DeGarmo's Materials & Processes in Manufacturing – Solutions Manual 2024

SolutionsManual l l




for DeGarmos Ma
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terials and Proces l l




ses in Manufactur
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ing, 13e Black, Ro
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nald Kohser (All C
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hapters)

, CHAPTERl1
IntroductionltolDeGarmo’slMaterialslandlProcesseslinlManufacturing


ReviewlQuestions

1. Thelavailabilitylandlcostloflmanufacturedlproductslarelanlimportantlpartloflourlcostlofl
livinglandlthelreallwealthloflthelnation.lThus,lreducinglthelcostloflproducerlandlconsumerlg
oodslimproveslthelproductivitylwhilelholdingldownlinflation,ltherebylimprovinglthelgener
allstandardloflliving.

2. Thislisltrueliflyoulconsiderlthatleveryonelwholusesltheloutputlfromlalprocess,lincludi
nglalllthelintermediatelsteps,lislalcustomer.l Theloperatorloflthelnextlprocesslisltheluserlandlc
ustomerloflthelproceedinglprocess.lInlfact,lsomelcompanieslidentifyltwolcustomers,lthele
xternallcustomerlwholbuyslthelfinishedlproductlandlthelinternallcustomer,lwholbuildslthel
productlonel-li.e.,lthelpeoplelwholworklinlthelmanufacturinglsystem.

3. Joblshopl-
lanlinjectionlmoldlmanufacturinglshop,lthelshoplatlallargeluniversitylthatlproduceslresearchl
equipmentlandlapparatus.l Joblshopslarelcapableloflproducinglproductslwithlgreatlvariety,lty
picallylemployinglhighlylskilledlworkers.

Flowlshopl–
lautomobilelassembly.lFlowlshopslarelusuallyllaidloutlsolthatlspecificlproductslpasslthr
oughlalserieslofloperationslwithlnolbackflow.l Thelproductlrangelisllimited,lproductionl
volumelisllargelandllaborlskilllisllowerlthanlinljoblshops.

Projectlshopl–ldiesel-
electricllocomotivelproductionlfacility.l Thelendlproductlislveryllargelandlsolmanylmach
ines,ltoolslandlpeoplelcomeltolthelproductltolproducelitlatlalrelativelylfixedllocation.

ThelSubwaylsandwichlshoplwouldlbelalflowlshop.

4. Inlthelcontextloflmanufacturing,lalmanufacturinglsystemlislalcollectionloflmen,lmac
hineltools,landlmaterial-
movinglsystems,lcollectedltogetherltolaccomplishlspecificlmanufacturinglorlfabricationls
equences,lresultinglinlcomponentslorlendlproducts.l Thelmanufacturinglsystemlislbackedl
uplbylandlsupportedlbylthelproductionlsystem,lwhichlincludeslfunctionsllikelcontrolloflqu
ality,linventory,lproduction,landlmanpower,laslwelllaslscheduling,lplanninglandlthellike.l
Withinlthelmanufacturinglsystem,ltherelwilllbelmachineltools,lwhichlcanlperformljobslor

5. No.lThelcuttingltoollislthelimplementlthatldoeslthelcutting.lItlcontainslthelcuttingledg
elandlislusedlinlthelmachineltool.llThelmachineltoolldriveslthelcuttingltoollthroughlthelwo
rklmaterial.

6. Thelbasiclmanufacturinglprocesseslare:lcastinglorlmolding,lforming,l(heat)ltr
eating,lmetallremoval,lfinishing,ljoiningl(welding),lassembly,landlinspection.


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,7. Castinglcouldlbelused,lprovidedlthelmateriallcanlbelmeltedlandlpouredlinlthelappropri
atelprocess.lBylcasting,ltheldesiredlshapedlinlfinallorlnear-
finallform,lcouldlbelobtained.lThislgreatlylreduceslthelnecessitylforlmachininglthelhard-
to-
machinelmetal.lLesslmachininglislneededlwhenlthelrawlmateriallshapelislcloseltolthelfinis
hedlpartlsizelandlshapel(calledlnearlnetlshapelcasting).lThelpartlcouldlalsolbelmadelinlsim
plerlsegmentslandlassembledlorljoined.

8. Thelwaxlpatternlislmeltedlandlremovedlaslalliquid.lAnylremaininglwaxlislthenlvap
orizedlwhenlthelmoldlislheatedlinlpreparationlforlthelpour.

9. Alrelief-
imagelislthelcavitylinltheldielthatlthelworklmateriallisldeformedlintolwhenltheldielislpresse
dlintolthelworkpiece.l Materiallonlthelworkpiecelmovinglintolthelcavity,l“concave,”loflthel
dielresultslinlthelraised,l“convex,”lpartloflthelmedallsurface.

10. Trainslstoplatlthelstationltolloadlandlunloadlpeoplelandlmaterials.lInlanlassemblylline,lpro
ductslstoplatlstationsltoltakelonlmaterialslorlhaveloperationslperformedlonlthem.

11. False.lStoragelislverylexpensivelbecauseltimelcostslthelcompanylmoney.lItlislexpe
nsiveltolkeepltrackloflstoredlmaterials,ltolputlthemlintolstorage,ltolgetlthemlbacklfromlsto
rage,ltoldamagelthemlaslalresultloflexcessivelhandling,landlsolon.lMorelimportantly,ls
toragelusuallyladdslnolvaluel-lverylfewlitemslappreciatelonlthelshelf.

12. Forlthelsimple,lconventionallpaperlclip,lforminglprocesseslarelfirstlusedltolmakelandlco
atlwire,lwhichlislthenlcutltollengthlandlformedlinlthreelbendingloperations.

13. Toolslarelusedltolhold,lcut,lshape,lorlformlthelunfinishedlproduct.lCommonlhandltool
slincludelthelsaw,lhammer,lscrewdriver,lchisel,lpunch,lsandpaper,ldrill,lclamp,lfile,ltorch,l
andlgrindstone.lBasically,lmachineslarelmechanizedlversionsloflsuchlhandltoolslandlarelc
alledlcuttingltools.lSomelexampleslofltoolslforlcuttinglareldrilllbits,lreamers,lsingle-
pointlturningltools,lmillinglcutters,lsawlblades,lbroaches,landlgrindinglwheels.lNoncuttin
gltoolslforlforminglincludelextrusionldies,lpunches,landlmolds.lToolslalsolincludelworkh
olders,ljigs,landlfixtures.lTheseltoolslandlcuttingltoolslarelgenerallylreferredltolasltheltooli
ng,lwhichlusuallylmustlbelconsideredl(purchased)lseparatelfromlmachineltools.

14. Inefficientlislalrelativeltermlhere.lIflwelcanleliminatelmachining,lwelcanlsaveltheltimela
ndlthelmoney.lMachininglprocesseslarelgenerallylthoselwhichlgivelthelpartlitslfinallsize,lsh
ape,landlsurfacelfinishlandladdlvalueltolthelpart.lBecauseltheyldolnotlproducelthelshapeland
lsizelinlbulk,lbutlratherlbyllocalizedlactionltheylmaylnotlbelaslefficientlaslforminglandlcasti
nglprocesses.lCuttingltoollandlworkholdingltoolinglexpenseslmaylalsolbelreduced,lsincelth
elsameltoollcanlworklonlmanyldifferentlproducts.

15. Figurel1-1landlfigurel1-
16lbothlshowllifelcyclelprogressions.l Forlanlaudiocassetteltape,litlwentltolalcommoditylp
roduct,landlislnowlinldeclinelaslCD’slareltakinglover.lWelwilllknowlthatlitlislinlseverelde
clinelwhenlthelnewlautoslnollongerlofferlcassettelplayers.


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, 16. Thelcostltolmanufacturelaltypicallmanufacturedlproductlisl20%l-
l30%loflthelsellinglprice.lForlthelmasslproducedlproductlatlthellowerlendloflthislrangelth
elmanufacturinglcostlisl$0.20.lThesel20lcentslincludeslmateriallandlprocessinglcosts.lPr
ocessinglincludeslassemblylinladditionltolproducinglthelcomponents.l Sincelthelbladelcostl
involveslformingltheledgelinlalmateriallitlislprobablylthelhighestlcostlpartloflthelrazor.
So,lwithl20lcentsltolcoverlmaterials,lprocessinglandlassembly,landlthelbladelthelmostlex
pensivelindividuallpartlanlestimatelofl2-
3lcentslislreasonablelforlthelproductionloflthelhighlprecisionl(inltermslofledge)lblade.
Thelsamelkindloflreasoninglcanlbelusedlwithlmanufacturinglcostlbeingl40%loflsel
linglcostlaslsuggestedlinlProblemsl1landl2.

17. Packaginglislusedltolprotectlthelproductlfromlthelenvironment,ltolprotectlthelproductldu
ringlshippinglandltolholdlfixedlnumbersloflproductslforlsale.

18. Assemblyloflalbinderltypelpaperlcliplinvolveslputtinglthelformedlwirelhandleslinltolthe
lspringlsteellbinderlpartloflthelclip.lAssemblyloflbicyclelwheelslinvolveslputtinglspokeslin
tolthelwheellandlhub.
Iflthelingredientsloflthelclublsandwichlarelalllinltheirlfinishedlstatelthenltheylcanlbelasse
mbled.lIflprocessinglislnecessarylaslinlslicinglaslturkey,lthelentirelprocesslislmorelthanljustlass
embly.

19. Thelphysicallelementsloflalmanufacturinglsystemlarelthelmachineltools,ltheltoolingllik
elworkholdingldevices,lmateriallhandlinglequipment,linspectionlequipmentlandlpeoplelw
holactuallylproducelthelproducts.lManufacturinglsystemslarelcharacterizedlbylmeasurable
lparametersl(throughputltime,lcycleltime,ldefectlrates,lproductionlrates,lnumberlofldirectll
aborers,lannuallproductionlvolumes,letc.).lMachineltoolslarelcharacterizedlbylthelsizeloflt
helworkpiecelthatlcanlbelprocessedlorlthelspindlelspeedsltheylcanlbelrunlat.lToolsllikeldies
lforlsheetlmetallforminglarelcharacterizedlbyltheirlsizelandlweight.lInspectionldeviceslhav
elmeasurementlresolutionllimits.lMeasurablelparameterslextendlpastlmachinelspecificatio
nsltolhigherllevell(involvinglmorelthanlonelaspectloflpartlproduction)ldescriptionsloflthelpr
ocesslsuchlaslproductionlrates.lThelmanufacturinglsystemlislmorelthanlthelphysicalleleme
nts.lSupportlandlcontrollsystems,lalonglwithlthelphysicallelements,larelcombinedlinlthelm
anufacturinglsystem.

20. Thelmanufacturinglengineerlislresponsiblelforlselectinglorldesigninglandloverseeinglop
erationloflthelmanufacturinglprocesses.lInlthelsenseloflimmediatelcontactlwithlprocesseslth
elmanufacturinglengineerlisloftenlthelcenterlofl“makinglthelproduct”.lHowever,ltheldecisio
nslmadelbylpartlandlproductldesignerslandlmaterialslengineerslhavellargelinfluenceslonlthel
kindloflprocesseslthatlcanlbelusedltolmakelthelpart.lHowlthelpartlcanlbelmadelislconstrainedl
bylpartldesignlandlmaterialslused.lSo,lalllindividualslwholmakeldecisionslthatldeterminelm
anufacturinglprocesslchoicelshouldlbelinvolvedlinlfiguringloutlhowltolmakelthelpart.

21. InlFigurel1-
8,lthellineslconnectinglthelprocesseslrepresentlpossiblelpathslaslmateriallmoveslthroughlth
elshopl–lfromlmachine-to-machinelorloperation-to-operation.




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