Th ere is a bro ad ran ge o f p o ssible so lu t io n s fo r p art t ran sfer, in clu d - in g t ran sp o rt d evices in t h e bro ad er sen se, su ch as t ilt in g m ech an ism s
fo r billet co n t ain ers, st eep co n veyo rs p u sh er o r ch ain co n veyo rs, vibrat in g co n veyo rs, sep arat in g d evices an d scales. Th erefo re, t h ese will
n o t be d ealt wit h h ere. Th is ch ap t er will co n cen t rat e in st ead o n t h e lo ad in g st at io n an d t h e t ran sfer st u d y fo r a m ech an ical co ld fo rm in g
p ress wit h 2D t ran sfer cf. Sect . 4.4.6
.
6.6.1 Loading station
Th e wid e d iversit y o f p art s t h at m u st be fed in t o a fo rm in g p ress calls fo r a n u m ber o f d ifferen t lo ad in g st at io n co n cep t s. W h ere cylin d rical
billet s wit h a len gt h d iam et er L D rat io great er t h an 0.8 are bein g p ro cessed , t h ey are lo ad ed fro m abo ve in t o t h e feed in g st at io n by
m ean s o f a feed ch an n el Fig. 6.6.1
, top. Th e bo t t o m -m o st p art s are h eld in a h o ld er, gen erally cylin d rical in sh ap e, t h at is p ro vid ed wit h
recesses o n t h e sid e t o allo w fo r t h e clo sin g m o vem en t o f t h e grip p er. Fo llo win g t h e rem o val o f t h e first p art , t h e weigh t o f t h e co lu m n cau s-
es it t o d ro p o n t o t h e base p lat e at t h e level o f t h e t ran sp o rt p lan e. W h ere billet s wit h d ifferen t d im en sio n s are fed , if n ecessary t h e feed
ch an n el an d t h e exch an geable p art s o r t h e co m p let e feed u n it can be exch an ged wit h t h e aid o f q u ick-act in g clam p s. Th e grip p ers are
eq u ip p ed fo r cylin d rical p art s wit h p rism at ic act ive grip p er elem en t s wh o se h eigh t sh o u ld be ap p ro x. 50 o f t h e billet len gt h t o en su re a
reliable grip p in g act io n . If th e L D ratio is below arou n d 0.8 to 1, or if form ed p arts with rela-
tively flat geom etry are bein g p rocessed Fig. 6.6.1
, bottom , th en th e p arts are con veyed in to th e load in g station sid e by sid e in sp ecially
d esign ed feed ch an n els. Th e p arts are p osition ed in itially below th e tran sp ort p lan e, an d are raised by a p u sh er to tran sp ort level in syn ch ro-
n ization with th e p ress cycle. After th e p u sh er retu rn s to its startin g p osi- tion , th e n ext p art slip s in to th e load in g station to be raised to th e tran s-
p ort p lan e. Th e startin g h eigh t an d feed an gle of th e feed ch an n els are con figu red in su ch a way th at th e billets con tin u e to slid e u n d er th eir
own weigh t. In th e case of form ed p arts, th e grip p ers are d esign ed for sh ap ed fit if a p rism atic grip p er exh ibits an u n favorable L D ratio an d
th ere is a d an ger th at billets cou ld rotate wh ile bein g h eld by th e grip p er.
479
Part transfer
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
480
Solid forming Forging
Fig. 6.6.1
Loading station concepts for cylindrical top, disc-shaped or flat shaped parts
bottom
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Fo r co ld fo rm in g p ro cesses, t h e grip p er u n it s are m o u n t ed o n clam p - in g rails wh ich are fixed in t u rn o n a base rail
Fig. 6.6.1 . W h en reset -
t in g fo r p ro d u cin g a d ifferen t p art , all t h at h as t o be exch an ged are t h e clam p in g rails in clu d in g t h e p re-set grip p ers. Th e fro n t grip p ers are
eq u ip p ed wit h p ro xim it y swit ch es t o m o n it o r p art t ran sfer. Part s wit h a h igh er L D rat io ap p ro x. 3 t o 8 m u st be t ran sferred
bet ween st at io n s by a 3D t ran sfer. Th is in vo lves t h e u se o f an ad d it io n - al h o rizo n t al p u sh er wh ich m o ves t h e p art t o get h er wit h it s ret ain er
in t o a p o sit io n fro m wh ere it can be raised vert ically. Here, t o o , t h e lev- el o f t h e base p lat e o n wh ich t h e p art s are p o sit io n ed is lo cat ed belo w
t h e t ran sp o rt p lan e. Sh aft -sh ap ed p art s wit h a billet L D rat io o f 6 can also be m o ved in t o t h e u p lift p o sit io n u sin g sp ecial d evices su ch as
ro t at in g sleeve ret ain ers. In warm fo rm in g, t h e lo ad in g st at io n h as t h e ad d it io n al fu n ct io n o f
segregat in g p art s wh ich eit h er h ave n o t been fed in co rrect syn ch ro - n izat io n wit h t h e p ress, o r wh ich h ave an in co rrect t em p erat u re. To
allo w t h ese p art s t o be eject ed , an o p en in g is released in t h e base p lat e o f t h e lo ad in g st at io n t h ro u gh wh ich t h e p art s d ro p d o wn in t o a ch u t e
fo r rem o val.
6.6.2 Transfer study
