3 Fundamentals of press design

Changing dies
are changed in solid forming (cf. Fig.6.7.1). For dies weighing under 10
to 15kg, this is generally performed manually. For heavier dies, when
changing individual die blocks or for hot forming, die changing arms
with a hoisting power of 50 to 800kg are used (Fig. 3.4.5). The up and
down movement is powered by electric motor in mechanical presses,
while hydraulic presses are fitted with hydraulic lifting cylinders. The
swivel or traversing movement into the die space can be executed manually,
or controlled by pushbuttons to the preselected die position.
Alternatively, fully automatic systems are also available.
3.4.2 Die clamping devices
The clamping of dies onto the bed and slide clamping plates must be performed
as quickly and reliably as possible. Clamping devices are either
electrically or hydraulically powered, in some cases also in combination
with manual actuation by means of spring power, threaded spindles, toggle
lever, wedge action or self-locking mechanisms. Whichever means is
used, safety is always a prior concern (Fig. 3.4.6). Different clamping
systems are often used for the upper and lower die, since the lower dies
Fig. 3.4.5 Die changing arm for solid forming
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
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