CIM课后习题.docx
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CIM课后习题.docx
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CIM课后习题
1.1Whataresomeoftherealitiesmentionedatthebeginningofthechapterwithwhichmodernmanufacturingenterprisesmustcope?
Namefour.
Answer:
1.Globalization
2.Internationaloutsourcing
3.Localoutsourcing
4.Contractmanufacturing
1.2Productionsystemscanbedividedintotwocategoriesorlevels.Nameandbrieflydefinethetwolevels
Answer:
1、Facilities—consistingofthefactory,theequipmentinthefactory,andtheequipmentisorganized.
2、Manufacturingsupportsystems—thesetofproceduresusedbythecompanytomanageproductionandtosolvethetechnicalandlogisticsproblemsencounteredinorderingmaterials,movingtheworkthroughthefactory,andensuringthatproductsmeetqualitystandards.
1.10Whatisprogrammablecomputerintegratedmanufacturing?
Answer:
CIM—thepervasiveuseofcomputersystemstodesigntheproducts,plantheproduction,controltheoperations,andperformthevariousinformation-processingfunctions.
1.11Whataresomeofthereasonswhycompaniesautomatetheiroperations?
Ninereasonsaregiveninthetext.Namefive.
Answer:
1、Toimproveworkersafety
2、Toimproveproductquality
3、Toreducemanufacturingleadtime
4、Toaccomplishwhatcannotbedonemanually
5、Toavoidthehighcostofnotautomating
1.14WhatistheUSAPrinciple?
Whatdoeseachofthelettersstandfor?
Answer:
TheUSAPrincipleisacommonsenseapproachtoautomationandprocessimprovementprojects.
USAstandsfor:
1、Understandtheexistingprocess
●Input/outputanalysis
●Valuechainanalysis
●Chartingtechniquesandmathematicalmodeling
2、Simplifytheprocess
●Reduceunnecessarystepsandmoves
3、Automatetheprocess
●Tenstrategiesforautomationandproductionsystems
●Automationmigrationstrategy
1.15Thetextliststenstrategiesforautomationandprocessimprovement.Identifyfiveofthesestrategies.
Answer:
1、Specializationofoperations
●involvingtheuseofspecial-purposeequipmentdesignedtoperformoneoperationwiththegreatestpossibleefficiency
2、Combinedoperations
●involvingreducingthenumberofdistinctproductionmachinesorworkstationsthroughwhichthepartmustberouted,reducingthenumberofseparatemachinesneeded,andreducingmaterialhandlingeffort,nonoperationtime,waitingtime,andmanufacturinglead.
3、Simultaneousoperations
●twoormoreprocessing(orassembly)operationsarebeingperformedsimultaneouslyonthesameworkpart,thusreducingtotalprocessingtime.
4、Integrationofoperations
●involvinglinkingseveralworkstationstogetherintoasingleintegratedmechanism,usingautomatedworkhandlingdevicestotransferpartsbetweenstations.
●reducingthenumberofseparateworkcentersthroughwhichtheproductmustbescheduled.
●withmorethanoneworkstation,severalpartscanbeprocessedsimultaneously,therebyincreasingtheoveralloutputofthesystem.
5、Increasedflexibility
●tryingtoachievemaximumutilizationofequipmentforjobshopandmedium-volumesituationsbyusingthesameequipmentforavarietyofpartsorproducts.
●involvingtheuseofflexibleautomationconcepts
●Objectives:
toreducesetuptimeandprogrammingtimefortheproductionmachine(lowermanufacturingleadtimeandlesswork-in-process)
Chapter2
2.2Whatarethethreebasicindustrycategories?
Answer:
1、Primaryindustries.
2、Secondaryindustries.
3、Tertiaryindustries.
2.4Whatisthedifferencebetweenaprocessingoperationandanassemblyoperation?
Answer:
Aprocessingoperationsusesenergytoalteraworkpart’sshape,physicalproperties,orappearancetoaddvaluetothematerial,whileaassemblyoperationsjionstwoormorecomponentstocreateanewentityorsomeothertermthatreferstothespecificjoiningprocess.
2.7Whatisthedifferencebetweenhardproductvarietyandsoftproductvariety?
Answer:
Hardproductvariety:
theproductsdiffersubstantially.
Softproductvariety:
thereareonlysmalldifferencesbetweenproducts.
2.12Whatisleanproduction?
Answer:
Leanproductionmeansoperatingthefactorywiththeminimumpossibleresourcesandyetmaximizingtheamountofworkthatisaccomplishedwiththeseresources.
2.3TheXYZcompanyisplanningtointroduceanewproductlineandwillbuildanewfactorytoproducethepartsandassemblythefinalproductsfortheproductlineandwillbuildanewfactorytoproducethepartsandassemblethefinalproductsfortheproductline.Thenewproductlinewillinclude100differentmodels.Annualproductionofeachmodelisexpectedtobe1000units.Eachproductwillbeassembledof600components,Allprocessingofpartsandassemblyofproductswillbeaccomplishedinonefactory.Thereareanaverageof10processingstepsrequiredtoproduceeachcomponent,andeachprocessingsteptakes30sec(includesanallowanceforsetuptimeandparthandling).Eachfinalunitofproducttakes3.0htoassemble.Allprocessingoperationsareperformedatworkcellsthateachincludesaproductionmachineandahumanworker.Productsareassembledonsingleworkstationsconsistingoftwoworkerseach.Ifeachworkcellandeachworkstationrequire200ft2,andthefactoryoperatesoneshift(2000hr/yr),determine;:
(a)howmanyproductionoperations.(b)howmuchfloor-space,and(c)howmanyworkerswillberequiredintheplant.
Answer:
(a)
operationsinthefactoryperyear.
(c)Totaloperationtime
At2000hours/yrperworker,
workers.
(b)Numberofworkstations
workstations
Totalfloor-space=(1325stations)(200ft2/station)=265,000ft2
Chapter3
3.1Whatisthecycletimeinamanufacturingoperation?
Answer:
Foranyproductionoperation,thecycletimeTcisdefinedasthetimethatoneworkunitspendsbeingprocessedorassembled.Itisthetimebetweenwhenoneworkunitbeginsprocessing(orassembly)andwhenthenextunitbegins.Tcisthetimeanindividualpartspendsatthemachine,butnotallofthistimeisproductive.
3.9Howarefixedcostsdistinguishedfromvariablecostsinmanufacturing?
Answer:
Fixedcosts—thatremainconstantforanylevelofproductionOutput.
Variablecosts—thatvaryinproportiontothelevelofproductionoutput.
3.10Namefivetypicalfactoryoverheadexpenses.
Answer:
1、Plantsupervision
2、Lineforeman
3、Maintenancecrew
4、Custodialservices
5、Securitypersonnel
3.11Namefivetypicalcorporateoverheadexpenses
Answer:
1、Engineering.
2、Applicationtaxes
3、Officespace.
4、Fringebenefits.
5、Lighting.
3.1Acertainpartisroutedthroughsixmachinesinabatchproductionplant.Thesetupandoperationtimesforeachmachinearegiveninthetablebelow.Thebatchsizeis100andtheaveragenon-operationtimepermachineis12hours.Determine(a)manufacturingleadtimeand(b)productionrateforoperation3:
Answer:
Average
Average
(a)
(b)
foroperation3:
3.5Anaverageof20newordersarestartedthroughacertainfactoryeachmonth.Onaverage,anorderconsistsof50partsthatareprocessedsequentiallythrough10machinesinthefactory.TheTheoperationtimepermachineforeachpart=15min.Thenonoperationtimeperorderateachmachineaverage8hours,andtherequiredsetuptimeperorder=4hours.Thereareatotalof25machineinthefactoryworkinginparallel.Eachofthemachinescanesetupforanytypeofjobprocessedintheplant.Only80%ofthemachinesareoperationatanytime(theother20%areinrepairormaintenance).Theplantoperates160hourspermonth.However,theplantmanagercomplainsthatatotalof100overtimemachine-hoursmustbeauthorizedeachmonthinordertokeepupwiththeproductionschedule.(a)Whatisthemanufacturingleadtomeforanaverageorder?
(b)Whatistheplantcapacity(onamonthlybasis)andwhymusttheovertimebeauthorized?
(c)Whatistheutilizationoftheplantaccordingtothedefinitiongieninthetext?
(d)Determinetheaveragelevelofwork-in-process(numberofparts-in-process)intheplant.
Answer:
(a)
(b)
Partslaunchedpermonth
Scheduleexceedsplantcapacityby
Thisrequiresovertimeintheamount
(c)Utilization
(d)
3.8Themeantomebetweenfailuresandmeantimetorepairinacertaindepartmentofthefactoryare400hoursand8hours,respectively.Thedepartmentoperates25machinesduringone8-hourshiftperday,5daysperweek,52weeksperyear.Eachtimeamachinebreaksdown,itcoststhecompany$200perhour(permachine)inlostrevenue.Aproposalhasbeensubmittedtoinstallapreventivemaintenanceprograminthisdepartment.Inthisprogram,preventivemaintenancewouldbeperformedonthemachinesduringtheeveningsothattherewillbenointerruptionstoproductionduringtheregularshift.TheeffectofthisprogramosexpectedtobethattheaverageMTBFwilldouble,andhalfoftheemergencyrepairtimenormallyaccomplishedduringthedayshiftwillbeperformedduringtheeveningshift.Thecostofthemaintenancecrewwillbe$1500perweek.However,areductionofmaintenancepersonnelonthedayshiftwillresultinasavingduringtheregularshiftof$700perweek.(a)Computetheavailabilityofmachinesinthedepartmentbothbeforeandafterthepreventivemaintenanceprogramosinstalled.(b)Determinehowmanytotalhoursperyearthe25machinesinthedepartmentareunderrepairbothbeforeandafterthepreventivemaintenanceprogramosinstalled.Inthispartandinpart(c),ignoreeffectsofqueueingofthemachinesthatmighthavetowaitforamaintenancecrew.(c)Willthepreventivemaintenanceprogrampayforitselfintermsofsavingsintermsofsavingsinthecostoflostrevenues?
Answer:
(a)Withoutpreventivemaintenance(PM),availability
WithPM,availability
This 99% value ignores the fact that half the repair time is on the evening shift. If
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