3 Fundamentals of press design

246 Sheet metal forming and blanking
case be sufficiently great to accommodate the crossbars. With a suitable
number and arrangement of the suction cups on the crossbars, it is possible
to transport large one-piece body side panels for passenger cars or
even minivan-type vehicles. The blank dimensions for this type of side
panel can be up to 4,200 � 1,900 mm.
In order to achieve smooth transfer in conjunction with maximum
output, the movement sequences are computer-optimized (Fig. 4.4.36).
Composite carbon fiber materials are used for the crossbars in order to
improve rigidity, damping and to reduce mass. This permits more reliable
part transport to be achieved even at high stroking rates.
With the use of universal stations between the uprights, it is possible
to achieve an optimum degree of production flexibility (Fig. 4.4.37 and
4.4.34). Program control of up to five axes allows the transport of parts
into the ideal position for subsequent operations, thus reducing the
expense of the dies and improving the reliability of die functions.
Furthermore, the universal stations allow the crossbars to assume an
asymmetrical parking position during die closure. This means a marked
reduction in the length of the part transfer and consequently an
stroke
[mm]
2600
2200
1800
1400
slide
mo ement
(slide 2to 5)
return stroke
unloading, parked position
1000
slide
mo ement
(slide 1)
loading, parked position
transport
600
returnstroketo
lift transfer
pick up part (3)
200
0
lower
lift
0 30 60 90 120 150 180 210 240 270 300 330 360
return stroke pick up
in parking position (2)
pickup
lift
Fig. 4.4.36 Motion diagram of a crossbar transfer press
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
die
1
uni ersal
2 3 station
parkedposition
pick up