8/18/2019 Design for Assembly - Part of the Design Process 1988
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Design for Assembly Part of the Design Process
H. . Warnecke I ) , R. Bal3ler
Received on January
20,1988
Assembl y-ori ent ed pr oduct desi gn of f er s a great pot ent i al f or rati onal i za-
t i on. Assembl y cost s are an i mport ant f actor i n t he overal l costs of t he
product. Theref ore a speci f i c procedur e f or assembl y-ori ent ed pr oduct de-
si gn i s needed.
Beyond a short descr i pti on of wel l - known methods of desi gn f or assembl y
t hi s paper pr esent s an assembl y- ori ent ed desi gn process as a new devel o-
ped procedure.
Keywords
:
Assembly, Design. C Q s t Evaluation.
1 I nt roducti on
The i ncreasi ng pr essur e of nati onal and i nt ernat i onal
compet i t i on i s f orci ng f i rms t o rati onal i ze even
f urt her, especi al l y i n t he f i el d of assembl y. I n order
t o perf orm assembl y tasks w t h the l east possi bl e
expendi t ure of t i me, assembl y f aci l i t i es, space re-
qui r ement s and per sonnel , i t has become necessar y t o
i ncl ude these obj ecti ves i n the devel opment st age of
t he pr oduct . Theref ore, assembl y- ori ent ed desi gn now
pr ovi des a good opport uni t y f or rat i onal i zati on
/ I / .
Assembl y- ori ent ed product desi gn means t hat t he pr o-
duct s shoul d be desi gned i n such a way t hat expen-
di t ure on assembl y and product i on cost s are reduced to
a mni mum
/ 2 /
I gnor i ng t he techni cal aspect s of assembl y dur i ng t he
devel opment st age of t he product f r equentl y l eads to
costl y assembl y systems bei ng i nstal l ed. A r epr esen-
t ati ve sampl i ng carr i ed out f or t he German M ni st r y
of
Resear ch and Technol ogy
/3 /
showed t hat t he r equi r e-
ment s f or assembl y- or i ent ed product desi gn are not
t aken i nt o account suf f i ci ent l y dur i ng the desi gn
process. The same r epr esentat i ve sampl i ng al so con-
f i rmed thi s si t uati on w th r egard t o obst acl es t o
aut omat i on i n t he f i el d of assembl y, as shown by
f i gure
1.
I t i s f or t hese reasons t hat hol i sti c met hods are
needed for product desi gn sui t abl e f or assembl y:
methods whi ch can be i ntegrat ed i nto t he manufacturi ng
pr ocess ri ght f r omt he out set . The two most i nt er -
nat i onal l y wel l - known methods of Boot hroyd and
Dewhurst and of Hi t achi are t hus expl ai ned bel ow
af t er whi ch t he assembl y-ori ent ed desi gn
pr ocess devel oped at t he I PA i s presented.
2
Known Met hods f or Desi gn f or Assembl y
2.1 The Boothroyd and Dewhurst Method
Thi s method i s ai med at m ni m zi ng assembl y t i mes and
cost s f or exi sti ng products
or
pr oduct desi gns, by
m ni m zi ng the number of i ndi vi dual part s and op-
t i m zi ng t he desi gn of t he part s i n
so
f ar
as
concerns
handl i ng and j oi ni ng.
Thi s method i s i mpl ement ed i n t he st ages shown i n
f i gure
2 :
-
Choi ce of t he assembl y pr i nci pl e
-
Anal ysi s of t he assembl y tasks and
- I mprovement of t he desi gn.
Assembl y pri nci pl es ar e di f f erent i ated i nt o manual
assembl y, aut omat i c si ngl e pur pose assembl y, and
assembl y by i ndust r i al r obots. The assembl y t asks are
t hen anal ysed i n r el ati on t o the assembl y pr i nci pl e.
The handl i ng and j oi ni ng t i mes f or t he part s, and the
t heoreti cal m ni mumnumber of i ndi vi dual part s are
cal cul ated f or manual assembl y usi ng t wo spreadsheets .
For
aut omati c si ngl e pur pose assembl y, as wel l as
for
assembl y by i ndust r i al r obots, a tot al of
4
r
6
spreadsheet s ar e used
to
cal cul ate t he handl i ng and
j oi ni ng cost s and the t heoret i cal m ni mumnumber of
i ndi vi dual part s.
I n addi t i on t o the assembl y cost s, a desi gn ef f i ci ency
( DE) f act or
i s
cal cul ated i n respect
of
assembl y
sui t abi l i t y. The actual number of i ndi vi dual part s i s
mul t i pl i ed by t he actual assembl y t i mes
or
costs. Thi s
val ue i s t hen compar ed w t h the product made f r omt he
t heoreti cal m ni mum of i ndi vi dual part s, mul t i pl i ed by
t he assembl y t i mes or costs f or i ndi vi dual part s of
opt i mumdesi gn. Thus a
DE
f i gur e of between ( poor)
and 1 (i deal pr oduct desi gn sui t abl e f or assembl y) i s
obt ai ned.
The theoreti cal m ni mumnumber of i ndi vi dual par t s i s
det er m ned by consi der i ng t he f ol l ow ng quest i ons: -
. Must t wo component s whi ch ar e connected to each
other move rel at i ve t o each other duri ng t he per -
cept i on of t he pr oduct f uncti on?
. Must t wo component s whi ch ar e connect ed t o each
other be made of di f f erent mater i al s?
.
Must t wo component s whi ch ar e connect ed to each
ot her be separat ed dur i ng assembl y
or
di sassembl y
of
ot her component s
or
dur i ng percept i on of t he pr oduct
f unct i on?
Al most al l anal yti cal st eps i n the Boot hr oyd and
Dewhur st method ar e avai l abl e i n t he f orm of PC sof t -
ware. A r api d appl i cat i on of t he method i s t hus
possi bl e.
2. 2
The Hi t achi Method
Hi t achi devel oped i t s Assembl abi l i t y Eval uati on Method
( AEM) sever al year s ago, and has al r eady sol d i t t o
many f i rms. These f i r ms have sl i ght l y modi f i ed and
f ur t her devel oped t he met hod. Hi t achi i t sel f has
al r eady t aught t he method t o more t han 1500 desi gners
and pr oj ect engi neers i n tr ai ni ng cour ses and se-
mnars. I t i s est i mated t hat t he method has
so
far
achi eved resul t s amount i ng t o sever al m l l i on dol l ars.
The method i s based on t he use of i nst r ument s f or
quant i f yi ng t he sui t abi l i t y f or assembl y. The ant i ci -
pat ed assembl y cost s can be deduced; t he est i mat ed
cost s do not di f f erent i ate between manual and aut o-
mat i c assembl y. The pr ocedur e i s shown i n f i gur e
3 .
The r esearch team cal cul ates the j oi ni ng sequence w t h
t he hel p of draw ngs and sampl es or usi ng the com
pl et ed AEM f orms. As a resul t t he j oi ni ng pr ocess i s
deci ded upon and recor ded i n t he f orm of j oi ni ng
symbol s on the f orms. The i nt erpret ati on of t he f orms
i s achi eved usi ng compar at i ve t abl es and a f ormul a
val ue. The pr ocess gi ves t he val ue E f or t he assembl y
sui t abi l i t y and t he val ue K, whi ch gi ves t he est i mated
r el ati onshi p of t he assembl y cost s of a new pr oduct t o
that of an i ni ti al product.
I f t he val ues
E
and
K
were t o reveal a pr oduct t o be
unaccept abl e, t hen t he known weaknesses of t he product
woul d have to be i mproved. The actual product desi gn
i s t hen the r esponsi bi l i t y of t he desi gner, who must
seek out ways of r educi ng t he number of par t s and t he
j oi ni ng movement s.
3
I nf l uenci ng t he Desi gn Pr ocess
I n or der t o desi gn pr oduct s i n an assembl y-ori ent ed
manner , t he t echni cal r equi r ement s r egardi ng t he
assembl y of t he f i nal product need t o be known. Know-
l edge of t he requi r ement s, t he pr oduct mounti ng, t he
vari ous methods of i mpl ement i ng manual , par t l y
or
f ul l y automated assembl y syst ems must be avai l abl e at
t he devel opment st age of t he pr oduct and must be
i nt egr ated i nto t he product desi gn. The assembl y
process must be taken i nto consi der at i on when t he
pr oduct i s f i r st creat ed. Dur i ng the devel opment of
t he product , t he assembl y pr ocess must be anal ysed and
pl anned i n paral l el ( w t h a sl i ght t i me l ag) w th t he
desi gn. Onl y i n t hi s way can pr oduct s be desi gned f or
Anna ls
of
the
lRP Vol 37/1/1988
8/18/2019 Design for Assembly - Part of the Design Process 1988
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si mpl e assembl y i n such a way as t o make f ul l use of
the pot ent i al f or rati onal i zat i on off ered by assembl y-
ori ent ed pr oduct desi gn / 4/ .
The t echni cal aspect s and r equi r ement s of t he assembl y
process must be consi der ed bef ore pl anni ng t he assem
bl y process i . e. bef ore the desi gn of t he pr oduct has
been compl eted. They shoul d be i ntegrat ed i nto t he
desi gn pr ocess as earl y as possi bl e. Those measur es
f or assembl y- ori ent ed pr oduct desi gn whi ch most af f ect
assembl y cost ( such as t he overal l mounti ng arr ange-
ment and t he subassembl i es) can onl y be successf ul l y
appl i ed when they ar e consi der ed at a very ear l y st age
of t he desi gn process.
The desi gn pr ocess i s di vi ded i nt o f our st ages
( pl anni ng, r ough desi gn, dr af t i ng and detai l ed desi gn)
/ 5 /
and t he needs f or assembl y- ori ent ed product
desi gn w l l vary w th di f f erent desi gn acti vi t i es.
I n order t o i nf l uence a desi gn pr ocess dur i ng i t s
di f f erent st ages, ai ds are r equi red. Some of t hese
ai ds ar e al r eady avai l abl e and some are par t l y used
f or di f f erent pur poses i n manuf act ur i ng practi ce.
However , some of t he ai ds essent i al f or t he appl i ca-
t i on of assembl y-ori ent ed product desi gn ei t her do not
yet exi st
or
ar e not pr operl y adapt ed t o t he pur pose.
I t i s vi tal that t he possi bi l i t i es for i nf l uenci ng the
sui t abi l i t y f or assembl y of t he desi gn be support ed by
t he ri ght ai ds at t he ri ght ti me. I n fi gure
4
t he ai ds
f or assembl y- ori ent ed pr oduct desi gn are l i st ed i n
accor dance w t h t he di f f erent desi gn stages.
4 Assembl y- or i ent ed Desi gn Process
The devel opment of t echni cal products i s car r i ed out
i n accordance w t h t he syst emati c desi gn procedures
descri bed i n
/5/.
I n order t o f ul f i l t he many r equi r e-
ment s made on a product , a great number of ai ds ar e
necessary. The t echni cal probl ems of assembl y must be
systemati cal l y i ncl uded i n t he convent i onal desi gn
process. On the one hand, t he necessary techni cal
r equi r ement s of assembl y are i ncl uded i n the desi gn of
t he pr oduct at var i ous st ages dur i ng t he desi gn pro-
cess. On t he ot her hand, t hi s causes i t erati ve l oops
dur i ng t he desi gn process. Al t hough t hese l oops become
more f r equent because of t he consi st ent appl i cati on of
ai ds, t hey are al so si gni f i cant l y short er . Thi s means
t hat at var i ous s t ages of t he assembl y- ori ent ed desi gn
process ther e w l l be the possi bi l i t y of checki ng t he
sui tabi l i ty for assembl y af ter rel ati vel y short i nter-
val s and, i f necessary,
of
maki ng t he appropr i ate
i mprovements.
I n
t hi s way i t i s possi bl e t o avoi d ti me
and ef f or t consumng product devel opment s whi ch mght
need t o be changed af t er t est i ng. Fi gur e
5
speci f i es
the al l ocati on of t he ai ds det ai l ed i n f i gur e 4 and
summari ses themf or an assembl y- or i ent ed desi gn pro-
cess
/2 / .
The assembl y- or i ent ed desi gn process shows t hat among
t he l arge number of appl i cabl e ai ds the most i mpor t ant
are the syst emati cal l y appl i ed desi gn r ul es and the
eval uat i on of t he sui t abi l i t y f or assembl y. Dur i ng the
var i ous st ages of t he desi gn pr ocess, di f f er ent r ul es
can i nf l uence t he pr oduct desi gn f r omt he techni cal
poi nt of vi ew of assembl y. Af t er compl eti ng each stage
of t he desi gn process, an eval uati on
of
i t s sui t abi l i -
ty f or assembl y i s necessary i n order t o determ ne if
t he desi gn needs t o be i mproved f or assembl y pur poses.
An assembl y-ori ent ed r evi eww l l pr ovi de i nf ormati on
on whi ch weak poi nts of a product must be i mproved
w th respect to i t s sui tabi l i ty f or assembl y.
Desi gn r ul es and t he eval uat i on of t he sui t abi l i t y f or
assembl y are dom nant among t he ai ds f or assembl y-
ori ent ed pr oduct desi gn. Ther ef ore, t hey w l l be
descri bed i n great er det ai l .
4. 1 Desi gn Rul es f or Assembl y-ori ent ed Product Desi gn
Desi gn r ul es repr esent a set of known and wel l - t r i ed
sol ut i ons f or cer t ai n desi gn t asks and can be con-
veni ent l y summari zed i n catal ogues. These cat al ogues
must meet cer t ai n general r equi r ement such as
:
-
qui ck, task- ori ented accessi bi l i ty
-
comprehensi ve r ange
of
sol uti ons
-
appl i cabi l i ty
to
convent i onal as wel l as to com
put er- ai ded desi gn /6/.
I n or der to f aci l i t at e usabi l i ty and to ensure f ast
access, t he cat al ogues must be sui t abl y cl assi f i ed i n
mai n and subsi di ary part s. These part s must r el aLe
Lo
t he st age
of
compl eti on and t he compl exi t y of t he
r ecor ded sol ut i ons. Thi s ki nd of cat al ogue st r uct ur e
has proved t o be more r eadi l y accepted by t he de-
si gners. I n t he devel oped catal ogue / 2/ the cl assi f i -
cat i on part
i s
di vi ded up i nt o
1
Measures f or t he product st r ucture
2 .
Measures f or subassembl i es
3 .
Measures f or i ndi vi dual components
4. Measur es f or j oi ni ng t echni ques.
I n t he mai n part of t hi s cat al ogue, t he act ual desi gn
rul es are l i sted i n det ai l , as shown by an extr act i n
f i gure 6 The access charact er i st i cs f or t hi s cat a-
l ogue are:
-
val i di t y of t he r ul es dur i ng the desi gn pr ocess
-
i mport ance of t he rul es ( A- , B- and C- rul es).
4 . 2
Eval uat i on of Sui tabi l i ty of Products f or
Assembl y
I n order t o eval uate the sui t abi l i ty of products f or
assembl y, i t i s necessary to consi der and eval uate al l
t he f actors of i nf l uence, i . e. the ent i r e spectr umof
assembl y- ori ent ed product desi gn.
The eval uat i on of t he sui t abi l i t y f or assembl y
of
pr oducts i n r el ati on t o the di f f erent st ages of t he
desi gn pr ocess requi r es t hat cruci al f act ors of i n-
f l uence be eval uated
/7 / .
Thi s can be achi eved usi ng
vari ous pri nci pl es. I n the case of t he assembl y-
ori ent ed desi gn pr ocess shown i n f i gur e 5 t he eval ua-
t i on a and b was car r i ed out w t h check l i st s whi ch
examne pr eci sel y t hose f actors whi ch are i mport ant
dur i ng t he var i ous st ages. AS f r omeval uati on C, t he
sui t abi l i t y f or assembl y can be eval uated w t h an
appr opr i ate procedure. The basi c i dea of t hi s pr oce-
dur e i s t hat t he pr oducts must be desi gned to f ul f i l
t he r equi r ement s and f unct i ons l i st ed on t he speci f i -
cat i on sheet . The pr oduct s ar e t hen assembl ed f rom
separ ate components and subassembl i es, each cont r i -
but i ng a share of t he t otal f unct i on of t he product:
t hi s assembl y met hod i nvol ves a cer t ai n ef f ort .
Accor di ng t o t he basi c pr i nci pl es of val ue anal ysi s
( det er m nati on of f uncti onal cost and f uncti onal
expendi t ure), t he rel ati on of t he f uncti onal cont ent
of a component t o t he r equi r ed assembl y expendi t ure
provi des one of t he cri t er i a f or assessi ng t he sui t a-
bi l i t y of an assembl y pr ocedur e. The eff i ci ency of an
assembl y procedure i s i mproved when component s w t h a
hi gh f unct i onal cont ent can be assembl ed w t h l ow
assembl y expendi t ure, compared t o cases where compo-
nent s w t h a l ow f uncti onal cont ent r equi r e a consi -
derabl e assembl y ef f ort .
TO carr y out such an eval uati on, t he f ol l ow ng st eps
are necessary:
1 t he sett i ng up of a funct i onal st r uct ur e
2 .
t he wei ghti ng of f unct i ons and t he det erm nat i on
of
3 .
t he sett i ng up of a subassembl y st r ucture
4 .
al l ocat i ng t he f uncti onal cont ent s to t he di f f er ent
5.
det erm nat i on of t he assembl y sequence
6. determ nat i on of assembl y expendi t ur e
7 . det er m nati on of val ues measur i ng t he sui t abi l i t y
f or assembl y
8
i dent i f i cat i on of t echni cal probl ems dur i ng assem
bl y.
t he f uncti onal cont ent
components
When usi ng conventi onal desi gn methods, a f unct i onal
st r uct ur e needs t o be creat ed. The f unct i onal cont ent
of t he di f f er ent f uncti onal uni t s can be deri ved f r om
thi s. Paral l el t o worki ng out t he det ai l s of t he
desi gn, t he subassembl y st r ucture can al so be est a-
bl i shed i n detai l ,
so
t hat i t becomes possi bl e to
al l ocat e the f uncti onal cont ent t o t he separ ate com
ponents and based on thi s, t o determ ne t he sequence
of assembl y. Al r eady dur i ng t he f i r st r ough desi gn, a
speci al l y devel oped pr ocedur e makes i t possi bl e t o
f i r st est i mate t he assembl y expendi t ure and t hen,
af t er f urt her detai l i ng of t he desi gn, t o determ ne i t
w t h gr eater preci si on. Wt h t he functi onal cont ent
det erm ned under poi nt
4
and t he corr espondi ng assem
bl y expendi t ure determ ned under poi nt
6,
t he val ue
f or t he sui t abi l i t y f or assembl y of t he respecti ve
assembl y procedure can be determ ned. AS a r esul t ,
compar abl e val ues of i ndi vi dual assembl y pr ocedures
are obt ai ned. The assembl y procedures w t h t he l owest
val ues are anal ysed f ur t her w t h t he hel p
of
a check-
l i st i n order t o i dent i f y t he act ual weak poi nt s of
t he techni cal aspects of assembl y. Thi s way, concr ete
pr oposal s f or a syst emati c r e-desi gni ng of t he weak
poi nt s can be worked out . Af t er t hi s r e-desi gn, t he
eval uati on of t he sui t abi l i t y f or assembl y may be
car r i ed out agai n,
Thi s pr ocedur e devel oped f or t he eval uati on of sui t a-
bi l i t y f or assembl y makes i t possi bl e to eval uate
di f f er ent product desi gns at di f f er ent st ages of
det ai l . Li nked t o the compl eti on st age of a pr oduct
desi gn, t he sui t abi l i t y f or assembl y can be repeat edl y
checked and i mproved as necessar y. Thi s cr eat es nume-
r ous shor t l oops i n t he desi gn pr ocess, as shown i n
2
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f i gur e
5.
These shor t l oops r epresent an i t e ra t i ve
devel opment of assembl y- or i ent ed product s. Thereby
t he l a te recogn i t i on o f weak po i n ts and t he resu l t i ng
r epet i t i on of work can be avo i ded . The eval udt i on
procedure can be appl i ed r i ght up to t he f i nal st age
o f t he pr oduct des i gn ( eva l uat i on s t ep H) .
4.3 Appl i c at i o n of t he Assess ment Met hod
I n t h e l ef t - ha nd pa r t o f f i gur e
7
a concr et e exampl e
i s g i ven whi ch assess es t he assembl y processes Of an
assembl y i n
so
f ar a s conc er n s i t s s ui t a bi l i t y f o r
assembl y. The i t em zat i on of t he assembl y weak poi nts
was carr i ed out dur i ng the assembl y pr occoscs wi t h l ow
c ha r ac t e r i s t i c v al u es , i . e. t h ose deno t e d i n f i g ur e 7
by an ar r ow. These assembl y processes were t hen r e-
desi gned, and are r epr esent ed by t he val ues i n the
r i ght - hand par t
of
f i gur e 7. The appropr i a te des i gns
f r o m f i gur e 7 ar e compar ed i n f i gur e 8.
On the bas i s o f t he ana l ys i s o f t he assembl y p rocess ,
i t
was est abl i shed, by compar i ng t he funct i ons of t he
i ndi v i dual components and t he r esul t i ng assembl y
cost s , t hat t he or i gi nal des i gn shows a number o f
i ndi v i dual par t s, whi ch among ot her t h i ngs need t o be
a sse mbl e d i n di f f e r ent j o i n i ng di r e c t i o ns , e xhi bi t f c w
j o i ni ng ai d s , r e qu i r e addi t i o na l sec ur i ng d ev i c es a nd
expens i ve t ypes o f connec t i on, and exhi b i t f ew o rder
and h andl i ng c har a c t e r i s t i c s .
Based on these weak poi nt s t he act ual r e- desi gni ng was
under t aken, as can be seen on the r i ght - hand s i de o f
f i gur e
8.
The f o l l owi ng re - des i gni ng t asks were
c ar r i e d o ut :
-
The r epl acement of t he spr ung shutt ers by cat ch
hooks and t he i ntegrat i on of t hese i nt o t he assembl y
housi ng ( no addi t i onal component s to be pr eassem
bl ed
) .
component housi ng ( so-ca1. l ed ext r uded f i l m)
t he r emova l o f t he shut t e r pro j ect i on.
be j o i n ed f r o m t op t o bot t om
-
The i n tegr a t i on o f t he bl i nd cover i ng i n to the
- ' The i mprovement of accessi bi l i t y at t he l ower end by
- The r a i s i ng o f t he p ropor t i on o f t he components t o
The new assessment of t he re- desi gn gave a s i gni f i cant.
i mprovement o f t he charac te r i s t i c va l ues f o r t he
sui t a bi l i t y f o r as se mbl y , a s c an be se en f r o m t he
compar i son i n f i gur e 8. W t h t h i s r e - de s i gn t h e i mp or -
t ant ass embl y weak poi nt s coul d be r emoved. F o u r of
t he wors t assembl y process es wer e abandoned and t hei r
f unct i ons were i n tegr a ted i nt o the hous i ng. The cha -
r a ct e r i s t i c val ue f or s u i t a bi l i t y f or a s s embl y o f t h e
overal l assembl y
hds
al most doubl ed dur i ng t he r e-
desi gni ng
to
1. 15. Thus i t was poss i bl e , wi t h respec t
t o assembl y, t o consi der abl y i mprove the assembl y by
t he del i bera te r e -des i gni ng o f t he weak poi n ts i dent i -
f
i ed.
T hi s a ct i o n sh ows , t h at p r e c i se anal y s i s o f t h e a ssem
bl y p rocess a t t he des i gn s t age i s ef f ec t i ve. A method
of assessment o f t he su i t abi l i t y fo r assembl y o f
product s
or
de s i g ns i s a pr e r e qui s i t e f o r d i s c ov er i ng
and r emovi ng weak poi nts . Thi s met hod of ass ess ment
was devel oped wi t h t he ai d of comput er s and used on
PCs
so t hat t he work st ages 1 - 7 of t he ni et. hod ca n
bc rapi dl y execut ed on a comput er. A ver y rapi d
pur pose f ul app l i ca t i on o f i ns t r ument s i s t hus r ender ed
pos s i bl e.
5
Prospects
An assembl y- or i ent ed desi gn pr ocess was devel oped, t ho
most i mpor t ant a i ds o f whi ch ar e ava i l abl e i n user -
or i ent ated, comput er- a i ded f orm At t he same t i me
i nst r ument s wer e devel oped whi ch can be used t o i nt e-
g r a t e t h e spe ci a l kno wl e dge of di f f e r ent o pe r a t i o na l
a r ea s . T hi s p r o ce dur e i s t he pr e r e qui s i t e for a
success fu l company o rgani za t i on o f any f u tu r e i n te -
grat i on of product devel opment and assembl y p l anni ng.
The next st ep
i s
t h e i nt egr a t i o n o f t hi s pr o c ed ur e
i nt o a CAD sy s t e m ( pa r t i c ul a r l y t h e des i gn c at a l o gue ) .
The des i gner must be prepared t o take the sui t abi l i t y
f o r assembl y i nto account i n hi s desi gn work dur i ng
t he whol e desi gn process usi ng comput er a i ds.
The most i mpor t ant p re requ i s i t e f o r econom cal assem
bl y automat i on i s a ho l i s t i c p roduct des i gn based on
su i t abi l i t y f o r assembl y , wh i ch means , t hat aspec t s of
assembl y t echnol ogy must be bor ne i n m nd r i ght f r om
t he out se t o f t he des i gn pr ocess . Thi s is t he p re re -
qui s i t e f o r t he f ut ur e r e al i z at i on of t h e t o t a l r a -
t i o nal i z at i on po t e nt i al i n t h e ar e a of assembl y. Onl y
t he r at i onal assembl y of products can guarantee l ong-
t e r m i nt e r n at i onal c ompet i t i v i t y .
The i nst r ument s a l r eady aval l abl e f o r p roduct des i gn
based on sui t abi l i t y f o r assembl y must be f u r t her
devel oped and compl et ed
so
as t o become hol i s t i c
i nstr ument s
f or
produc t des i gn su i t abl e
for
produc-
t i o n. T he ai m i s t o de ve l o p i nt e gr a t ed sys t e ms f o r
p roduct des i gn su i t abl e fo r p roduc t i on, so a s t o f u l l y
r e al i z e t he pot e nt i al f or r at i onal i z at i on i n t he ar e a
of product manufact ure.
6
Ref erences
__
/ I / Abel e ,
E . :
Bai G er , R . ; Wo l f , E. , 1984, Anwendungs-
mbgl i chkei t en von f l exi bel aut omat i s i e r t en Mont a -
gesyst emen. Wur zbur g, Maschi nenmar kt , 90:31 - 32.
. - ~ ~r o duk t g es t a l t u ng n d zn K 0 ns t r u k t i o n sp : o z T
St ut t ga r t , Uni ver s i t a t , F ak ul t d t F er t i gungs t e ch-
ni k , Di s s . Dr . - I ng. Spr i nger V er l ag Ber l i n u. a.
/ 3 /
Abel e ,
E.:
Baf l l er , R. ; et al , 1984, Ei nsat zmbg-
/ 2 /
BaBl e r ,
t i .
1988.
I nt e r at i on der monta eger echt en
l i chkei t en von f l exi bel aut omat i s i e r t en Mont age-
sys t emen
.
i n de r i ndus t r i el l en P r o duk t i on,
VDI - Ver l a g Dussel dor f . ( S ch r i f t e nr e i h e Hu ma ni s i e -
r ung des Ar bei t s l ebens Band 61
~
/4/ Sc hr a f t , R. D. : Bai G er , R. , 1984, Pos si bi l i t i es t o
r eal i ze assembl y -o r i ent ed p roduct des i gn.
Proceedi ngs o f t he 5t h I CAA, Par i s .
/5/ N. N. ,
1977,
VDI - R i c ht l i ni e
2222,
Bl at t 1 ,
Konst r ukt i onsmethodi k, Konz i p i eren t echni scher
Produkte . Ber l i n, Co l ogne: Beut h -Ver l ag.
/6/ P ahl ,
G.;
Bei t z ,
M .
1986, Kons t r uk t i o ns l e hr e :
Handbuch f u r S tudi umund Prax i s , zwe i t e Auf l age .
Ber l i n , He i del berg , New Yor k , London, Par i s ,
Tokyo : Spr i nger Ver l ag.
/ 7 / Sc hr a f t , R. D. : BhBl er , R. ,
1986,
Mdgl i chkei t en zur
Umset zung des montageger echten Konst r ui er ens.
Tagung: Mont agegerechtes Konst r u i eren, 13t h/ 14t h
Mar ch
1986,
St u t t ga r t . VDI - Be r i c ht
592,
VDI - Ve r l a g, Dussel do r f .
0 crlmn mrc
to
1 5 5
f l r rnr
l - r t than one choice mswblcl
Fi gur e 1: Obst ac l es agai nst aut omati on i n
assembly-
or i ent ed product desi gn
F i gu r e 2 : Pr ocedure
of
t he Boot hr oyd Dewhurs t Met hod
3
8/18/2019 Design for Assembly - Part of the Design Process 1988
4/4
Figure 3:
I
4.
FINAL DESIGN
Evaluation of the assembly suitability by Hitachi
Rules for assembly orlented product deslgn
Maasurrr for subalKernblles
Dtrlnn
of
the b a l k
uult
o.
2.3.1
2.3.2
2.3.3
Mounting
of
subassembl ies on the
ba sk uni t preferably complete
subassembly on one basic Unit)
Basic unit must have good
posltlonal stabil ity
Basic unit must have a preter-
A
B
B
117
i
1117
I
I
I
ably large and plane surface
Figure 6: Design rules for assembly-oriented product
design extract)
I\
I CREATIVE I CORRECTIVE
AIDS
FOR
ASSEMBLY
ORIENTED PRODUCT
: H
t a
n 5
B :
g g
1
STEPS IN THE DESIGN PROCESS
3
: :
1 PLANNING STAGE
1.1 recognlllon of requlrementa
1.2 deflnlllon of
t nnkn
2.2 creale lunctlonal structure
2.5
aelsct nrlnclnlan I I
2.6 prapnre solution vnrlnnla
3.1 drnf llng the maln functlonnl unlts
3.2 drnftlng the remdnlnp luncllonal unlts
3.7 annlyala
of
cost
recovery
3.8 draft comDIellon I
4.3
nnnlyala
of
producllon
data
1 PLANNING STAGE
1.1 rscognlllon
1
requr.m.n*
1.2
dsllnll lm 01
m a k s
4
1.3 create a reaulramenls 111
+
.2
crenle the IYnCllml~I lN C I U I O
-a
2.3 c r e a te m r l a l l o n s 01 the functlanal slmcture
a
EEL
-
__o
r .2
dralllng
the remalnlng luncllonal unlm +
~--+
+
.4
delermlne
i01~tl0ns
or each
luncl lon
4
2.5 se~octpflncwes
2.6
propt.re
aolutlon
varlsnta
+ .7 w o r k
oul
d l l l a r e n l concapls
.8 eve.baIe and solact Ihe dllleranl concept8
3.DRAFTING STAGE
3.1
dralllng Ihe
maln
luncllond u n h 4
Em
-
3.3 s ~ l s c l ullable parla
a1
Ihe droll
t
.4
de la l l ad design 1 the mnln snd auxl l lary luncllonal unlla - - - -
- .5 check and
Improva df8 l tn
3.6 r a ce
Iaulls
and problems
3 1
sna l ya l s
el coil recovery
:z
D 3.8 r l l l eomplallon
__o
3.9
declslon
on
droll
r
.1 dslalllnp
m
a
4.2 vork lng out spsclllcallona 4
4.3 analyds 01 prcducllon
dam
4.4 Inbase 10 DrOdYcllon
Legend wldelln.s and example cata log @ ~asombly-Drlorlly graph
colalog
of n la t lvs cost
a
alui ana ly i ls
valuation of sUItabll l ty tor issembly
~~
Figure 5: Assembly-oriented design process
Q
Figure
8:
Cornparision of t he d esigns
Figure 4: Aids for assembly-oriented product design
4
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