Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
METAL CASTING PROCESSES P ROCESSES 11 METAL Review Questions 11.1
N!e N!e the the t"o t"o bsi# bsi# #te$or #te$ories ies of #st #stin$ in$ pro#es pro#esses ses.. Answer. %he t"o #te$ories re (1) e&pendble !old pro#esses, nd (2) per!nent !old pro#esses.
11.2 11.2
%here re vrious vrious types types of ptterns ptterns used in snd snd #stin$. #stin$. Wht is is the diffe differen#e ren#e bet"een bet"een split split pttern pttern nd !t#h'plte !t#h'plte pttern pttern Answer. split pttern is pttern tht #onsists of t"o pie#es* !t#h'plte pttern #onsists of the t"o split ptterns tt#hed to opposite sides of plte.
11.+ 1.+
Wht ht is #hp #hpllet et Answer. hplets re !etl supports of vrious desi$ns used to hold the #ore in pl#e in the snd !old.
11.-
Wht Wht proper propertie tiess deter!i deter!ine ne the the ulit ulity y of snd snd !old for for snd snd #stin #stin$ $ Answer. %he usul properties re (1) stren$th ' bility to !intin shpe in the f#e of the flo"in$ !etl, (2) per!ebility ' bility of the !old to llo" hot ir nd $ses to es#pe fro! the #vity, (+) ther!l stbility ' bility to resist #r#/in$ nd bu#/lin$ "hen in #ont#t "ith the !olten !etl, (-) #ollpsibility ' bility of the !old to $ive "y durin$ shrin/$e of the solidified #stin$, nd (5) reusbility ' #n the snd be reused to !/e other !olds
11.5 1.5
Wht Wht is is the the nti ntio# o#h h pro# pro#es ess s Answer. %he ntio#h pro#ess refers to the !/in$ of the !old. %he !old is 50 snd nd 50 plster plster heted heted in n uto#lve uto#lve nd then dried. dried. %his !old !old hs $reter $reter per!ebilit per!ebility y thn plster plster !old.
11. 11.
Wht is the the differ differen#e en#e bet"een v#uu! per!nent'!old per!nent'!old #stin$ #stin$ nd nd v#uu! v#uu! !oldin !oldin$ $ Answer. #uu! per!nent'!old #stin$ is for! of lo"'pressure #stin$ in "hi#h v#uu! is used to dr" !olten !etl into the #vity. #uu! !oldin$ is snd #stin$ in "hi#h the snd !old is held to$ether by v#uu! pressure rther thn by #he!i#l binder.
11.3
Wht Wht re re the the !ost !ost #o!! #o!!on on !et !etls ls used used in die die #st #stin$ in$ Answer. o!!on die'#stin$ !etls in#lude 4in#, tin, led, lu!inu!, brss, nd !$nesiu!.
11. 11.
Whi#h die'#stin$ die'#stin$ !#hines !#hines usully usully hve hve hi$her hi$her produ#t produ#tion ion rte, rte, #old'#h!ber #old'#h!ber or hot'#h!ber hot'#h!ber,, nd "hy Answer. 6ot'#h!ber !#hines re fster be#use #old'#h!ber die #stin$ !#hines reuire !olten !etl to be ldled into the #h!ber fro! n e&ternl sour#e. 7dlin$ t/es !ore ti!e thn in8e#tin$ the !olten !etl into the die s in the hot'#h!ber opertion.
11.9 1.9
Wht Wht is is fls flsh h in die die #st #stin in$ $ Answer. :lsh is thin portion of !etl t the e&terior of #stin$ tht results fro! !olten !etl bein$ suee4ed suee4ed into the sp#es sp#es bet"een bet"een the die die hlves hlves of the the !old t the prtin$ prtin$ line, line, or into into the #lern#es round the #ores nd e8e#tor pins.
11.10 11.10 Wht is the differen#e differen#e bet"een bet"een true true #entrifu$l #entrifu$l #stin$ #stin$ nd se!i#entrifu$ se!i#entrifu$l l #stin$ #stin$ Answer. ;n true #entrifu$l #stin$, tubulr !old is used nd nd tubulr prt is produ#ed. ;n se!i#entrifu$l #stin$, the shpe is solid* n e&!ple is ril"y "heel. %he !old is rotted so <erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
11'1
Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
tht #entrifu$l for#e is used to distribute the !olten !etl to the e&terior of the !old so tht the density of the finl !etl is $reter t the outer se#tions. 11.11 1.11 Wht Wht is #up #upol ol Answer. #upol is verti#l #ylindri#l furn#e euipped "ith tppin$ spout ner its bse. upols re used for !eltin$ #st irons.
11.12 11.12 Wht re so!e of the opertion opertionss reuired in snd snd #stin$ fter fter the #stin$ #stin$ is re!oved fro! fro! the !old Answer. %he opertions in#lude (1) tri!!in$, in "hi#h the sprues, runners, risers, nd flsh re re!oved, (2) #ore re!ovl, (+) surf#e #lenin$, (-) inspe#tion, (5) repir if needed, () het tret!ent, nd (3) !#hinin$.
11.1+ 11.1+ Wht re so!e of the $enerl $enerl defe#ts defe#ts en#ountered en#ountered in #stin$ #stin$ pro#esses pro#esses N!e nd briefly briefly des#ribe des#ribe three. Answer. Generl defe#ts in#lude= (1) !isruns, in "hi#h the #stin$ solidifies before fillin$ the !old #vity* (2) #old shuts, in "hi#h t"o portions of !etl flo" to$ether but there is l#/ of fusion t the 8oint* 8oint* (+) #old #old shots, shots, "here "here solid solid $lobul $lobules es of #st #st !etl !etl be#o!e entrpped entrpped in the #stin$* #stin$* (-) shrin/$e #vity, "hi#h is depression on the #stin$ surf#e or n internl void in the #stin$ #used by solidifi#tion shrin/$e* (5) !i#roporosity, "hi#h is net"or/ of s!ll voids throu$hout the #stin$ #used by lo#li4ed solidifi#tion shrin/$e* nd () hot terin$, "hi#h is #r#/ in the #stin$ #used by !old tht does not yield to the !etl durin$ the erly st$es of solidifi#tion shrin/$e.
Problems ns"ers to proble!s lbeled (A) re listed in n ppendi& ppendi& t the b#/ of the boo/. uo!"n#! $or#e
11.1
(A) (S; units) n lu!inu!'#opper lloy (92 l, u) #stin$ is !de in snd !old usin$ snd #ore tht "ei$hs 15 /$. >eter!ine the buoyn#y for#e in Ne"tons tendin$ to lift the #ore durin$ pourin$. Solution= Snd density ? 1. $@#! + ? 0.001 /$@#! + ore volu!e " ? ?
[email protected] ? 9+35 #! + >ensity of lu!inu!'#opper lloy ? ? 2.1 $@#! + ? 0.0021 /$@#! + (%ble 11.1) Wei$ht of displ#ed l'u # ? ? 9+35(0.0021) ? 2.+- /$ 1 /$ ? 9.1 N $ b ? # m ' # c ? 9.1 (2.+- ' 15) ? 111%& N
11.2
(ASS (ASS unit units) s) snd snd #ore #ore hs hs volu!e volu!e of 53.0 53.0 in +. ;t is lo#ted inside !old #vity used to #st #st iron pu!p housin$. >eter!ine the buoyn#y for#e tht tends to lift the #ore durin$ pourin$. Solution= Snd density ? 0.05 lb@in + # c ? 53(0.05) ? +.+1 lb :ro! %ble %ble 1+.1, density of #st iron ? ? 0.2 lb@in + # m ? 53(0.2) ? 1-.2 lb $ b ? # m ' # c ? 1-.2 ' +.+1 ? 11%'1 lb
11.+ 11.+
(ASS units) units) plets plets re used used to suppor supportt snd #ore #ore inside inside snd !old #vity #vity.. %he desi$n desi$n of of the #plets nd the !nner in "hi#h they re pl#ed in the !old #vity surf#e llo"s e#h #plet to sustin for#e of lb. Severl #plets re lo#ted beneth the #ore to support it before pourin$* nd severl other #plets re pl#ed bove the #ore to resist the buoyn#y for#e durin$ pourin$. ;f the volu!e of the #ore ? 120 in +, nd the !etl is brss, deter!ine the !ini!u! nu!ber of #plets tht should be pl#ed () beneth the #ore, nd (b) bove the #ore.
<erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
11'2
Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
? 0.+1+ lb@in +. Solution= Snd density ? 0.05 lb@in +. :ro! %ble 11.1, density of brss ? () # c ? 120(0.05) ? % lb lthou$h the rtio .9@ is less thn 1, to be sfe, * #"+lets should be used beneth to support the "ei$ht of the #ore before pourin$. Probbly + or - #plets "ould be better to #hieve stbility. (b) # m ? 120(.+1+) ? +3.5 lb $ b ? +3.5 ' .9 ? &,% lb !ini!u! of - #"+lets re reuired bove the #ore to resist the buoyn#y for#e. 11.11.-
(S; units) units) snd snd #ore used to for! for! the intern internll surf#es surf#es of steel steel #stin$ #stin$ e&perien#e e&perien#ess buoyn#y buoyn#y for#e of 225 N. %he volu!e of the !old #vity for!in$ the outside surf#es of the #stin$ ? --0 #!+. Wht is the "ei$ht of the finl #stin$ ;$nore #onsidertions of shrin/$e. Solution= Snd density ? 1. $@#! +, steel #stin$ density ? 3.2 $@#! + <uivlen#y= 225 N ? 225@9.1 ? 22.9 /$ $ b ? # m ' # c ? 3.2" 3.2" ' ' 1." 1." ? ? .22" .22" ? ? 22.9 /$ ? 22,900 $ " ? ? +3 #! + vity volu!e " ? ? --0 #! + olu!e of #stin$ " ? ? --0 ' +3 ? 115+ #! +. Wei$ht of the finl #stin$ # ? ? 115+(3.2) ? 9,01 $ ? %,1 ./
Centri0u/"l C"stin/
11.5
(A) (S; units) opper tubes re produ#ed by hori4ontl true #entrifu$l #stin$. %he tube len$ths ? 2.0 !, outside di!eter ? 1.0 #!, nd inside di!eter ? 15.0 #!. ;f the rottionl speed of the pipe ? 900 rev@!in, deter!ine the G'f#tor. Solution= :ro! <. (11.-), %$ ? & ? &(( ' @+0) @+0)2@ ? ? ((900)@+0)2@91 ? *%-
11. 11.
(S; units) units) hori4on hori4ontl tl true true #entrifu$l #entrifu$l #stin$ #stin$ pro#ess pro#ess is is used to to !/e stinles stinlesss steel tubin$ tubin$ for for #he!i#l pro#essin$ plnts. %ube len$th ? 0.5 !, outside di!eter ? 30 !!, nd "ll thi#/ness ? .0 !!. >eter!ine the rottionl speed tht "ill provide G'f#tor ? 0. Solution= ( ? 30 !! ? 0.03 !. $ ? 9. !@s2 ' ? ? +0(2 & & %$ @ () ().5@ ? ? +0(2 & 9. &
[email protected]) .5@ ? ? 1*&2 rev3min
11.3 11.3
(ASS units) units) hori4ontl hori4ontl true true #entrifu$l #entrifu$l #stin$ #stin$ opert opertion ion is perfor!ed perfor!ed to to !/e #st #st iron pipe. pipe. %he %he pipes hve len$th ? 32.0 in, outside outside di!eter di!eter ? .0 in, nd "ll thi#/n thi#/ness ess ? 0.+35 0.+35 in. in. () ;f ;f the rottionl speed of the pipe ? 350 rev@!in, deter!ine the G'f#tor. (b) ;s the opertion li/ely to be su##essful (#) ;f not, "ht should the rottionl speed be to #hieve G'f#tor of 0 Solution= () Asin$ outside "ll of #stin$, & ? & ? 0.5()@12 ? 0.25 ft ) ? &' @+0 @+0 ? (0.25)(350)@+0 (0.25)(350)@+0 ? 19.+ ft@se#. 2 %$ ? ? ) @ & & ? ? (19.+) 2@(0.25 & +2.2) ? -%
(b) Sin#e the G'f#tor is less thn 0, the rottionl speed is not suffi#ient, nd the opertion is li/ely to be unsu##essful. (#) Asin$ G'f#tor ? 0, N ? (+0@B)(2 & +2.2 & 0@(@12)) 0.5 ? 9.55(332) 0.5 ? 2-, rev3min 11. 11.
(S; units) units) Crss Crss bushin$s bushin$s re !de !de by hori4ont hori4ontl l true true #entrifu$l #entrifu$l #stin$. #stin$. %he %he bushin$s bushin$s hve hve len$th len$th ? 10 #!, outside di!eter ? 15 #!, nd inside di!eter ? 12 #!. () >eter!ine the rottionl speed tht obtins G'f#tor of 30. (b) When opertin$ t this speed, "ht is the #entrifu$l for#e per sure !eter (P) i!posed by the !olten !etl on the inside "ll of the !old >ensity of brss ? .2 $@#! +. Solution= () Asin$ the outside "ll di!eter of the #stin$, "hi#h is eul to the inside "ll di!eter of the !old, ( !old, ( ? ? 15 #! .5 ' ? ? (+0@ )(2 )(2 & & 30@15) ? 1&% rev3min%
<erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
11'+
Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
(b) Ase 1.0 #! of !old "ll len$th s bsis of re #l#ultions. re of this len$th of !old "ll A "ll A ? ? (o * ? * ? (15 (15 #!)(1 #!) ? 15 #! #!2 ? 15 (10 (10'-) !2 olu!e of #st !etl " ? ? ( &o2 ' & ' &i2)(1.0) ? ((3.5) ((3.5)2 ' ()2)(1.0) ? +.2 #! + Mss m ? (.2 @#! @#!+)(+.2 #! +) ? 5-.- 5-.- ? 0.5-- /$ ) ? &' @+0 Ase !en rdius & ? & ? (3.5 D .0)@2 ? .35 #! ) ? (.35)(91+.3)@+0 (.35)(91+.3)@+0 ? -5. #!@s ? .-55 !@s entrifu$l for#e per sure !eter on !old "ll ? $ c@ A "here A "here $ $ c ? m)2@ & & 2 '2 2 $ c ? (0.5-- /$)(.-5 !@s) @(.35 & 10 !) ? ++.9 /$'!@s Given tht 1 N ? 9.1 /$'!@s 2, $ c ? ++.9@9.1 ? +-.55 N $ c@ A ? A ? (+-.55 N)@(15 & & 10'- !2) ? ,%&&1(1,-) N3m* 4 &&1 P" 11.9
(A) (S; units) %rue #entrifu$l #stin$ is perfor!ed hori4ontlly to !/e #opper tube se#tions. %he tubes hve len$th ? 1.0 !, di!eter ? 0.25 !, nd "ll thi#/ness ? 15 !!. () ;f the rottionl speed of the pipe ? 300 rev@!in, deter!ine the G'f#tor on the !olten !etl. (b) ;s the rottionl speed suffi#ient to void ErinE (#) Wht volu!e of !olten !etl !ust be poured into the !old to !/e the #stin$ if solidifi#tion shrin/$e nd solid ther!l #ontr#tion for #opper re ? -.5 nd ? 3.5, respe#tively (both re volu!etri# #ontr#tions).
? )2@ & ? 9. !@s 2 Solution= () %$ ? & ? ) ? &' @+0 @+0 ? (.125)(300)@+0 (.125)(300)@+0 ? 9.1+ !@s 2 %$ ? ? (9.1+) @(0.125 & 9.) ? 2%'(b) G'f#tor is suffi#ient for su##essful #stin$ opertion. (#) olu!e of finl produ#t fter solidifi#tion nd #oolin$ is " ? ? (0.252 ' (0.25'.0+) 2) & & 1.0@- ? 0.25 (0.25 (0.252 ' 0.222) ? 0.01103- ! + Given solidifi#tion shrin/$e ? -.5 nd solid ther!l #ontr#tion ? 3.5 for #opper, nd t/in$ these f#tors into ##ount, olu!e of !olten !etl " ? ? 0.01103-@(1 ' 0.0-5)(1 ' 0.035) ? ,%,1*'- m& 11.10 11.10 ;f true #entrifu$l #entrifu$l #stin$ #stin$ opertion opertion "ere perfor!ed perfor!ed in sp#e sttion sttion #ir#lin$ #ir#lin$ the <rth, <rth, ho" "ould "ei$htlessness ffe#t the pro#ess Solution= %he !ss of !olten !etl "ould be unffe#ted by the bsen#e of $rvity, but its "ei$ht "ould be 4ero. %hus, in the G'f#tor eution ( %$ ? ? )2@ & & ), ), %$ "ould "ould theoreti#lly $o to infinity if if ? ? 0. %hus, it should be possible to for#e the !etl $inst the "lls of the !old in #entrifu$l #stin$ "ithout the nuisn#e nuisn#e of Frinin$ inside the #vity. #vity. 6o"ever, 6o"ever, this ll ssu!es tht the !etl is inside the !old nd rottin$ "ith it. ;n the bsen#e of $rvity, there "ould be proble! in pourin$ the !olten !etl into the !old #vity #vity nd $ettin$ it to dhere dhere to the !old "ll s the the !old be$ins to rotte. rotte. With no $rvity the liuid liuid !etl "ould not be for#ed for#ed $inst the lo"er surf#e surf#e of the !old to initite the #entrifu$l #tion.
11.11 11.11 (S; units) units) 6ori4ontl 6ori4ontl true #entrifu$l #entrifu$l #stin$ #stin$ is used to !/e lu!inu! lu!inu! rin$s rin$s "ith len$th len$th ? 5 #!, outside di!eter ? 5 #!, nd inside di!eter ? 0 #!. () >eter!ine the rottionl speed tht "ill provide provide G'f#tor G'f#tor ? 0. 0. (b) Suppose Suppose tht the the rin$ "ere !de !de out of of steel steel insted insted of lu!inu lu!inu!. !. ;f the the rottionl speed #o!puted in prt () "ere used in the steel #stin$ opertion, deter!ine the G'f#tor nd (#) #entrifu$l for#e per sure !eter (P) on the !old "ll. (d) Would this rottionl speed result in su##essful opertion %he density of steel ? 3.3 $@#! +. (11.5), ( ? ? ( (o ? 5 #!. Ase Ase ? ? 91 #!@s 2, Solution= () Ase inside di!eter of !old in <. (11.5), ( ' ? ? +0(2 & & %$ @ () ().5@ ? ? +0(2 & 91 & 0@5) .5@ ? ? -,%- rev3min (b) Hottionl speed "ould be the s!e s in prt () be#use !ss does not enter the #o!puttion of rottionl speed. ' speed. ' ? -,%- rev3min (#) Ase 5 #! rin$ len$th s bsis of re #l#ultions. <erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
11'-
Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
re of this len$th of !old "ll A "ll A ? ? (o * ? * ? (5 (5 #!)(5 #!) ? 1021 #! 2 ? 0.1021 ! 2 olu!e of #st !etl " ? ? ( &o2 ' & ' &i2)( *) *) ? ((5@2) ((5@2)2 ' (0@2)2)(5.0) ? 2-5-.- #! + >ensity of steel ? 3.3 $@#! + Mss m ? (3.3$@#!+)(2-5-.- #!+) ? 19,+15.9 $ ? 19.+1 /$ ) ? &' @+0 Ase !en rdius & ? & ? (5 D 0)@- ? +1.25 #! ? 0.+125 ! ) ? (+1.25)(-0.-)@+0 (+1.25)(-0.-)@+0 ? 1+29.9 #!@s ? 1+.299 !@s entrifu$l for#e per sure !eter on !old "ll ? $ c@ A "here A "here $ $ c ? m)2@ & & 2 2 $ c ? (19.+1 /$)(1+.299 !@s) @(0.+125 !) ? 10,9+2.1 /$'!@s Given tht 1 N ? 9.1 /$'!@s 2, $ c ? 10,9+2.1@9.1 ? 111-.- N $ c@ A ? A ? (111-.- N)@(0.1021 ! 2) ? 1,51-% N3m* 4 1,51-% P" (d) %he G'f#tor of 0 "ould probbly result in su##essful #stin$ opertion. 11.12 11.12 (S; units) units) :or the steel rin$ of pre#edin$ pre#edin$ Proble! Proble! 11.10(b 11.10(b), ), deter!ine deter!ine the volu!e of !olten !olten !etl tht !ust be poured into the !old, $iven tht the liuid shrin/$e is 0.5, solidifi#tion shrin/$e ? +, nd solid #ontr#tion fter free4in$ ? 3.2 (ll re volu!etri# #ontr#tions). ? ( & &o2 ' & ' &i2) * ? * ? (+2.52 ' +02)(5) ? 2-5-.- #! + Solution= olu!e of finl #stin$ " ? Given tht the !olten !etl shrin/$e ? 0.5, nd fro! %ble 10.1, the solidifi#tion shrin/$e for steel ? + nd the solid #ontr#tion durin$ #oolin$ ? 3.2, the totl volu!etri# #ontr#tion is (1'0.005)(1'0.0+)(1'0.032) (1'0.005)(1'0.0+)(1'0.032) ? 0.953 %he reuired strtin$ volu!e of !olten !etl " ? ? 2-5-.-@(0.953) ? *-,%* #m& 11.1+ 11.1+ (S; units) erti#l erti#l true #entrifu$ #entrifu$ll #stin$ is used to produ#e produ#e lu!inu! bushin$s bushin$s tht re 200 !! lon$ nd 200 !! outside di!eter. ;f the rottionl speed durin$ solidifi#tion is 500 rev@!in, deter!ine the inside di!eter t the top of the bushin$ if the inside di!eter t the botto! is 150 !!. Solution= * ? * ? 200 !! ? 0.2 !. & !. &b ? 150@2 ? 35 !! ? 0.035 !. 2 2 .5 ' ? ? (+0@ )(2 )(2 *@( *@( &t ' & &b ) ? (+0@ )(2 )(2 & 9. & 0.2@( &t 2 ' 0.0352)).5 ' ? ? (+0@ )(+.92@( )(+.92@( & &t 2 ' 0.00525)) .5 ? 500 rev@!in (+.92@( & &t 2' 0.00525)) .5 ? 500 @+0 @+0 ? 52.+ 2 2 +.92@( & &t '.00525) ? (52.+) ? 23-1.5 2 &t '.00525 ?
[email protected] ? 0.001-+ &t 2 ? .00525 D 0.001-+0 ? 0.003055 &t ? ? (0.003055) .5 ? .0+99 ! ? +.99 !! (t ? ? 2(+.99) ? 1%2 mm
11.1- (A) (ASS units) %ubes re produ#ed by verti#l true #entrifu$l #stin$. 7en$th of e#h tube ? 12.0 in nd its outside di!eter ? .0 in. ;nside di!eters of the tube ? .5 in t the top nd .0 in t the botto!. botto!. t "ht "ht speed speed !ust the tube tube be rotted rotted durin$ the opertio opertion n to #hieve #hieve these these spe#ifi# spe#ifi#tions tions Solution= Ase <. (11.) to !/e the #o!puttion= ' ? ? (+0@ )(2 )(2 *@( *@( & &t 2' & &b2).5 * ? * ? 12 in ? 1.0 ft &t ? ? .5@2 ? +.25 in ? 0.230++ ft &b ? .0@2 ? +.00 in ? 0.25 ft ' ? (+0@ )(2 )(2 & +2.2 & 1.0@(0.230++2 ' 0.252).5 ? 9.5-9+(59+5) .5 ? &'% rev3min
11.15 11.15 (ASS units) units) verti#l verti#l true #entrifu$l #entrifu$l #stin$ #stin$ pro#ess is used used to #st brss tubin$ tubin$ tht tht is 15.0 in lon$ nd "hose outside di!eter ? .0 in. ;f the speed of rottion durin$ solidifi#tion is 1000 rev@!in, deter!ine the inside di!eters t the top nd botto! of the tubin$ if the totl "ei$ht of the finl #stin$ ? 35.0 lbs. Solution= :or brss, density ? ? 0.+1+ lb@in + (%ble 11.1). olu!e of #stin$ " ? ? 35.0@.+1+ ? 2+9. in + <erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
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Solutions for Fundamentals of Modern Manufacturing , 5e (published by Wiley) MPGroover 2012
ssu!e the inside "ll of the #stin$ is stri$ht fro! top to botto! (n ppro&i!tion of the prboli# shpe). %he ver$e inside rdius rdius &i ? ( & &t D & D &b)@2 2 2 2 2 olu!e " ? ? ( & &o ' & ' &i ) * ? * ? (-.0 (-.0 ' & ' &i )(15.0) ? 2+9. in + (-.02 ' & ' &i2) ? 2+9.@15 ? ? 5.05 2 &i ? 1.0 ' 5.05 ? 10.915 in 2 &i ? +.+0- in 7et & 7et &t ? & ? &i D y D y ? ? +.+0- D y D y nd nd & &b ? & ? &i ' y ' y ? ? +.+0- ' y ' y,, "here y "here y ? ? one'hlf the differen#e bet"een &t nd & nd &b. ' ? ? (+0@ )(2 )(2 *@( *@( &t 2' & &b2).5 ? (+0@ )(2 )(2 & +2.2 & 12 & 15@((+.+0-D y 15@((+.+0-D y))2'(+.+0-' y) y)2)).5 Given ' Given ' ? ? 1000 rev@!in, thus 1000 @+0 @+0 ? (11592@((+.+0-D y (11592@((+.+0-D y))2'(+.+0-' y) y)2)).5 ((+.+0-D y) y)2'(+.+0-' y) y)2).5 ? +0(11592) .5@1000 ? ? 1.0212 2 2 2 .5 (+.+0- D .0 y D y D y y ' (+.+0- ' .0 y D y D y y )) ? 1.0212 2 2 (+.+0- D .0 y D y D y y ' +.+0- D .0 y ' y ' y y2).5 ? 1.021(2 & .0 y) y).5 ? (1+.21 y) y).5 ? 1.021+.+5 ( y) y).5 ? 1.021 y ? y ? .00 in &t ? ? +.+0- D 0.00 ? +.+- in &b ? +.+0- ' 0.00 ? +.22- in
Dt 4 4 %2 in Db 4 %--2 in
6e0e#ts "n7 6esi/n Consi7er"tions
11.1 11.1 %he housin$ housin$ for #ertin !#hinery !#hinery produ#t produ#t is !de of t"o #o!ponent #o!ponents, s, both lu!inu! lu!inu! #stin$s. #stin$s. %he lr$er #o!ponent hs the shpe of dish sin/, nd the se#ond #o!ponent is flt #over tht is tt#hed to the first #o!ponent to #rete n en#losed sp#e for the !#hinery prts. Snd #stin$ is used to produ#e the t"o #stin$s, both of "hi#h re pl$ued by defe#ts in the for! of !isruns nd #old shuts. %he fore!n #o!plins tht the prts re too thin, nd tht is the reson for the defe#ts. 6o"ever, it is /no"n tht the s!e #o!ponents re #st su##essfully in other foundries. Wht other e&plntion #n be $iven for the defe#ts fluidity. Ine possible reson for the defe#ts in Solution= Misruns nd #old shuts result fro! lo" fluidity. this #se is tht the thi#/ness of the #stin$ #ross se#tions is too s!ll. 6o"ever, $iven tht the #stin$ of these prts is su##essfully ##o!plished t other foundries, t"o other possible e&plntions re (1) the pourin$ te!perture is too lo", nd (2) the pourin$ opertion is perfor!ed too slo"ly. 11.13 11.13 lr$e lr$e steel snd #stin$ #stin$ sho"s the #hr#terist #hr#teristi# i# si$ns of penetrtion penetrtion defe#t= defe#t= surf#e surf#e #onsistin$ #onsistin$ of !i&ture of snd nd !etl. () Wht steps #n be t/en to #orre#t the defe#t (b) Wht other possible possible defe#ts defe#ts !i$ht !i$ht result result fro! fro! t/in$ t/in$ e#h e#h of these these steps steps Solution= () Wht re the possible #orre#tive steps (1) Hedu#e pourin$ te!perture. (2) ;n#rese the p#/in$ of the !old snd to resist penetrtion. (+) %ret the !old #vity surf#e to !/e it hrder.
(b) Wht possible defe#ts !i$ht result fro! e#h of these steps ;n the #se of step (1), the ris/ is for #old shuts nd !isruns. Steps (2) nd (+) "ould redu#e per!ebility of the snd, thus in#resin$ the ris/ of snd blo"s nd pin holes.
<erpts fro! this "or/ !y be reprodu#ed by instru#tors for distribution on not'for'profit bsis for testin$ or instru#tionl purposes only to students enrolled in #ourses for "hi#h the te&tboo/ hs been dopted. Any other reproduction reproduction or translation of this work work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyriht Act without the permission of the copyriht owner is unlawful!
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