3 Fundamentals of press design

392 Sheet metal forming and blanking
These so-called A-parts – there are generally between 30 and 40 of
them per vehicle type – must be grouped together to families of parts.
These are then allocated to the different press systems on which they
can be economically manufactured.
Figure 4.9.2 and Table 4.9.1 illustrate the correlation between part size
and press system. When processing medium-sized panels, a press line with
a medium bed size or a tri-axis transfer press will be employed. Press lines
with large bed sizes or crossbar transfer presses offer the ideal conditions
for processing large panels with low inherent stiffness or double panels.
Figure 4.9.3 offers a more precise allocation of parts to both available
transfer press systems. Some parts can be handled by crossbars with
suction cups as well as by gripper rail systems. They represent the
overlap between two families of parts. Some of these parts, such as
doors, are produced as single parts using gripper rail transfer systems
(cf. Fig. 4.4.29) or as double parts using a crossbar transfer system
(cf. Fig. 4.4.34).
medium dimension:
typical family of parts
press line
up to 3,000 mm
tri-axis transfer press
crossbar transfer press
Fig. 4.9.2 Press systems for the manufacture of car body parts
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
up to 3,000 mm
large dimension:
typical family of parts
press line
up to 5,000 mm
up to 5,000 mm
time