3 Fundamentals of press design

Presses for hydroforming
Controllable pumps fill the workpieces up to a defined initial pressure
with pressure medium. Pressure levels exceeding this are generated
by the pressure intensifier. The line control system is configured for at
least four controlled hydraulic axes – one pressure intensifier, two horizontal
cylinders and one counterpressure cylinder. All these axes can
be controlled to be displacement or pressure-dependent. The closing
process for coined bends is provided as the fifth axis. The number of
axes can be increased, for example if different components or components
with subsequent stroke have to be formed in a single press stroke.
All the necessary process data is entered at the host computer (cf.
Sect. 3.5). The sequence of the forming process is executed in the form
of a series of steps containing the data on various axes and any additional
control commands. The pressure and position of all axes can be
monitored during execution of the process on-line on the screen. They
can also be recorded. The programmed data from the step chain can be
viewed at any time in the form of a diagram. It is possible to draw up a
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
Fig. 5.6.1
Four-upright hydroforming press
with a closing force of 25,000 kN
427