Academic Edi o s: Umbe o Galie i,
Gab iele A cidiacono, En ico
A men ani, Da ide Cas agne i,
Vigilio Fon ana i, Au elio Somà and
Nicola Bono a
Published: 13 Feb ua y 2025
Ci a ion: Guadagno, M.;
Innocen i, E.; Be zi, L.; Co si, S.;
Delogu, M. De elopmen o
P ocedu es o Disassembly o
Indus ial P oduc s in Py hon
En i onmen . Eng. P oc. 2025,85, 6.
h ps://doi.o g/10.3390/
engp oc2025085006
Copy igh : © 2025 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
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A ibu ion (CC BY) license
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P oceeding Pape
De elopmen o P ocedu es o Disassembly o Indus ial
P oduc s in Py hon En i onmen †
Mau izio Guadagno * , Eleono a Innocen i , Lo enzo Be zi , Sa e io Co si and Massimo Delogu
Depa men o Indus ial Enginee ing, Uni e si y o Flo ence, Via di San a Ma a 3, 50139 Fi enze, I aly;
[email p o ec ed] (E.I.); [email p o ec ed] (L.B.); [email p o ec ed] (S.C.);
[email p o ec ed] (M.D.)
*Co espondence: [email p o ec ed]
†
P esen ed a he 53 d Con e ence o he I alian Scien i ic Socie y o Mechanical Enginee ing Design (AIAS 2024),
Naples, I aly, 4–7 Sep embe 2024.
Abs ac : Ci cula Design me hodology is essen ial o sus ainable indus ial p ac ices.
This s udy p o ides a me hodology wi h a Py hon-based compu a ional ool ha op imizes
indus ial p oduc s’ disassembly sequences, ocusing on Design o End o Li e (D EoL)
and Design o Disassembly (D D) o p omo e Ci cula Design. The ool c ea es disas-
sembly p ecedence g aphs and shows he bes disassembly pa h o a ge componen s,
acili a ing ma e ial eco e y and en i onmen al sus ainabili y. The ool was applied o
a case s udy on an Axial Flux Pe manen Magne (AFPM) elec ic mo o . The app oach
p o ides a lexible and open access solu ion o op imizing p oduc design wi hin a Ci cula
Design amewo k.
Keywo ds: ci cula design; design o disassembly; end o li e; disassembly sequence
planning; axial lux pe manen magne elec ic mo o
1. In oduc ion
The Eu opean G een Deal [
1
] has made i e en mo e e iden how c ucial i is o
adop Ci cula Economy and Ci cula Design p inciples in indus ial p oduc ion. The
Ci cula Economy (CE) p o ides a compelling al e na i e o he cu en p oduc ion model,
cha ac e ized by pe pe ual g ow h and escala ing demand [
2
]. By p omo ing closed-loop
p oduc ion models wi hin economic sys ems, CE aims o imp o e esou ce use e iciency,
especially conce ning indus ial was e, o achie e a balanced economic, en i onmen al,
and socie al ela ionship [
2
]. Acco ding o he Ellen MacA hu Founda ion, i is possible
o “p e en he c ea ion o was e and pollu ion igh a he s a , and egene a e na u e by
design” [
3
]. Thus, Ci cula Design p inciples a e essen ial o achie ing he goals epo ed in
he Ci cula Economy Ac ion Plan [
4
]. The e o e, i is help ul o de elop Ci cula Economy
F amewo k models, o example, in he au omo i e sec o [
5
], o e alua e he li e cycle
o indus ial p oduc s and hei sus ainabili y in his new economic sys em. The ci cula
app oach o indus ial p oduc ion hus con as s wi h he adi ional linea business model
o p oduc ion, he ake–make–use–dispose model [
6
], and aims o achie e he goal h ough
he use o h ee main ac ions, called he 3Rs: educe, euse, and ecycle [
2
]. This esea ch
wo k i s he goals o Ci cula Design, seeking o imp o e he end-o -li e (EoL) phase o
indus ial p oduc s om he ea lies s ages o design by p omo ing he implemen a ion o
ecodesign [7] in he au omo i e indus y.
Rega ding he c i icali y o was e in some ca ego ies o end-o -li e ehicles (ELVs),
he Eu opean Union has se ambi ious euse, ecycle, and eco e y (RRR) a ge s h ough
Eng. P oc. 2025,85, 6 h ps://doi.o g/10.3390/engp oc2025085006
Eng. P oc. 2025,85, 6 2 o 13
Di ec i e 2000/53/EC. As pe his “ELV Di ec i e”, he RR ( euse and ecycle) a e mus
be a leas 85% by a e age weigh pe ehicle pe yea , and he RRR a e, which includes
eco e y, mus be a leas 95% by a e age weigh pe ehicle pe yea [
8
,
9
]. So, he
oppo uni y o euse and emanu ac u ing can be a c i ical business, and o achie e his,
he disassembly o indus ial p oduc s is a p elimina y bu c ucial s ep [10].
Rega ding WEEE (Was e om Elec ic and Elec onic Equipmen ), a compa able
app oach is on o ce, and p ope RR and RRR a ge s also ha e o be achie ed, which a y
depending on he p oduc class.
1.1. Resea ch Backg ound
“Design o Disassembly” (D D) is an ecodesign app oach ocused on imp o ing he
disassembly p ocesses a p oduc will unde go du ing i s li ecycle. This me hod educes
main enance expenses and acili a es economic euse, emanu ac u ing, and ecycling [
11
].
D D is a pa o one o he phases in which Disassembly Sequence Planning (DSP) can
be used. DSP e e s o planning an o de ly and op imized sequence o disassembling
p oduc componen s, conside ing speci ic c i e ia [
12
,
13
]. In he li e cycle o a p oduc , DSP
has h ee main a eas o applica ion: he design phase (D D), use phase (main enance and
epai ), and disposal phase (end-o -li e disassembly) [
12
]. The desi able cha ac e is ics
o disassembly in hese h ee s ages include high modula i y, simple connec ions, easy
accessibili y, and clea pa iden i ica ion a e disassembly [12].
Acco ding o he li e a u e s udy by Ong e al. [
12
], se en main cha ac e is ics a e
used o ca ego ize disassembly sequencing esea ch:
•
“Disassembly p ocesses” a e di ided in o des uc i e, non-des uc i e, and manual
o au oma ic.
•“Disassembly le el” is di ided in o comple e o pa ial/selec i e disassembly, which
can be single a ge o mul i- a ge .
•“Disassembly ype” is ca ego ized in o sequen ial o pa allel.
•
“P oduc ep esen a ion”, o how p ecedence in o ma ion is o med o la e p ocessing
wi h o mulas o algo i hms, has se e al ca ego ies, including g aph-based ep esen a-
ions (e.g., AND/OR g aphs and hie a chical g aphs), ma ix-based ones (such as con-
ac o in e e ence ma ices), o o he ypes (such as Pe i ne -based ep esen a ion).
•
“Op imiza ion objec i es” can include he minimum disassembly ime, minimum
disassembly cos , minimum emo al ools used, minimum changes in disassembly
di ec ions, o maximum disassembly p o i and maximum p oduc eco e y alue.
•
Di e en ypes o “solu ion app oaches” may exis depending on he complexi y o
he p oduc o ep esen a ion o be used. Fo example, he e a e app oaches based
on ma hema ical p og amming me hods, simula ions (like i ual eali y), hyb id
me hods, and o he s.
•
Va ious “ alida ion me hods” can be used o e i y he quali y o he esul s achie ed
by DSP, by ei he using i ual models o p ac icing expe imen al es s on an
ac ual p oduc .
The a ious me hodologies ha e di e en ad an ages and disad an ages. G aph-
based me hods allow a clea ep esen a ion o he a ious s eps bu may be subjec o combi-
na o ial explosion and ha e high compu a ional equi emen s o complex pa s [
12
,
14
–
17
].
Ma ix-based me hods a e help ul in being compu e -p ocessed and can be au oma ically
c ea ed om CAD models bu a e less lexible in conside ing complica ed disassembly
mo ions [
10
–
12
,
18
]. Me hodologies based on cus omized in o ma ion models a e lexi-
ble ega ding disassembly unce ain ies bu equi e manual inpu s and a e challenging
o scale o complex p oduc s [
12
,
19
,
20
]. The ule-based o sequence able me hodology
p o ides a clea ep esen a ion o he s eps, bu he ules/ ables may be subjec i e and,
Eng. P oc. 2025,85, 6 3 o 13
he e o e, may no show all possible sequences [
12
,
21
,
22
]. Las ly, hyb id e olu iona y com-
pu ing algo i hm-based me hodologies ha e well-de ined goals and can o e nea -op imal
solu ions bu use complex algo i hms [12,23,24].
Va ious so wa e and ools ha e been c ea ed o e he yea s o add ess he issue o
D D. Ou analysis sugges s ha mos o he ools a e s ill a he de elopmen le el and ha e
educed comme cial ele ance and/o educed inclusion in majo CAE and PLM sui es.
Fo example, He mann e al. [25] p oposed a so wa e called P odTec , a ool o p oduc
a chi ec s o con ol he pe o mance o he EoL h ough a ious calcula ions, e.g., he
ecycling a e and op imal disassembly dep h. Ano he example is he p o essional so wa e
DFMA [
26
]; howe e , i is dedica ed o he assembly phase, which can be conside ed he
same as he disassembly phase only i speci ic geome ic cons ain s a e p esen [
14
].
LeanD D [
10
,
27
,
28
] is a signi ican so wa e o his s udy. This ool iden i ies he mos
pe o man disassembly sequences o a ge componen s by conside ing disassembly
p ecedencies, componen connec ions, and speci ic p ope ies o accu a ely e lec he
p oduc ’s condi ion a i s end o li e. This ool acili a es he e alua ion o a p oduc ’s
demoun abili y and ecyclabili y, s a ing om i s CAD model and Bill o Ma e ials (BOM),
while equi ing some use inpu , such as de ails on ma e ials and p ecedencies [10,27,28].
This p elimina y s udy o he li e a u e sugges s ha i may be use ul o p opose simple
and accessible me hodologies o s udying he disassembly phase o indus ial p oduc s
o imp o e hei ci cula i y and sus ainabili y. I should be no ed ha D D o in-use
in e en ions (e.g., o main enance) and D D o EoL may imply di e en equi emen s
and lead o di e en design solu ions, mainly due o he ac des uc i e disman ling
me hods may be accep ed o EoL; he e o e, he no a ion DEoL (Design o End o Li e)
should be p ope ly used o ac i i ies ela ed o his speci ic phase.
1.2. Wo k S uc u e and Objec i es
This wo k in oduces a disassembly p ocedu es s udy me hodology based on exis ing
li e a u e me hods. This me hodology can be ailo ed o speci ic p oduc ca ego ies and
help designe s de elop mo e en i onmen ally and economically sus ainable solu ions.
This esea ch pape , he e o e, aims o p opose a simple and accessible ool, de eloped in
Py hon, ha can be pa o mo e gene al me hodologies ela ed o Model-Based Sys em
Enginee ing (MBSE) and can be in eg a ed in o mo e complex sys ems ha allow o he
in e change o in o ma ion among a ious s akeholde s. This a icle p esen s he p oposed
me hodology a e he In oduc ion abo e ega ding he backg ound o his esea ch. Nex ,
he applica ion o he me hodology o a case s udy o one o he speci ic p oduc s o which
he ool will be used, namely an Axial Flux Pe manen Magne (AFPM) elec ic mo o , will
be shown. Finally, he las pa o his pape includes a discussion o he me hodology’s
esul s, me i s, and sho comings.
2. Ma e ials and Me hods
The me hodology p esen ed in his pape is p edominan ly g aph-based and Py hon-
based; in ac , i used p ecedence [
29
] and “AND/OR”- ype g aphs [
30
] o choose he bes
disassembly pa h o a gi en a ge conside ing a ious ac o s ela ed o he EoL phase.
The s a ing poin is he s udy o he designe , o he ool use , o he p oduc CAD
model and i s BOM. These ins umen s a e necessa y o c ea ing a ealis ic g aph; he e o e,
i is necessa y o ha e good knowledge o he p oduc . To compile he ma ix, he use
can use CAD ools like he exploded iew and he con ac lis o he a ious componen s
in con ac wi h each o he . Howe e , an a en i e e alua ion o he con ac lis is c ucial
because i may no e u n he same esul s necessa y o he p ecedence ma ix, o example,
due o geome ic cons ain s o compene a ing pieces no ac ually connec ed o each o he .
Eng. P oc. 2025,85, 6 4 o 13
The p ecedence ma ix is cons uc ed simila ly o he “le el ma ix” by Mandolini e al. [
10
]
bu wi h some di e ences. The ma ix is buil wi h he indus ial p oduc componen s on
bo h ows and columns. The alues en e ed will be 1 i he componen in he j- h column is
“dependen ” on he componen in he i- h ow: he componen in ha column is dependen
i i is ela ed, wi h a as ene o ano he assembly ype, o he componen in he ow a
a g ea e dep h o disassembly. In o he wo ds, he alue is 1 i he componen on he
column is di ec ly assembled wi h he componen on he ow, and i can be disassembled
only a e he disassembly o he ow componen . In o he cases, he alue en e ed is 0.
So, in his case, dependences on componen s “p io ” o hose di ec ly connec ed a e no
en e ed in o he ma ix: he alue 1 is assigned only i he column componen is di ec ly
linked and dependen on he ow componen . Al hough his cons uc ion may lose he
possibili y o di ec ly ha ing he sum o he componen s equi ed o be disassembled o
ob ain ano he one [
10
], i simpli ies he c ea ion o he g aph, which will ep esen no
only he p ecedencies o disassembly ope a ions bu can also isually show he liaison
ela ionships be ween componen s.
A e his s ep, he ma ix can be en e ed in o a g aph eade so wa e; in his case, yEd
G aph Edi o (yEd 3.23.2) [
31
] was used. Once he ma ix has been en e ed in o he so wa e,
a hie a chical p ecedence g aph is ob ained, in which each componen is ep esen ed by a
node ha can ha e en e ing o lea ing a cs. Thus, in his amewo k, he p ecedence g aph
conside s as a disassembly ope a ion [
29
] he demoun ing o he componen o which he
node is assigned. Nodes ha do no ha e en y a cs a e a a disassembly dep h le el [
10
] o
0: hey can be disassembled wi hou i s disassembling o he componen s. Nodes wi h
en e ing a cs equi e, in o de o be dismoun ed, he disassembly o he componen s (nodes)
om which he a cs s a . Figu e 1is an example o a p ecedence ma ix used in his wo k,
wi h Figu e 2as he esul ing p ecedence g aph.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 4 o 14
connec ed o each o he . The p ecedence ma ix is cons uc ed simila ly o he “le el ma-
ix” by Mandolini e al. [10] bu wi h some diffe ences. The ma ix is buil wi h he in-
dus ial p oduc componen s on bo h ows and columns. The alues en e ed will be 1 i
he componen in he j- h column is “dependen ” on he componen in he i- h ow: he
componen in ha column is dependen i i is ela ed, wi h a as ene o ano he assembly
ype, o he componen in he ow a a g ea e dep h o disassembly. In o he wo ds, he
alue is 1 i he componen on he column is di ec ly assembled wi h he componen on
he ow, and i can be disassembled only a e he disassembly o he ow componen . In
o he cases, he alue en e ed is 0. So, in his case, dependences on componen s “p io ” o
hose di ec ly connec ed a e no en e ed in o he ma ix: he alue 1 is assigned only i he
column componen is di ec ly linked and dependen on he ow componen . Al hough
his cons uc ion may lose he possibili y o di ec ly ha ing he sum o he componen s
equi ed o be disassembled o ob ain ano he one [10], i simpli ies he c ea ion o he
g aph, which will ep esen no only he p ecedencies o disassembly ope a ions bu can
also isually show he liaison ela ionships be ween componen s.
A e his s ep, he ma ix can be en e ed in o a g aph eade so wa e; in his case,
yEd G aph Edi o (yEd 3.23.2) [31] was used. Once he ma ix has been en e ed in o he
so wa e, a hie a chical p ecedence g aph is ob ained, in which each componen is
ep esen ed by a node ha can ha e en e ing o lea ing a cs. Thus, in his amewo k, he
p ecedence g aph conside s as a disassembly ope a ion [29] he demoun ing o he com-
ponen o which he node is assigned. Nodes ha do no ha e en y a cs a e a a disas-
sembly dep h le el [10] o 0: hey can be disassembled wi hou i s disassembling o he
componen s. Nodes wi h en e ing a cs equi e, in o de o be dismoun ed, he disassem-
bly o he componen s (nodes) om which he a cs s a . Figu e 1 is an example o a p ec-
edence ma ix used in his wo k, wi h Figu e 2 as he esul ing p ecedence g aph.
Figu e 1. An example o a p ecedence ma ix used in his wo k.
Figu e 2. P ecedence g aph esul an om he ma ix in Figu e 1.
Figu e 1. An example o a p ecedence ma ix used in his wo k.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 4 o 14
connec ed o each o he . The p ecedence ma ix is cons uc ed simila ly o he “le el ma-
ix” by Mandolini e al. [10] bu wi h some diffe ences. The ma ix is buil wi h he in-
dus ial p oduc componen s on bo h ows and columns. The alues en e ed will be 1 i
he componen in he j- h column is “dependen ” on he componen in he i- h ow: he
componen in ha column is dependen i i is ela ed, wi h a as ene o ano he assembly
ype, o he componen in he ow a a g ea e dep h o disassembly. In o he wo ds, he
alue is 1 i he componen on he column is di ec ly assembled wi h he componen on
he ow, and i can be disassembled only a e he disassembly o he ow componen . In
o he cases, he alue en e ed is 0. So, in his case, dependences on componen s “p io ” o
hose di ec ly connec ed a e no en e ed in o he ma ix: he alue 1 is assigned only i he
column componen is di ec ly linked and dependen on he ow componen . Al hough
his cons uc ion may lose he possibili y o di ec ly ha ing he sum o he componen s
equi ed o be disassembled o ob ain ano he one [10], i simpli ies he c ea ion o he
g aph, which will ep esen no only he p ecedencies o disassembly ope a ions bu can
also isually show he liaison ela ionships be ween componen s.
A e his s ep, he ma ix can be en e ed in o a g aph eade so wa e; in his case,
yEd G aph Edi o (yEd 3.23.2) [31] was used. Once he ma ix has been en e ed in o he
so wa e, a hie a chical p ecedence g aph is ob ained, in which each componen is
ep esen ed by a node ha can ha e en e ing o lea ing a cs. Thus, in his amewo k, he
p ecedence g aph conside s as a disassembly ope a ion [29] he demoun ing o he com-
ponen o which he node is assigned. Nodes ha do no ha e en y a cs a e a a disas-
sembly dep h le el [10] o 0: hey can be disassembled wi hou i s disassembling o he
componen s. Nodes wi h en e ing a cs equi e, in o de o be dismoun ed, he disassem-
bly o he componen s (nodes) om which he a cs s a . Figu e 1 is an example o a p ec-
edence ma ix used in his wo k, wi h Figu e 2 as he esul ing p ecedence g aph.
Figu e 1. An example o a p ecedence ma ix used in his wo k.
Figu e 2. P ecedence g aph esul an om he ma ix in Figu e 1.
Figu e 2. P ecedence g aph esul an om he ma ix in Figu e 1.
Eng. P oc. 2025,85, 6 5 o 13
Be o e using he g aph wi hin he Py hon-based ool, he use can add an “OR”
condi ion o componen s wi h en e ing a cs. The OR condi ion allows a componen o be
disassembled wi hou “unlocking” all he p e ious en e ing a cs, bu i is su icien ha
only one o he p e ious disassembly pa hs has been pe o med. An example is in Figu e 2,
whe e componen F, o be disassembled, mus be disassembled a e all o he componen s,
i.e., A, B, C, D, and E. In he case o Figu e 3, an edge label was gi en manually o add
he OR condi ion; componen F can be disassembled ei he by disassembling B-D o by
disassembling A-C-E.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 5 o 14
Be o e using he g aph wi hin he Py hon-based ool, he use can add an “OR” con-
di ion o componen s wi h en e ing a cs. The OR condi ion allows a componen o be dis-
assembled wi hou “unlocking” all he p e ious en e ing a cs, bu i is sufficien ha only
one o he p e ious disassembly pa hs has been pe o med. An example is in Figu e 2,
whe e componen F, o be disassembled, mus be disassembled a e all o he componen s,
i.e., A, B, C, D, and E. In he case o Figu e 3, an edge label was gi en manually o add he
OR condi ion; componen F can be disassembled ei he by disassembling B-D o by disas-
sembling A-C-E.
Figu e 3. Example o he OR condi ion, ep esen ed by he ed a ows.
A e he cha ac e iza ion, he p ecedence g aph is inse ed wi hin he ool in a
Py hon en i onmen (Py hon 3.11.0). The Py hon sc ip uses, among o he s, he Ne wo kX
lib a y, which enables g aph analysis [32]. The p ocedu e implemen ed in Py hon is in-
ended o educe manual effo in pa h calcula ion. I consis s o se e al s eps in which
inpu s a e eques ed, ei he en e ed manually by he use o aken au oma ically om
p e iously c ea ed da abases, and ou pu s a e ob ained, including g aphs o possible
pa hs and a anking o he bes ones: he main scheme o how he sc ip wo ks is shown
in Figu e 4. The ool was c ea ed o ha e a cus om ool ha can be used and modi ied o
he analysis o speci ic indus ial p oduc s and o imp o e hei design o op imize he
disassembly s eps bo h du ing main enance and a he end o li e o ma e ial eco e y.
Figu e 4. Main scheme o Py hon sc ip .
The i s pa o he sc ip s a s by analyzing he p ecedence g aph, ocusing on he
numbe o en e ing and lea ing a cs o each node and checking o OR condi ions. This
analysis allows o he iden i ica ion o all possible disassembly pa hs. Nex , he sc ip
c ea es a new AND/OR g aph ha includes all po en ial disassembly scena ios. This g aph
shows all he possible pa hs ha he disassembly p ocess could ollow, making i easie
o use s o explo e and analyze diffe en scena ios. The g aph can be opened in yEd
G aph Edi o o allow use analysis. The sc ip , applied o he example p ecedence g aph
in Figu e 3, gene a es he AND/OR g aph shown in Figu e 5. In his g aph, he nodes
Figu e 3. Example o he OR condi ion, ep esen ed by he ed a ows.
A e he cha ac e iza ion, he p ecedence g aph is inse ed wi hin he ool in a Py hon
en i onmen (Py hon 3.11.0). The Py hon sc ip uses, among o he s, he Ne wo kX lib a y,
which enables g aph analysis [
32
]. The p ocedu e implemen ed in Py hon is in ended o
educe manual e o in pa h calcula ion. I consis s o se e al s eps in which inpu s a e
eques ed, ei he en e ed manually by he use o aken au oma ically om p e iously
c ea ed da abases, and ou pu s a e ob ained, including g aphs o possible pa hs and a
anking o he bes ones: he main scheme o how he sc ip wo ks is shown in Figu e 4.
The ool was c ea ed o ha e a cus om ool ha can be used and modi ied o he analysis
o speci ic indus ial p oduc s and o imp o e hei design o op imize he disassembly
s eps bo h du ing main enance and a he end o li e o ma e ial eco e y.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 5 o 14
Be o e using he g aph wi hin he Py hon-based ool, he use can add an “OR” con-
di ion o componen s wi h en e ing a cs. The OR condi ion allows a componen o be dis-
assembled wi hou “unlocking” all he p e ious en e ing a cs, bu i is sufficien ha only
one o he p e ious disassembly pa hs has been pe o med. An example is in Figu e 2,
whe e componen F, o be disassembled, mus be disassembled a e all o he componen s,
i.e., A, B, C, D, and E. In he case o Figu e 3, an edge label was gi en manually o add he
OR condi ion; componen F can be disassembled ei he by disassembling B-D o by disas-
sembling A-C-E.
Figu e 3. Example o he OR condi ion, ep esen ed by he ed a ows.
A e he cha ac e iza ion, he p ecedence g aph is inse ed wi hin he ool in a
Py hon en i onmen (Py hon 3.11.0). The Py hon sc ip uses, among o he s, he Ne wo kX
lib a y, which enables g aph analysis [32]. The p ocedu e implemen ed in Py hon is in-
ended o educe manual effo in pa h calcula ion. I consis s o se e al s eps in which
inpu s a e eques ed, ei he en e ed manually by he use o aken au oma ically om
p e iously c ea ed da abases, and ou pu s a e ob ained, including g aphs o possible
pa hs and a anking o he bes ones: he main scheme o how he sc ip wo ks is shown
in Figu e 4. The ool was c ea ed o ha e a cus om ool ha can be used and modi ied o
he analysis o speci ic indus ial p oduc s and o imp o e hei design o op imize he
disassembly s eps bo h du ing main enance and a he end o li e o ma e ial eco e y.
Figu e 4. Main scheme o Py hon sc ip .
The i s pa o he sc ip s a s by analyzing he p ecedence g aph, ocusing on he
numbe o en e ing and lea ing a cs o each node and checking o OR condi ions. This
analysis allows o he iden i ica ion o all possible disassembly pa hs. Nex , he sc ip
c ea es a new AND/OR g aph ha includes all po en ial disassembly scena ios. This g aph
shows all he possible pa hs ha he disassembly p ocess could ollow, making i easie
o use s o explo e and analyze diffe en scena ios. The g aph can be opened in yEd
G aph Edi o o allow use analysis. The sc ip , applied o he example p ecedence g aph
in Figu e 3, gene a es he AND/OR g aph shown in Figu e 5. In his g aph, he nodes
Figu e 4. Main scheme o Py hon sc ip .
The i s pa o he sc ip s a s by analyzing he p ecedence g aph, ocusing on he
numbe o en e ing and lea ing a cs o each node and checking o OR condi ions. This
analysis allows o he iden i ica ion o all possible disassembly pa hs. Nex , he sc ip
c ea es a new AND/OR g aph ha includes all po en ial disassembly scena ios. This
g aph shows all he possible pa hs ha he disassembly p ocess could ollow, making i
easie o use s o explo e and analyze di e en scena ios. The g aph can be opened in
yEd G aph Edi o o allow use analysis. The sc ip , applied o he example p ecedence
g aph in Figu e 3, gene a es he AND/OR g aph shown in Figu e 5. In his g aph, he
nodes ep esen he subassemblies, and he labels on he edges indica e he componen s
Eng. P oc. 2025,85, 6 6 o 13
disassembled du ing each ope a ion, illus a ing he p ocess om he assembled p oduc
( oo ) o he disassembled componen s (lea es).
Eng. P oc. 2025, 85, x FOR PEER REVIEW 6 o 14
ep esen he subassemblies, and he labels on he edges indica e he componen s disas-
sembled du ing each ope a ion, illus a ing he p ocess om he assembled p oduc ( oo )
o he disassembled componen s (lea es).
Figu e 5. Example o a disassembly pa h AND/OR g aph.
A e ha , he use mus en e a a ge componen o calcula e he bes disassembly
pa h. The a ge componen is decided h ough a p elimina y classi ica ion, which can be
based on diffe en me hodologies. Fo example, Li e Cycle Sus ainabili y Assessmen
(LCSA) can be use ul in choosing a componen wi h ele an en i onmen al, economic,
and social impac s. Ano he classi ica ion me hod may be based on assessing p oduc
ecyclabili y coefficien s o ensu e compliance wi h egula ions [8,9]. A his poin , he
use can p oceed o he nex s ep o choose o add a cons ain : o a i e a he a ge
componen by necessa ily disassembling ano he componen . This unc ionali y can be
use ul because he e may be ano he impo an componen o disassemble, such as o
economic alue. Rega dless o whe he a cons ain is added o no , he ool e u ns
g aphs ha a e subassemblies o he comple e g aph, such as he one shown in Figu e 5,
so ha he use can ha e he abili y o ac ually see all he disassembly pa hs ha can be
analyzed o ha speci ic a ge componen . A his poin , he ool calls up a able in which
a alue is assigned o each componen : his can be de ined as a “bonus/penal y ac o ”,
i.e., a numbe ha de ines he “disassembly alue” o he componen du ing he
p ocedu e. I can conside se e al ac o s, such as he disassembly ime, cos o he
disassembly ope a ion, e c. Some possible disassembly penal ies can be ela ed o p oduc
manipula ion, low isibili y/iden i iabili y, he use o uncommon ools, and non- eusable
Figu e 5. Example o a disassembly pa h AND/OR g aph.
A e ha , he use mus en e a a ge componen o calcula e he bes disassembly
pa h. The a ge componen is decided h ough a p elimina y classi ica ion, which can
be based on di e en me hodologies. Fo example, Li e Cycle Sus ainabili y Assessmen
(LCSA) can be use ul in choosing a componen wi h ele an en i onmen al, economic,
and social impac s. Ano he classi ica ion me hod may be based on assessing p oduc
ecyclabili y coe icien s o ensu e compliance wi h egula ions [
8
,
9
]. A his poin , he
use can p oceed o he nex s ep o choose o add a cons ain : o a i e a he a ge
componen by necessa ily disassembling ano he componen . This unc ionali y can be
use ul because he e may be ano he impo an componen o disassemble, such as o
economic alue. Rega dless o whe he a cons ain is added o no , he ool e u ns g aphs
ha a e subassemblies o he comple e g aph, such as he one shown in Figu e 5, so ha
he use can ha e he abili y o ac ually see all he disassembly pa hs ha can be analyzed
o ha speci ic a ge componen . A his poin , he ool calls up a able in which a alue
is assigned o each componen : his can be de ined as a “bonus/penal y ac o ”, i.e., a
numbe ha de ines he “disassembly alue” o he componen du ing he p ocedu e. I can
conside se e al ac o s, such as he disassembly ime, cos o he disassembly ope a ion,
e c. Some possible disassembly penal ies can be ela ed o p oduc manipula ion, low
isibili y/iden i iabili y, he use o uncommon ools, and non- eusable connec o s [
33
]. In
his wo k, his ac o is ep esen ed by a disassembly ope a ion ime assigned by he use o
each componen . Once he alues a e loaded, he ool e u ns he pa h wi h he minimum
sum o he alues, so in his wo k, he bes disassembly pa h is ep esen ed by he as es
Eng. P oc. 2025,85, 6 7 o 13
disassembly pa h o he a ge componen . I a cons ain has been inse ed, he ool will
e u n he bes pa h ha in ol es disassembly o he cons ain componen as well. Fo
example, in Figu e 3, i he same bonus/penal y ac o is assigned o each componen , he
bes pa h o ge o F is o disassemble B, hen D, and hen F. I he use wan s o also ob ain
componen E du ing he disassembly p ocedu e, he cons ain op ion can be used so ha
he ool will e u n he pa h A-C-E-F.
The lowcha in Figu e 6summa izes how he p oposed me hodology wo ks.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 7 o 14
connec o s [33]. In his wo k, his ac o is ep esen ed by a disassembly ope a ion ime
assigned by he use o each componen . Once he alues a e loaded, he ool e u ns he
pa h wi h he minimum sum o he alues, so in his wo k, he bes disassembly pa h is
ep esen ed by he as es disassembly pa h o he a ge componen . I a cons ain has
been inse ed, he ool will e u n he bes pa h ha in ol es disassembly o he cons ain
componen as well. Fo example, in Figu e 3, i he same bonus/penal y ac o is assigned
o each componen , he bes pa h o ge o F is o disassemble B, hen D, and hen F. I he
use wan s o also ob ain componen E du ing he disassembly p ocedu e, he cons ain
op ion can be used so ha he ool will e u n he pa h A-C-E-F.
The lowcha in Figu e 6 summa izes how he p oposed me hodology wo ks.
Figu e 6. Me hod lowcha .
Case S udy: An Axial Flux Pe manen Magne Mo o
Pe manen magne s, pa icula ly hose composed o Neodymium, I on, and Bo on
(NdFeB), a e used in a ious applica ions, including elec ic mo o s o ehicles, wind
gene a o s, and o he consume elec onics p oduc s, such as ha d disk d i es. Some
ma e ials o which hese magne s a e composed a e conside ed Ra e Ea h Elemen s
(REE), pa icula ly Neodymium, bu also o he ma e ials, such as Dysp osium o
P aseodymium, which a e pa o he lis o C i ical Raw Ma e ials (CRM) [34]. The Eu o-
pean C i ical Raw Ma e ials Ac (CRMA) encou ages he ci cula i y o hese ma e ials [35],
so hey a e o g ea s a egic impo ance. The e o e, s udying he end o li e o hese com-
ponen s o possible euse and unc ional ecycling may be impo an in achie ing hese
goals; i should be no ed, in ac , ha ypical sh edding p ocesses adop ed o me al-based
componen lead o alloy dispe sion and dilu ion, causing he loss o he a ailabili y o he
ci ed CRMs e en i he ecycling a e is appa en ly e y high.
Thus, an Axial Flux Pe manen Magne (AFPM) elec ic mo o was chosen as a case
s udy o a disassembly pa h analysis. The analyzed elec ic mo o CAD model is
ep esen ed in Figu e 7. Fo he case s udy p esen ed he e, i is assumed ha disman ling
is necessa y wi h compa able effo o bo h componen egene a ion and EoL ea men
due o he need o p ese e ce ain alloys.
Figu e 6. Me hod lowcha .
Case S udy: An Axial Flux Pe manen Magne Mo o
Pe manen magne s, pa icula ly hose composed o Neodymium, I on, and Bo on
(NdFeB), a e used in a ious applica ions, including elec ic mo o s o ehicles, wind
gene a o s, and o he consume elec onics p oduc s, such as ha d disk d i es. Some
ma e ials o which hese magne s a e composed a e conside ed Ra e Ea h Elemen s (REE),
pa icula ly Neodymium, bu also o he ma e ials, such as Dysp osium o P aseodymium,
which a e pa o he lis o C i ical Raw Ma e ials (CRM) [
34
]. The Eu opean C i ical Raw
Ma e ials Ac (CRMA) encou ages he ci cula i y o hese ma e ials [
35
], so hey a e o g ea
s a egic impo ance. The e o e, s udying he end o li e o hese componen s o possible
euse and unc ional ecycling may be impo an in achie ing hese goals; i should be
no ed, in ac , ha ypical sh edding p ocesses adop ed o me al-based componen lead o
alloy dispe sion and dilu ion, causing he loss o he a ailabili y o he ci ed CRMs e en i
he ecycling a e is appa en ly e y high.
Thus, an Axial Flux Pe manen Magne (AFPM) elec ic mo o was chosen as a case
s udy o a disassembly pa h analysis. The analyzed elec ic mo o CAD model is ep e-
sen ed in Figu e 7. Fo he case s udy p esen ed he e, i is assumed ha disman ling is
necessa y wi h compa able e o o bo h componen egene a ion and EoL ea men due
o he need o p ese e ce ain alloys.
Eng. P oc. 2025,85, 6 8 o 13
Eng. P oc. 2025, 85, x FOR PEER REVIEW 8 o 14
O he esea che s ha e conduc ed simila wo ks on elec ic mo o s, con i ming he
ele ance o esea ch in his ield. Hansjos en and Fleische conduc ed an in e es ing
analysis on a diffe en ype o elec ic mo o [36]. Ano he example was p esen ed by E d-
mann e al. [37], who e alua ed disassembly p ac icali y o he possible sui abili y o e-
manu ac u e elec ic bicycle mo o s.
Figu e 7. Elec ic mo o analyzed.
3. Resul s
Ini ially, a CAD model o an AFPM mo o was c ea ed o analyze he con ac s and
connec ions be ween he a ious componen s; he exploded iew o he model is shown
in Figu e 7. In designing his model, some cons uc ion assump ions we e made ega ding
he disassembly o he componen s. Thus, his is a gene ic, basic model o an axial lux
elec ic mo o , wi h he main componen s comp ising i .
In making he p ecedence ma ix, some simpli ying assump ions we e implemen ed
in designing he componen ’s dependencies o possible disassembly pa hs. In he
analysis, he o o s o which he pe manen magne s a e connec ed a e conside ed unique
pieces, as is he s uc u e con aining he coppe coils inside he s a o .
In Table 1, i is possible o see he lis o componen s associa ed wi h hei e e ence
le e . Wi h he CAD model and in s udying he con ac s and connec ions be ween
componen s, he p ecedence ma ix was cons uc ed and inse ed wi hin yEd G aph
Edi o o ob ain he hie a chical p ecedence g aph.
Table 1. Componen lis and associa ed le e s.
Componen Le e
Ca e ex 1 A
Ca e ex 2 B
Bea ing 1 C
Bea ing 2 D
Ro o 1 E
Ro o 2 F
S a o pla e 1 G
S a o pla e 2 H
Sha I
Coil s uc u e J
S a o ca e K
Connec o housing L
Figu e 7. Elec ic mo o analyzed.
O he esea che s ha e conduc ed simila wo ks on elec ic mo o s, con i ming he
ele ance o esea ch in his ield. Hansjos en and Fleische conduc ed an in e es ing
analysis on a di e en ype o elec ic mo o [
36
]. Ano he example was p esen ed by
E dmann e al. [
37
], who e alua ed disassembly p ac icali y o he possible sui abili y o
emanu ac u e elec ic bicycle mo o s.
3. Resul s
Ini ially, a CAD model o an AFPM mo o was c ea ed o analyze he con ac s and
connec ions be ween he a ious componen s; he exploded iew o he model is shown in
Figu e 7. In designing his model, some cons uc ion assump ions we e made ega ding
he disassembly o he componen s. Thus, his is a gene ic, basic model o an axial lux
elec ic mo o , wi h he main componen s comp ising i .
In making he p ecedence ma ix, some simpli ying assump ions we e implemen ed
in designing he componen ’s dependencies o possible disassembly pa hs. In he analysis,
he o o s o which he pe manen magne s a e connec ed a e conside ed unique pieces, as
is he s uc u e con aining he coppe coils inside he s a o .
In Table 1, i is possible o see he lis o componen s associa ed wi h hei e e ence
le e . Wi h he CAD model and in s udying he con ac s and connec ions be ween com-
ponen s, he p ecedence ma ix was cons uc ed and inse ed wi hin yEd G aph Edi o o
ob ain he hie a chical p ecedence g aph.
Table 1. Componen lis and associa ed le e s.
Componen Le e
Ca e ex 1 A
Ca e ex 2 B
Bea ing 1 C
Bea ing 2 D
Ro o 1 E
Ro o 2 F
S a o pla e 1 G
S a o pla e 2 H
Sha I
Coil s uc u e J
S a o ca e K
Connec o housing L
Eng. P oc. 2025,85, 6 9 o 13
The esul ing p ecedence g aph is shown in Figu e 8, in which an OR condi ion was
added ega ding he disassembly o he s uc u e con aining he coppe coils, gi en he
symme y o he mo o analyzed.
Eng. P oc. 2025, 85, x FOR PEER REVIEW 9 o 14
The esul ing p ecedence g aph is shown in Figu e 8, in which an OR condi ion was
added ega ding he disassembly o he s uc u e con aining he coppe coils, gi en he
symme y o he mo o analyzed.
Figu e 8. AFPM mo o p ecedence g aph. Red a ows ep esen he OR condi ion.
The pa h o each one o he wo o o s o which he pe manen magne s a e
connec ed was s udied because o hei impo ance, as desc ibed in he p e ious sec ion.
Subsequen ly, he ou e o he s uc u e con aining he coils was also s udied, as coppe is
also conside ed a S a egic Raw Ma e ial (SRM) despi e no mee ing CRM h esholds [34].
The e o e, E (Ro o 1) was chosen as he i s case s udy a ge , and J (coil s uc u e) was
chosen as he second.
The disassembly alues assigned o he componen s, which in he case s udy a e he
disassembly imes, a e based on e alua ing he connec ions wi h which each componen
is assembled, he ools used o disassembly, and he size and condi ion o he junc ions.
The disassembly imes, as epo ed in he wo ks by Mandolini e al. [10] and Fa i e al.
[27], we e used as he da abase. The pa ial wea o componen s and connec ions we e
conside ed o he co ec i e ac o s, as a ailable om Ma coni [28]. Ano he me hod ha
could ha e been used o calcula e disassembly imes is ela ed o he use o Time
Measu emen Uni s (TMUs) assigned o each componen based on i s disassembly- ela ed
cha ac e is ics and pa ame e s [38–40].
The disassembly ime ela i e o each componen is he ime equi ed o disassemble
i om he componen s o which i is connec ed ia he lea ing a cs. Addi ional
modi ica ions o he da abase imes we e made based on he au ho s’ expe ience. Fo
example, some assump ions we e made ega ding he mo emen o componen s in he
disassembly phase. Also, when possible, he bes a ailable disassembly ools, such as a
sc ewe , we e conside ed ins ead o manual disassembly.
Figu e 8. AFPM mo o p ecedence g aph. Red a ows ep esen he OR condi ion.
The pa h o each one o he wo o o s o which he pe manen magne s a e connec ed
was s udied because o hei impo ance, as desc ibed in he p e ious sec ion. Subsequen ly,
he ou e o he s uc u e con aining he coils was also s udied, as coppe is also conside ed
a S a egic Raw Ma e ial (SRM) despi e no mee ing CRM h esholds [
34
]. The e o e, E
(Ro o 1) was chosen as he i s case s udy a ge , and J (coil s uc u e) was chosen as
he second.
The disassembly alues assigned o he componen s, which in he case s udy a e he
disassembly imes, a e based on e alua ing he connec ions wi h which each componen is
assembled, he ools used o disassembly, and he size and condi ion o he junc ions. The
disassembly imes, as epo ed in he wo ks by Mandolini e al. [
10
] and Fa i e al. [
27
], we e
used as he da abase. The pa ial wea o componen s and connec ions we e conside ed
o he co ec i e ac o s, as a ailable om Ma coni [
28
]. Ano he me hod ha could
ha e been used o calcula e disassembly imes is ela ed o he use o Time Measu emen
Uni s (TMUs) assigned o each componen based on i s disassembly- ela ed cha ac e is ics
and pa ame e s [38–40].
The disassembly ime ela i e o each componen is he ime equi ed o disassemble i
om he componen s o which i is connec ed ia he lea ing a cs. Addi ional modi ica ions
o he da abase imes we e made based on he au ho s’ expe ience. Fo example, some
assump ions we e made ega ding he mo emen o componen s in he disassembly phase.
Also, when possible, he bes a ailable disassembly ools, such as a sc ewe , we e conside ed
ins ead o manual disassembly.
