自动化课后答案ch18 cellular mfg3esi.docx

自动化课后答案ch18 cellular mfg3esi.docx

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自动化课后答案ch18cellularmfg3esi

Chapter18

CELLULARMANUFACTURING

REVIEWQUESTIONS

18.1Whatisgrouptechnology?

Answer:

Asdefinedinthetext,grouptechnologyisamanufacturingphilosophyinwhichsimilarpartsareidentifiedandgroupedtogethertotakeadvantageoftheirsimilaritiesindesignandproduction.

18.2Whatiscellularmanufacturing?

Answer:

Asdefinedinthetext,cellularmanufacturingisanapplicationofgrouptechnologyinwhichdissimilarmachinesorprocesseshavebeenaggregatedintocells,eachofwhichisdedicatedtotheproductionofapartorproductfamilyoralimitedgroupoffamilies.

18.3Whataretheproductionconditionsunderwhichgrouptechnologyandcellularmanufacturingaremostapplicable?

Answer:

Theconditionsidentifiedinthetextare

（1）theplantcurrentlyusestraditionalbatchproductionandaprocesstypelayout,andthisresultsinmuchmaterialhandlingeffort,highin-processinventory,andlongmanufacturingleadtimes;and

（2）thepartscanbegroupedintopartfamilies.

18.4Whatarethetwomajortasksthatacompanymustundertakewhenitimplementsgrouptechnology?

Answer:

Thetwomajortasksare

（1）identifyingthepartfamiliesand

（2）rearrangingproductionmachinesintomachinecells.

18.5Whatisapartfamily?

Answer:

Asdefinedinthetext,apartfamilyisacollectionofpartsthataresimilareitherbecauseofgeometricshapeandsizeorbecausesimilarprocessingstepsarerequiredintheirmanufacture.

18.6Whatarethethreemethodsforsolvingtheproblemofgroupingpartsintopartfamilies?

Answer:

Thethreemethodsare

（1）visualinspection,

（2）partsclassificationandcoding,and（3）productionflowanalysis.

18.7Whatisthedifferencebetweenahierarchicalstructureandachain-typestructureinaclassificationandcodingscheme?

Answer:

Inahierarchicalstructure,alsoknownasamonocode,theinterpretationofeachsuccessivesymboldependsonthevalueoftheprecedingsymbols.Inachain-typestructure,alsoknownasapolycode,theinterpretationofeachsymbolinthesequenceisalwaysthesame;itdoesnotdependonthevalueofprecedingsymbols.

18.8Whatisproductionflowanalysis?

Answer:

Asdefinedinthetext,productionflowanalysisisamethodforidentifyingpartfamiliesandassociatedmachinegroupingsthatusestheinformationcontainedonproductionroutesheetsratherthanpartdrawings.Workpartswithidenticalorsimilarroutingsaregroupedintopartfamilies.

18.9Whatarethetypicalobjectiveswhenimplementingcellularmanufacturing?

Answer:

Asenumeratedinthetext,theobjectivesareto

（1）shortenmanufacturingleadtimes,byreducingsetup,workparthandling,waitingtimes,andbatchsizes;

（2）reducework-in-processinventory;（3）improvequality;（4）simplifyproductionscheduling;and（5）reducesetuptimes.

18.10Whatisthecompositepartconcept,asthetermisappliedingrouptechnology?

Answer:

Thecompositepartconceptisbasedonpartfamilies.Itconceivesofahypotheticalpartforagivenfamilythatincludesallofthedesignandmanufacturingattributesofthefamily.Ingeneral,anindividualpartinthefamilywillhavesomeofthefeaturesthatcharacterizethefamily,butnotallofthem.Thecompositepartpossessesallofthefeatures.

18.11WhatarethefourcommonGTcellconfigurations,asidentifiedinthetext?

Answer:

ThefourGTcellconfigurationslistedinthetextare

（1）singlemachinecell,

（2）groupmachinecellwithmanualhandling,（3）groupmachinecellwithsemiintegratedhandling,and（4）flexiblemanufacturingcellorflexiblemanufacturingsystem.

18.12Whatisthekeymachineconceptincellularmanufacturing?

Answer:

Thekeymachineconceptacknowledgesthatthereistypicallyacertainmachineinacellthatismoreexpensivetooperatethantheothermachinesorthatperformscertaincriticaloperations.Thismachineisreferredtoasthekeymachine.Itisimportantthattheutilizationofthiskeymachinebehigh,evenifitmeansthattheothermachinesinthecellhaverelativelylowutilizations.Theothermachinesarereferredtoassupportingmachines,andtheyshouldbeorganizedinthecelltokeepthekeymachinebusy.

18.13Whatisthedifferencebetweenavirtualmachinecellandaformalmachinecell?

Answer:

Virtualmachinecellsinvolvethecreationofpartfamiliesandthededicationofequipmenttothemanufactureofthesepartfamilies,butwithoutthephysicalrearrangementofmachinesintoformalcells.Themachinesinthevirtualcellremainintheiroriginallocationsinthefactory.FormalmachinecellsrepresenttheconventionalGTapproachinwhichagroupofdissimilarmachinesarephysicallyrelocatedintoacellthatisdedicatedtotheproductionofoneoralimitedsetofpart.

18.14Whatistheprincipalapplicationofgrouptechnologyinproductdesign?

Answer:

Asindicatedinthetext,theprincipalapplicationofGTindesignistoimplementadesignretrievalsystemthatreducespartproliferation.

18.15Whatistheapplicationoftherankorderclustering?

Answer:

TheapplicationoftherankorderclusteringinGTisgroupingmachinesintocellsbasedonthepart-machineincidencematrix,whichinturnisbasedonroutesheets.

PROBLEMS

PartsClassificationandCoding

18.1Developtheformcode（firstfivedigits）intheOpitzSystemforthepartillustratedinFigureP18.1.

Solution:

L/D=0.06/0.80=0.075

Digit1=0

Externalshape=smooth

Digit2=0

Internalshape=smooth,noshapeelement

Digit3=1

Planesurfacemachining=none

Digit4=0

Auxiliaryholes,etc.,=none

Digit5=0

FormcodeinOpitzsystem=00100

18.2Developtheformcode（firstfivedigits）intheOpitzSystemforthepartillustratedinFigureP18.2.

Solution:

L/D=2.5/1.5=1.667

Digit1=1

Externalshape=stepped,onehole

Digit2=1

Internalshape=smoothhole

Digit3=1

Planesurfacemachining=none

Digit4=0

Auxiliaryholes,etc.,=none

Digit5=0

FormcodeinOpitzsystem=11100

18.3Developtheformcode（firstfivedigits）intheOpitzSystemforthepartillustratedinFigureP18.3.

Solution:

L/D=121/36=3.361

Digit1=2

Externalshape=steppedbothendswithfunctionalgroove

Digit2=6

Internalshape=nohole

Digit3=0

Planesurfacemachining=none

Digit4=0

Auxiliaryholesandgearteeth=spurgear.

Digit5=6

FormcodeinOptiz=26006

RankOrderClustering

18.4Applytherankorderclusteringtechniquetothepart-machineincidencematrixinthefollowingtabletoidentifylogicalpartfamiliesandmachinegroups.Partsareidentifiedbyletters,andmachinesareidentifiednumerically.

Parts

Machines

A

B

C

D

E

1

1

2

1

1

3

1

1

4

1

1

5

1

Solution:

Step1

Step2

A

B

C

D

E

Rank

A

B

C

D

E

1

1

2

3

1

1

2

1

1

4

1

1

3

1

1

1

4

1

1

4

1

1

3

2

1

1

5

1

5

5

1

Rank

1

3

4

2

5

Step3

Step4

A

D

B

C

E

Rank

A

D

B

C

E

3

1

1

1

3

1

1

1

1

2

1

1

4

1

1

4

5

1

2

1

1

5

4

1

1

5

1

3

2

1

1

Partfamiliesandmachinegroups:

I=（A,D）and（3,1,5）,II=（B,C,E）and（4,2）.

18.5Applytherankorderclusteringtechniquetothepart-machineincidencematrixinthefollowingtabletoidentifylogicalpartfamiliesandmachinegroups.Partsareidentifiedbyletters,andmachinesareidentifiednumerically.

Parts

Machines

A

B

C

D

E

F

1

1

1

2

1

1

3

1

1

4

1

1

5

1

1

6

1

1

1

Solution:

Step1

Step2

A

B

C

D

E

F

Rank

A

B

C

D

E

F

1

1

1

2

3

1

1

2

1

1

6

1

1

1

3

1

1

1

5

1

1

4

1

1

5

6

1

1

1

5

1

1

3

4

1

1

6

1

1

1

4

2

1

1

Rank

1

2

5

4

3

6

Step3

A

B

E

D

C

F

Rank

Partfamiliesandmachinegroups:

3

1

1

1

I=（A,B,E）and（3,1,5）

1

1

1

2

II=（D,C,F）and（6,4,2）

5

1

1

3

6

1

1

1

4

4

1

1

5

2

1

1

6

18.6Applytherankorderclusteringtechniquetothepart-machineincidencematrixinthefollowingtabletoidentifylogicalpartfamiliesandmachinegroups.Partsareidentifiedbyletters,andmachinesareidentifiednumerically.

Parts

Machines

A

B

C

D

E

F

G

H

I

1

1

1

2

1

1

3

1

1

1

4

1

1

1

5

1

1

6

1

1

7

1

1

8

1

1

Solution:

Step1

Step2

A

B

C

D

E

F

G

H

I

Rank

A

B

C

D

E

F

G

H

I

1

1

1

2

7

1

1

2

1

1

4

1

1

1

3

1

1

1

5

4

1

1

1

4

1

1

1

3

2

1

1

5

1

1

7

3

1

1

1

6

1

1

8

8

1

1

7

1

1

1

5

1

1

8

1