Ci a ion: G a , A.; K äusel, V.; Weise,
D.; Pe ˚u, J.; Kozio ek, J.; Bhanda i, P.
De e mina ion o he In luence o he
Tool Side S ess Supe posi ion and
Tool Geome y on he Cu Su ace
Quali y du ing P ecision Shea
Cu ing. J. Manu . Ma e . P ocess.
2023,7, 145. h ps://doi.o g/
10.3390/jmmp7040145
Academic Edi o : S e en Y. Liang
Recei ed: 29 June 2023
Re ised: 31 July 2023
Accep ed: 1 Augus 2023
Published: 8 Augus 2023
Copy igh : © 2023 by he au ho s.
Licensee MDPI, Basel, Swi ze land.
This a icle is an open access a icle
dis ibu ed unde he e ms and
condi ions o he C ea i e Commons
A ibu ion (CC BY) license (h ps://
c ea i ecommons.o g/licenses/by/
4.0/).
Manu ac u ing and
Ma e ials P ocessing
Jou nal o
A icle
De e mina ion o he In luence o he Tool Side S ess
Supe posi ion and Tool Geome y on he Cu Su ace Quali y
du ing P ecision Shea Cu ing
Alexande G a 1,∗, Ve ena K äusel 2, Die e Weise 2, Jana Pe ˚u 3, Jiˇ í Kozio ek 4
and P a ishan Bhanda i 1
1P o esso ship o Fo ming and Joining, Chemni z Uni e si y o Technology, Reichenhaine S aße 70,
09126 Chemni z, Ge many
2F aunho e Ins i u e o Machine Tools and Fo ming Technology IWU, Reichenhaine S aße 88,
09126 Chemni z, Ge many
3Facul y o Mechanical Enginee ing, VSB—Technical Uni e si y o Os a a, 17. Lis opadu 2172/15,
708 00 Os a a , Czech Republic
4
Facul y o Elec ical Enginee ing and Compu e Science, VSB–Technical Uni e si y o Os a a, 17. Lis opadu
2172/15, 708 00 Os a a, Czech Republic
*Co espondence: alexande [email p o ec ed]; Tel.: +49-371-53139938
Abs ac :
Shea ing high-s eng h s eels o en leads o a subpa cu quali y and excessi e s ess on he
ool componen s. To enhance he quali y o he cu su ace, in ica e echniques like ine blanking a e
commonly employed. Howe e , o applica ions wi h lowe quali y equi emen s, p ecision shea
cu ing o e s an al e na i e solu ion. This esea ch pape in oduces a no el app oach o di ec ly
supe impose adial s ess on a wo kpiece du ing he p ecision shea cu ing p ocess and showcases
o he i s ime how he applica ion o di ec s ess supe imposi ion can impac he cu su ace
by concu en ly modi ying he shea cu ing edge and punch su ace. A s a is ical expe imen al
design is employed o in es iga e he in e ela ionships be ween he pa ame e s and hei e ec s.
The esul s indica e ha he o e all cu quali y, including cylind ici y, clean-cu angle, ollo e heigh ,
and ool s ess, de ined by punch o ce and e ac ion o ce, is in luenced by he supe imposed s ess.
Rega ding he clean-cu zone, he s a is ical signi icance o di ec adially supe imposed s ess was
no obse ed, excep when in e ac ing wi h shee hickness and clea ance. Addi ionally, he shee
hickness and cu ing gap eme ged as signi ican pa ame e s a ec ing he o e all quali y o he
cu su ace.
Keywo ds:
high s eng h s eel; me al shea ing; p ecision shea cu ing; s ess supe posi ion; ool
su ace modi ica ion; s a is ical expe imen al design
1. In oduc ion
The au omo i e sec o ’s g owing emphasis on educed emissions has made ligh weigh
cons uc ion a c i ical ac o , leading o he inc eased usage o Ad anced High S eng h S eel
(AHSS) wi h a minimum ensile s eng h o 440MPa [
1
]. By employing ully enginee ed
s eel body s uc u es, weigh educ ions o up o 180 kg a e achie able, esul ing in a nea ly
70% dec ease in he o e all li e cycle o g eenhouse gas emissions [
2
]. The shea cu ing
p ocess, known o i s speed, cos -e ec i eness, and chipless na u e, is widely employed
in indus ial applica ions. As he shea ing ope a ion is equen ly in eg a ed in o a ious
o ming p ocesses, he quali y o he pos - o ming s age elies hea ily on he quali y o he
shea ed edge. Howe e , eg ession analyses o cu su ace da a ha e e ealed ha as he
ensile s eng h o he wo kpiece inc eases, he clean-cu zone and ollo e diminish while
he ough ac u e zone expands [
3
]. The hole expansion es , which e alua es he s e ch
langeabili y o he shea ed edge, exhibi s lowe limi ing expansion a ios o specimens
wi h highe ensile s eng hs. In hese cases, he impac o mac oscopic i egula i ies
J. Manu . Ma e . P ocess. 2023,7, 145. h ps://doi.o g/10.3390/jmmp7040145 h ps://www.mdpi.com/jou nal/jmmp
J. Manu . Ma e . P ocess. 2023,7, 145 2 o 13
ou weighs he signi icance o ac u e zone oughness [
4
]. Mo eo e , educing oughness
is desi able o enhancing he a igue limi o high-s eng h s eel [
5
]. Consequen ly, he e
is a u gen need o adap con en ional shea cu ing p ocesses o achie e high-quali y
shea ing o high-s eng h s eel, wi h p ecision shea cu ing inco po a ing di ec adial
p e-s ess supe posi ion and a modi ied ool se up being one p omising me hod [
6
]. This
s udy ocuses on measu ing he cha ac e is ics o he cu su ace, as well as he o m and
posi ional ole ances o holes, shea ed using di e en sys em pa ame e s such as clea ance,
cu ing edge and ace geome y a he punch, shee hickness, and adial p e-s ess. The
ob ained esul s a e subsequen ly subjec ed o a s a is ical analysis o iden i y he mos
in luen ial ac o s and de e mine he op imal pa ame e combina ion o achie ing a high-
quali y cu su ace.
1.1. Single-S oke Shea Cu ing and I s Cha ac e is ics
Single s oke shea cu ing is a cu ing me hod whe e he en i e cu line is comple ed
in a single s oke. The ool se up and pa ame e s a y depending on he desi ed cu su ace
quali y and he complexi y o he ooling. In he con en ional shea cu ing p ocess, he
wo kpiece is shea ed be ween a die and punch wi h a la ge clea ance ( anging om 5%
o 15% o he ini ial shee hickness, deno ed as
s0
), while he shee is held by he blank
holde [7].
On he o he hand, he ine blanking p ocess u ilizes a coun e punch and a
blank holde equipped wi h a ee- ing. This p ocess allows o a much smalle clea ance
(0.5% o
s0
) and enables he achie emen o a clean-cu zone ha spans 100% o
s0
[
8
].
P ecision shea cu ing, in e ms o cu quali y, alls be ween he con en ional shea cu ing
and ine blanking me hods. I o e s achie able ole ances anging om IT 7 o IT 11 wi h
ela i ely simple equipmen [
6
]. This sys em is cha ac e ized by a la blank holde and
coun e punch, a ounded punch o die edge, and a smalle clea ance (1.3% o s0) [7].
1.2. Cu Su ace Cha ac e is ics and In luencing Fac o s
Acco ding o he VDI 2906-2 [
9
], he cu su ace o a shea ed shee me al pa consis s o
he ollo e , clean-cu zone, ac u e zone, and bu , as shown in Figu e 1. These cha ac e -
is ics a e associa ed wi h he di e en phases unde gone du ing he shea cu ing p ocess.
shee
hickness
s0
ollo e wid h bE
clean-cu angle α
ac u e su ace angle β
bu wid h bG
bu heigh hG
ac u e zone hB
clean-cu zone hS
ollo e heigh hE
Figu e 1.
De ini ion o he cu su ace cha ac e is ics in e e ence o VDI 2906-2 [
9
] on a c oss-sec ion
o a cu su ace [Image sou ce: Au ho s].
In gene al, a good cu su ace quali y is cha ac e ized by a smalle alue o ollo e
heigh and wid h, smalle ac u e zone, smalle bu heigh and wid h, and a la ge clean-
cu zone wi h a 90◦clean-cu angle [7]. The impo an p ocess pa ame e s in luencing he
cu su ace quali y a e clea ance, he geome y o he ac i e ool pa s, wo kpiece ma e ial,
cu ing speed, e c. [
9
]. The in luence o clea ance, which is he cu ing gap be ween wo
blades o be ween punch and die, has been s udied many imes in he li e a u e. The
J. Manu . Ma e . P ocess. 2023,7, 145 3 o 13
inc easing clea ance gene ally dec eases he cu quali y by inc easing he ollo e , ac u e
zone, ac u e angle, and bu , and dec easing he clean-cu zone [
3
,
9
]. These obse a ions
a e linea o up o 20–30% o he clea ance [
10
]. Fu he in es iga ion o he in luence o
he cu ing gap was done wi h he help o he Cock o & La ham ailu e c i e ion in [
11
].
In de ail, an inc ease in he cu ing gap means an inc ease in he shea band, which in
u n leads o p ema u e sepa a ion in he ma e ial. Howe e , he expe imen done by
Han [
12
] did no show any change in he clean-cu zone o high s eng h s eel g ea e han
500 MPa wi h a shee hickness o 1.42 mm. As al eady de ined by p ecision shea cu ing,
he ounding o he cu ing edge has a posi i e e ec on he quali y o he shea ed edge. The
FEM is a sui able ool o in es iga ing he in luence o cu ing edge geome y. Fo example,
he load on a ool coa ing du ing he shea ing p ocess can be de e mined. The in es iga ion
shows ha he combina ion o a cham e and a ounding on he cu ing edge can educe he
load conside ably [
13
]. Fu he in es iga ion in o he modelling o he cu ing punch o
shea cu ing o high s eng h ma e ials wi h an open cu ing line can be ound in [
14
]. The
ailu e is desc ibed by a phenological model wi h a modi ied Moh –Coulomb app oach. In
he simula ion esul s, a 7
◦
cham e on he ace is shown o be use ul o educe he s ess in
he cu ing punch, e en i he maximum cu ing o ce inc eases compa ed o he la ace.
The inc ease o he punch adius inc eases he clean-cu zone [
15
]. Howe e , he inc eased
ounding adius may addi ionally inc ease he ollo e and bu o ma ion. The e o e, a
small ounding adius is op imum o ul a-high s eng h s eel (UHSS) in e ms o bo h he
ool li e and he clean-cu zone [
16
]. Di e en punch aces a e bene icial o educing he
load while shea ing high s eng h s eel. Fo example, by using wo-way con ex shea ed
oo op punches, he punching o ce is signi ican ly educed wi h an inc ease in shea angle
as compa ed o he la punch. Bu a he same ime, ollo e and bu heigh also become
la ge [
17
]. The ini e elemen analysis has shown minimum bu heigh s o cham e ed
and con ex punches compa ed o la punches [
18
]. Ano he pa ame e in luencing he
quali y o he cu su ace du ing ine blanking is he blank holde o ce and he coun e
holde o ce. In [
19
], his in luence is discussed wi h he help o he FEM; i is shown ha a
highe cu ing su ace quali y can be achie ed wi h inc eased blank holde and coun e
holde o ces. The adiaba ic sepa a ion based on a high-speed impac cu ing machine
wi h a eloci y up o 10 m/s is de ined by he F aunho e Ins i u e o Machine Tools and
Fo ming Technology, wi h he possibili y o achie e almos bu - ee cu su aces [
20
]. The
expe imen s done wi h a ious cu ing speeds ha e shown a dec eased ollo e , smoo he
su ace, and negligible bu wi h high-speed se ings [
21
]. The in es iga ions in [
22
] also
came o simila esul s, whe eby he minimum necessa y shea cu ing ene gy could be
de e mined by using linea mo o s in a es bench.
1.3. Supe posi ion o Comp ession S ess
The beha io o a ma e ial du ing loading is de e mined by i s s ess s a e. The s ess
enso can be di ided in o hyd os a ic and de ia o ic componen s, wi h he hyd os a ic
pa being negligible in a cons an - olume o ming p ocess. Howe e , as discussed in
Doege [
23
], supe imposing a s ess s a e o inc ease he comp ession componen o he
hyd os a ic pa enhances de o mabili y. In he shea cu ing phase, he p opo ion o he
clean-cu zone inc eases when he ini ia ion o he c ack leading o he ac u e zone can
be delayed. This delay can be achie ed by inc easing he comp essi e s ess s a e, which
is obse ed in ine and p ecision shea cu ing. The educ ion in hyd os a ic s ess has
been add essed by Hö mann [
24
] in ela ion o lowe clea ance, ounded cu ing edges,
and shea ing wi h a ee- ing. Simila ly, a nume ical s udy demons a ed ha a highe
comp essi e s ess s a e can be a ained by employing a conca e nose punch ins ead o a
con en ional punch shape. The op imized geome ical alue o he punch esul ed in a
clean-cu zone p opo ion o 73% e en in a con en ional ool se up [25]. Subsequen ly, an
expe imen al s udy con i med he inc eased clean-cu zone p opo ion using he conca e
nose punch [
26
]. The same au ho s conduc ed ano he nume ical s udy o in es iga e he
eplacemen o he con en ional blank holde wi h a Z-shaped blank holde , aiming o
J. Manu . Ma e . P ocess. 2023,7, 145 4 o 13
supe impose a comp ession s a e on he blank p io o shea cu ing. In his case, he
achie able clean-cu zone p opo ion was 67% e en wi h a con en ional ool se up [
27
]. In
his s udy, unlike cu en echnologies, he applica ion o di ec adial o ces on he ou
edges o he wo kpiece using ou hyd aulic block cylinde s is employed o supe impose
comp essi e s ess. This app oach enables he manipula ion o he s ess s a e o an
imp o ed shea cu ing pe o mance.
2. Ma e ials and Me hods
The de eloped ool concep o s ess supe imposi ion in p ecision shea cu ing is
shown in Figu e 2a. The uppe ool is guided o he lowe ool ia ou columns. In he
uppe ool, he e a e helical comp ession sp ings o applying he holding-down o ces in
he ange o 16 o 80 kN. In he lowe ool (Figu e 2b), he cu ing die can be changed in he
die holding pla e o a y he cu ing gaps be ween 1.3 o 10% o he shee hickness. The
applica ion o he s ess supe posi ion in he p ocess is ca ied ou by he ou hyd aulic
block cylinde s, which p ess e enly on he ou wo kpiece edges. They allow a maximum
p e- ension o 100 kN pe cylinde . The senso s in eg a ed in o he se o sc ew p ess
enabled he measu emen o punch displacemen , blank holde o ce, and displacemen ,
as well as coun e holde o ce and displacemen wi h a maximum sys em-dependen
measu ing equency o 1000 Hz. The punch and ou slide o ces we e measu ed ia he
o ce ings buil in o he ool and a cha ge ampli ie was used o eco d hese o ces a a
measu ing equency o 10,000 Hz.
column guide
blank holde
head pla e
base pla e
hyd aulic pipe
hyd aulic dis ibu o block hyd aulic block cylinde s
modula slide assembly
die holding
pla e
place o
wo kpiece
(a) (b)
Figu e 2.
(
a
) Design o he expe imen al ool o p ecision shea cu ing wi h s ess in luence on he
ool side and (b) assembly o he lowe pa o he ool wi h he clamping de ice.
To educe he numbe o expe imen s de e mined acco ding o he mo phological box,
he s a is ical design ool in eg a ed wi h O igin 2020 so wa e was used. The high-s eng h
ho - olled mic o-alloyed s eel S500MC was used o all es s, and he mechanical p ope ies
we e de e mined in ad ance (Table 1). The ex emes in Table 2we e p eselec ed as inpu
pa ame e s o he expe imen al design. Speci ically, he shee hickness
s0
a ied be ween
3 and 8 mm, and he punch ace a ied be ween a la shape and a con ex shape wi h a
adius o 100 mm. Addi ionally, ei he a sha p cu ing edge o a cu ing edge wi h a adius
o 0.2 mm was used. The a ia ion o he cu ing punch geome y is also ou lined in he
h ee shapes in Figu e 3.
J. Manu . Ma e . P ocess. 2023,7, 145 5 o 13
30
(a) 30
R100
(b) 30
R 0.2
(c)
Figu e 3.
D awing o he a ia ion o he geome y o he shea cu ing punch: (
a
) la punch ace and
sha p cu ing edge; (b) con ex punch ace; (c) ounded cu ing edge.
Table 1.
Summa y o he mechanical p ope ies o he mic oalloyed s eel S500MC de e mined in he
ensile es .
Shee
Thickness
s0[mm]
Rolling
Di ec ion
[◦]
Young’s
Modulus
[GPa]
Yield
S eng h
Re[MPa]
Tensile
S eng h
Rm[MPa]
Elonga ion
a B eak
A80 [%]
3
0 188 520 601 10.3
45 184 532 578 9.9
90 249 574 612 9.1
8
0 181 516 601 10.5
45 189 542 574 9.3
90 221 576 625 8.8
Table 2. Selec ed inpu pa ame e s o he s a is ical design o expe imen s.
Le els
Shee
Thickness
s0[mm]
(A)
Punch
Face
Geome y
(B)
Cu ing
Edge
Geome y
(C)
Cu ing
Clea ance
[% o s0]
(D)
Radial
P e-S ess
[% o Re]
(E)
−1 3 la sha p 1.3 0
1 8 kon ex
(R100) adius (R0.2) 10 45
The cu ing gap was a ied as a pe cen age o he shee hickness om 1.3 o 10%. The
selec ion o he s ess supe posi ion was based on he esul s o Neugebaue e al. [
6
], and
i was de ined by he pe cen age o he yield s eng h
Re
. Using he 2
5−1
design app oach
wi h i e inpu ac o s esul ed in 16 ials and he ac o combina ion o each ial is
shown in Table 3. Each es combina ion was pe o med wi h i e epe i ions bu each
measu emen ask was done o a single sample. The shea cu ing oil used had a iscosi y
o 180 mm
2
/s, and he coun e -holding o ce was calcula ed as 15% o he maximum cu ing
o ce, which was 18.5 kN o he es s wi h a shee hickness o 3 mm and 54.5 kN o 8 mm.
The cu ing speed was cons an a 1 mm/s o all es s.
The de e mina ion o he quali y o he cu su ace was ca ied ou on he pe o a ed
wo kpiece in acco dance wi h he VDI guideline 2906-2 [
8
] and was measu ed using he
Keyence VHX-600 digi al mic oscope. Since a signi ican ad an age o s ess-supe imposed
p ecision shea cu ing is p ima ily he imp o emen o he clean-cu zone o he unc ional
su ace e en wi h he cu ing gaps usually p esen in con en ional shea cu ing, his
c i e ion was he main ocus when de e mining he cu su ace pa ame e s. The wo kpieces
we e ma ked acco dingly be o e shea cu ing so ha he subsequen measu ing poin s o
he p ima y smoo h cu we e di ec ly compa able wi h each o he (Figu e 4a). Addi ional
quali y c i e ia o he p oduc ion o in e nal con ou s a e he de ia ion om he cylinde
and he pe pendicula i y o he axis o he su ace. Fo measu ing he de ia ion o he
cu su ace om i s ideal geome y, cylind ici y was used as a shape measu emen , and
pe pendicula i y was used as an o ien a ion measu emen . The 3D scanne used was he
GOM A os Co e 200, based on inge p ojec ion wi h a na owband blue ligh o il e ou

J. Manu . Ma e . P ocess. 2023,7, 145 6 o 13
any ambien ligh . The scanned da a was polygonized and he c ea ed mesh was expo ed
in o GOM Inspec ion 2019, whe e a i ing cylinde wi h he Chebyshe bes i was c ea ed
in he middle loca ion. The cylind ici y de ia ion is calcula ed as de ined in DIN EN ISO
12180-1,2 [
28
,
29
]. Simila ly, he Chebyshe bes i was also used o c ea e a e e ence plane
on he lowe su ace o he scanned pa and pe pendicula i y de ia ion as de ined in he
ISO 1101 s anda d [
30
] wi h a ’ci cula ole ance zone’ ype being used. An exempla y
e alua ion o cylind ici y and pe pendicula i y in he GOM Inspec so wa e ( e sion:
2022-156191; c ea o : Ca l Zeiss GOM Me ology GmbH; B aunschweig, Ge many) a e
he measu emen is shown in Figu e 4b.
Table 3. Expe imen al design o he cu quali y analysis.
T ial No. A B C D E
[mm] [% o S0] [% o Re]
1 3 la sha p 10 0
2 3 la adius 1.3 0
3 3 kon ex sha p 1.3 0
4 3 kon ex adius 10 0
5 3 la sha p 1.3 45
6 3 la adius 10 45
7 3 kon ex sha p 10 45
8 3 kon ex adius 1.3 45
9 8 la sha p 1.3 0
10 8 la adius 10 0
11 8 kon ex sha p 10 0
12 8 kon ex adius 1.3 0
13 8 la sha p 10 45
14 8 la adius 1.3 45
15 8 kon ex sha p 1.3 45
16 8 kon ex adius 10 45
(a)
0◦45◦
90◦
135◦
180◦
225◦
270◦
315◦
I
IIIII
IV
(b)
0.300
0.225
0.150
0.075
0.000
−0.075
−0.150
−0.225
[mm]
Figu e 4.
Cu su ace cha ac e is ics measu emen : (
a
) cu s o di ide he sample and (
b
) op ical
scanned su ace in GOM Inspec .
3. Resul s and Discussion
The p elimina y assessmen o he clean-cu zone a di e en angula posi ions o he
esul ing 16 ials wi h di e en inpu pa ame e combina ions is depic ed in Figu e 5. I
appea s ha he clean-cu zone has highe alues a posi ions anging om 180
◦
o 315
◦
compa ed o posi ions om 0
◦
o 135
◦
. One possible explana ion o his end could be a
misma ch be ween he cen e o he punch and he die. A b ie analysis o he s anda d
de ia ion shows ha he de ia ion is g ea e o he con igu a ion wi h 1.5% clea ance and
3 mm shee hickness, which a e bo h associa ed wi h a smalle absolu e alue o clea ance
gap. Fu he analysis om his poin onwa d was done a he measu ing posi ion wi h a
minimum alue o clean-cu pe cen age.
J. Manu . Ma e . P ocess. 2023,7, 145 7 o 13
8
T ial No.
16
T ial No.
Figu e 5. Clean-cu zone pe cen age a di e en angula posi ions.
3.1. In luence on Cylind ici y and Pe pendicula i y E o
The e ec plo displays he di e ence in mean alues o a ac o o in e ac ion a wo
gi en le els. In expe imen s wi h no eplica ion, O igin employs Len h’s me hod o d aw
he e e ence line o s a is ical signi icance. Figu e 6shows such a plo o a signi icance
le el o 5%. Fo pe pendicula i y, only shee hickness showed a signi ican e ec , whe eas
o cylind ici y, clea ance, adial p e-s ess, and he in e ac ion be ween shee hickness
and clea ance (AD) we e all ound o be signi ican .
A CD E D CE BD AD BC BE C AB DE AC AE B
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.058
0.032
E ec s [mm]
Te m
Pe pendicula i y e o
Cylind ici y e o
Pe pendicula i y e o
Cylind ici y e o
Fac o Name
A Shee hickness
B Punch ace geome y
C Cu ing edge geome y
D Clea ance
E Radial p e-s ess
Figu e 6. E ec plo o cylind ici y and pe pendicula i y e o s.
As shown in he ba plo s in Figu e 7a,b, he e o s inc ease wi h an inc ease in shee
hickness (A), which is likely due o he highe possibili y o de ia ion when measu ing a
la ge su ace a ea compa ed o a smalle su ace. The p esence o a smalle clea ance (D)
o 1.3% and p e-s ess (E) leads o a ela i ely highe alue o he clean-cu zone, which is
obse ed o educe he cylind ici y e o . The absolu e alue o clea ance is dependen on
he shee hickness, causing he in e ac ion AD o be signi ican o cylind ical de ia ion.
Al hough he li e a u e [
16
,
24
] suppo s good cu quali y o ounded cu ing edges, he
signi ican in luence o he geome ical cha ac e is ics o he ool, such as he punch ace (B)
and cu ing edge (C), could no be conclusi ely de e mined in his expe imen . This esul
could be aced back o he clean-cu zone, which in his expe imen is also no signi ican ly
in luenced by he punch ace and cu ing edge geome y. The p obable eason o i can be
ha s ess educ ion, due o he educed no ch e ec o he ounded edge, is only signi ican
when he clea ance is much lowe han 1.3%.
J. Manu . Ma e . P ocess. 2023,7, 145 8 o 13
(a)
A
B
C
D
E
-1
1
0.0
0.1
0.2
0.3
0.4
0.5
Le els
Mean o cylind ici y e o [mm]
Fac o s
(b)
A
B
C
D
E
-1
1
0.00
0.02
0.04
0.06
0.08
0.10
Le els
Mean o pe pendicula i y e o [mm]
Fac o s
Figu e 7. Main e ec plo o he (a) cylind ici y e o and (b) pe pendicula i y e o .
3.2. In luence on he Clean-Cu Zone
The main e ec s o he hickness (A) and clea ance (D) we e also ound o be signi ican
o he clean-cu zone. As shown in Figu e 8a, he e was no signi ican di ec in luence
o punch ace geome y (B), punch cu ing edge geome y (C), and adial p e-s ess (E),
bu signi ican in e ac ion e ec s we e obse ed o AD, BC, DE, and AE. I is e iden ha
a highe hickness esul s in a highe absolu e amoun o he clean-cu zone, bu when
exp essed in e ms o shee hickness pe cen age, he alues we e nea ly he same. The
highe alue o he clean-cu amoun a 1.3% clea ance han a 10% (Figu e 8b) is due o an
inc eased comp essi e s ess s a e in he shea zone, leading o a delayed ac u e [24].
(a)
A D AD BC DE AE BE B C CD CE BD E AC AB
0
500
1000
1500
2000
2500
305.96
E ec s [µm]
Te m
Clean cu zone
(b)
A
B
C
D
E
-1
1
0
500
1000
1500
2000
2500
3000
3500
Le els
Mean o clean cu zone [ m]
Fac o s
Figu e 8. S a is ical plo o he clean-cu zone (a) e ec s plo and (b) main e ec plo .
3.3. In luence on he Clean-Cu Angle and F ac u e Su ace Angle
Fo a lowe pe pendicula i y de ia ion, i is a o able i he angles associa ed wi h
he clean-cu zone and ac u e zone a e as close as possible o 90
◦
. Fo all he 16 ials
conduc ed, he clean-cu angles a e in he ange be ween 87
◦
o 89.5
◦
. Ou o he i e inpu
pa ame e s, only shee hickness (A) and adial p e-s ess (E) we e ound o signi ican ly
in luence he clean-cu angle, al hough i was expec ed o ind he signi icance o clea ance
as well (Figu e 9a). As seen in Figu e 9b, when using an 8 mm hick blank and wi h adial
p e-s ess, he angle ge s close o 90
◦
by 2
◦
in compa ison o a blank wi h 3 mm o hickness
and wi h no adial p e-s ess. A longe s oke leng h wi h highe hickness means highe
ime o he blank ma e ial o be shea ed along he punch side walls and his may ha e
helped he clean-cu zone o e ain pe pendicula i y. As will be seen in he nex sec ion, he
addi ional p e-s ess helps in educing he ollo e heigh signi ican ly and his could be
he eason why he clean-cu angle is close o 90◦ o he case o supe posed s ess.
J. Manu . Ma e . P ocess. 2023,7, 145 9 o 13
In con as , ac u e su ace angles ha e highe dispe sion o he 16 ials wi h he
ange be ween 72
◦
o 85
◦
. He e, he adial p e-s ess had no signi ican e ec , bu only
he cu ing edge adius (C) and clea ance (D) (Figu e 10a). The plo o he indi idual
pa ame e can be seen in Figu e 10b. As expec ed, a highe gap be ween he punch and
die causes he ac u e o a el along a lowe -angled pa h and hus esul ing in a lowe
ac u e angle. This can be isualised using basic igonome y. In he case o a ounded
cu ing edge, he be e angle could be ela ed o he ac ha when using a ounded punch
and a sha p die, he c ack o ma ion in he blank akes place only om he die edge side as
shown in [16].
(a)
A E C D B
0.0
0.5
1.0
1.5
2.0
2.5
3.0
2.228
S anda dized E ec s
Te m
Clean cu angle
(b)
A
B
C
D
E
-1
1
0
87.0
87.5
88.0
88.5
89.0
89.5
Le els
Mean o clean cu angle [°]
Fac o s
Figu e 9. S a is ical plo o he clean-cu angle (a) e ec s plo and (b) main e ec plo .
(a)
D C A E B
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
2.228
S anda dized E ec s
Te m
F ac u e su ace angle
(b)
A
B
C
D
E
-1
1
0
72
73
74
75
76
77
78
79
80
81
82
83
84
Le els
Mean o ac u e su ace angle [°]
Fac o s
Figu e 10. S a is ical plo o he ac u e su ace angle (a) e ec s plo and (b) main e ec plo .
3.4. In luence on Rollo e Heigh and Wid h
In con as o he clean-cu zone, a lowe alue o ollo e heigh and wid h is desi able
o a good cu quali y. All main ac o s we e ound o be signi ican ly ac i e in in luencing
he ollo e heigh . Addi ionally, Figu e 11a shows ha he in e ac ion be ween shee
hickness (A) and adial p e-s ess (E) is also impo an . Thicke shee s and inc eased
clea ance (D) la gely inc ease he ollo e heigh (Figu e 11b). The la ge cu ing gap
inc eases he bending momen and allows mo e ma e ial o low in o i . A he beginning
o he shea ing p ocess, when a punch wi h a con ex ace (B) is used, he e ec i e cu ing
gap inc eases as he poin o con ac be ween he punch and blank is shi ed owa ds he
cen e , leading o an inc eased momen and hus, ollo e heigh .
The addi ional adial p e-s ess has a posi i e e ec on educing he s e ching o he
ou e shee ma e ial, he eby educing he ollo e heigh . Fu he mo e, he in luence o
addi ional s ess is mo e ad an ageous in educing he ollo e heigh o a hicke shee ,
as shown by he AE in e ac ion plo in Figu e 12a. VDI 2906-5 p o ides a ela ion whe e