3 Fundamentals of press design

6 Solid forming (Forging)
6.6 Part transfer
Cold and warm forming are mass production processes whose high output
levels and economy are achieved in particular by automation.
Automation in this context includes all devices which, in addition to
loading the wire coil or filling the containers with sheared billets, permit
the transfer of the billet, the preformed part between forming, and where
applicable any scrap (piercing, trimming operations) within the press.
Installations that use wire coil have the advantage that once the wire
end has been fed in, the billet material always assumes a defined position
during the straightening (cf. Sect. 4.8.3), drawing and shearing (cf.
Sect. 6.3). The material is transported within the press by means of a
mechanical transfer device, and the parts leave the press following the
last forming station by sliding down through a chute. In installations
that use sheared billets, the billets must be fed in, oriented, possibly
weighed and conveyed to the pick-up point of the transfer device. The
main focus of investigation part handling is the transportation of workpieces
from one station to the next within the press. The objective is to
utilize kinematic factors and die layout so to:
– guarantee absolutely reliable part transfer – this entails preventing
the part from assuming an undefined, i.e. free position at any
time –,
– ensure that no collision is possible either between the die elements or
between die elements and grippers during idle stroking of the press
(e.g. on start-up or when running the press empty), and
– minimize contact times, in particular in the case of warm forming.
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998