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7/24/2019 Manufacturing Technology - Extrusion
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EXTRUSION : A
MANUFACTURING PROCESS
Presented By -I.Rajkuar!a"asa"#na$un#%ers#ty
&e'artent () Me*+an#*a" En$#neer#n$!a"asa"#n$a Un#%ers#ty
,!a"asa"#n$a A*adey () Resear*+and Edu*at#(n
kr#s+nank(%#" /
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E0trus#(n:-• It is a manufacturing process, in which a block ofmetal enclosed in a container is forced to ow throughthe opening of a die.
• The metal is subjected to plastic deformation & itundergoes reduction & elongation.
• Basicall it is an adaption of!pen "ie forging.
Uses:-• #anufacture of solid & hollow sections from non
ferrous metals & allos.• $liding doors, tubing ha%ing %arious cross sections,
door & window frames.
INTRO&UCTION
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C4ASSIFICATION OF EXTRUSION PROCESSES
E0trus#(n
By&#re*t#(n
ByE5u#'e
nt
ByO'erat#n$
Te'erature
Ind#re*
t 6Ba*k3
ard
&#re*t6
F(r3ard
1(tC("d
1(r#7(nta"
8ert#*a"
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C4ASSIFICATION B9 &IRECTION
1. &#re*t E0trus#(n:-
• It is a process in which the metal billet, placed in a
container is forced b a ram to pass through a die.
• In this tpe the direction
of ow of metal is, in same
as that of mo%ement of ram.
• The punch closel )ts the die ca%it to pre%ent
backward ow of the material.
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C4ASSIFICATION B9 &IRECTION
2. In-d#re*t E0trus#(n:-
• It is a process in which a hollow ram containing the
die is forced into the container, containing metal.
• +ollow ram limits the applied load.• The mo%ement of metal is opposite to the direction
of ram motion.
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T9PES OF 1OT EXTRUSION
KALASALINGAM
1(tE0trus#(n
4ur#*ate
d
1ydr(sta
t#*
N(n-
4ur#*ated
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4UBRICATE& 1OT EXTRUSION
KALASALINGAM
Before the billet is inserted into the hot e-trusion container,
a suitable lubricating sstem is positioned immediatel
ahead of the die in order to reduce frictional stresses.
!il and graphite are used at lower
temperature whereas at higher temperatures,
glass powder is used.
7opper allos, titanium allos, allo steels,
stainless steels, and tool steels are e-truded using
lubrication.
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NON-4UBRICATE& 1OT EXTRUSION
KALASALINGAM
8o lubrication is used on the billet, container, or
die for reducing frictional stresses.
It has the abilit to produce %er comple-
sections with e-cellent surface )nishes
and low dimensional tolerances.
$olid and hollow dies with at shear faces are
tpicall used.
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19&ROSTATIC EXTRUSION
KALASALINGAM
• In the hdrostatic e-trusion process the billet iscompletel surrounded b a pressuri9ed li:uid,
e-cept where the billet contacts the die.
• The rate, with which the billet mo%es whenpressing in the direction of the die, is thus not
e:ual to the ram speed, but is proportional to the
displaced hdrostatics medium %olume.• The process must be carried out in a sealed
clinder to contain the hdrostatic medium.
• ressure ; 1' #pa <appro-.=
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C(ntd..
KALASALINGAM
Ad%anta$es:
• >limination of large friction force between the
billet and the container wall.
• ossible to use dies with a %er low semi cone
angle <?42=.
• This process can be done hot, warm, or cold,
howe%er the temperature is limited b the
stabilit of the uid used.
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C(ntd..
KALASALINGAM
4##tat#(ns:
@8ot suitable for hot4working due to pressuri9ed
li:uid.
@A practical limit on uid pressure is around
1.a currentl e-ists because of the strength of
the container.
@The li:uid should not solidif at high pressure this
limits the obtainable.
A''"#*at#(ns:
• 7ladding of metals
• #aking wires of less ductile materials
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A&8ANTAGES OF 1OT EXTRUSION
KALASALINGAM
7omple- solid or hollow shapes can be produced.
$mall :uantities can be economicall produced.
"eli%er times are often far shorter than alternati%e
processes.
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4IMITATIONS OF 1OT EXTRUSION
KALASALINGAM
+igh e:uipment set up and maintenance cost.
>-trusion process for metals is at %er high
temperatures.
"ie is preheated to increase its life, so there are chances
of o-idation of hot billet.
rocess Castage is higher as compared to rolling.
8on4homogeneous.
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C4ASSIFICATION B9 OPERATING TEMPERATURE
KALASALINGAM
. C("d E0trus#(n:-
• 7old e-trusion is the process done at room
temperature or slightl ele%ated temperatures.
• This process can be used for materials that can
withstand the stresses created b e-trusion.
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A&8ANTAGES OF CO4& EXTRUSION
KALASALINGAM
Impro%ed #echanical properties.
ood control of dimensional tolerances.
Impro%ed surface )nish.
8o need for heating billet.
8o o-idation takes place.
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&ISA&8ANTAGES OF CO4&EXTRUSION
KALASALINGAM
Tooling cost is high, therefore large production
lot si9e is re:uired.
$pecial coating is re:uired to reduce friction
and to maintain a lubricant )lm throughout.
Dimited deformation can be obtained.
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APP4ICATIONS OF CO4& EXTRUSION
KALASALINGAM
7u, b, $n, Al Allos, Ti, #o, E, $teel, Fr parts can
be e-truded.
Tubes, ear Blanks, Aluminum 7ans, 7linders,
Gire >-tinguisher 7ases, $hock Absorber 7linders,
and Automoti%e istons are manufactured.
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IMPACT EXTRUSION
KALASALINGAM
I'a*t e0trus#(n-
• A manufacturing process in
which a small shot of solid
material is placed in the die
and is impacted b a ram,
which causes cold ow in
the material.
• It ma be either direct or
indirect e-trusion and it is
usuall performed on a high4
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contd..
KALASALINGAM
A''"#*at#(ns-
• Although the process is generall performed cold,
considerable heating results from the high speed
deformation.
• A short lengths of hollow shapes, such as
collapsible toothpaste tubes or spra cans.
• e:uires soft materials such as Al, b, 7u or $n.
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C4ASSIFICATION B9 E;UIPMENT
KALASALINGAM
1(r#7(nta" e0trus#(n 'r(*ess-• The laout of operating machine is hori9ontal and
mo%ement of billet as well as of ram is hori9ontal
in direction.
• 1(4( #8 capacit.
• It is mostl used for commercial e-trusion of bars
and shapes.
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C4ASSIFICATION B9 E;UIPMENT
KALASALINGAM
8ert#*a" e0trus#(n 'r(*ess-• The mo%ement of billet and ram is %ertical in
orientation.
• 42 #8 capacit.
• #ainl used in the production of thin4wall tubing.
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&IE MATERIA4S
KALASALINGAM
7ommonl used materials are Tool $teels and7arbides
"iamond dies are used for )ne wire.
Gor impro%ed wear resistance, steel dies ma be
chromium plated, and carbide dies ma be coatedwith titanium nitride
Gor +ot drawing, cast4steel dies are used .
"ies are made from highl allo tools steels or
ceramics <$i8'=.+eat treatments such as nitriding are re:uired
<se%eral times= to increase hardness <1411+%or *(4 +7=. This impro%es die life.
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4UBRICATION
KALASALINGAM
NEE&- roper lubrication is essential in e-truding, in order
to impro%e die life, reduce drawing forces andtemperature, and impro%e surface )nish.
Ty'es () 4ur#*at#(n-a< =et dra3#n$ 3 "ies and ods are completel
immersed in lubricant.
< &ry dra3#n$ 3 $urface of the rod to be drawn iscoated with a lubricant.
*< C(at#n$ 3 od or Cire is coated with a soft metalthat acts as a solid lubricant.
d< U"tras(n#* 8#rat#(n : of the dies and mandrels.
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FACTORS AFFECTING T1E EXTRUSION FORCE
KALASALINGAM
/. Ty'e () e0trus#(n
. E0trus#(n rat#(
>. =(rk#n$ te'erature
?. &e)(rat#(n
@. Fr#*t#(na" *(nd#t#(ns at t+e d#e and t+e
*(nta#ner 3a""
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MAT1EMATICA4 RE4ATIONS
KALASALINGAM
/. E0trus#(n rat#( R -
It is de)ned as the ratio of the initial cross4
sectional area , Ao, of the billet to the )nal
cross4sectional area , Af, after e-trusion.
f A
A R 0= '31 for hot e-trusion of
steels. '31 for aluminum.
.Fra*t#(na" redu*t#(n #narea r -
0
1 A
Ar
f −=
r R
−
=
1
1
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C(ntd..
KALASALINGAM
>. 8e"(*#ty -
Eelocit of e-truded product ; <am %elocit= -<=
?. E0trus#(n )(r*e -
where k ; e-trusion constant,
f A
AkA P 0
0 ln=
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EFFECTS OF TEMPERATURE ON 1OT EXTRUSION
KALASALINGAM
The temperature of the work piece in metalworking depends on34
The initial temperature of the tools and thematerials.
+eat generated due to plastic deformation.
+eat generated b friction at the
dieJmaterial interface.+eat transfer between the deforming
material and the dies and surroundingen%ironment.
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EXTRUSION &EFECT
KALASALINGAM
/< In+(($ene(us de)(rat#(n - In direct e-trusion, a dead 9one along
the outer surface of the billet due to themo%ement of metal in the centre being
higher than the peripher. After 2J of the billet is e-truded, the
outer surface of the billet <normall witho-idised skin= mo%es toward the centre ande-trudes to the through the die, resulting ininternal o-ide stringers.
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C(ntd..
KALASALINGAM
< Sur)a*e *ra*k#n$It is the ranging from a badl roughened
surface to repetiti%e trans%erse crackingcalled )r4tree cracking.
It is due to longitudinal tensile stressesgenerated as the e-trusion passes throughthe die.
In hot e-trusion, this form of crackingusuall is intergranular and is associatedwith hot shortness.
The most common case is too high ram
speed for the e-trusion temperature.
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KALASALINGAM
>< Centre urst (r *+e%r(n *ra*k#n$It can occur at low e-trusion ratio due to
low frictional conditions on the 9one of
deformation at the e-trusion die.
+igh friction<at a the tool4billet interface=.
Dow friction centre burst.
C(ntd..
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KALASALINGAM
?< 8ar#at#(ns #n stru*ture and 'r('ert#es $tructure & properties are %aried within the
e-trusions due to non4uniform deformation for
e-ample at the front and the back of the e-trusionin both longitudinal and trans%erse directions.
egions of e-aggerated
grain growth, due to high
hot working temperature.
C(ntd..
Gra#nGr(3t+
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KALASALINGAM
@< 1(t s+(rtness <in aluminium e-trusion=
+igh temperatures generated cause
incipient melting, which causes cracking.
C(ntd..
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stock !ar"
# $ullin% &orc'"
(ir')i'stock !ar"
# $ullin% &orc'"
(ir')i'
&RA=ING PROCESS
&ra3#n$ It is an operation in which the cross4sectionof solid rod, wire or tubing is reduced orchanged in shape b pulling it through adie.
=(rk#n$ Pr#n*#'"e The principle of this procedure consist ofreducing the thickness of a pointed ,taperedwire b drawing it through a conical
opening in a tool made of a hardKALASALINGAM
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C(ntd..8ar#(us %ar#a"es ae*t#n$ t+e
&ra3#n$ Pr(*ess
1.Cork #aterial
2.eduction in cur%e section
."ie angle
'."rawing speed
(.Dubrication
N(te:-
It is almost similar to e-trusion, e-ceptKALASALINGAM
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REFERENCES
KALASALINGAM
Kalpakjian $eope, $chmid $te%en .3LManufacturing Engineering & Technology Mearson >ducation India, 26, pp 6(4'2.
$harma, .7. A textbook of productionengineering. 11. 8ew ">D+I3 $.7hand & 7ompan
Dtd, 26, ('4(1(. rint.$harma, .7. A textbook of production
Technology . . 8ew "elhi3 $.7hand & 7ompanDtd, 211, 2*(425. rint.
Todd +. obert, Allen K. "ell, AltingDeo. Manufacturing processes referenceguide.1. 8ew ork3 Industrial ress Inc, 166', pp.26(4266.
ajput, . K. A textbook of Manufacturing
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E il ID bkd l il &
KALASALINGAM
UNIVERSITYi rajkumar@klu ac in5