Seminar Report

SEMINAR REPORT  TOPIC:

LASER BEAM MACHINING MACHINING

BY • • • • •

NAVAROJ KM ROHITH PR SREERAM R SHINTO G VISHNU PP

INTRODUCTION

Laser Beam Machining or more broadly laser material processing deals with machining and material processing like heat treatment, alloying, cladding, sheet metal bending etc. Such processing is carried out utilizing the energy of coherent photons or laser beam, which is mostly converted into thermal energy upon interaction with most of the materials. The cost of cutting hardtomachine materials by conventional mechanical machining processes is high due to the low material removal rate and short tool life, and some materials are not possible to be cut by the conventional machining process at all. Laser beam machining is the machining processes involving a laser beam as a heat source. !t is a thermal process used to remove materials without mechanical engagement with work piece material where the work piece is heated to melting or boiling point and removed by melt e"ection, vaporization, or ablation mechanisms. !n contrast with a conventional machine tool, the laser radiation does not e#perience wear, and material removal is not dependent on its hardness but on the optical properties of the laser and the optical and thermo physical properties of the material. Laserbeam machining $LBM% is accomplished by precisely manipulating a  beam of coherent light to vaporize unwanted material. Laser beam can very easily be focused using optical lenses as their wavelength ranges from half micron to around &' microns. (ocussed laser beam as indicated earlier can have  power density in e#cess of ) M*+mm. -s laser interacts with the material, the energy of the photon is absorbed by the work material leading to rapid substantial rise in local temperature. This in turn results in melting and vaporisation of the work material and finally material removal.  LBM is particularly suited to making accurately placed holes. !t can be used to  perform precision micromachining on all microelectronic substrates such as ceramic, silicon, diamond, and graphite. #amples of microelectronic micromachining include cutting, scribing / drilling all substrates, trimming any hybrid resistors, patterning displays of glass or plastic and trace cutting on semiconductor wafers and chips.

PROCESS DETAILS OF LBM

LBM uses the liht e!e"# $% & l&se" 'e&( t$ "e($)e (&te"i&l '# )&*$"i+&ti$! &!, &'l&ti$!- I! this *"$.ess the e!e"# $% .$he"e!t liht 'e&( is %$.use, $*ti.&ll# %$" *"e/,e.i,e, l$!e" *e"i$, $% ti(e- The 'e&( is *ulse, s$ th&t the "ele&se, e!e"# "esults i! &! i(*ulse &&i!st the 0$"1 su"%&.e th&t ,$es (elti! &!, e)&*$"&ti$!- He"e the 0&# $% (et&l "e($)i! is s&(e &s th&t $% EDM *"$.ess 'ut (eth$, $% e!e"&ti$! $% he&t is ,i2e"e!t- The &**li.&ti$! $% he&t is )e"# 3!el# %$.use, i! .&se $% LBM P"$.ess ,et&ils $% LBM &"e sh$0! i! li!e ,i&"&(

Laser Tube and Lamp Assembly  This is the (&i! *&"t $% LBM setu*- It .$!sists $% & l&se" tu'e4 & *&i" $% "e5e.t$"s4 $!e &t e&.h e!, $% the tu'e4 & 5&sh tu'e $" l&(*4 &! &(*li3.&ti$! s$u".e4 & *$0e" su**l# u!it &!, & .$$li! s#ste(- This 0h$le setu* is 3tte, i!si,e & e!.l$su"e4 0hi.h .&""ies $$, 6u&lit# "e5e.ti! su"%&.es i!si,e- I! this setu* the 5&sh l&(* $es t$ l&se" tu'e4 th&t e7.ites the &t$(s $% the i!si,e (e,i&4 0hi.h &'s$"' the "&,i&ti$! $% i!.$(i! liht e!e"#- This e!&'les the liht t$ t"&)el t$ &!, %"$ 'et0ee! t0$ "e5e.ti! (i""$"s- The *&"ti&l "e5e.ti! (i""$" ,$es !$t "e5e.t the t$t&l liht '&.1 &!, & *&"t $% it $es $ut i! the %$"(

$% & .$he"e!t st"e&( $% ($!$.h"$(&ti. liht- This hihl# &(*li3e, st"e&( $% liht is %$.use, $! the 0$"1 *ie.e 0ith the hel* $% .$!)e"i! le!s- The .$!)e"i! le!s is &ls$ the *&"t $% this &sse('l#

Work piee  The "&!e $% 0$"1 *ie.e (&te"i&l th&t .&! 'e (&.hi!e, '# LBM i!.lu,es hih h&",!ess &!, st"e!th (&te"i&ls li1e .e"&(i.s4 l&ss t$ s$%te" (&te"i&ls li1e *l&sti.s4 "u''e" 0$$,4 et.- A $$, 0$"1 *ie.e (&te"i&l h&s hih liht e!e"# &'s$"*ti$! *$0e"4 *$$" "e5e.ti)it#4 *$$" the"(&l .$!,u.ti)it#4 l$0 s*e.i3. he&t4 l$0 (elti! *$i!t &!, l$0 l&te!t he&t-

Coolin! Me"anism A .$$li! (e.h&!is( .i".ul&tes .$$l&!t i! the l&se" tu'e &sse('l# t$ &)$i, its $)e"he&ti! i! l$! .$!ti!u$us $*e"&ti$!-

#eed Me"anism Tool  The"e is !$ t$$l use, i! the LBM *"$.ess- F$.usi! l&se" 'e&( &t & *"e/,e.i,e, *$i!t i! the 0$"1 *ie.e se")e the *u"*$se $% t$$l- As the "e6ui"e(e!t $% 'ei! %$.use, shi%ts ,u"i! the $*e"&ti$!4 its %$.us *$i!t .&! &ls$ 'e shi%te, "&,u&ll# &!, &..$",i!l# '# ($)i! the .$!)e"i! le!s i! & .$!t"$lle, (&!!e"- This ($)e(e!t $% the .$!)e"i! le!s is the t$$l %ee, (e.h&!is( i! LBM *"$.ess-

PROCESS PRINCIPLE THE LASING PROCESS Lasing process describes the basic operation of laser, i.e. generation of coherent (both temporal and spatial) beam of light by “li ght amplification” using “stimulated emission”.

I! the ($,el $% &t$(4 !e&ti)el# .h&"e, ele.t"$!s "$t&te &"$u!, the *$siti)el# .h&"e, !u.leus i! s$(e s*e.i3e, $"'it&l *&ths- The e$(et"# &!, "&,ii $% su.h $"'it&l *&ths ,e*e!, $! & )&"iet# $% *&"&(ete"s li1e !u('e" $% ele.t"$!s4 *"ese!.e $% !eih'$u"i! &t$(s &!, thei" ele.t"$! st"u.tu"e4 *"ese!.e $% ele.t"$(&!eti. 3el, et.- E&.h $% the $"'it&l ele.t"$!s is &ss$.i&te, 0ith u!i6ue e!e"# le)els- At &'s$lute +e"$ te(*e"&tu"e &! &t$( is .$!si,e"e, t$ 'e &t "$u!, le)el4 0he! &ll the ele.t"$!s $..u*# thei" "es*e.ti)e l$0est *$te!ti&l e!e"#- The ele.t"$!s &t "$u!, st&te .&! 'e e7.ite, t$ hihe" st&te $% e!e"# '# &'s$"'i! e!e"# %$"( e7te"!&l s$u".es li1e i!."e&se i! ele.t"$!i. )i'"&ti$! &t ele)&te, te(*e"&tu"e4 th"$uh .he(i.&l "e&.ti$! &s 0ell &s )i& &'s$"'i! e!e"# $% the *h$t$!- Fi ,e*i.ts s.he(&ti.&ll# the &'s$"*ti$! $% & *h$t$! '# &! ele.t"$!- The ele.t"$! ($)es %"$( & l$0e" e!e"# le)el t$ & hihe" e!e"# le)el-

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sti(ul&te, e(issi$! 0$ul, i!iti&te l&si! &.ti$!- Sti(ul&te, e(issi$! $% *h$t$!s .$ul, 'e i! &ll ,i"e.ti$!s- M$st $% the sti(ul&te, *h$t$!s4 !$t &l$! the l$!itu,i!&l ,i"e.ti$! 0$ul, 'e l$st &!, e!e"&te 0&ste he&t- The *h$t$!s i! the l$!itu,i!&l ,i"e.ti$! 0$ul, %$"( .$he"e!t4 hihl# ,i"e.ti$!&l4 i!te!se l&se" 'e&(-

LASING MEDIUM M&!# (&te"i&ls .&! 'e use, &s the he&"t $% the l&se"De*e!,i! $! the l&si! (e,iu( l&se"s &"e .l&ssi3e, &s s$li, st&te &!, &s l&se"- S$li,/st&te l&se"s &"e .$(($!l# $% the %$ll$0i! t#*e ? Ru'# 0hi.h is .h"$(iu( @ &lu(i!& &ll$# h&)i! & 0&)ele!th $% =- ( ? N,/l&ss l&se"s h&)i! & 0&)ele!th $% <- ( ? N,/YAG l&se" h&)i! & 0&)ele!th $% <-= (  These s$li,/st&te l&se"s &"e e!e"&ll# *"$.essi! The e!e"&ll# use, &s l&se"s &"e ? Heliu( @ Ne$! ? A"$! ? CO et.-

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L&se"s .&! 'e $*e"&te, i! .$!ti!u$us ($,e $" *ulse, ($,e T#*i.&ll# CO &s l&se" is $*e"&te, i! .$!ti!u$us ($,e &!, N, @ YAG l&se" is $*e"&te, i! *ulse, ($,e-

CONSTRUCTION OF LASER

Fi sh$0s & t#*i.&l N,/YAG l&se"- N,/YAG l&se" is *u(*e, usi! 5&sh tu'e- Fl&sh tu'es .&! 'e heli.&l4 &s sh$0! i! Fi4 $" the# .&! 'e 5&t- T#*i.&ll# the l&si! (&te"i&l is &t the %$.&l *l&!e $% the 5&sh tu'e-

 Th$uh heli.&l 5&sh tu'es *"$)i,e 'ette" *u(*i!4 the# &"e ,i.ult t$ (&i!t&i!Fi sh$0s the ele.t"i.&l .i".uit %$" $*e"&ti$! $% & s$li,/st&te l&se"- The 5&sh tu'e is $*e"&te, i! *ulse, ($,e '# .h&"i! &!, ,is.h&"i! $% the .&*&.it$"- Thus the *ulse $! ti(e is ,e.i,e, '# the "esist&!.e $! the 5&sh tu'e si,e &!, *ulse $2  ti(e is ,e.i,e, '# the .h&"i! "esist&!.e- The"e is &ls$ & hih )$lt&e s0it.hi! su**l# %$" i!iti&ti$! $% *ulses-

Fi sh$0s & CO l&se"- G&s l&se"s .&! 'e &7i&l 5$04 &s sh$0! i! Fi4 t"&!s)e"se 5$0 &!, %$l,e, &7i&l 5$0 &s sh$0! i!- The *$0e" $% & CO l&se" is t#*i.&ll# &"$u!, <== &tt *e" (et"e $% tu'e le!th- Thus t$ (&1e & hih *$0e" l&se"4 & "&the" l$! tu'e is "e6ui"e, 0hi.h is 6uite i!.$!)e!ie!t- F$" $*ti(&l use $% 5$$" s*&.e4 hih/*$0e"e, CO l&se"s &"e (&,e $% %$l,e, ,esi!I! & CO l&se"4 & (i7tu"e $% CO4 N &!, He .$!ti!u$usl# .i".ul&te th"$uh the &s tu'e- Su.h .$!ti!u$us "e.i".ul&ti$! $%  &s is ,$!e t$ (i!i(i+e C $!su(*ti$! $% &ses- CO &.ts &s the (&i! l&si! (e,iu( 0he"e&s Nit"$e! hel*s i! sust&i!i! the

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MERITS AND DEMERITS Traditional machining includes the use of metal machining tools such as planers, lathes and mills. This  pro ce ss us es sh ar pen ed metal pie ces to cut and shape other metal o!ects. Though this can e done "ith  prec ision, a non tradition al method of mach ini ng #n o"n as laser eam machining, or L$M, can e used to cut metal "ith e%en greater precision on numerous surfaces including those not made from metal.

MERITS

Ma$erial %apori&a$ion Aordin! $o En!ineers'andbook( laser beam ma"inin! is preisely manipula$in! a beam o) o"eren$ li!"$ $o *apori&e un+an$ed ma$erial, T"e in$ensi$y o) $"e laser used in su" applia$ions an be manipula$ed $o bore preise "oles on numerous sur)aes +i$"ou$ ma"ine +as$e, T"e laser *apori&es ma$erial ins$ead o) mo*in! i$ as +i$" $radi$ional ma"inin! $ools( makin! $"e u$s and "oles mu" leaner and )ree o) debris Preision In $radi$ional ma"inin!( $"e +ork-piee and $"e ma"inin! $ool "a*e $o be preisely alibra$ed and measured( $"en one $"e piee is mo*ed( all measuremen$s mus$ be made a seond $ime, T"is is done $o make u$s and s"ape me$als $o spei. de!rees and an!les or $o )orm a spei. diame$er and dep$" )or

u$s or "oles, Wi$" laser beam ma"inin!( $"e ma"ine an be se$ $o $"e spei.s o) $"e pro/e$ and make $"e desired u$s or "oles +i$" a preision do+n $o one miron, One se$( $"e ma"inin! proess +ill run au$oma$ially and $ake less $ime( makin! seond or $"ird measuremen$s unneessary,



%ersa$ili$y L&se" 'e&( (&.hi!i! &s .$(*&"e, t$ t"&,iti$!&l (&.hi!i! *"$.esses is (u.h e!tle"- ith l&se" 'e&( (&.hi!i!4 the (&.hi!ist is &'le t$ (&.hi!e .ut thi! *ie.es $% (et&l &!, $the" (&te"i&l 0ith$ut 0$""#i! &'$ut ,&(&i! $" $the"0ise 0&"*i! the *ie.e &s 0ith t"&,iti$!&l (&.hi!i! t$$ls- The )&"iet# $% (&te"i&l th&t l&se" 'e&( (&.hi!i! .&! 0$"1 $! is &ls$ (u.h "e&te" th&! 0ith .$!)e!ti$!&l (&.hi!i! t$$ls- A..$",i! t$ E!i!ee"sH&!,'$$14 the l&se" .&! e7e.ute s."i'i!4 (&"1i! &!, ,"illi! .ut thi! (et&ls &!, .e"&(i.s t"i( "esist$"s &!, *"$.ess sili.$!4 *l&sti.4 "&*hite &!, ,i&($!, 0ith t$le"&!.es t$ $!e (i."$!-

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APPLICATIONS OF LBM  The &,&*t&'ilit# $% l&se" 'e&( (&.hi!i! &ll$0s the( t$ *e"%$"( ($"e th&! $!e %u!.ti$!4 &!, the 0i,e "&!e $% i!,ust"ies th&t $%te! use l&se" 'e&( (&.hi!i! te.h!$l$# i!.lu,es &ut$(&1e"s &!, e0elle"sL&se" .&! 'e use, i! 0i,e "&!e $% (&!u%&.tu"i! &**li.&ti$!s ? M&te"i&l "e($)&l @ ,"illi!4 .utti! &!, t"e/*&!!i! ? el,i! ? Cl&,,i! ? All$#i! D"illi! (i."$/si+e, h$les usi! l&se" i! ,i.ult @ t$ @ (&.hi!e (&te"i&ls is the ($st ,$(i!&!t &**li.&ti$! i! i!,ust"#- I! l&se" ,"illi! the l&se" 'e&( is %$.use, $)e" the ,esi"e, s*$t si+e- F$" thi! sheets *ulse l&se" .&! 'e use,- F$" thi.1e" $!es .$!ti!u$us l&se" (&# 'e use,-