Tran sp o rt co n t ain ers wit h st ack lat ch es p erm it in d ivid u al rem o val by in d u st rial ro bo t s. Th e u n it is also eq u ip p ed wit h a d et ect io n syst em fo r
t ran sp o rt co n t ain ers an d wit h an elect rical an d m ech an ical co n t ro l sys- t em fo r t h e st ack lat ch es. Th is en su res t h at t h e t ran sp o rt co n t ain ers
belo n gin g t o t h e vario u s fin ish ed p art s are m ad e read y an d t h at t h e st ack lat ch es are ad ju st ed t o t h e geo m et ry o f t h e fo rm ed sh eet m et al
p art s. Th e t ran sp o rt co n t ain ers arran ged o n bo t h sid es o f t h e co n veyo r belt
gu aran t ee co n t in u o u s st ackin g even d u rin g co n t ain er ch an geo ver. A su p p lem en t ary co n veyo r belt can be u sed t o t ran sp o rt p art s o u t o f t h e
p ress in t h e even t o f a m alfu n ct io n in t h e st ackin g u n it o r fo r in sp ec- t io n p u rp o ses wit h o u t in t erru p t in g t h e p ress o p erat io n .
In ad d it io n t o t h e so lu t io n u sin g o verh ead feed ers, in d u st rial ro bo t s wit h six axes can be u sed fo r rem o val an d st ackin g o f fin ish ed p art s.
Th is t yp e o f au t o m at io n co n cep t m akes p art icu lar sen se wh en t h e p art s are p laced t o be read y in t h e assem bly p o sit io n by t h e h an d lin g d evice,
n ecessit at in g an ad d it io n al ro t at in g o r t ilt in g m o vem en t . Th is t yp e o f co n cep t is fo u n d n o t o n ly in p resses bu t also fo r flan gin g an d weld in g
o p erat io n s u sed in p lan t co n st ru ct io n ap p licat io n s cf. Sect . 4.6.5
.
4.4.11 Control systems for large-panel transfer presses
Th an ks t o t h e p ro gress m ad e in m icro elect ro n ic en gin eerin g n o w elec- t ro n ic co n t ro l syst em s, in d u st rial PCs, h igh -sp eed co m m u n icat io n sys-
t em s an d d igit al d rive syst em s are available an d can be u sed in t h e d evelo p m en t o f eco n o m ical p ress co n t ro l syst em s o fferin g m axim u m
co n t ro l cap abilit y fo r t h e o p erat in g t eam . Co n t ro l syst em s able t o co m p ly wit h t h e sp ecific req u irem en t s o f
large-p an el p resses m u st fu lfil t h e fo llo win g crit eria: – clearly arran ged , easily u n d erst o o d p ress co n t ro l st ru ct u re,
– u se o f st an d ard m o d u les an d id en t ical p art s t o red u ce co m p o n en t variet y,
– clearly arran ged o p erat in g an d visu al d isp lay syst em wit h o u t excess am o u n t s o f in fo rm at io n ,
– o p erat o r su p p o rt wh erever o p erat o rs are lo cat ed ,
254
Sheet metal forming and blanking
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
– efficien t t ro u blesh o o t in g, back-u p in co rrect in g m alfu n ct io n s an d rep airin g failed co m p o n en t s,
– u se o f p ro ven st an d ard co m p o n en t s fro m m an u fact u rers o fferin g wo rld wid e service,
– u se o f st an d ard co m m u n icat io n syst em s, – n o n -st an d ard so lu t io n s o n ly in fu n ct io n al areas wh ere t h is is u n -
avo id able, – co m p lian ce wit h cu st o m er regu lat io n s an d sp ecificat io n s,
– co o rd in at io n wit h an d ap p ro val fro m cu st o m er regard in g t h e co n t ro l co n cep t .
As an exam p le o f co n t ro l en gin eerin g ap p lied in large-p an el p resses, t h e fo llo win g is a d escrip t io n o f control concepts for large-panel transfer press-
es with crossbar transfer system cf. Sect . 4.4.8
. Th e m o d u lar m ech an ical st ru ct u re an d t h e act ive u n iversal st at io n s are o f p art icu lar relevan ce fo r
t h e st ru ct u re o f t h e co n t ro l syst em . Th e con sisten tly m odu lar decen tralized con trol stru ctu re direct-
ly reflects th e m odu lar m ech an ical stru ctu re of th e p ress itself Fig. 4.4.42
. Th e blan klo ad er, each p ress m o d u le an d t h e asso ciat ed u n iversal st a-
t io n are each eq u ip p ed wit h t h eir o wn co n t ro l u n it , t h e so -called local control unit. It co n sist s o f t h e co n ven t io n al p art , t h e PLC syst em , t h e
d ecen t ral in p u t o u t p u t syst em an d t ask-sp ecific in d ivid u al elect ro n ic co n t ro l syst em s, an d each h as it s o wn lo cal visu alizat io n u n it .
Cen t ral fu n ct io n s su ch as m o d e select io n , clu t ch brake, m ain d rive, t ran sfer syst em wit h lo ad in g feed er, o p erat in g u n it s an d t o o l d at a m an -
agem en t are t h e resp o n sibilit y o f a central control unit in co n ju n ct io n wit h a cen t ral visu alizat io n u n it .
All t h e lo cal co n t ro l u n it s o f t h e p ress are id en t ical in t h eir in t ern al st ru ct u re, o n ly t h e first co n t ro l u n it d iffers fro m t h e o t h ers. Here, t h e
fu n ct io n s fo r t h e bed cu sh io n are ad d ed an d t h e fu n ct io n s relat in g t o t h e u n iversal st at io n s d o n o t ap p ly. Th e PLC p ro gram s o f all lo cal co n -
t ro l u n it s are id en t ical: Differen t fu n ct io n al req u irem en t s are d et ect ed by t h e p ro gram by m ean s o f h ard ware id en t ifiers at t h e PLC in p u t s.
Th e lo gical co m m u n icat io n st ru ct u re is st rict ly st ar-sh ap ed , i. e. n ei- t h er d at a n o r sign als are exch an ged bet ween t h e lo cal co n t ro l u n it s.
Th ese st ru ct u ral ch aract erist ics resu lt in st an d ard ized , easily m an age- able co n t ro l u n it s wit h a t ran sp aren t flo w o f in fo rm at io n an d a n u m ber
o f ap p reciable ben efit s fo r t h e u ser:
255
Sheet metal forming lines
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
– red u ced fam iliarizat io n p erio d s fo r t h e u n it o p erat o rs an d m ain t e- n an ce st aff,
– sim p lified t ro u blesh o o t in g an d m ain t en an ce, – sim p le d at a lin k t o h igh er-level syst em s.
Th e u n d erlyin g ch aract erist ics o f t h e elect rical eq u ip m en t an d t h u s also t h e p ress co n t ro l syst em were d escribed in
Sect . 3.5 . Th e exp lan at io n
p ro vid ed h ere d eals wit h t h e sp ecific p ro p ert ies an d fu n ct io n al ch arac- t erist ics o f t h e co n t ro l syst em fo r t h e abo ve-m en t io n ed p ress t yp e.
Operating m odes of the press Th e u ser h as t h e fo llo win g p ress o p erat in g m o d es available:
– Set-up: Th is m o d e is u sed fo r execu t in g m an u al o p erat io n s, fo r exam - p le o n in it ial p ress ru n -u p , wh en rest art in g aft er a m alfu n ct io n o r
wh en ru n n in g in n ew d ies. – Single cycle: O n e p ress cycle is execu t ed at a lo w st ro kin g rat e.
256
Sheet metal forming and blanking
Fig. 4.4.42
Control structure of a crossbar transfer press
central PLC
PLC PLC PLC PLC PLC PLC
industrial PC
production line bus system
destacker production
operating data and measured data
acquisition
central control
and visualization
local control systems
local visualization
production line
printer printer
PLC: programmable, logic controller AST: axis control VIS: visualization Z: universal station 5 NC axes FEEDER
crossbar transfer press Z
Z Z Z
AST AST
AST AST
STATION 1 STATION 2 STATION 3 STATION 4 STATION 5
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
– Autom atic: Th is is t h e m o d e u sed fo r p art p ro d u ct io n . Th e p ress exe- cu t es cyclical p ro d u ct io n st ro kes at t h e set st ro kin g rat e, e. g. 15
st ro kes p er m in u t e. – Die change: In th is m od e, th e lin e is reset for th e n ext job. Th e en tire
d ie set an d all th e d ie-sp ecific toolin g are exch an ged . In case of fu lly au tom atic d ie ch an ge, all fu n ction s are con trolled by th e PLC with ou t
an y in terven tion by op eratin g staff. Th e seq u en ce can be m on itored at th e visu alization system u sin g th e syn op tic d ie ch an ge d isp lay.
Conventional control system Th e co m p o n en t s an d m ain fu n ct io n s o f t h e co n ven t io n al p ress co n t ro l
system were d escribed in Sect. 3.5. A m ajor com p on en t of con ven tion al con trol system s is safety control. Tod ay, th is still gen erally m akes u se of
con ven tion al tech n ology u sin g con tacts, alth ou gh m ach in es su p p lied to au tom obile m an u factu rers in th e US are freq u en tly op erated u sin g
red u n d an t PLC system s. Fo r co n sid erat io n s o f o p erat in g safet y, t h e aim is t o also allo w t ran s-
fer p resses t o o p erat e even in t h e set -u p m o d e o n ly wit h clo sed p ro t ec- t ive gear; t h is p erm it s co n sid erable sim p lificat io n o f t h e safet y co n t ro l
syst em wh ile at t h e sam e t im e en h an cin g wo rkin g safet y fo r p erso n n el. Electronic control system
Th e elect ro n ic co n t ro l syst em co m p rises t h e p ro gram m able lo gic co n - t ro llers PLC, t h e in p u t o u t p u t syst em , t h e axis co n t ro l syst em s an d
t h e co m m u n icat io n syst em p ress bu s syst em . Every PLC is assign ed t o an in p u t o u t p u t syst em . Th e co m p o n en t s o f t h e inputoutput system , t h e
in p u t o u t p u t m o d u les, are lo cat ed in t h e t erm in al bo xes lo cat ed at t h e in d ivid u al st ru ct u ral elem en t s o f t h e m ach in e.
Co m m u n icat io n bet ween t h e PLC an d t h e relevan t in p u t o u t p u t m o d u les is execu t ed by a h igh -sp eed , easily in st alled field bus system
wit h a d et erm in ist ic co n st an t , p re-calcu lable t im e resp o n se. To co n - t ro l t h e NC Nu m erical Co n t ro l axes, t h e u n iversal st at io n s an d o t h er
fu n ct io n al u n it s, axis control system s are u sed in co n ju n ct io n wit h h igh - ly-d yn am ic servo d rives an d abso lu t e p o sit io n m easu rin g syst em s. Th e
axis m o vem en t cycles m u st be execu t ed in syn ch ro n izat io n wit h t h e t ran sfer m o vem en t . Th e line com m unication system lin ks t h e p ro gram -
m able lo gic co n t ro llers wit h each o t h er an d wit h t h e cen t ral u n it s o f t h e visu alizat io n syst em .
257
Sheet metal forming lines
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Th e switch cabinets wh ich acco m m o d at e t h e co m p o n en t s o f t h e elec- t rical co n t ro l syst em are arran ged wh erever p o ssible o n t h e p ress cro wn .
Swit ch cabin et s fo r t h e vario u s u n it s su ch as t h e h yd rau lic u n it , t h e lu bricat io n syst em an d t h e h yd rau lic d raw cu sh io n are m o u n t ed in t h e
p ress p it . O verall, t h is p ro d u ces an efficien t ly fu n ct io n in g, d ecen t ral- ized , m o d u lar-st ru ct u re p ress co n t ro l syst em .
Operating and visualization system In co m p lex p ro d u ct io n lin es wh ich are sp read o ver a wid e area su ch as
large-p an el t ran sfer p resses, t h e o p erat in g syst em is o f m ajo r sign ifi- can ce in d et erm in in g p ro d u ct ivit y levels. A d et ailed , clearly arran ged
rep resen t at io n o f t h e lin e st at u s, co m p reh en sive o p erat o r p ro m p t in g fo r set -u p fu n ct io n s, an d an efficien t t ro u blesh o o t in g syst em are im p o r-
t an t p rereq u isit es fo r safe an d efficien t o p erat io n , as well as fo r red u c- in g p ress d o wn t im e.
Co n t ro l u n it s are p o sit io n ed at all t h e m ajo r o p erat in g st at io n s o f t h e p ress lin e
Fig. 4.4.43 . Lo cal co n t ro l p an els are m ain ly lo cat ed o n t h e
p ress o p erat in g sid e an d also in red u ced fo rm at t h e rear o f t h e p ress.
258
Sheet metal forming and blanking
Fig. 4.4.43
Operating points on a crossbar transfer press
ST1L
ZBP visualization unit + control and signalling devices
visualization unit + control and signalling devices
control and signalling devices STxR
STxL central control desk
control panel, right control panel, left
moving bolster
moving bolster
ST1R ST2R ST3R ST4R ST5R ST6R ST2L ST3L ST4L ST5L ST6L
ZBP
upright
right left
2 3 4 5 6
1
throughfeed direction
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Lo cal o p erat in g u n it s are eq u ip p ed wit h all t h e n ecessary fu n ct io n s relat ed t o t h e o p erat in g st at io n in q u est io n .
Cen t ral co n t ro l fu n ct io n s su ch as p reselect io n o f o p erat in g m o d es, m ain d rive syst em O N o r st art o f d ie ch an ge, are execu t ed fro m t h e cen -
t ral co n t ro l d esk. In m ach in es d elivered t o US au t o m o bile m an u fact u r- ers, p en d en t co n t ro l u n it s are freq u en t ly m o u n t ed alo n g t h e len gt h o f
t h e p ress wh ich allo w cen t ral co n t ro l fu n ct io n s t o be m ad e available lo cally t o o p erat in g st aff.
Alo n gsid e t h e classical o p erat in g an d d isp lay elem en t s su ch as p u sh - bu t t o n s an d p ilo t lam p s, m o d ern o p erat in g syst em s fo r co m p lex lin es
freq u en t ly m ake u se o f co lo r grap h ic visu alizat io n syst em s. Dep en d in g o n t h e level o f co m p lexit y o f t h e visu alizat io n syst em , in d u st rial PCs o r
co m p act , in t elligen t o p erat in g t erm in als wit h grap h ic cap abilit y are u sed in lo cal co n t ro l p an els.
Th e visu alizat io n syst em is u sed fo r u ser p ro m p t in g an d gu id an ce d u rin g st art -u p , o p erat io n an d m o n it o rin g o f t h e eq u ip m en t , an d also
fo r t ro u blesh o o t in g an d d iagn o st ic fu n ct io n s. Figure 4.4.44
in d icat es
259
Sheet metal forming lines
Fig. 4.4.44
Functions of the visualization system used on large-panel presses
logging communication
die data
maintenance instructions
error messages
machine data
line operation
– with the line control system – with higher-le el systems
– production data – error and standstill signals
– die data – machine data
– error messages – display of cause, error type
and error location te t and graphics
– machine data input display masks
– machine data storage –
reely programmable maintenance instructions with
inter al strokes per hour
isuali ation system
– die inde – die data input display masks
– die data storage and management
– limit alue check on input machine data
– ready-to-run synoptic o er iew, oom-in
– operator prompt synoptics – status displays
– die change synoptic – line o er iew
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
t h e fu n ct io n s o f a visu alizat io n syst em u sed in large-p an el p resses. Usin g m o d ern o p erat in g t ech n iq u es su ch as p u ll-d o wn m en u s an d win -
d o ws t ech n o lo gy, t h e p ress o p erat o r is able t o access t h e req u ired fu n c- t io n s q u ickly an d sim p ly. It is also p o ssible t o ju m p acro ss bet ween
fu n ct io n al areas an d fro m o n e im age t o t h e n ext . Th e im age fram e is st ru ct u red id en t ically fo r all t h e m asks, an d t h e fu n ct io n key assign -
m en t an d o p erat in g p ro ced u res are st an d ard ized t h ro u gh o u t . No grap h ic in p u t d evice su ch as a m o u se o r t rackball is req u ired . Th is
m akes wo rkin g wit h t h e u ser in t erface o f t h e visu alizat io n syst em ext rem ely easy t o learn . Wit h a m in im u m o f p ract ice, t h e syst em can be
q u ickly an d safely o p erat ed . Th e ready-to-run synoptic display
Fig. 4.4.45 , freq u en t ly also referred
t o as t h e p ress syn o p t ic, serves t o p ro m p t t h e u ser o n e st ep at a t im e u n t il read y-t o -ru n st at u s is reach ed . Green sq u ares rep resen t fu lfilled
an d red sq u ares u n fu lfilled co n d it io n s. Alo n gsid e read y-t o -ru n st at u ses o f t h e fu n ct io n al areas o f t h e p ress, read y-t o -ru n st at u ses o f o t h er lin e
260
Sheet metal forming and blanking
Fig. 4.4.45
Ready-to-run synoptic of a crossbar transfer press
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
m o d u les are also in d icat ed ; in t h is case o f t h e blan k lo ad er. Wit h t h e aid o f t h e so -called zo o m fu n ct io n , it is p o ssible t o access a d et ailed syn o p -
t ic fo r each o f t h e list ed co n d it io n s. Th is can be act u at ed m an u ally by select in g wit h t h e cu rso r, o r in t h e “Au t o m at ic” syn o p t ic m o d e. Here, a
d et ailed syn o p t ic is d isp layed au t o m at ically wit h t h e first u n fu lfilled co n d it io n . As syn o p t ic d isp lays are so clear an d easy t o u n d erst an d ,
t h ey are also u sed fo r t h e d ie ch an gin g seq u en ce an d fo r o p erat o r p ro m p t in g. Th e die change synoptic d isp lays all t h e seq u en t ial st ep s an d
t h eir cu rren t execu t io n st at u s. Operator prom pt synoptics p ro vid e t h e u ser wit h an in d icat io n o f all
t h e co n d it io n s fo r in it iat in g in d ivid u al fu n ct io n s in t h e “set -u p ” an d “d ie ch an ge” m o d es
Fig. 4.4.46 . Th e visu alizat io n syst em m akes t h is
t yp e o f syn o p t ic available fo r each set -u p fu n ct io n . Th e m alfunction diagnostics syst em d et ect s m alfu n ct io n s o ccu rrin g
an ywh ere t h ro u gh o u t t h e p ress. Th e visu alizat io n syst em in d icat es t h e exist en ce o f a m alfu n ct io n in each im age by h igh ligh t in g t h e m en u
261
Sheet metal forming lines
Fig. 4.4.46
User prompting for slide adjustments in a crossbar transfer press
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
p oin t “Error” in th e m en u lin e. Error m essages con tain an error n u m ber, p lain lan gu age, referen ce to th e affected assem bly op eratin g resou rces
id en tification an d referen ce to th e p oin t in th e PLC p rogram . Th is in form ation , in con ju n ction with th e statu s d isp lays, su p p orts th e
d etection an d localization of th e sou rce an d cau se of th e m alfu n ction . Die-d ep en d en t d at a relat ed t o all d ies u sed in t h e lin e can be en t ered
an d ed it ed at t h e visu alizat io n syst em . Th ey are st o red an d m an aged in t h e visu alizat io n syst em . Du rin g d ie ch an ge, t h is d at a is au t o m at ically
t ran sm it t ed t o t h e relevan t co n t ro l u n it s. Alo n gsid e t h e visu alizat io n syst em , wh ich is im p erat ive fo r lin e o p er-
at io n an d m o n it o rin g, PC-based syst em s are also freq u en t ly u sed fo r t h e acq u isit io n an d p ro cessin g o f m ach in e an d o p erat io n al d at a as well
as m easu red valu es. Machine and production data acquisition and evaluation
Th e m ach in e an d p ro d u ct io n d at a acq u isit io n syst em MDA PDA – o r PMS Press Man agem en t Syst em fo r sh o rt – lo gs erro r an d st an d st ill
d at a as well as p ro d u ct io n d at a accu m u lat ed in t h e p ress lin e. As su ch , it p lays an im p o rt an t ro le in d et ect in g an d an alysin g weak p o in t s an d
in regist erin g an d m o n it o rin g p ress lin e p ro d u ct ivit y. Th e h ard ware basis o f t h e PMS is an in d u st rial PC wh ich is d irect ly
lin ked t o t h e lin e’s co n t ro l syst em . Th e cen t ral PLC is resp o n sible fo r m akin g available t h e n ecessary d at a, an d so fu n ct io n s as t h e co m m u n i-
cat io n p art n er fo r t h e PMS. Table 4.4.1
in d icat es t h e sp h eres o f o p era- t io n o f a PMS fo r large-p an el p resses.
Th e field o f m ach in e d at a acq u isit io n is su bd ivid ed acco rd in g t o t h e acq u isit io n an d evalu at io n o f erro rs an d st an d st ill p erio d s.
Acco rd in g t o t h e d efin it io n u sed h ere, erro rs are co n st it u t ed by m ach in e st at u ses wh ich are t h e d irect resu lt o f fau lt y o r d am aged lin e
elem en t s o r co m p o n en t s an d wh ich gen erally n ecessit at e rep air wo rk. Erro rs are au t o m at ically classified by t h e PMS. In ad d it io n , a freely co n -
figu red even t -relat ed co m m en t is p o ssible fo r each erro r m essage. Errors d o n o t , h o wever, always cau se a st an d st ill; St an d st ills, in t u rn ,
d o n o t n ecessarily resu lt in erro rs. As a resu lt , alo n gsid e t h e d et ect io n o f erro rs, sep arat e acq u isit io n o f all p ress st an d st ill st at u ses is req u ired .
Standstill, in acco rd an ce wit h t h e d efin it io n u sed h ere, co n sist s o f all t im es d u rin g wh ich n o p art s are p ro d u ced cf.
Sect . 4.9.2 . Dep en d in g
o n t h e lin e in q u est io n , a d ifferen ce is m ad e bet ween ap p ro x. 30 d iffer-
262
Sheet metal forming and blanking
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
M achineproduction data acquisition and evaluation automatic
errors standstill job data,
acquisition
– during production production data – during die change
manual
commentaries commentaries number of reject parts,
acquisition
plain language plain language, number of rew ork parts classification
evaluations
chronological list chronological list chronological list, individual printout
job data table sorting according to:
sorting according to: sorting according to:
error frequency, standstill frequency, die number, total duration, total duration, w orkpiece number,
error category frequency error category frequency batch size and total duration and total duration
selection according to: selection according to:
selection according to: period, period, period,
shift, shift, shift, job number, job number, job number,
die number, die number, die number error number, standstill number,
error categories standstill categories
Table 4.4.1: Functional areas of machine and production data acquisition systems in large-panel presses
en t cau ses o f st an d st ill. Th e co n d it io n s o f t h e read y-t o -ru n st at u s syn - o p t ic fo rm t h e basis fo r m o n it o rin g st an d st ills.
An im p o rt an t fu n ct io n in m o n it o rin g st an d st ill p erio d s is t h e d et er- m in at io n o f t h e act u al cau se o f t h e st an d st ill. Th e co n t ro l syst em fre-
q u en t ly d et erm in es o n ly t h e so -called seco n d ary cau ses, in p art icu lar in t h e case o f m an u al o p erat o r in t erven t io n . Th e act u al cau se o f t h e p ro b-
lem , t erm ed t h e p rim ary cau se, can be d et erm in ed by t h e u ser by m ean s o f even t -relat ed m o d ificat io n o f t h e st an d ard st an d st ill classificat io n
an d by t h e ad d it io n o f even t -relat ed co m m en t s. Th e field o f production data acquisition is su bd ivid ed in t o jo b d at a
acq u isit io n an d , based o n t h is, p ro d u ct io n d at a d et erm in at io n . Jo b d at a refers t o t h e in d ivid u al p ro d u ct io n o rd ers. It s acq u isit io n st o p s o n co m -
p let io n o f t h e o rd er, an d t h e relevan t d at a is st o red Fig. 4.4.47
. Jo b d at a is au t o m at ically acq u ired , su p p lem en t ed by o p t io n al m an u -
al in p u t s in t h e p ress co n t ro l syst em . At t h e en d o f a sh ift , an d at t h e en d o f an o rd er, t h e cu rren t d at a t able is t ran sm it t ed t o t h e PMS. Th e
263
Sheet metal forming lines
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
production data is ascert ain ed o n t h e basis o f t h is in fo rm at io n fo r an evalu at io n p erio d wh ich can be freely d efin ed by t h e o p erat o r.
Th e p rod u ction statu s illu strated in Fig. 4.4.48
offers a su rvey of th e m ost im p ortan t d ata from all th e sh ifts of a p rod u ction d ay. In ad d ition ,
th e p re-p rocessed d ata can be exp orted in a stan d ard d ata form at in ord er to give th e u ser th e ch an ce to execu te h is or h er own evalu ation .
Data acquisition and processing for draw cushions Th e acq u isit io n an d p ro cessin g syst em fo r m easu red valu es fo r t h e d raw
cu sh io n , kn o wn as t h e Cu sh io n Mo n it o rin g Syst em CMS, p erm it s t h e o bservat io n o f t h e d rawin g p ro cess. In ad d it io n , t h is p ro vid es su p p o rt
fo r rep air p erso n n el in t erm s o f m alfu n ct io n d iagn o st ics an d also wh en resu m in g p ro d u ct io n aft er a co m p o n en t failu re. All t h e relevan t set val-
u es, co n t ro l sign als an d p ro cess variables act u al valu es fo r p re-acceler- at io n an d fo r t h e act u al d rawin g p ro cess are m o n it o red an d st o red , fo r
exam p le
264
Sheet metal forming and blanking
Fig. 4.4.47
Job data
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
– set d rawin g p ressu re valu es – act u al d rawin g p ressu re valu es
– act u al syst em p ressu re valu es – p ress an gle
– slid e p o sit io n an d – d raw cu sh io n p o sit io n .
Th e CMS com p rises a u n it for m easu red data acq u isition an d an in du stri- al PC with software cap ability for acq u isition , evalu ation an d disp lay of
th e above sign als an d data. Th e system p erm its th e grap h ic disp lay of th e p rogress of p re-acceleration , th e drawin g p rocess an d u p stroke both in th e
form of an overview Fig. 4.4.49
an d cf. Sect. 3.1.4
an d detail disp lays. Th e m easu rem en t can be dep icted in real tim e for every in dividu al stroke.
Zoom fu n ction s an d th e op tion al rep resen tation of m easu red valu es rela- tive to th e tim e or th e p ress cran k an gle p erm it detailed an alysis of m ea-
su red valu es. Th e m easu rem en ts are stored in th e PC an d can be accessed at a later date if req u ired. In addition , th e CMS p rovides diagn ostic im ages
for trou blesh ootin g an d settin gs du rin g start-u p of th e p ress lin e.
265
Sheet metal forming lines
Fig. 4.4.48
Overview of one day’s production data
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
Outlook Fu rt h er d evelo p m en t s in t h e field o f co n t ro l en gin eerin g in large-p an el
p resses will be d et erm in ed by t ech n ical an d eco n o m ic fact o rs an d also by o rgan izat io n al req u irem en t s. In it ially, t h e in n n o vat io n in au t o m a-
t io n co m p o n en t s is relevan t . No wad ays, lo w-co st sm all co n t ro l syst em s wit h co m m u n icat io n
cap abilit y, fast field bu s syst em s an d d ecen t ral in p u t o u t p u t m o d u les are available. Th is o p en s u p t h e p o ssibilit y fo r fu rt h er d ecen t ralizat io n
o f co n t ro l syst em s, an d co n seq u en t ly fo r a su bst an t ial red u ct io n n o t o n ly o f co st s an d syst em co m p lexit y bu t also o f in p u t fo r in st allat io n ,
st art -u p an d t ro u blesh o o t in g. An alo gu e t ech n o lo gy, in p art icu lar in co n t ro llers fo r elect rical an d
h yd rau lic d rive syst em s, is bein g rep laced by d igit al t ech n o lo gy. Th is p erm it s t h e p aram et erizat io n o f co n t ro llers by m ean s o f d at a t ran sm is-
266
Sheet metal forming and blanking
Fig. 4.4.49
Overview of process signals for the draw ing process using a four-point draw cushion: slide displacement red, draw depth blue, set pressure value red right-
angled curve, actual pressure value green right-angle curve, cursor yellow
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
sio n fo llo win g a ch an ge o f req u irem en t s o r aft er exch an gin g d efect ive co m p o n en t s. Th e ben efit s h ere in clu d e sh o rt er rep air t im es an d t h u s an
in crease o f p ress u p -t im e. High ly-d yn am ic elect rical feed syst em s in co n ju n ct io n wit h efficien t
co n t ro l an d regu lat io n syst em s fo r m o vem en t syn ch ro n izat io n are in creasin gly rep lacin g m ech an ically co u p led d rive syst em s. Th is d evel-
o p m en t n o t o n ly allo ws m ech an ical m ech an ism s t o be sim p lified an d flexibilit y t o be fu rt h er in creased , bu t in cert ain cases also en h an ces
p ro d u ct ivit y. Th e ch an ges t akin g p lace in t h e field o f wo rk o rgan izat io n in m an y
st am p in g p lan t s are im p o sin g n ew d em an d s, in p art icu lar o n t h e lin e co n t ro l cen t er. Pro d u ct io n lin es are bein g m an aged in creasin gly by
in d ep en d en t ly act in g t eam s o f em p lo yees o n t h eir o wn resp o n sibilit y. Th ese t eam s req u ire in fo rm at io n o n sit e relat ed t o p ro d u ct io n an d
m ach in e d at a, t o p ro d u ct io n q u alit y, wait in g p ro d u ct io n jo bs an d m ain t en an ce wo rk t o be carried o u t . O n ly wit h t h is in fo rm at io n at
t h eir fin gert ip s are t eam m em bers in a p o sit io n t o o p t im ize t h e p ro d u c- t ivit y o f t h eir lin e an d t o assu m e co n t ro l fu n ct io n s o n t h e p ro d u ct io n
level. As a resu lt , m ach in e an d p ro d u ct io n d at a acq u isit io n syst em s su ch as t h o se d escribed abo ve will co n t in u e t o be m o re ext en sively u sed
an d t h e fu n ct io n al sco p e o f t h eir ap p licat io n ext en d ed t o co ver ever wid er field s.
Mu lt i m ed ia-based p ro d u ct io n lin e in fo rm at io n syst em s wh ich p er- m it fast , select ive access t o st o red lin e d o cu m en t at io n an d ad d it io n al
in fo rm at io n o n t h e elim in at io n o f fau lt s an d ro u t in e m ain t en an ce will be in t egrat ed in t h e fu t u re in t o t h e p ress co n t ro l cen t er. Usin g t h ese
syst em s, it will also be p o ssible fo r o p erat in g p erso n n el t o en t er t h eir o wn fin d in gs in t o t h e in fo rm at io n d at a base an d so d evelo p t h eir o wn
exp erien ce d at a base. In gen eral t erm s, fu t u re d evelo p m en t s in t h e field o f co n t ro l en gi-
n eerin g will co n cen t rat e o n red u cin g co m p lexit y an d o n t h e d evelo p - m en t o f m o re efficien t syst em s fo r rep air an d m ain t en an ce su p p o rt t o
red u ce t h e co st s o f p ress co n t ro l an d in crease p ro d u ct io n lin e u p t im e.
267
Sheet metal forming lines
Metal Forming Handbook Schuler c Springer-Verlag Berlin Heidelberg 1998
4 Sheet metal forming and blanking
4.5 Blanking processes
