Process control

1. Process control at Polaroid
ChulanuntThaiyanunt
Basing your analysis on both quantitative and qualitative tools, what evidence is there
that quality is getting better?
Pod Weightcontrol
Accordingto PodWeightcontrol chart inAppendix,the podweightperformance variabilityiswithinthe
control limit(between 2.774- 2.835), whichmeansthe processisin control. Thisindicatesthe qualityis
gettingbettersince the PodWeightdefectrate isnormal (PodWeightmeasurementisapart of defect
reportissuedbyoperator,whichcontinue 1% afterGreenlightimplementation) andincontrol,although
theyreduce the numberof qualitycontrol samples. However,eachaverage of sample of the lastfive
shiftshasdecreasingtrend.Therefore,Polaroidmightwanttoinvestigate the cause before the process
isout of control.
LessQualityControl expense
Since qualitycontrol activitiesdonotaddvalue tothe Polaroidcamera, acompanynormallywantsto
reduce the cost of qualitycontrol as muchas possible.InPolaroid,the qualitycontrol process itself can
increase the defectrate andmakesthe samplingproducttobe reworked. Therefore,reducingthe
numberof samplesbyimplementingGreenlightsavesthe company’sexpense.
Standardizetheprocess
Priorto the Greenlightproject,the processqualityatPolaroidwasrelyonoperators’individual
performance since eachof themhad theirownmindsethow tohandle the machinesfromtheir
experience.The knowledge of dealingwithmachinesbelongedtooperators,notthe company. The
Greenlightprojects providesthe standarddirection,whichbenefitstothe companysince now the
knowledge belongstothe company.
Basing your analysis on both quantitative and qualitative tools, what evidence is there
that quality is getting worse?
FingerHeightcontrol
The control chart of FingerHeightmeasurementinappendix isnotasgood as PodWeight.20 of 45
samplingdataare outof control. Moreover,the interval betweenthe maximumandaverage value and

2. the minimumandaverage value isalmostequal ineachshiftunlikePodWeightcontrol chart. This
meansthe processat Polaroidisalreadystable since variantisalmostthe same butthe operatorsstill
tweakthe machinesif theyfeel itwouldimprove the processquality. Finally,the trendsof control chart
are differentwhencomparedbyeach shift.Mostof data inshiftA exceedsthe uppercontrol limitwhile
data inshiftB is mostlyincontrol andbelow the lowercontrol limitinshiftC. The relationbetween
trendand operatorshiftfurtheremphasize thatthe operatorsmake adjustmenttoequipmentontheir
own.
Defect Ratereportedby auditor
The defectrate reportedbyauditoris increaseddramaticallyfromaround1% to 10% after
implementingprojectGreenllight. The mosttype of defectdetected isexcessreagents(22%,according
to Exhibit5),whichisnot fatal since customerswouldneveraware of thistype of defect buttheystill
consideritas a defect. The increase of excessreagentsfrom10% to 22% causesPolaroidwastingtheir
moneythanbefore because theyhave toreworkmore defectsthatdonotaffectthe customer’s
satisfaction.
What recommendations would be in order to (further) improve quality?
Investigatethecauseof problem
Most of samplesof FingerHeightmeasurementare outof control.Polaroidshouldinvestigate the cause
of thisproblemsothey can preventthe same problemoccurredinthe future. Also,the expenseof
processcontrol qualitywill be reducedafterfindingthe cause.
Ensuretheoperatorsfollowthe process
The company cannotpreciselymeasurethe qualityof processif theydonothave the data that reflects
the actual process.Inorderto collectthe meaningful data,Polaroidhastoensure everyonefollow the
process,notadjustequipmentontheir own.
Revisethetypes ofdefect
Some typesof defect,suchas excessreagents,are notrelatedtocustomer’sneed.The quality controls
of these measurementscause unnecessaryexpense forthe company. If the companycan reduce the
numberof controlleddefecttypes,theywill save the expense whilemaintainthe productquality.

3. Appendix
Pod Weight Control Chart
Form base-line datainexhibit3,meanand standarddeviationcanbe calculatedas2.805 and0.025,
respectively.
Polaroidsetcontrol limitat3 standard deviations
𝑈𝑝𝑝𝑒𝑟 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝐿𝑖𝑚𝑖𝑡 = 𝜇 + 3𝜌/√ 𝑛𝑢𝑚𝑏𝑒𝑟𝑂𝑓𝑆𝑎𝑚𝑝𝑙𝑒
= 2.805 + 3(0.025)/√6
= 2.835
𝐿𝑜𝑤𝑒𝑟 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝐿𝑖𝑚𝑖𝑡 = 𝜇 − 3𝜌/√ 𝑛𝑢𝑚𝑏𝑒𝑟𝑂𝑓𝑆𝑎𝑚𝑝𝑙𝑒
= 2.805 − 3(0.025)/√6
= 2.774
By usingmean,maximumandminimumvalueof PodWeightsample ineachshift,the control chartof
PodWeightcan be drawas the followingdiagram
2.720
2.740
2.760
2.780
2.800
2.820
2.840
2.860
2.880
Mean UCL LCL Max Min

4. Finger Height Control Chart
Form base-line datainexhibit3,meanand standarddeviationcanbe calculatedas2.805 and0.025,
respectively.
Polaroidsetcontrol limitat3 standard deviations
𝑈𝑝𝑝𝑒𝑟 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝐿𝑖𝑚𝑖𝑡 = 𝜇 + 3𝜌/√ 𝑛𝑢𝑚𝑏𝑒𝑟𝑂𝑓𝑆𝑎𝑚𝑝𝑙𝑒
= 2.805 + 3(0.025)/√6
= 2.835
𝐿𝑜𝑤𝑒𝑟 𝐶𝑜𝑛𝑡𝑟𝑜𝑙 𝐿𝑖𝑚𝑖𝑡 = 𝜇 − 3𝜌/√ 𝑛𝑢𝑚𝑏𝑒𝑟𝑂𝑓𝑆𝑎𝑚𝑝𝑙𝑒
= 2.805 − 3(0.025)/√6
= 2.774
By usingmean,maximumandminimumvalueof FingerHeightsample ineachshift,the control chartof
FingerHeightcanbe drawas the followingdiagram
1.600
1.700
1.800
1.900
2.000
2.100
2.200
2.300
2.400
2.500
2.600
Mean UCL LCL Max Min

5. FingerHeight Control Chartof ShiftA
FingerHeight Control Chartof ShiftB
FingerHeight Control Chartof ShiftC
1.500
1.700
1.900
2.100
2.300
2.500
2.700
Mean UCL LCL Min Max
1.700
1.800
1.900
2.000
2.100
2.200
2.300
2.400
Mean UCL LCL Min Max
1.500
1.600
1.700
1.800
1.900
2.000
2.100
2.200
2.300
2.400
Mean UCL LCL Min Max