Horizontal presses with m odified knuckle-joint If lo n ger fo rm in g st ro kes are n ecessary, a m o d ified kn u ckle-jo in t d rive
syst em can be u sed as a sp ecial variat io n o f t h e st an d ard kn u ckle-jo in t p o wer u n it . Th e fo rce-st ro ke cu rve an d t h e slid e velo cit y co rresp o n d t o
t h e vert ical p ress sh o wn in Fig. 6.8.3
.
6.8.3 Hydraulic presses
Hyd rau lic p resses are also d esign ed in vert ical an d h o rizo n t al layo u t s. Th ey en jo y ext rem ely u n iversal ap p licat io n in so lid fo rm in g bo t h o n a
sin gle-st at io n an d m u lt ip le-st at io n basis, eit h er wit h m an u al o p erat io n fo r sm all bat ch sizes o r fu lly au t o m at ically fo r p ro d u ct io n rat es o f u p t o
1.8 m illio n p ressed p art s p er year. Th ey are freq u en t ly u sed as p resses fo r lo n g sh aft s an d sh aft -t yp e p art s, o r fo r large p art s wit h weigh t s o f u p
t o ap p ro x. 15 kg. As in m ech an ical p resses, t h e select io n o f t h e n ecessary p ress size is
m ad e o n t h e basis o f p art geo m et ry, wo rkp iece m at erial an d o f t h e req u ired m an u fact u rin g p ro cess. Th e basic p rin cip les are d escribed in
Sect s. 3.3 an d
6.5 .
Vertical design Th e h yd rau lic co m p o n en t s an d o il t an ks are gen erally acco m m o d at ed
in t h e p ress cro wn Fig. 6.8.8
. A service p lat fo rm o ffers co n ven ien t m ain t en an ce o f t h e easily accessib le u n it s. Th e u p righ t s are gen erally
co n figu red in t h e fo rm o f a weld ed m o n o b lo c o r p an el st ru ct u re cf. Fig. 3.1.1
. In sp ecial cases fo r exam p le in t h e even t o f sp ace p ro blem s o r t o
red u ce n o ise, t h e p u m p s an d m o t o rs can also be m o u n t ed in t h e fo u n - d at io n o r in a sep arat e ro o m . Vert ical h yd rau lic p resses are gen erally
u sed fo r co ld fo rm in g. Ho wever, it is n o t u n u su al fo r t h em t o also be u sed fo r h o t fo rm in g u n d er cert ain circu m st an ces cf.
Sect . 6.8.5 . Par-
t icu larly wh ere large p art s are in vo lved weigh t s abo ve 5 kg, h yd rau lic p resses are freq u en t ly u sed fo r h o t fo rgin g. Th e u su al p ress fo rces lie
bet ween 1,600 an d 36,000 kN, an d p resses wit h slid e st ro kes o f u p t o 1.5 m h ave alread y been m an u fact u red .
514
Solid forming Forging
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Horizontal design Lo n g t u b u lar p art s su ch as sh o ck ab so rb er sleeves are d rawn fro m
flat b lan ks o r b ackward cu p ext ru sio n s m ad e fro m circu lar b lan ks cf. Fig. 6.1.1
. A su b seq u en t iro n in g p ro cess o ver several st ages t h en red u ces t h e wall t h ickn ess cf.
Fig. 6.1.2 . Th e wo rkp iece is h eld b y a
p u n ch , wh ich d raws it t h ro u gh o n e o r m o re iro n in g rin gs. Th e b o t t o m t h ickn ess rem ain s u n ch an ged . Fo r t h is p ro cess, ext rem ely lo n g fo rm in g
st ro kes are req u ired . Th erefo re, in su ch ap p licat io n s h yd rau lic p resses are m o st freq u en t ly u sed .
A h o rizo n t al p ress layo u t h as a n u m ber o f ben efit s t o o ffer h ere: – set -u p o n flo o r level,
– sim p le gravit y feed , – sim p le d isch arge by m ean s o f syn ch ro n ized co n veyo r belt s,
– sim p le in terlin kin g, for exam p le with au tom atic edge trim m in g de- vices.
515
Presses used for solid forming
Fig. 6.8.8
Hydraulic multiple-station press nominal press force 20,000 kN, four stations, loading system, transfer feed and die change support
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Figure 6.8.9 illu st rat es t h e layo u t o f a p art icu larly eco n o m ical p ress sys-
t em fo r iro n in g. Th e slid e is d riven o n t wo sid es by p lu n ger p ist o n s. Th e d ie set s are lo cat ed o n bo t h sid es wit h lo ad in g ch am bers p o sit io n ed in
fro n t . Th e righ t an d left -h an d p u n ch es are gu id ed im m ed iat ely in fro n t o f t h e wo rkp iece lo ad in g ch am ber u sin g an ad d it io n al p u n ch su p -
p o rt . Wit h each st ro ke, alt ern at ively fo rm in g an d st rip p in g o f t h e fo rm ed p art t ake p lace o n eit h er sid e. Each n ew wo rkp iece p u sh es t h e
p revio u sly st rip p ed p art t h ro u gh t h e wo rkp iece h o ld er o u t o f t h e p ress. Wit h t h e sam e fo rm in g p ro cess t akin g p lace in t h e left an d righ t -h an d
d ie set s, it is p o ssible t o alm o st d o u ble t h e o u t p u t co m p ared t o a co n - ven t io n al vert ical p ress d esign . Alt ern at ively, t h e p art p ro d u ced in o n e
o f t h e d ie set s can be fu rt h er p ro cessed in t h e o t h er d ie set fo llo win g in t erm ed iat e t reat m en t . In t h e case o f t h ick-walled blan ks, an u p st ream
d eep -d rawin g p ro cess can be in t egrat ed as an in it ial o p erat io n . Precise slid e gu id an ce o n t h e p ress bed an d p recisely ad ju st able p u n ch gu id -
an ce p erm it t o o bt ain ext rem ely n arro w t o leran ces co n cern in g t h e co n - cen t ricit y o f d im en sio n s.
516
Solid forming Forging
Fig. 6.8.9
Horizontal hydraulic press w ith one slide and tw o press beds
punch guide loading chamber
punch support ironing ring
stripper
slide die chamber slide stroke
die holder die holder
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
6.8.4 Supplementary equipment
