3 Fundamentals of press design

Hydraulic presses
Design of the drive system
The piston force of the slide cylinder, fastened to the press crown, acts
directly on the slide (Fig. 3.3.2 and cf. Fig. 3.1.10). The nominal press
force is the sum of the active surfaces of all pistons multiplied by the
hydraulic pressure. The movement sequence during the press cycle is
executed by the slide cylinder with the slide control. The number of
active hydraulic cylinders does not affect the press function. Whether
the slide is driven at one, two or four points is determined on the basis
of static calculations (cf. Fig. 3.1.3).
The function of the hydraulic system
Hydraulic systems convert electrical energy into hydraulic energy,
which in turn is transformed into mechanical energy with the aid of
the individual hydraulic cylinders inside the press. The hydraulic fluid
in the cylinders actuates the press slide as follows:
filling al e
pressure pipe
piston
return
pipe
die
slide
control
bar
slide
bar bar
part
press
bed
lowering
module
high-speed closure forming returnstroke
Fig. 3.3.2 Functional principle of a hydraulic cylinder driving the slide of a hydraulic press
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
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