagement of
hydraulic clutches can also be damped in order to reduce wear and tear
on the drive system and to reduce noise (cf. Sect. 3.2.4).
Automation
The work sequence of a press line begins with the destacking of blanks
by the destacker, cleaning, lubrication and feed of the blanks to the lead
press (cf. Sect. 4.4.4). On completion of the forming operation, the parts
are fed for further processing such as restriking, trimming, flanging or
piercing. Stacking of the finished parts takes place at the end of the
press line.
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998