Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
,_~ P0717 ~ 33
2 3
PROCBSS AND ARR~G1~3T POR ~ZW~PACT~ING
B~:Y~RAGE~ 3 0~ ~I~
The invention relates to a proces~ for manufac-
5 turing a beveraye can made of aluminum an~ to an arrange-
ment for carrylng out the process and to a co~e~ponding
beverage can made o~ pure aluminum.
Beverage can~ m~de of aluminum are manufactured
according to the prior art by means of, in a fir~t step,
10 a cup being prodllced by cuppirlg fr~m a ro~lnd piec~ of
body sheet, said cup b0i.ng cylindrical having a bot tom
area which i~ greater than the bottom area of the fin-
i~hed can, and having a cylinder height w~lich i~ ~ller
than t1~at of thQ f inif3hed can . In a ~econd ~;t~p, t.his
cupped cup is formed, by ironin~, lnto a cylindrical CaII
whoae dimensions corr~pond to the dimen3ions of the
f i~iah~d can, apart ~rom ~ slightly great~r wall h~ight.
During this second proca~ing Btep~ the ironing, the
bottom i~ formed at the ~ame time. The can i~ then
20 proce~ed into a f~nlshed beveraga can by means o
cutting to lengthJ cl~ning, lacquering (outaide and
inside), necking and flanging. A proces~ of tbi~ type i
nor~ally used to manuf~ctur~ beverage can~i made of
alloyed alu~rlinum.
A fu~ther proceas for manufact~ring beverage cans
made o~ alumi~ tar~s from a ~3lug from which, by ~eans
of impact extru~ion, a c~n body i8 for~ed, whone dimen-
~3ions~ apart ~ro~ a ~lightly gre~er wall height, corre
cpond to tho~e of the fini~hed c~n. ThiEI can body i~
30 llkawi~a prvccEI~ad by cutting to length, cleaning,
lacquering, necking and flanging to give, the fini~had
be~e~age can. U~ lly thi~ Becond proceaB iB u~ed to
manu~acture beverage c~ns msde Of pure aluminum.
The c:anr) manufactured accordin~ to the two
35 proces~es msntioned bo~h ha~e the drawback that their
wall thickne~, at lea~3t zonally, iB not de'cermined by
the strerl~th of the ma~e:rial and ~he strength
, ~ ~
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pO717 - 2 ~ 33~2
..
re~uirem~nt~ relatin~ to the Can, but by th~ manufac-
turing pr~CesB. In t~e cas~ o~ th~ ~upping proc~Gs thi3
~, particula~ly relate~ to the can bottom, whone thicknesn
e~aentially corresponds to the thickne3s of the body
nheet, and to the can wall zone at a dîstance from the
1~j bottom, which zone, for the purposc of problem-free
,~$,',1 necking, must be thicker than required in term~ of
3I strength. In the impact extrusio~ procens it ~elaten ~o
the ent.ire can wall, whlch haa a minimum thicknens deter-
mined by tho im~act extru~ion procen3, a~ well a~ the
transition zone between wall and bottom which likewine
~ han a thickne~n defined by the process. I~ other words,
l this ~eans that the beverage cans manufactured according
to the prior art processe6 are heavier than absolutely
neces~ary~
Furthermore, the round piece~l of sheet metal,
which are punched from a Htrip o~ roll~d ~heet me~al and
are u6ed as the qtarting material for the cupping pro-
. ce~s, cause iDevi~able wastage of ~ 3tarting material
which, having been produced by a number of process ~teps,
is of high quality.
The object of the inventi~n then iD to specify aproce~ and to prov.ide an arrangement by meann of which
beverage cann made of al~minum can be manufactured, whose
wall thickne~ in ~ ones are [~ic] de~ined not by the
manufacturing proce3n but by the str~ngth of tlle material
used and by the ~trength requirements r.elating to the
can. At the name time, the proae~g in to make it posnible
to uDe, a~ the ~tarting material, a material which can be
manufactured an simply ac~ ponnible ~nd in Eew proc~s~
~3teps, in 9u~:h a Way th~t lrlevital~le .scrap~ c~s well as
the cans themnelveu, can be reproce~d i~to th~ ~tartiIIg
material with little ~ost and effort (recycling). The
actual proce~ accordin~ to the inv~ntion i~ to nati~fy
high environmental requirem~t~ At the name time, the
proce~n according to the invention, without iner~a~ed
CQst of appliancen, ia to provide or productio~ rate~
which are ~omparable with the production rates of the
,~ P~7~7 ~ 3 ~ ~ ~33~2
prior art proce~s~
This ob~ect i~ achi~ed by the proce~ ha~ing the
eaturs8 according to P~te~t Clai~ 1 a~d the ar~angement
having the eature9 according ~o Patent Claim 4.
The proc~3 ac~ording ~o the invention ~tart
from ~lug~ made of pure aluminum, whlch ~re punched ~ro~
unrolled ~heet metal a~d are commercially availa~l~ as
~uch, which mlnimize~ the wa~t~ge problem for the manu-
factur2r. ~he proce~ according to ~he in~ention i~ ba6ed
on forming from E~uch a alug, by mean~ of impact extru-
8ion, a cyl~ndrical cup who~e botto~ haa ~ greater
diameter than haE~ the bottom of the fini~h~d can. Thi~
cup i~ molded into ~ can body by iro~ing, the bottom at
the same time b0ing molded by pre~slng. ~he can body i6
then p~ocessed by means of cutting t~ l~g~h, cleaning,
lacquerlng, necking ~nd flanging to ~ive the finished
c~n.
The impact ~xtr~l~ion proce~3E~ per~i~a the di~
tribution of material acroE~E) the can b~ttom to be
tallorcd to the ~trength requirement~ relating to the
fini~hed can, i.e . t~e central zone of the bottom advan-
tageou~ly to b~ mad~ thinner than the ~i~ zone. The
mini~u~ wall thick~e~ ~chievable ~f the imp~ot-e~ruded
cup in the vicinity of the cylinder wall and in parti-
cular in the cyli~der wall-bottom tran~ition ~one i6
determined by the .impact extru~ion proce~. sy mean~ Of
~he ironing ~ep it i3 pos~ible, howe~er, to reduce thi~
wall thickns~s to ~ degxae d0~in2d by th~ ~rength
requirementa, includi~g, in particular, in the wall-
~ot~om ~ran~ition zone, if ~he diame~er o~ the cup iB
chosen to be ~lightly larger khan the di~n~ter o ~he can
and, a~ ~ ~re~ult, during ironing the material of the
outer~o~t ~ction~ of the cup botto~ i~ al~o inYolved in
the irolling pro~e~.
3S The proce~ according to the in~ention thu~
e~ble~ ~aslufactur~ o~ a beverag~ can who~e wall ~hick-
ne~e in each zone (~yli~der wall, bottom and tran~itio~
zone) ean be freely predefined within wlde range~ and
2:~333~2
~ P0717 - 4 -
- thu~ be adju~ted in accordance wlth the ~trength r~quir~- m~nt~, whe~e~ accordlng to the known cuppi~g proce6s
thi~ only applies to the bottom zone of the can wall a~d
according to the known impact extrunion proce~s only to
th~ can botto~ ln neither ca~e the~efore applying to t~e
top zone of the can wall and to ~he transition zons
be~ween can wall and san bottom. Thi~ al~o ~e~, how-
ever, that the proce~s according to the i~vention enables
manufacture of a can with a minimum of ma~erial. This
economic adv~ntage ic further reinforc~d by the fact that
the ~tarting material in the ~orm o~ slug~ of pure
aluminum i8 inexpenaive, thank~ to waate recycling
pos~ible at very little co~ ikewi~e, prod~ction o~
slug~ from u3ed cans i~ Blmple and not e~pen6ive. The~e
lS economic advantaga~ fa~ outweigh th~ additional materi~l
required owing ~o the lower ~trengt~ o~ pure aluminum.
In addltlon to the economic ad~antage# of the
can~ manufactured in accordance with the proce~ accord-
ing to the lnvention ther~ are environmental advantages
which, in particular, a~e that it i~ po~sible to l~e, for
impact ~xtrusion o~ pure ~luminum, a ~oap-ha~ed lubricant
and that the cans can then be wa~hed with a~ environ-
mentally adva~tageou~, mildly alkaline cleaning medium,
~urface gllalities being produced in the proce~s whlch
preae~t no problem~ what#oev~r in ~b~eque~t lacquering.
~n contra~t, canD made of alloyed alumin~m have to be
wa~hed acidically to achieve the ~ame ~urface q~a}ity,
which cau~e~ di~po8al problem~.
The proca~ according to th~ invention and an
arra~gement fo~ aarryl~ out the proces~ will now b0
de~cribed in d~t~l with r~fere~ce to the following
figure~, in which:
Pigure 1 8how8 ~chemat2cally, how a beYe~ag~ can i8
produced in acaorda~ce with tho procees accord-
ing to kha i~ventio~;
Yi~urs 2 ~how~ a ~chsmatic pre~entation o~ the
arrange~e~t for carrying out th8 proce
according to the invention;
~333~
P0717 - 5 -
~igure 3 ~how~ a ~ch~matic ~ection through an ex~mpla~y
be~er~ge can ma~ufactured by mean~ of the
proce~ according to the inventi~n.
Figuxe 1 ~howa, ochematically, the individual
5 Bt3ge8 of the proce~c according to ~he invention.
In a fir~t pSOCf'5~ tep (lubricating), a glu~ 10
~ade o:E purs alumin~ (purity 99 . 0% or higher) i~ coated
with a soap-based lubrlcant. ~his ia done, for example.
in a alug drum whlch ic ch~rged with 81ug~ and lubricant.
I~ a ~econd proce~ ~tep ~impact extru~ion) thore
i~ produced by imp~ct extru~ion, fro~ the ~lug 10, a
cylindrical cup 2~ havlng ~ cup wall 21 and a cup ~otto~
22. To thi~ end, the 81ug ia placed i~to a female die
and, by mean~ of a male die, i~ pre~sed again~t the
f~male die, mate~ial. flowing in the oppoRlta direction
between male and female die and thu~ bein~ for~ed into
the cup w~ll 21. I~ ~o doi~g, the face of the malo dle
and the male die travel are designed in BUCh a way that
the ~up ~o~tom 22 o~ tho cup 20 produced e~entially cor-
20 re~pond~, in t~3r~ of ma~erial di~3tribution, ~o thepredefined bottom of the fini~hed can. Advant2geously,
the cup bottom 22 o~ ~he cup produced il3, a~ ~hown,
thinner in the ce~tral ~one than in the ri~ zone~. The
cup wall 21 h~ ~ height which i~ ~malle~ than tho wall
height of the finiehed can ~for example from 25 to 75
thereof ), and the cup bottom 22 ha5 a diam~ter which i~
greater than ~he diameter of the bottom o~ the fini~hed
can.
The second p~oce~e ~tep can be carried out by
~0 employlng a conventional i~pact extru~ion appliance. The
tr~vel o~ the lmpact extru~ion mal~ die for producin~ the
cup ~0 in con~iderably chol-t.er th~n the tra~el o~ a cor^
re6pondi~lg tool ~or manufacturirlc~ a can body (proc~ss
according to the prior art) . Since the time required for
i~npac~ extru~lon primaxily depend~ on qaid tr~vel, this
~ea~ an increaae in capaclty ~or the proce~ accordiug
~o ~he invention.
In a third proc2~ 8tep ~iro~ling and botto~
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~ ~0717 - 6 2133312
formlng) there i8 in~erted into the cup 20 an ironing ram
who~e diameter corre~po~d~ to the inte~nal diameter o~
the flni~h~d can. With the aid of ~aid ironing ram, the
cup 20 i~ drawn through one or mo~e ironing rings having
an lnte~nal diameter whl~h decre~e~ in the direction o~
movamsnt of ~he cup. The clearence ~etwee~ the last
ironing ri~g and the iro~ing ram corre~pond~ to the
~tipulated wall thickness o ths ini~hed can. In the
same operation, the bottom of the cup i~ pres~ed into a
stipulated shape between the face of the i~oning ra~ and
a co~nter^tool. ~he two tool~ molding ~he boktom to this
end have ~hape~ corresponding to one another. The product
of the ironlng and bottoM-formi~g ~t~p i~ a can hody 30,
whose ca~ wall 31 haa ~ thickne~s which satisfie~ the
strength re~uireme~t~, ~or example i~ ~sentially
con~tant over the entir~ can wall, and w~1ich iA slightly
higher than that o~ the fini6hed c~n. In crder ~o
increa~e the ~tability under load of the can, the can
botto~ 3~, molded in th.i~ proce~s step, i~ advantageously
~O not only curved concavely toward the can lnterior but ha~
additional ~hape el~ment3 which incre~e re~istance to
pre~ure and by means of which the bottom thick~ess
required can be ~urthe~ reduced. Such a shape elemen~
increasing re~istance to pre~ure i~, for example as
~how~, a ~tiffening ring 35 who6e diameter i~ small~r
than the ext~rnal diameter of the can and approximately
~orre~po~d~ to the in~arnal diameter o a recessed can
lid, in ~uch a way that the Atiffen~ng ring additionally
as~i~t~ the ~tackablli~y of the cans.
The thi~d proce~s step can be carried out by
e~ploying a convent~onal ironing appliaPce.
In furthe~ proce~a stepA~ the can body, in a
mannër k~own per ~e, iB cu~ to size, cleaned, lacque~ed
out~ide and in~ide, neckod ~nd flanged. Thu~ the finished
35 be~era~e ca~ 40 1c produced. For ~he purpo6e of cleaning~
the can body, cut to ~i~e, is wa~hed with a mildly
alkaline, aqueou~ cleaning medium and i~ the~ rin~ed and
dried.
,r~ P0717 ~ 7 ~ ~1333~2
Fis~r~ 2 BhOW~, ~chematically, an ex~plary
arrange~ent for manufacturing beverage cans made of
aluminu~ in accordance wlth the proce~ according to the
invention. Thiu arrangement e~nentially ~on~ist~ of an
appliance S for coatlng the ~lugs Wit}l lubricant, for
exAmple a ~lug dru~, o~ at leaat one, adv~n~a~ously two
appli~nce(~) r~.l and F.2 for impact extruaion of the
91ug~ to form cups, an appliance A for ironing the cups,
can bodie~ to form an appliance s or cutting the can
bodie~ to ~ize, au ~ppliance W for cleaning the ca~
bod~e~ cu~ to ~iz0, a~ appliance L for lacqueri~g and an
appliance ~ for neckin~ and f lanying the can~. All the~e
appliances are known per ~e and therefore need not be
de~crib~d here i~ detail.
Figure 3 ~hows, llfe-ai~e, a ~ection thro~gh an
ex~mpl~ry beverags ca~ manu~actur0d in accordance with
th~ proceE~ accordi~g to ths in~entio-n. The left half
~how~ the fi~ished (necked and flanged) be~erage can, the
right half Qhowa the can body cut to ~ize. The can ahown
2U haa an internal ~olu~e o~ 350 ~1 and iB de~ig~ed for a
minimum bur~ti~g pre~ure of 12 bar. It i~ made of
A19g.~. It ha~ tha ~ollowing wall thicknea~ea: central
zone 41 of ~h~ bottom 0.46~0.01 mm, outer xone 42 of the
bottom 0.66i0.01 mm, can wall 43 ~.24~0.01 mm. The
tranaition ~on~ 4~ ~etwe~n bottom and wall 1~ narrow and
ha~ a conti~uou~ tran~itio~ f~o~ th~ bottom th~ckness
(0.65 ~ to t~e wall thic~ness (0.24 ~m).
Obviously it .i~ alao pos~ible ~or larger or
~maller cans to be manufactured in accordance with the
30 process accord.ing ~o the invention. It i0 al~o possible
for the can to ba necked more markedly in order to b~
able to be closed with a ~maller ea~y-open e~d. In prin-
ciple it is poa~ibla to manufacture, ill accordance with
the proceas accordin~ ko the i~en~ion, beverag~ can3
which can be clo~ed With any ~ize of lid (sm~ller than
the can diameter). ~he can shown in Figure 3 can be
; ~uikably ~ecked for lid~ ha~ing di~meter~ lea5 than
60 mm.
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