Supplementary equipment Presses used for solid forming .1 Choice of press

6.8.4 Supplementary equipment

A large n u m ber of sp ecial m easu res an d eq u ip m en t are available to ad - d ress ever m ore strin gen t d em an d s for m axim u m p ossible p rod u ction ou tp u ts, low set-u p tim es an d th e m in im u m ach ievable m an u factu rin g costs. Th e m ost im p ortan t elem en ts h ere are system s for th e au tom atic load in g an d tran sfer of p arts th rou gh variou s d ie station s. Loading system s for blanks and pre-form ed workpieces W h ere p art s weigh in g less t h an 150 g are p ro d u ced , p resses are gen eral- ly lo ad ed u sin g vibrat io n feed in g d evices wh ich are filled u sin g in clin ed co n veyo rs. Heavier p art s are gen erally fed u sin g in clin ed co n veyo rs wit h ro t at in g st eel belt s o r – in p art icu lar wh ere p re-fo rm ed p art s are bein g fed – by m ean s o f p u sh in g co n veyo rs. Th e o u t feed area o f t h ese syst em s is eq u ip p ed wit h d evices fo r p art o rien t at io n t o en su re t h at t h e p art s are co rrect ly align ed wh en t h ey en t er t h e in -feed ch an n el an d t h e lo ad in g st at io n Fig. 6.8.10 . 517 Presses used for solid forming Fig. 6.8.10 Loading device for cold extrusion press lines Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998 Feed system s A n u m ber o f d ifferen t feed syst em s can be u sed t o t ran sfer t h e p art s t h ro u gh t h e p ress an d in t o t h e d ies. Th e so -called t ran sfer feed syst em is t h e d o m in at in g m et h o d fo r vert ical m u lt ip le-st ep p resses. Feed sys- t em s co m e in a d u al-axis versio n , o r wit h an ad d it io n al lift in g st ro ke fo r lo n g p art s, in t h e fo rm o f a t ri-axis t ran sfer. Th e co n t ro l cam s are d riven in m ech an ical p resses by d irect co u p lin g wit h t h e p ress d rive syst em . In t h e case o f h yd rau lic p resses, t h e vario u s u n it s are act u at ed by servo d ri- ve syst em s Fig. 6.8.11 . Hyd rau lically d riven swivel-m o u n t ed grip p ers are u sed t o t ran sp o rt h eavy p ressed p art s wit h weigh t s o ver 5 kg Fig. 6.8.12 . Th e co n t ro lled grip p ers are co n figu red fo r a su bst an t ially h igh er clam p in g fo rce t h an is p o ssible u sin g t ran sfer feed syst em s. Th e swivel-m o u n t ed grip p ers gen - erally execu te a liftin g m ovem en t. A load in g arm swivel or lin ear m ove- m en t is u sed to tran sfer th e p arts from th e load in g station in to th e first p ressin g station , an d on e grip p er arm is allocated to each d ie station . 518 Solid forming Forging Fig. 6.8.11 Tw o-axis transfer feed Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998 In ad d it io n t o t h ese syst em s, a n u m ber o f o t h er feed d evices is u sed in clu d in g t h e freely p ro gram m able h an d lin g ro bo t . In h o rizo n t al m u l- t ip le-st at io n p resses, grip p er arm s p o wered in d ivid u ally by cam s o r ser- vo d rive syst em s are u sed . W eight control W h en billet s are p rep ared , weigh t d ifferen ces are u n avo id able. Th ese are t h e resu lt n o t o n ly o f len gt h t o leran ces o ccu rrin g d u rin g t h e billet sep arat io n , bu t also so m et im es t o a far great er ext en t o f d iam et er t o l- eran ces in t h e st art in g m at erial. Part icu larly wh en u sin g clo sed t rap p ed d ie syst em s, exceed in g t h e ad m issible blan k weigh t m ay cau se d ie failu re. W h en t ran sp o rt in g t h e co n t ain er filled wit h billet s t o t h e in t erm ed i- at e t reat m en t p ro cesses an d t o t h e p ress, it is also p o ssible fo r p art s t o be accid en t ally p laced in t h e wro n g co n t ain ers. Th is can n at u rally lead t o d ie d am age wh en p ressin g. In o rd er t o elim in at e t h e risk o f feed in g in co rrect p art s, au t o m at ed p ress lin es are freq u en t ly eq u ip p ed wit h a 519 Presses used for solid forming Fig. 6.8.12 Sw ivel arm feed for pressed parts w ith piece w eights up to 15 kg Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998 d evice wh ich ch ecks p art weigh t . Th e d evices u sed h ere are elect ro n i- cally co n t ro lled au t o m at ic scales, wh ich are m o u n t ed bet ween t h e lo ad in g syst em an d t h e feed in g st at io n . Part s wh ich are t o o h eavy o r t o o ligh t are au t o m at ically eject ed . Th e weigh in g accu racy is belo w 0.2 o f wo rkp iece weigh t . Th ese d evices are able t o weigh au t o m at i- cally u p t o 80 p art s p er m in u t e. Die change Fast d ie ch an ge can be a d ecisive factor wh en it com es to th e econ om ic viability of a p ress, in p articu lar wh en workin g with sm all batch sizes. Both d ie set an d in d ivid u al d ie ch an gin g system s are u sed cf. Fig. 3.4.5 . Th e basic d ie ch an ge p rin cip le u sed in p resses for sh eet m etal form in g an d solid form in g are very sim ilar. A m ore d etailed d escrip tion is p ro- vid ed in Sect. 3.4 . However, d ie ch an ge is on ly on e asp ect wh ich d eter- m in es sh ort set-u p tim es in au tom atic p ress lin es. Fast resettin g of th e load in g an d feed system s is eq u ally im p ortan t h ere.

6.8.5 Special features of hot and w arm forming lines