Andrea GrilliQuality EngineerSustain EngineerLean Six Sigma Green BeltMaster FESTO Academy 10°ed. 2012Quality DepartmentPower-One Italy S.p.A.2013 March 26th(Minitab Convention reviewed. May 2013)FTY improvement(PVI-3KW area)
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALPVI-3KW family: PVI-3.0, PVI-3.6, PVI-4.2The most common residential inverter is the ideal size for an average-sizedfamily home. This single-phase string inverter complements the typical numberof rooftop solar panels, allowing home-owners to get the most efficient energyharvesting for the size of the property.This rugged outdoor inverter has been designed as a completely sealed unit towithstand the harshest environmental conditions. One of the key benefits of thisinverter is the dual input section to process two strings with independent MPPTespecially useful for rooftop installations with two different orientations (ie Eastand West). The high speed MPPT offers real-time power tracking and improvedenergy harvesting. The transformer-less operation gives the highest efficiency ofup to 96.8% (>95%; MEAN 96%). The wide input voltage range makes theinverter suitable to low power installations with reduced string size.Available in the following countries:Australia – Belgium – China – Greece - IrelandIsrael – Portugal – Spain - Czech RepublicFrance – Germany – Hungary - ItalySpain - United Kingdom - United StatesProduct Presentation2 of 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALBusiness Case TeamIn PVI-3KW [PVI-3.0KW, PVI-3.6KW, PVI-4.2KW] production area we havea low rate of FTY%. This condition leads to negative economic results.Leader: Andrea GrilliChampion: Luciano RaviolaProblem Statement Coach: Giuseppe Mangano (BB)The weekly rate of FTY% during year 2012 is low. In the last productionMonth October 2012, FTY% was 88.8%.Up to now we were focused on the fails gone through repair area with noconsideration of test Operator self-repair units; ATE inefficiencies; ATEoperator wrong operation; re-tested units.Members: Paolo Donzellini (Testing)Claudio Serboli (Mngr Mfg)Letizia Badii (Ripair)Luca Scala (IE)Samanta Marzielli (QC)Vincenzo Russino (R&D)Project Scope (In-Out) TargetIn scopeThe Team will be focused on the October 2012 production data collectionas representative and significant sample of the entire year. All kind offails will be included in the analysis.Out of scopeFails for problems already under analysis at the beginning of this project.Estimated Soft saving:Employee at repair station will work part time to other jobs.Estimated Hard Saving:Increasing to 93% FTY rate will allow:Remove two temporary employees at ATE.Reduce cost for scrap components.Reduce overtime work.40.000€ per year starting from April 2013.MilestonesD 29-11-2012 (Closed)M 17-12-2012 (Closed)A 18-01-2013 (Closed)I 15-02-2013 (Closed)C 20-03-2013 (Closed)Project CharterDEFINE MEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVE CONTROLCONTROL3 of 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALVOC: Increase FTY% in the «PVI-3KW» Department%# # 100 %# # 100Increase FTY Reduce total defects=CTQ: FAIL %VOC (Voice of the Customer) and CTQ (critical to quality)DEFINE MEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVE CONTROLCONTROL4 of 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL!One Repair Station for 12ATES and inspection phasesRepair process mapping – Flow diagramMUDA!One Quality EngineerStation for 12ATES and inspection phases7DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROLANALYZEANALYZEof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALWeek44Week42Week40Week38Week35Week32Week30Week28Week26Week24Week22Week20Week180,130,120,110,100,090,080,070,06Production WeekProportion_P=0,09225UCL=0,12329LCL=0,06120P Chart of Failed6 months Weekly FAIL proportion P-Chart (May - October 2012)Project Ring!Proportion of FAILS is stable.8CTQ FAIL%# of Failed units through process# of Outputs100 11,26% (FTY%=88,74%)We use all historical data recorded in October 2012 as year 2012 representative and significant sample. During October 2012 we have add newmanual data collection form in order to collect defects since now not analyzed (test Operator self-repair; ATE inefficiencies; ATE operatorinefficiencies and errors; units tested more than one time) because not automatically reported by Testing Software (Abort Test form).Outputs test data and results are recorded automatically by «SigmaQuest-Camstar» System software.ABORT TEST units are collected manually by Quality Control team in a dedicated excel form.FAIL repaired units data collection are recorded by repair team in «Data Collection» System Software.DEFINE MEASUREMEASURE IMPROVEIMPROVE CONTROLCONTROLANALYZEANALYZEof 29Why use P-chart?To see varible time trend when we have:Discrete data by attributes (Proportion).Varible subsroups.To see dataprocess stability analysis
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALData Collection reading (October-2012)DEFINEDEFINE MEASURE IMPROVEIMPROVE CONTROLCONTROL9ANALYZEANALYZEProject work will be developed for: «FAIL for manualoperation@ATE» and «FAIL for Low Efficiency on 3000W model»«Defects already under analysis» will be not considered, theiranalysis started before beginning of this projectof 29Why use Pareto Diagram?To understand the factors (defects)incidence on total effects (FAIL rate).Defect Phase Work FAILs FAIL %FAIL for manual operation @ ATE 5,57Defects already under analysis 2,32Low Efficiency on 3000W model 1,04FAIL for Supplier process 0,31TK58H005A Coil damaged 0,25IGBT-damaged 0,22Inverted Coil Cables at MB 0,1850 Pole flat cable 0,16Inverted Coil Cables at BB 0,16Board 02 PTH Assembly 0,16DSP-damaged 0,16Mechanical assembly board 02 0,09# of Outputs FAILs FAIL %11,26FAILs 8 8 8 8 32327 149 61 21 15 10 9 9Percent 1 1 1 1 549 22 9 3 2 2 1 1Cum % 92 93 94 95 10049 72 81 84 86 88 89 90OtherMechanical assemblyboard02InvertedCoil Cablesat BBDSP-damagedBoard02PTHAssemblyInvertedCoil Cablesat MB50Poleflat cableIGBT-damagedTK58H005ACoil damagedFAILforSupplierprocessLowEfficiencyon3000WmodelDefectsalreadyunder analysisFAILformanual operation@ATE7006005004003002001000100806040200FAILsPercentPareto Chart of Defect Phase Work49!8 8 8 8 32327 149 61 21 15 10 9 9M8888323271496121151099M
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE Root Causes 13DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROL1. Intermittent Cabling: The AC cable terminals could be deformed or damaged by use. If the operator doesn’t plug the cables correctlyor if he move the roll cable the connections could become intermittent. Also the narrow space makes it difficult to insert the cables.2. VDR wrong assembly: This phase is performed at CAL test, in low light condition when the PVI is already assembled in Chassis. AlsoVDR lead speacing doesn’t match with PCB Connector.3. Serialization error: Because there are two PVIs in a trolley, the operator could wrongly read the Bar-code of the unit NOT under test.4. S1 switch not moved: The S1 switching phases (3 times) are performed manually, in low light condition and by an inadequate tool.Sometimes the operator switch partially the S1 causing a fail unit.5. Protection moved: The Safety protection has two metal sensors that enable the beginning of the test when the sensors are in contactwith the metallic PVI chassis. Because of the protection is unstable, if the operator moves the protection the test will aborted.6. Missing reset : The RESET TEST is a semi-manual test, the station is very close the ATE Final test. For this reason the operator can testwrongly the PVI directly to FT instead of to RESET TEST.7. ABORT button pushed: The safety «ABORT» push button is located in coincidence to trolley or PVI during the test. This could causethe operator involuntary push of the button.11ANALYZEMEASUREMEASUREATE FT RESET11 22 33 4455 66 77of 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALC1C2C4C5C3C7C8C9C10C12C13Low Illumination at ATERESET test station too close at ATEC11Wrong VDR assembly phase (PVI in chassis)To many manual phases at ATETwo PVI in a trolleyRESET test is complicated Manual testATEs equipment safety protection poor designATEs equipment AC WIRINGS not sufficiently robustATEs equipment AC WIRINGS difficult insertionC6Improper tool to switch S1ATEs equipment ABORT button inadequate positionVDR-CONNECTOR pin step mismatchVDR bad packaging cause terminals bentIntermittent CablingSerialization ErrorWrong VDR assemblyMissing resetS1 switch not movedProtection movedABORT PushFAIL for Manual Operation @ ATE Root Causes 23Causes Effects!A cause can produce more than one effect12DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 29!An effect is produced by more than one cause
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL13FAIL for Manual Operation @ ATE Root Causes 33C436%C515%C811%C911%C15%C34%C24%C133%C113%C123%C102%C62%C71%«Weight» of each cause on the CTQ (FAIL%).Causes C4; C5; C8, C9 and C1 will be addressed as priority!DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL96,396,095,795,495,194,8MedianMean95,97595,97095,96595,96095,95595,9501st Quartile 95,851Median 95,9573rd Q uartile 96,096Maximum 96,47995,954 95,97295,948 95,9690,225 0,238A -Squared 28,69P-V alue < 0,005Mean 95,963StDev 0,231V ariance 0,053Skewness -1,18216Kurtosis 5,25829N 2623Minimum 94,620A nderson-Darling Normality Test95% C onfidence Interv al for Mean95% C onfidence Interv al for Median95% Confidence Interval for StDev95% Confidence IntervalsSummary for EFFICIENCYFAIL for Low Efficiency % Analysis 14The minimum efficiency spec value for 3.0KW inverter is 95%. We have FAILs due to efficiency% lower than spec value. To repair these units,we must replace output coils and scrap the removed ones.Here we want to verify the data distribution.!Data are not Normal; P-Value < 0,05.!Box Plot shows there are lots of outliers.!Some units are out of minimum spec (95%).This condition requires further investigation.14DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 29Why use Graphical Summary Tool?Main Information:Data (Efficiency%) distributionnormalityPosition IndicesDispersion IndicesConfidence Interval
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Low Efficiency % Analysis 24Here we want to establish a FULL DOE (Design Of Experiment) to understand the more impacting factors on efficiency %, in order to get morestable and within spec this value.1. Statement of the Problem:Basing on the results of the meetings and brainstorming performed in December 2012:the most probable cause of Efficiency % variation is the saturation Inductance value of the Output Coils.Since now we never studied the effects of the difference Inductance between the two inverter coils on the Efficiency. We want alsounderstand if a longer warm up time of the Inverter (rise of the internal inverter temperature) could change the efficiency.2. Response Variable :Efficiency %.3. Factors and Levels:FactorA: L1 Inductance – Level+: 540uH (SAT inductance@20A); Level-: 470uH (SAT inductance@20A).FactorB: L2 Inductance – Level+: 540uH (SAT inductance@20A); Level-: 470uH (SAT inductance@20A).Factor C: Inverter Warm-up Time – Level+: 10min; Level-: 1min4. Choice of Design:Full Factorial Design – 3 repetitions.!3 Factors; 2 levels = 23 Tests x 3 repetition = 24 Tests15DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL5. Perform ExperimentFAIL for Low Efficiency % Analysis 34The more impacting factor on the Efficiency % is theinteraction of A+B (Inductance L1 + inductance L2) .6. Data Analysis part 116BABCACABCCAB140120100806040200TermStandardized Effect2,1A L1(SA T)B L2(SA T)C Warm-Up TimeFactor NamePareto Chart of the Standardized Effects(response is Efficiency, Alpha = 0,05)DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 29Why use DOE Tool?To understand the more impactingfactors (L1SAT,L2SAT, Warm-ip Time), onResponse Variable (Efficiency%)
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL54047095,895,695,495,295,094,894,6L2(SAT)Mean470540L1(SAT)Interaction Plot for EfficiencyData MeansFAIL for Low Efficiency % Root Causes 447. Data Analysis part 2If L1 and L2 inductances have different value we obtain a low Efficiency%. We have higher Efficiency% when L1 and L2 have the same value.17DEFINEDEFINE IMPROVEIMPROVE CONTROLCONTROLANALYZEMEASUREMEASUREof 290,040,030,020,010,00-0,01-0,02-0,03-0,04999590807060504030201051ResidualPercentMean 2,960595E-15StDev 0,01445N 24RJ 0,997P-Value >0,100Probability Plot of ResidualNormalWhy use Residual Normality Tool?To understand if other unknown factorsoccurred and influenced measurements,then if the results are reliable. Residual isthe difference between 3repMean andthe relative measure.
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE Solutions 14DEFINEDEFINE ANALYZEANALYZE IMPROVE CONTROLCONTROLAdd a portable Led light for eachoperator at ATEModified transport: One PVI for TrolleyInstalled VDR pins preforming machineand packagingNew ATE interface PAD and SWS5S1S4S8Protected ABORT button(keeping safety standards)S6RESET automated in new ATE HWSWS2C1C2C4C5C3C7C8C9C10C12C13Low Illumination at ATERESET test station too close at ATEC11Wrong VDR assembly phase (PVI in chassis)Operator Oversight. To many manual phases at ATETwo PVI in a trolleyRESET test is complicated Manual testATEs equipment safety protection poor designATEs equipment AC WIRINGS not sufficiently robustATEs equipment AC WIRINGS difficult insertionC6Improper tool to switch S1ATEs equipment ABORT button inadequate positionVDR-CONNECTOR pin step mismatchVDR bad packaging cause terminals bentModified Work-phases flow layoutS3MOVED VDR1 and VDR3 at ICTS718MEASUREMEASUREof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE Solutions 2/4DEFINEDEFINE IMPROVE CONTROLCONTROLBIBURN-INOPOPOPBurn-InDepositOPOPTakelabelLABELLabel AssemblyCALPRE-TESTONE OPERATORDRIVE TWO ATETake2 VDRs2 VDR AssemblyVDROPINSPAC CableconnectionDC PADconnectionAC CablescrewingOPFTRSTFINAL TESTOPOPASSEMBLY LINECAL OPERATORPHASEINSPOPDC PADconnectionAC PADscrewingOPProtectioninstallProtectioninstallOPDC PADconnectionAC PADscrewingFT OPERATORPHASES3 Test Line process mapping – ASME logic diagram (After)Modified Work-phases flow layout19ANALYZEMEASUREMEASURE ANALYZEANALYZEof 29SAFETY -TESTSAFETY -TESTRESET-TESTRESET-TEST
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE Solutions 3/4DEFINEDEFINE IMPROVE CONTROLCONTROLWork phases BeforeAfter ComparisonTakt time = Daily available time = 14h = 50400sec = 102.8“Customer Demand 490 490Cycle Time(Before) = 1110secN° operators(Before) = Cycle Time(Before) = 1110sec = 10,8Takt time 102,8secSymbol Meaning Work Process before Corrective action Work process after corrective action "Saving"Transformation Operation 3 2 1InspectionTest 7 5 2TransportMovement 34 24 10Waiting 8 5 3DepositStorage 1 1 0Transformation Operation Support 24 11 13N° operators(After) = Cycle Time(After) = 810sec = 7,8Takt time 102,8secCycle Time(After) = 810secS320ANALYZEANALYZEMEASUREMEASURESortingSorting SettingSetting ShineShine StandardizingStandardizing SustainSustainEliminateduseless tools anddocuments.Made processmore ergonomic(toolsdocument)Add procedure tokeep place cleanand well organizedStandardizedTools andWork-stationsKeep controlmaintaining andreviewing standardsThree temporary operators lessof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE Solutions 4/4Here we want to evaluate the possible risk we could have using the new ATE Interface PAD, understanding witch kind of failure it couldcause and provide a preventive corrective action. So we use a FMEA (Failure Mode Effect Analysis).OccurrenceDetectionSeverityRPMOccurrenceDetectionSeverityRPMBreaking of theconnectorFAIL RESET testInterface bumps with connectors if notcentered during his installation7 2 8 112Add plastic guide to keep Interface inthe right position during hisinstallation3 2 8 48Plastic Slip offRadio Board cannot beinstalledPCB connector not perfectly straight 6 4 8 192Modified Soldering tray to keepstraight connector.2 4 8 64TerminationSwitchBreak of the cursor(not identifiable)Missing terminationline on the fieldAB interface bumps with TS if not welllifted up5 7 6 210Modified AB interface lift systemadding a magnet to keep it lifted.2 6 7 84INDPAR Switch Break of the cursor Fail Cal or Ft testAB interface bumps with IP swotch if notwell lifted up3 2 8 48Automatic bar code reader out ofposition for wrong pressure calibration2 2 8 32Wrong barcode label Position 3 2 8 48AUX BUSconnectorSerializationFMEA parameter Final ParameterComponent Fail Mode Effect Cause ModificationWrong seril numberrecorded in memoryTest FAILFAIL for Low Efficiency % SolutionsAs per result of DOE the root cause is theunbalancing SAT Inductances (20A)between the two Inverter coils.In order to improve and keep stable > 95%the Efficiency we will use coils paired withbalanced Inductance Value (6 pairings).S9C1421DEFINEDEFINE IMPROVE CONTROLCONTROLANALYZEANALYZEMEASUREMEASUREof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALS1 S3S2Solutions Implementation StagesSolution Implementation Stage1Start date 07-Jan-2013 Solution Implementation Stage2Start date 11-Feb-2013S9S9S7S7S8S8Solution # Stage2 Solutions short descriptionS07 MOVED VDR1 and VDR3 at ICTS08 Installed VDR pins preforming machine and packagingS09 Coils paired with balanced Inductance Value (6 pairing).Solution#Stage1 Solutions short descriptionS01 Add a portable Led light for each operator at ATES02 RESET automated in new ATE HWSWS03 Modified Work-phases flow layoutS04 Modified transport: One PVI for TrolleyS05 New ATE interface PAD and SWS06 Protected ABORT button22S4 S5S6DEFINEDEFINE IMPROVE CONTROLCONTROLANALYZEANALYZEMEASUREMEASUREof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL23Control SystemsDEFINEDEFINE IMPROVEIMPROVE CONTROLVisual alarms at ATENew Work-phases flow layoutNew SpecificationAnd ProcedureANALYZEANALYZEMEASUREMEASURE ANALYZEANALYZENew ATE fixtureof 29
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Manual Operation @ ATE control25Missing RESETS1 Switch not movedProtection MovedABORT PushClearedIntermittent Cabling 80,6% reducedWrong VDR Assembly 72,5% reducedRS485 not insertedAUX-BUS not insertedUSB not insertedNew Issues05/03/201327/02/201321/02/201316/02/201312/02/201429/10/201223/10/201217/10/201211/10/201205/10/201201/10/20120,100,080,060,040,020,00MFG DataProportion_P=0,0126UCL=0,0280LCL=0Before AfterP Chart of FAIL for Manual operations@ATE by TimeResultsResultsDEFINEDEFINE IMPROVE CONTROLANALYZEMEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVEof 29Failed Q.ty 103 84 60 30 21 15 14Percent 31,5 25,7 18,3 9,2 6,4 4,6 4,3Cum % 31,5 57,2 75,5 84,7 91,1 95,7 100,0ABORTPushProtectionmovedS1switchnot movedMissingresetWrongVDRassySerializzationErrorIntermittent Cabling350300250200150100500100806040200FailedQ.tyPercentPareto Chart of FAIL for Manual Operation @ ATE Oct-12Failed Q.ty 33 27 26 19 16Percent 27,3 22,3 21,5 15,7 13,2Cum % 27,3 49,6 71,1 86,8 100,0USBCablenot insertedAUX-BUSconnector not insertedRS485ConnectorNOTInsertedWrongVDRAssemblyIntermittent Cabling120100806040200100806040200FailedQ.tyPercentPareto Chart of Manual Operation @ ATE - AFTER8 8 8 8 32327 149 61 21 15 10 9 9M8 8 8 8 32327 149 61 21 15 10 9 9M8888323271496121151099M8888323271496121151099M
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL26S=0,1 (StD estimated)d=0,018 (accuracy established)C2D2= 123 unitsFAIL for Low Efficiency % control 1/226Sample size (min) calculation to estimate the Efficiency% MEAN96,596,095,5Mean514641363126211611611,00,50,0Range51464136312621161161Xbar-R ChartsConfirm that the Before and After process conditions are stable.Normality PlotsThe points should be close to the line.Normality Test(Anderson-Darling)Results Fail PassP-value < 0,005 0,080Before AfterBefore/After Capability Comparison for Efficiency A vs Efficency AfDiagnostic ReportBefore AfterBefore After100%> 0,50,10,050NoYesP = 0,029> 0,50,10,050NoYesP = 0,189BeforeLSL USLAfterActual (overall) capability is what the customer experiences.-- The process mean did not change significantly (p > 0.05).-- The process standard deviation was reduced significantly (p < 0.05).ConclusionsBefore: Efficiency A After: Efficency Af95 * 97Lower Spec Target Upper SpecCustomer RequirementsMean 95,951 95,985 0,033926Standard deviation 0,26381 0,19539 -0,068420CapabilityPp 1,26 1,71 0,44Ppk 1,20 1,68 0,48Z.Bench 3,55 4,97 1,42% Out of spec 0,02 0,00 -0,02PPM (DPMO) 191 0 -191Statistics Before After ChangeReduction in % Out of Specto 0,00%.% Out of spec was reduced by 100% from 0,02%Before/After Capability Comparison for Efficiency A vs Efficency AfSummary ReportWas the process standard deviation reduced?Did the process mean change?Actual (overall) CapabilityAre the data inside the limits?CommentsDEFINEDEFINE IMPROVE CONTROLANALYZEMEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVEof 29Why use Xbar-R Chart?To see varible time trend when we have:Continuos data.Sample subgroups size<10 and>1.To see dataprocess stability.Why use BeforeAfter tool?To compare data before - after improve:Normality, StDV, Mean, Capability,DPPM, final response of improvement= 112 units112 units112 units112 unitsCK =C1 LCEfficiency% manual measurements using LAB instruments duringproduction. Because the large production per day , it is not possiblemeasure 100% of the produced units. Basing on productiontimequantity, we can perform a systematic subgroups sampling: 3untis each 30 produced (38 sampling) repeated for units «before» andunits «after» Solution.
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIALFAIL for Low Efficiency % control 2/2Specification for Efficiency% MEAN is 96%. Here we want to understand if, after improvement, Efficiency% MEAN of population (EFF%PMEAN)will be statistically equal to Spec value 96% (EFF%SMEAN). We use the 1-Sample-t test (Hypothesis Testing).96,3096,1596,0095,8595,7020151050X_HoEfficency AfterFrequencyHistogram of Efficency After(with Ho and 95% t-confidence interval for the mean)Hypotesis:H0: EFF%PMEAN = EFF%SMEANHA: EFF%PMEAN ≠ EFF%SMEANResults:P-Value >0,05 (HA refusal).Population MEAN is statistically not different from Spec Value(with 95% of confidence)The Confidence Interval of the sample MEAN contains H0 thatmeans the Population MEAN is not different than MEAN SpecValue (with 95% of confidence)27DEFINEDEFINE IMPROVE CONTROLANALYZEMEASUREMEASURE ANALYZEANALYZE IMPROVEIMPROVEof 29Why use Hypotesis Test 1 sample T-test?To compare MEAN of the statistic samplewith Reference MEAN; see if there arestatistically equal or not (with 95% ofconfidence).
|||| CONFIDENTIALCONFIDENTIALCONFIDENTIALCONFIDENTIAL28Scrap coils: 9.000€3 temporary employees operators at ATE: 120.000€Savings of the Project WorkDEFINE MEASURE IMPROVE CONTROLConsidering a 2013 stable production rate we canestimate the following SAVINGS:Charges for ATEs new release: 51.000€++-=Total Saving: 86.000€ (first year)Overtime work: 8.000€Removed one ATE and used in another AREA.+Lesson learnedSix Sigma and Lean toolsDMAIC approach as problem solvingTeam WorkSampling efficacyHARD SAVINGSANALYZEMEASURE ANALYZE IMPROVENext StepsImprovement of VDR assemblyKnow How exporting in other areasNew Project work developmentImprovement of Intermittent cablingStart new Lean &Sigma ProjectsThe reduction by half of the FAIL% allowing saving:SOFT SAVINGS Operator at repair station can be dedicated also to other jobs.Sustaining Engineer can be dedicated to other Project Work.of 29