Manufacturing Technology - Extrusion

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

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E0trus#(n

By&#re*t#(n

ByE5u#'e

nt

ByO'erat#n$

Te'erature

Ind#re*

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ard

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F(r3ard

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C4ASSIFICATION B9 &IRECTION

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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.



C4ASSIFICATION B9 &IRECTION

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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.



T9PES OF 1OT EXTRUSION

KALASALINGAM

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1(tE0trus#(n

4ur#*ate

d

1ydr(sta

t#*

N(n-

4ur#*ated



4UBRICATE& 1OT EXTRUSION

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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.



NON-4UBRICATE& 1OT EXTRUSION

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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.



19&ROSTATIC EXTRUSION

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• 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-.=



C(ntd..

KALASALINGAM

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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.



C(ntd..

KALASALINGAM

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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



A&8ANTAGES OF 1OT EXTRUSION

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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.



4IMITATIONS OF 1OT EXTRUSION

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+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.



C4ASSIFICATION B9 OPERATING TEMPERATURE

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. 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.



A&8ANTAGES OF CO4& EXTRUSION

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Impro%ed #echanical properties.

ood control of dimensional tolerances.

Impro%ed surface )nish.

8o need for heating billet.

8o o-idation takes place.



&ISA&8ANTAGES OF CO4&EXTRUSION

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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.



APP4ICATIONS OF CO4& EXTRUSION

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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.



IMPACT EXTRUSION

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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



contd..

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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.



C4ASSIFICATION B9 E;UIPMENT

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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.



C4ASSIFICATION B9 E;UIPMENT

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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.



&IE MATERIA4S

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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.



4UBRICATION

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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.



FACTORS AFFECTING T1E EXTRUSION FORCE

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/. 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""



MAT1EMATICA4 RE4ATIONS

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/. 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



C(ntd..

KALASALINGAM

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>. 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=



EFFECTS OF TEMPERATURE ON 1OT EXTRUSION

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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.



EXTRUSION &EFECT

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/< 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.



C(ntd..

KALASALINGAM

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< 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.



KALASALINGAM

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>< 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..



KALASALINGAM

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?< 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+



KALASALINGAM

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@< 1(t s+(rtness <in aluminium e-trusion=

+igh temperatures generated cause

incipient melting, which causes cracking.

C(ntd..



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

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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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KALASALINGAM

UNIVERSITYi rajkumar@klu ac in5

Manufacturing Technology - Extrusion

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