Delem
V1101, 9.25
Requirements and recommendations for part support systems
The following remarks are meant to give some recommendations for building an adequate part
support system.
Acceleration and deceleration of the part support system
The part support mechanism should be capable of fast movement and quick response: it should
be able to move with the maximum required speed during bending but it should also be capable
of changing speed quickly when a bending starts or stops.
When a large maximum part support speed is required, even so a large acceleration and
deceleration of the part support is needed to limit the maximum position error and overshoot.
The relation between maximum part support speed and required acceleration / deceleration is
quadratic. When the maximum speed becomes twice as large, the required acceleration becomes
four times as large to maintain the same maximum position error.
Hydraulic part support systems
1. Hose lines
Special care should be taken when using hose lines, because they react elastically on internal
over pressures. Hose lines can have the following disadvantages:
• An increased maximum position error.
• An increased amount of overshoot.
Hose lines should not be mounted between the flow control valve and the cylinder, but for
instance between the pressure control valve and the flow control valve.
2. Flow control valve
The maximum flow of the control valve should not be too large, but should be just large enough
to be able to reach the desired maximum part support speed.
To limit the maximum position error of the part support, it is better to select a flow control valve
which has a relatively short response time.
The flow control valve should be mounted as close as possible to the cylinder, to eliminate the
effect of hydraulic lines between the flow control valve and the cylinder.
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